diff --git a/adb/client/bugreport.cpp b/adb/client/bugreport.cpp
index e162aaa..f2e722a 100644
--- a/adb/client/bugreport.cpp
+++ b/adb/client/bugreport.cpp
@@ -104,7 +104,9 @@
             SetLineMessage("pulling");
             status_ =
                 br_->DoSyncPull(srcs, destination.c_str(), false, line_message_.c_str()) ? 0 : 1;
-            if (status_ != 0) {
+            if (status_ == 0) {
+                printf("Bug report copied to %s\n", destination.c_str());
+            } else {
                 fprintf(stderr,
                         "Bug report finished but could not be copied to '%s'.\n"
                         "Try to run 'adb pull %s <directory>'\n"
diff --git a/adb/client/transport_mdns.cpp b/adb/client/transport_mdns.cpp
index 9db2453..9611212 100644
--- a/adb/client/transport_mdns.cpp
+++ b/adb/client/transport_mdns.cpp
@@ -680,6 +680,13 @@
 std::optional<MdnsInfo> mdns_get_connect_service_info(std::string_view name) {
     CHECK(!name.empty());
 
+    // only adb server creates these registries
+    if (!ResolvedService::sAdbTransportServices && !ResolvedService::sAdbSecureConnectServices) {
+        return std::nullopt;
+    }
+    CHECK(ResolvedService::sAdbTransportServices);
+    CHECK(ResolvedService::sAdbSecureConnectServices);
+
     auto mdns_instance = mdns::mdns_parse_instance_name(name);
     if (!mdns_instance.has_value()) {
         D("Failed to parse mDNS name [%s]", name.data());
diff --git a/adb/transport.cpp b/adb/transport.cpp
index b6b6984..c33d5af 100644
--- a/adb/transport.cpp
+++ b/adb/transport.cpp
@@ -1533,8 +1533,7 @@
         keys_.pop_front();
     }
 
-    std::shared_ptr<RSA> result = keys_[0];
-    return result;
+    return Key();
 }
 
 void atransport::ResetKeys() {
diff --git a/fastboot/fastboot.cpp b/fastboot/fastboot.cpp
index 0e9713d..86cf30d 100644
--- a/fastboot/fastboot.cpp
+++ b/fastboot/fastboot.cpp
@@ -992,10 +992,69 @@
            fb->GetVar("partition-type:vbmeta_b", &partition_type) == fastboot::SUCCESS;
 }
 
+static std::string fb_fix_numeric_var(std::string var) {
+    // Some bootloaders (angler, for example), send spurious leading whitespace.
+    var = android::base::Trim(var);
+    // Some bootloaders (hammerhead, for example) use implicit hex.
+    // This code used to use strtol with base 16.
+    if (!android::base::StartsWith(var, "0x")) var = "0x" + var;
+    return var;
+}
+
+static void copy_boot_avb_footer(const std::string& partition, struct fastboot_buffer* buf) {
+    if (buf->sz < AVB_FOOTER_SIZE) {
+        return;
+    }
+
+    std::string partition_size_str;
+    if (fb->GetVar("partition-size:" + partition, &partition_size_str) != fastboot::SUCCESS) {
+        die("cannot get boot partition size");
+    }
+
+    partition_size_str = fb_fix_numeric_var(partition_size_str);
+    int64_t partition_size;
+    if (!android::base::ParseInt(partition_size_str, &partition_size)) {
+        die("Couldn't parse partition size '%s'.", partition_size_str.c_str());
+    }
+    if (partition_size == buf->sz) {
+        return;
+    }
+    if (partition_size < buf->sz) {
+        die("boot partition is smaller than boot image");
+    }
+
+    std::string data;
+    if (!android::base::ReadFdToString(buf->fd, &data)) {
+        die("Failed reading from boot");
+    }
+
+    uint64_t footer_offset = buf->sz - AVB_FOOTER_SIZE;
+    if (0 != data.compare(footer_offset, AVB_FOOTER_MAGIC_LEN, AVB_FOOTER_MAGIC)) {
+        return;
+    }
+
+    int fd = make_temporary_fd("boot rewriting");
+    if (!android::base::WriteStringToFd(data, fd)) {
+        die("Failed writing to modified boot");
+    }
+    lseek(fd, partition_size - AVB_FOOTER_SIZE, SEEK_SET);
+    if (!android::base::WriteStringToFd(data.substr(footer_offset), fd)) {
+        die("Failed copying AVB footer in boot");
+    }
+    close(buf->fd);
+    buf->fd = fd;
+    buf->sz = partition_size;
+    lseek(fd, 0, SEEK_SET);
+}
+
 static void flash_buf(const std::string& partition, struct fastboot_buffer *buf)
 {
     sparse_file** s;
 
+    if (partition == "boot" || partition == "boot_a" || partition == "boot_b") {
+        copy_boot_avb_footer(partition, buf);
+    }
+
     // Rewrite vbmeta if that's what we're flashing and modification has been requested.
     if (g_disable_verity || g_disable_verification) {
         if (partition == "vbmeta" || partition == "vbmeta_a" || partition == "vbmeta_b") {
@@ -1491,15 +1550,6 @@
     fb->RawCommand(command, "");
 }
 
-static std::string fb_fix_numeric_var(std::string var) {
-    // Some bootloaders (angler, for example), send spurious leading whitespace.
-    var = android::base::Trim(var);
-    // Some bootloaders (hammerhead, for example) use implicit hex.
-    // This code used to use strtol with base 16.
-    if (!android::base::StartsWith(var, "0x")) var = "0x" + var;
-    return var;
-}
-
 static unsigned fb_get_flash_block_size(std::string name) {
     std::string sizeString;
     if (fb->GetVar(name, &sizeString) != fastboot::SUCCESS || sizeString.empty()) {
diff --git a/fastboot/fuzzy_fastboot/fixtures.cpp b/fastboot/fuzzy_fastboot/fixtures.cpp
index bd76ff4..9b5e5f7 100644
--- a/fastboot/fuzzy_fastboot/fixtures.cpp
+++ b/fastboot/fuzzy_fastboot/fixtures.cpp
@@ -45,6 +45,7 @@
 #include <vector>
 
 #include <android-base/stringprintf.h>
+#include <android-base/strings.h>
 #include <gtest/gtest.h>
 
 #include "fastboot_driver.h"
@@ -76,8 +77,7 @@
 }
 
 bool FastBootTest::IsFastbootOverTcp() {
-    // serial contains ":" is treated as host ip and port number
-    return (device_serial.find(":") != std::string::npos);
+    return android::base::StartsWith(device_serial, "tcp:");
 }
 
 bool FastBootTest::UsbStillAvailible() {
@@ -182,19 +182,14 @@
 }
 
 void FastBootTest::ConnectTcpFastbootDevice() {
-    std::size_t found = device_serial.find(":");
-    if (found != std::string::npos) {
-        for (int i = 0; i < MAX_TCP_TRIES && !transport; i++) {
-            std::string error;
-            std::unique_ptr<Transport> tcp(
-                    tcp::Connect(device_serial.substr(0, found), tcp::kDefaultPort, &error)
-                            .release());
-            if (tcp)
-                transport =
-                        std::unique_ptr<TransportSniffer>(new TransportSniffer(std::move(tcp), 0));
-            if (transport != nullptr) break;
-            std::this_thread::sleep_for(std::chrono::milliseconds(10));
-        }
+    for (int i = 0; i < MAX_TCP_TRIES && !transport; i++) {
+        std::string error;
+        std::unique_ptr<Transport> tcp(
+                tcp::Connect(device_serial.substr(4), tcp::kDefaultPort, &error).release());
+        if (tcp)
+            transport = std::unique_ptr<TransportSniffer>(new TransportSniffer(std::move(tcp), 0));
+        if (transport != nullptr) break;
+        std::this_thread::sleep_for(std::chrono::milliseconds(10));
     }
 }
 
diff --git a/fs_mgr/Android.bp b/fs_mgr/Android.bp
index f5daf91..cd64599 100644
--- a/fs_mgr/Android.bp
+++ b/fs_mgr/Android.bp
@@ -162,10 +162,13 @@
     defaults: ["fs_mgr_defaults"],
     static_libs: [
         "libavb_user",
+        "libutils",
+        "libvold_binder",
     ],
     shared_libs: [
         "libbootloader_message",
         "libbase",
+        "libbinder",
         "libcutils",
         "libcrypto",
         "libext4_utils",
diff --git a/fs_mgr/fs_mgr.cpp b/fs_mgr/fs_mgr.cpp
index b2c7a27..0ae5787 100644
--- a/fs_mgr/fs_mgr.cpp
+++ b/fs_mgr/fs_mgr.cpp
@@ -301,10 +301,13 @@
     return true;
 }
 
+static bool needs_block_encryption(const FstabEntry& entry);
+static bool should_use_metadata_encryption(const FstabEntry& entry);
+
 // Read the primary superblock from an ext4 filesystem.  On failure return
 // false.  If it's not an ext4 filesystem, also set FS_STAT_INVALID_MAGIC.
-static bool read_ext4_superblock(const std::string& blk_device, struct ext4_super_block* sb,
-                                 int* fs_stat) {
+static bool read_ext4_superblock(const std::string& blk_device, const FstabEntry& entry,
+                                 struct ext4_super_block* sb, int* fs_stat) {
     android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(blk_device.c_str(), O_RDONLY | O_CLOEXEC)));
 
     if (fd < 0) {
@@ -321,7 +324,29 @@
         LINFO << "Invalid ext4 superblock on '" << blk_device << "'";
         // not a valid fs, tune2fs, fsck, and mount  will all fail.
         *fs_stat |= FS_STAT_INVALID_MAGIC;
-        return false;
+
+        bool encrypted = should_use_metadata_encryption(entry) || needs_block_encryption(entry);
+        if (entry.mount_point == "/data" &&
+            (!encrypted || android::base::StartsWith(blk_device, "/dev/block/dm-"))) {
+            // try backup superblock, if main superblock is corrupted
+            for (unsigned int blocksize = EXT4_MIN_BLOCK_SIZE; blocksize <= EXT4_MAX_BLOCK_SIZE;
+                 blocksize *= 2) {
+                uint64_t superblock = blocksize * 8;
+                if (blocksize == EXT4_MIN_BLOCK_SIZE) superblock++;
+
+                if (TEMP_FAILURE_RETRY(pread(fd, sb, sizeof(*sb), superblock * blocksize)) !=
+                    sizeof(*sb)) {
+                    PERROR << "Can't read '" << blk_device << "' superblock";
+                    return false;
+                }
+                if (is_ext4_superblock_valid(sb) &&
+                    (1 << (10 + sb->s_log_block_size) == blocksize)) {
+                    *fs_stat &= ~FS_STAT_INVALID_MAGIC;
+                    break;
+                }
+            }
+        }
+        if (*fs_stat & FS_STAT_INVALID_MAGIC) return false;
     }
     *fs_stat |= FS_STAT_IS_EXT4;
     LINFO << "superblock s_max_mnt_count:" << sb->s_max_mnt_count << "," << blk_device;
@@ -662,7 +687,7 @@
     if (is_extfs(entry.fs_type)) {
         struct ext4_super_block sb;
 
-        if (read_ext4_superblock(blk_device, &sb, &fs_stat)) {
+        if (read_ext4_superblock(blk_device, entry, &sb, &fs_stat)) {
             if ((sb.s_feature_incompat & EXT4_FEATURE_INCOMPAT_RECOVER) != 0 ||
                 (sb.s_state & EXT4_VALID_FS) == 0) {
                 LINFO << "Filesystem on " << blk_device << " was not cleanly shutdown; "
@@ -692,7 +717,7 @@
          entry.fs_mgr_flags.fs_verity || entry.fs_mgr_flags.ext_meta_csum)) {
         struct ext4_super_block sb;
 
-        if (read_ext4_superblock(blk_device, &sb, &fs_stat)) {
+        if (read_ext4_superblock(blk_device, entry, &sb, &fs_stat)) {
             tune_reserved_size(blk_device, entry, &sb, &fs_stat);
             tune_encrypt(blk_device, entry, &sb, &fs_stat);
             tune_verity(blk_device, entry, &sb, &fs_stat);
@@ -1019,7 +1044,8 @@
 
 class CheckpointManager {
   public:
-    CheckpointManager(int needs_checkpoint = -1) : needs_checkpoint_(needs_checkpoint) {}
+    CheckpointManager(int needs_checkpoint = -1, bool metadata_encrypted = false)
+        : needs_checkpoint_(needs_checkpoint), metadata_encrypted_(metadata_encrypted) {}
 
     bool NeedsCheckpoint() {
         if (needs_checkpoint_ != UNKNOWN) {
@@ -1037,7 +1063,7 @@
             return true;
         }
 
-        if (entry->fs_mgr_flags.checkpoint_blk) {
+        if (entry->fs_mgr_flags.checkpoint_blk && !metadata_encrypted_) {
             call_vdc({"checkpoint", "restoreCheckpoint", entry->blk_device}, nullptr);
         }
 
@@ -1146,6 +1172,7 @@
 
     enum { UNKNOWN = -1, NO = 0, YES = 1 };
     int needs_checkpoint_;
+    bool metadata_encrypted_;
     std::map<std::string, std::string> device_map_;
 };
 
@@ -1779,11 +1806,11 @@
 // in turn, and stop on 1st success, or no more match.
 static int fs_mgr_do_mount_helper(Fstab* fstab, const std::string& n_name,
                                   const std::string& n_blk_device, const char* tmp_mount_point,
-                                  int needs_checkpoint) {
+                                  int needs_checkpoint, bool metadata_encrypted) {
     int mount_errors = 0;
     int first_mount_errno = 0;
     std::string mount_point;
-    CheckpointManager checkpoint_manager(needs_checkpoint);
+    CheckpointManager checkpoint_manager(needs_checkpoint, metadata_encrypted);
     AvbUniquePtr avb_handle(nullptr);
 
     if (!fstab) {
@@ -1893,12 +1920,13 @@
 }
 
 int fs_mgr_do_mount(Fstab* fstab, const char* n_name, char* n_blk_device, char* tmp_mount_point) {
-    return fs_mgr_do_mount_helper(fstab, n_name, n_blk_device, tmp_mount_point, -1);
+    return fs_mgr_do_mount_helper(fstab, n_name, n_blk_device, tmp_mount_point, -1, false);
 }
 
 int fs_mgr_do_mount(Fstab* fstab, const char* n_name, char* n_blk_device, char* tmp_mount_point,
-                    bool needs_checkpoint) {
-    return fs_mgr_do_mount_helper(fstab, n_name, n_blk_device, tmp_mount_point, needs_checkpoint);
+                    bool needs_checkpoint, bool metadata_encrypted) {
+    return fs_mgr_do_mount_helper(fstab, n_name, n_blk_device, tmp_mount_point, needs_checkpoint,
+                                  metadata_encrypted);
 }
 
 /*
diff --git a/fs_mgr/fs_mgr_remount.cpp b/fs_mgr/fs_mgr_remount.cpp
index 052efa7..b8b074e 100644
--- a/fs_mgr/fs_mgr_remount.cpp
+++ b/fs_mgr/fs_mgr_remount.cpp
@@ -24,6 +24,7 @@
 #include <unistd.h>
 
 #include <string>
+#include <thread>
 #include <utility>
 #include <vector>
 
@@ -31,6 +32,8 @@
 #include <android-base/logging.h>
 #include <android-base/properties.h>
 #include <android-base/strings.h>
+#include <android/os/IVold.h>
+#include <binder/IServiceManager.h>
 #include <bootloader_message/bootloader_message.h>
 #include <cutils/android_reboot.h>
 #include <fec/io.h>
@@ -103,8 +106,23 @@
     ::exit(0);  // SUCCESS
 }
 
+static android::sp<android::os::IVold> GetVold() {
+    while (true) {
+        if (auto sm = android::defaultServiceManager()) {
+            if (auto binder = sm->getService(android::String16("vold"))) {
+                if (auto vold = android::interface_cast<android::os::IVold>(binder)) {
+                    return vold;
+                }
+            }
+        }
+        std::this_thread::sleep_for(2s);
+    }
+}
+
 }  // namespace
 
+using namespace std::chrono_literals;
+
 enum RemountStatus {
     REMOUNT_SUCCESS = 0,
     NOT_USERDEBUG,
@@ -117,7 +135,9 @@
     BAD_OVERLAY,
     NO_MOUNTS,
     REMOUNT_FAILED,
-    MUST_REBOOT
+    MUST_REBOOT,
+    BINDER_ERROR,
+    CHECKPOINTING
 };
 
 static int do_remount(int argc, char* argv[]) {
@@ -194,6 +214,22 @@
         return NO_FSTAB;
     }
 
+    if (android::base::GetBoolProperty("ro.virtual_ab.enabled", false) &&
+        !android::base::GetBoolProperty("ro.virtual_ab.retrofit", false)) {
+        // Virtual A/B devices can use /data as backing storage; make sure we're
+        // not checkpointing.
+        auto vold = GetVold();
+        bool checkpointing = false;
+        if (!vold->isCheckpointing(&checkpointing).isOk()) {
+            LOG(ERROR) << "Could not determine checkpointing status.";
+            return BINDER_ERROR;
+        }
+        if (checkpointing) {
+            LOG(ERROR) << "Cannot use remount when a checkpoint is in progress.";
+            return CHECKPOINTING;
+        }
+    }
+
     // Generate the list of supported overlayfs mount points.
     auto overlayfs_candidates = fs_mgr_overlayfs_candidate_list(fstab);
 
diff --git a/fs_mgr/include/fs_mgr.h b/fs_mgr/include/fs_mgr.h
index 86090c1..2a67b8c 100644
--- a/fs_mgr/include/fs_mgr.h
+++ b/fs_mgr/include/fs_mgr.h
@@ -69,7 +69,7 @@
 int fs_mgr_do_mount(android::fs_mgr::Fstab* fstab, const char* n_name, char* n_blk_device,
                     char* tmp_mount_point);
 int fs_mgr_do_mount(android::fs_mgr::Fstab* fstab, const char* n_name, char* n_blk_device,
-                    char* tmp_mount_point, bool need_cp);
+                    char* tmp_mount_point, bool need_cp, bool metadata_encrypted);
 int fs_mgr_do_mount_one(const android::fs_mgr::FstabEntry& entry,
                         const std::string& mount_point = "");
 int fs_mgr_do_tmpfs_mount(const char *n_name);
diff --git a/fs_mgr/libsnapshot/fuzz.sh b/fs_mgr/libsnapshot/fuzz.sh
index 0e57674..5995cef 100755
--- a/fs_mgr/libsnapshot/fuzz.sh
+++ b/fs_mgr/libsnapshot/fuzz.sh
@@ -11,7 +11,7 @@
 
 build_normal() (
     pushd $(gettop)
-    NATIVE_COVERAGE="" NATIVE_LINE_COVERAGE="" COVERAGE_PATHS="" m ${FUZZ_TARGET}
+    NATIVE_COVERAGE="" NATIVE_LINE_COVERAGE="" NATIVE_COVERAGE_PATHS="" m ${FUZZ_TARGET}
     ret=$?
     popd
     return ${ret}
@@ -19,7 +19,7 @@
 
 build_cov() {
     pushd $(gettop)
-    NATIVE_COVERAGE="true" NATIVE_LINE_COVERAGE="true" COVERAGE_PATHS="${PROJECT_PATH}" m ${FUZZ_TARGET}
+    NATIVE_COVERAGE="true" NATIVE_LINE_COVERAGE="true" NATIVE_COVERAGE_PATHS="${PROJECT_PATH}" m ${FUZZ_TARGET}
     ret=$?
     popd
     return ${ret}
diff --git a/fs_mgr/libsnapshot/snapshot.cpp b/fs_mgr/libsnapshot/snapshot.cpp
index 5909cff..55214f5 100644
--- a/fs_mgr/libsnapshot/snapshot.cpp
+++ b/fs_mgr/libsnapshot/snapshot.cpp
@@ -2277,6 +2277,10 @@
         auto operations_it = install_operation_map.find(target_partition->name());
         if (operations_it != install_operation_map.end()) {
             cow_creator->operations = operations_it->second;
+        } else {
+            LOG(INFO) << target_partition->name()
+                      << " isn't included in the payload, skipping the cow creation.";
+            continue;
         }
 
         cow_creator->extra_extents.clear();
diff --git a/fs_mgr/libsnapshot/snapshot_metadata_updater.cpp b/fs_mgr/libsnapshot/snapshot_metadata_updater.cpp
index 60bf796..051584c 100644
--- a/fs_mgr/libsnapshot/snapshot_metadata_updater.cpp
+++ b/fs_mgr/libsnapshot/snapshot_metadata_updater.cpp
@@ -62,6 +62,8 @@
                                                std::string(it->second) + target_suffix_, &p});
         }
     }
+
+    partial_update_ = manifest.partial_update();
 }
 
 bool SnapshotMetadataUpdater::ShrinkPartitions() const {
@@ -82,6 +84,18 @@
 }
 
 bool SnapshotMetadataUpdater::DeletePartitions() const {
+    // For partial update, not all dynamic partitions are included in the payload.
+    // TODO(xunchang) delete the untouched partitions whose group is in the payload.
+    // e.g. Delete vendor in the following scenario
+    // On device:
+    //   Group A: system, vendor
+    // In payload:
+    //   Group A: system
+    if (partial_update_) {
+        LOG(INFO) << "Skip deleting partitions for partial update";
+        return true;
+    }
+
     std::vector<std::string> partitions_to_delete;
     // Don't delete partitions in groups where the group name doesn't have target_suffix,
     // e.g. default.
@@ -139,6 +153,11 @@
 }
 
 bool SnapshotMetadataUpdater::DeleteGroups() const {
+    if (partial_update_) {
+        LOG(INFO) << "Skip deleting groups for partial update";
+        return true;
+    }
+
     std::vector<std::string> existing_groups = builder_->ListGroups();
     for (const auto& existing_group_name : existing_groups) {
         // Don't delete groups without target suffix, e.g. default.
diff --git a/fs_mgr/libsnapshot/snapshot_metadata_updater.h b/fs_mgr/libsnapshot/snapshot_metadata_updater.h
index 83c9460..5b1cbf9 100644
--- a/fs_mgr/libsnapshot/snapshot_metadata_updater.h
+++ b/fs_mgr/libsnapshot/snapshot_metadata_updater.h
@@ -79,6 +79,7 @@
     const std::string target_suffix_;
     std::vector<Group> groups_;
     std::vector<Partition> partitions_;
+    bool partial_update_{false};
 };
 
 }  // namespace snapshot
diff --git a/fs_mgr/libsnapshot/test_helpers.cpp b/fs_mgr/libsnapshot/test_helpers.cpp
index f82a602..de3d912 100644
--- a/fs_mgr/libsnapshot/test_helpers.cpp
+++ b/fs_mgr/libsnapshot/test_helpers.cpp
@@ -52,10 +52,19 @@
 
 bool TestPartitionOpener::GetInfo(const std::string& partition_name,
                                   android::fs_mgr::BlockDeviceInfo* info) const {
-    if (partition_name == "super") {
-        return PartitionOpener::GetInfo(fake_super_path_, info);
+    if (partition_name != "super") {
+        return PartitionOpener::GetInfo(partition_name, info);
     }
-    return PartitionOpener::GetInfo(partition_name, info);
+
+    if (PartitionOpener::GetInfo(fake_super_path_, info)) {
+        // SnapshotUpdateTest uses a relatively small super partition, which requires a small
+        // alignment and 0 offset to work. For the purpose of this test, hardcode the alignment
+        // and offset. This test isn't about testing liblp or libdm.
+        info->alignment_offset = 0;
+        info->alignment = std::min<uint32_t>(info->alignment, static_cast<uint32_t>(128_KiB));
+        return true;
+    }
+    return false;
 }
 
 std::string TestPartitionOpener::GetDeviceString(const std::string& partition_name) const {
diff --git a/fs_mgr/libsnapshot/update_engine/update_metadata.proto b/fs_mgr/libsnapshot/update_engine/update_metadata.proto
index 8a11eaa..202e39b 100644
--- a/fs_mgr/libsnapshot/update_engine/update_metadata.proto
+++ b/fs_mgr/libsnapshot/update_engine/update_metadata.proto
@@ -77,4 +77,5 @@
 message DeltaArchiveManifest {
     repeated PartitionUpdate partitions = 13;
     optional DynamicPartitionMetadata dynamic_partition_metadata = 15;
+    optional bool partial_update = 16;
 }
diff --git a/init/builtins.cpp b/init/builtins.cpp
index 0ac66f2..0b456e7 100644
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -1221,6 +1221,20 @@
     return {};
 }
 
+static Result<void> MountLinkerConfigForDefaultNamespace() {
+    // No need to mount linkerconfig for default mount namespace if the path does not exist (which
+    // would mean it is already mounted)
+    if (access("/linkerconfig/default", 0) != 0) {
+        return {};
+    }
+
+    if (mount("/linkerconfig/default", "/linkerconfig", nullptr, MS_BIND | MS_REC, nullptr) != 0) {
+        return ErrnoError() << "Failed to mount linker configuration for default mount namespace.";
+    }
+
+    return {};
+}
+
 static bool IsApexUpdatable() {
     static bool updatable = android::sysprop::ApexProperties::updatable().value_or(false);
     return updatable;
@@ -1319,11 +1333,14 @@
 }
 
 static Result<void> do_enter_default_mount_ns(const BuiltinArguments& args) {
-    if (SwitchToDefaultMountNamespace()) {
-        return {};
-    } else {
-        return Error() << "Failed to enter into default mount namespace";
+    if (auto result = SwitchToMountNamespaceIfNeeded(NS_DEFAULT); !result.ok()) {
+        return result.error();
     }
+    if (auto result = MountLinkerConfigForDefaultNamespace(); !result.ok()) {
+        return result.error();
+    }
+    LOG(INFO) << "Switched to default mount namespace";
+    return {};
 }
 
 // Builtin-function-map start
diff --git a/init/mount_namespace.cpp b/init/mount_namespace.cpp
index f3b584c..b9d5d67 100644
--- a/init/mount_namespace.cpp
+++ b/init/mount_namespace.cpp
@@ -176,20 +176,6 @@
     return true;
 }
 
-static Result<void> MountLinkerConfigForDefaultNamespace() {
-    // No need to mount linkerconfig for default mount namespace if the path does not exist (which
-    // would mean it is already mounted)
-    if (access("/linkerconfig/default", 0) != 0) {
-        return {};
-    }
-
-    if (mount("/linkerconfig/default", "/linkerconfig", nullptr, MS_BIND | MS_REC, nullptr) != 0) {
-        return ErrnoError() << "Failed to mount linker configuration for default mount namespace.";
-    }
-
-    return {};
-}
-
 static android::base::unique_fd bootstrap_ns_fd;
 static android::base::unique_fd default_ns_fd;
 
@@ -290,40 +276,20 @@
     return success;
 }
 
-bool SwitchToDefaultMountNamespace() {
-    if (IsRecoveryMode()) {
-        // we don't have multiple namespaces in recovery mode
-        return true;
+Result<void> SwitchToMountNamespaceIfNeeded(MountNamespace target_mount_namespace) {
+    if (IsRecoveryMode() || !IsApexUpdatable()) {
+        // we don't have multiple namespaces in recovery mode or if apex is not updatable
+        return {};
     }
-    if (default_ns_id != GetMountNamespaceId()) {
-        if (setns(default_ns_fd.get(), CLONE_NEWNS) == -1) {
-            PLOG(ERROR) << "Failed to switch back to the default mount namespace.";
-            return false;
-        }
-
-        if (auto result = MountLinkerConfigForDefaultNamespace(); !result.ok()) {
-            LOG(ERROR) << result.error();
-            return false;
+    const auto& ns_id = target_mount_namespace == NS_BOOTSTRAP ? bootstrap_ns_id : default_ns_id;
+    const auto& ns_fd = target_mount_namespace == NS_BOOTSTRAP ? bootstrap_ns_fd : default_ns_fd;
+    const auto& ns_name = target_mount_namespace == NS_BOOTSTRAP ? "bootstrap" : "default";
+    if (ns_id != GetMountNamespaceId() && ns_fd.get() != -1) {
+        if (setns(ns_fd.get(), CLONE_NEWNS) == -1) {
+            return ErrnoError() << "Failed to switch to " << ns_name << " mount namespace.";
         }
     }
-
-    LOG(INFO) << "Switched to default mount namespace";
-    return true;
-}
-
-bool SwitchToBootstrapMountNamespaceIfNeeded() {
-    if (IsRecoveryMode()) {
-        // we don't have multiple namespaces in recovery mode
-        return true;
-    }
-    if (bootstrap_ns_id != GetMountNamespaceId() && bootstrap_ns_fd.get() != -1 &&
-        IsApexUpdatable()) {
-        if (setns(bootstrap_ns_fd.get(), CLONE_NEWNS) == -1) {
-            PLOG(ERROR) << "Failed to switch to bootstrap mount namespace.";
-            return false;
-        }
-    }
-    return true;
+    return {};
 }
 
 }  // namespace init
diff --git a/init/mount_namespace.h b/init/mount_namespace.h
index c41a449..d4d6f82 100644
--- a/init/mount_namespace.h
+++ b/init/mount_namespace.h
@@ -16,12 +16,15 @@
 
 #pragma once
 
+#include <android-base/result.h>
+
 namespace android {
 namespace init {
 
+enum MountNamespace { NS_BOOTSTRAP, NS_DEFAULT };
+
 bool SetupMountNamespaces();
-bool SwitchToDefaultMountNamespace();
-bool SwitchToBootstrapMountNamespaceIfNeeded();
+base::Result<void> SwitchToMountNamespaceIfNeeded(MountNamespace target_mount_namespace);
 
 }  // namespace init
 }  // namespace android
diff --git a/init/property_service.cpp b/init/property_service.cpp
index 82f5b8c..612854d 100644
--- a/init/property_service.cpp
+++ b/init/property_service.cpp
@@ -711,8 +711,8 @@
                 if (it == properties->end()) {
                     (*properties)[key] = value;
                 } else if (it->second != value) {
-                    LOG(WARNING) << "Overriding previous 'ro.' property '" << key << "':'"
-                                 << it->second << "' with new value '" << value << "'";
+                    LOG(WARNING) << "Overriding previous property '" << key << "':'" << it->second
+                                 << "' with new value '" << value << "'";
                     it->second = value;
                 }
             } else {
diff --git a/init/reboot.cpp b/init/reboot.cpp
index ffd58a3..19e83cc 100644
--- a/init/reboot.cpp
+++ b/init/reboot.cpp
@@ -544,6 +544,18 @@
     return still_running;
 }
 
+static Result<void> UnmountAllApexes() {
+    const char* args[] = {"/system/bin/apexd", "--unmount-all"};
+    int status;
+    if (logwrap_fork_execvp(arraysize(args), args, &status, false, LOG_KLOG, true, nullptr) != 0) {
+        return ErrnoError() << "Failed to call '/system/bin/apexd --unmount-all'";
+    }
+    if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
+        return {};
+    }
+    return Error() << "'/system/bin/apexd --unmount-all' failed : " << status;
+}
+
 //* Reboot / shutdown the system.
 // cmd ANDROID_RB_* as defined in android_reboot.h
 // reason Reason string like "reboot", "shutdown,userrequested"
@@ -698,6 +710,11 @@
     // 5. drop caches and disable zram backing device, if exist
     KillZramBackingDevice();
 
+    LOG(INFO) << "Ready to unmount apexes. So far shutdown sequence took " << t;
+    // 6. unmount active apexes, otherwise they might prevent clean unmount of /data.
+    if (auto ret = UnmountAllApexes(); !ret.ok()) {
+        LOG(ERROR) << ret.error();
+    }
     UmountStat stat =
             TryUmountAndFsck(cmd, run_fsck, shutdown_timeout - t.duration(), &reboot_semaphore);
     // Follow what linux shutdown is doing: one more sync with little bit delay
@@ -736,18 +753,6 @@
     StartSendingMessages();
 }
 
-static Result<void> UnmountAllApexes() {
-    const char* args[] = {"/system/bin/apexd", "--unmount-all"};
-    int status;
-    if (logwrap_fork_execvp(arraysize(args), args, &status, false, LOG_KLOG, true, nullptr) != 0) {
-        return ErrnoError() << "Failed to call '/system/bin/apexd --unmount-all'";
-    }
-    if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
-        return {};
-    }
-    return Error() << "'/system/bin/apexd --unmount-all' failed : " << status;
-}
-
 static std::chrono::milliseconds GetMillisProperty(const std::string& name,
                                                    std::chrono::milliseconds default_value) {
     auto value = GetUintProperty(name, static_cast<uint64_t>(default_value.count()));
@@ -831,7 +836,7 @@
         sub_reason = "apex";
         return result;
     }
-    if (!SwitchToBootstrapMountNamespaceIfNeeded()) {
+    if (!SwitchToMountNamespaceIfNeeded(NS_BOOTSTRAP)) {
         sub_reason = "ns_switch";
         return Error() << "Failed to switch to bootstrap namespace";
     }
diff --git a/init/service.cpp b/init/service.cpp
index 165b848..68365b3 100644
--- a/init/service.cpp
+++ b/init/service.cpp
@@ -465,6 +465,16 @@
         pre_apexd_ = true;
     }
 
+    // For pre-apexd services, override mount namespace as "bootstrap" one before starting.
+    // Note: "ueventd" is supposed to be run in "default" mount namespace even if it's pre-apexd
+    // to support loading firmwares from APEXes.
+    std::optional<MountNamespace> override_mount_namespace;
+    if (name_ == "ueventd") {
+        override_mount_namespace = NS_DEFAULT;
+    } else if (pre_apexd_) {
+        override_mount_namespace = NS_BOOTSTRAP;
+    }
+
     post_data_ = ServiceList::GetInstance().IsPostData();
 
     LOG(INFO) << "starting service '" << name_ << "'...";
@@ -496,7 +506,8 @@
     if (pid == 0) {
         umask(077);
 
-        if (auto result = EnterNamespaces(namespaces_, name_, pre_apexd_); !result.ok()) {
+        if (auto result = EnterNamespaces(namespaces_, name_, override_mount_namespace);
+            !result.ok()) {
             LOG(FATAL) << "Service '" << name_
                        << "' failed to set up namespaces: " << result.error();
         }
diff --git a/init/service_utils.cpp b/init/service_utils.cpp
index 484c2c8..05e632b 100644
--- a/init/service_utils.cpp
+++ b/init/service_utils.cpp
@@ -194,7 +194,8 @@
     return Descriptor(ANDROID_FILE_ENV_PREFIX + name, std::move(fd));
 }
 
-Result<void> EnterNamespaces(const NamespaceInfo& info, const std::string& name, bool pre_apexd) {
+Result<void> EnterNamespaces(const NamespaceInfo& info, const std::string& name,
+                             std::optional<MountNamespace> override_mount_namespace) {
     for (const auto& [nstype, path] : info.namespaces_to_enter) {
         if (auto result = EnterNamespace(nstype, path.c_str()); !result.ok()) {
             return result;
@@ -202,9 +203,10 @@
     }
 
 #if defined(__ANDROID__)
-    if (pre_apexd) {
-        if (!SwitchToBootstrapMountNamespaceIfNeeded()) {
-            return Error() << "could not enter into the bootstrap mount namespace";
+    if (override_mount_namespace.has_value()) {
+        if (auto result = SwitchToMountNamespaceIfNeeded(override_mount_namespace.value());
+            !result.ok()) {
+            return result;
         }
     }
 #endif
diff --git a/init/service_utils.h b/init/service_utils.h
index 3f1071e..e74f8c1 100644
--- a/init/service_utils.h
+++ b/init/service_utils.h
@@ -19,12 +19,14 @@
 #include <sys/resource.h>
 #include <sys/types.h>
 
+#include <optional>
 #include <string>
 #include <vector>
 
 #include <android-base/unique_fd.h>
 #include <cutils/iosched_policy.h>
 
+#include "mount_namespace.h"
 #include "result.h"
 
 namespace android {
@@ -66,7 +68,8 @@
     // Pair of namespace type, path to name.
     std::vector<std::pair<int, std::string>> namespaces_to_enter;
 };
-Result<void> EnterNamespaces(const NamespaceInfo& info, const std::string& name, bool pre_apexd);
+Result<void> EnterNamespaces(const NamespaceInfo& info, const std::string& name,
+                             std::optional<MountNamespace> override_mount_namespace);
 
 struct ProcessAttributes {
     std::string console;
diff --git a/libappfuse/FuseBridgeLoop.cc b/libappfuse/FuseBridgeLoop.cc
index f71d0c3..22f381c 100644
--- a/libappfuse/FuseBridgeLoop.cc
+++ b/libappfuse/FuseBridgeLoop.cc
@@ -311,6 +311,8 @@
     }
 };
 
+std::recursive_mutex FuseBridgeLoop::mutex_;
+
 FuseBridgeLoop::FuseBridgeLoop() : opened_(true) {
     base::unique_fd epoll_fd(epoll_create1(EPOLL_CLOEXEC));
     if (epoll_fd.get() == -1) {
@@ -328,7 +330,7 @@
 
     std::unique_ptr<FuseBridgeEntry> bridge(
         new FuseBridgeEntry(mount_id, std::move(dev_fd), std::move(proxy_fd)));
-    std::lock_guard<std::mutex> lock(mutex_);
+    std::lock_guard<std::recursive_mutex> lock(mutex_);
     if (!opened_) {
         LOG(ERROR) << "Tried to add a mount to a closed bridge";
         return false;
@@ -372,7 +374,7 @@
         const bool wait_result = epoll_controller_->Wait(bridges_.size(), &entries);
         LOG(VERBOSE) << "Receive epoll events";
         {
-            std::lock_guard<std::mutex> lock(mutex_);
+            std::lock_guard<std::recursive_mutex> lock(mutex_);
             if (!(wait_result && ProcessEventLocked(entries, callback))) {
                 for (auto it = bridges_.begin(); it != bridges_.end();) {
                     callback->OnClosed(it->second->mount_id());
@@ -385,5 +387,13 @@
     }
 }
 
+void FuseBridgeLoop::Lock() {
+    mutex_.lock();
+}
+
+void FuseBridgeLoop::Unlock() {
+    mutex_.unlock();
+}
+
 }  // namespace fuse
 }  // namespace android
diff --git a/libappfuse/include/libappfuse/FuseBridgeLoop.h b/libappfuse/include/libappfuse/FuseBridgeLoop.h
index 6bfda98..d5fc28f 100644
--- a/libappfuse/include/libappfuse/FuseBridgeLoop.h
+++ b/libappfuse/include/libappfuse/FuseBridgeLoop.h
@@ -50,6 +50,10 @@
     // thread from one which invokes |Start|.
     bool AddBridge(int mount_id, base::unique_fd dev_fd, base::unique_fd proxy_fd);
 
+    static void Lock();
+
+    static void Unlock();
+
   private:
     bool ProcessEventLocked(const std::unordered_set<FuseBridgeEntry*>& entries,
                             FuseBridgeLoopCallback* callback);
@@ -60,7 +64,7 @@
     std::map<int, std::unique_ptr<FuseBridgeEntry>> bridges_;
 
     // Lock for multi-threading.
-    std::mutex mutex_;
+    static std::recursive_mutex mutex_;
 
     bool opened_;
 
diff --git a/liblog/pmsg_reader.cpp b/liblog/pmsg_reader.cpp
index 0e39aab..5640900 100644
--- a/liblog/pmsg_reader.cpp
+++ b/liblog/pmsg_reader.cpp
@@ -96,7 +96,7 @@
           ((logger_list->start.tv_sec != buf.l.realtime.tv_sec) ||
            (logger_list->start.tv_nsec <= buf.l.realtime.tv_nsec)))) &&
         (!logger_list->pid || (logger_list->pid == buf.p.pid))) {
-      char* msg = reinterpret_cast<char*>(&log_msg->entry) + log_msg->entry.hdr_size;
+      char* msg = reinterpret_cast<char*>(&log_msg->entry) + sizeof(log_msg->entry);
       *msg = buf.prio;
       fd = atomic_load(&logger_list->fd);
       if (fd <= 0) {
diff --git a/libmodprobe/include/modprobe/modprobe.h b/libmodprobe/include/modprobe/modprobe.h
index a7687af..4806b08 100644
--- a/libmodprobe/include/modprobe/modprobe.h
+++ b/libmodprobe/include/modprobe/modprobe.h
@@ -36,7 +36,7 @@
                             std::vector<std::string>* post_dependencies);
     void ResetModuleCount() { module_count_ = 0; }
     int GetModuleCount() { return module_count_; }
-    void EnableBlacklist(bool enable);
+    void EnableBlocklist(bool enable);
     void EnableVerbose(bool enable);
 
   private:
@@ -55,7 +55,7 @@
     bool ParseSoftdepCallback(const std::vector<std::string>& args);
     bool ParseLoadCallback(const std::vector<std::string>& args);
     bool ParseOptionsCallback(const std::vector<std::string>& args);
-    bool ParseBlacklistCallback(const std::vector<std::string>& args);
+    bool ParseBlocklistCallback(const std::vector<std::string>& args);
     void ParseKernelCmdlineOptions();
     void ParseCfg(const std::string& cfg, std::function<bool(const std::vector<std::string>&)> f);
 
@@ -65,8 +65,8 @@
     std::vector<std::pair<std::string, std::string>> module_post_softdep_;
     std::vector<std::string> module_load_;
     std::unordered_map<std::string, std::string> module_options_;
-    std::set<std::string> module_blacklist_;
+    std::set<std::string> module_blocklist_;
     std::unordered_set<std::string> module_loaded_;
     int module_count_ = 0;
-    bool blacklist_enabled = false;
+    bool blocklist_enabled = false;
 };
diff --git a/libmodprobe/libmodprobe.cpp b/libmodprobe/libmodprobe.cpp
index d193796..5a6ae8b 100644
--- a/libmodprobe/libmodprobe.cpp
+++ b/libmodprobe/libmodprobe.cpp
@@ -194,17 +194,17 @@
     return true;
 }
 
-bool Modprobe::ParseBlacklistCallback(const std::vector<std::string>& args) {
+bool Modprobe::ParseBlocklistCallback(const std::vector<std::string>& args) {
     auto it = args.begin();
     const std::string& type = *it++;
 
-    if (type != "blacklist") {
-        LOG(ERROR) << "non-blacklist line encountered in modules.blacklist";
+    if (type != "blocklist") {
+        LOG(ERROR) << "non-blocklist line encountered in modules.blocklist";
         return false;
     }
 
     if (args.size() != 2) {
-        LOG(ERROR) << "lines in modules.blacklist must have exactly 2 entries, not " << args.size();
+        LOG(ERROR) << "lines in modules.blocklist must have exactly 2 entries, not " << args.size();
         return false;
     }
 
@@ -214,7 +214,7 @@
     if (canonical_name.empty()) {
         return false;
     }
-    this->module_blacklist_.emplace(canonical_name);
+    this->module_blocklist_.emplace(canonical_name);
 
     return true;
 }
@@ -331,16 +331,16 @@
         auto options_callback = std::bind(&Modprobe::ParseOptionsCallback, this, _1);
         ParseCfg(base_path + "/modules.options", options_callback);
 
-        auto blacklist_callback = std::bind(&Modprobe::ParseBlacklistCallback, this, _1);
-        ParseCfg(base_path + "/modules.blacklist", blacklist_callback);
+        auto blocklist_callback = std::bind(&Modprobe::ParseBlocklistCallback, this, _1);
+        ParseCfg(base_path + "/modules.blocklist", blocklist_callback);
     }
 
     ParseKernelCmdlineOptions();
     android::base::SetMinimumLogSeverity(android::base::INFO);
 }
 
-void Modprobe::EnableBlacklist(bool enable) {
-    blacklist_enabled = enable;
+void Modprobe::EnableBlocklist(bool enable) {
+    blocklist_enabled = enable;
 }
 
 void Modprobe::EnableVerbose(bool enable) {
diff --git a/libmodprobe/libmodprobe_ext.cpp b/libmodprobe/libmodprobe_ext.cpp
index 6589708..fb1f5e7 100644
--- a/libmodprobe/libmodprobe_ext.cpp
+++ b/libmodprobe/libmodprobe_ext.cpp
@@ -35,7 +35,7 @@
     android::base::unique_fd fd(
             TEMP_FAILURE_RETRY(open(path_name.c_str(), O_RDONLY | O_NOFOLLOW | O_CLOEXEC)));
     if (fd == -1) {
-        LOG(ERROR) << "Could not open module '" << path_name << "'";
+        PLOG(ERROR) << "Could not open module '" << path_name << "'";
         return false;
     }
 
@@ -49,7 +49,7 @@
         options = options + " " + parameters;
     }
 
-    LOG(INFO) << "Loading module " << path_name << " with args \"" << options << "\"";
+    LOG(INFO) << "Loading module " << path_name << " with args '" << options << "'";
     int ret = syscall(__NR_finit_module, fd.get(), options.c_str(), 0);
     if (ret != 0) {
         if (errno == EEXIST) {
@@ -57,7 +57,7 @@
             module_loaded_.emplace(canonical_name);
             return true;
         }
-        LOG(ERROR) << "Failed to insmod '" << path_name << "' with args '" << options << "'";
+        PLOG(ERROR) << "Failed to insmod '" << path_name << "' with args '" << options << "'";
         return false;
     }
 
@@ -80,8 +80,8 @@
 
 bool Modprobe::ModuleExists(const std::string& module_name) {
     struct stat fileStat;
-    if (blacklist_enabled && module_blacklist_.count(module_name)) {
-        LOG(INFO) << "module " << module_name << " is blacklisted";
+    if (blocklist_enabled && module_blocklist_.count(module_name)) {
+        LOG(INFO) << "module " << module_name << " is blocklisted";
         return false;
     }
     auto deps = GetDependencies(module_name);
diff --git a/libmodprobe/libmodprobe_ext_test.cpp b/libmodprobe/libmodprobe_ext_test.cpp
index 9ee5ba7..e79bfaf 100644
--- a/libmodprobe/libmodprobe_ext_test.cpp
+++ b/libmodprobe/libmodprobe_ext_test.cpp
@@ -72,7 +72,7 @@
 
 bool Modprobe::ModuleExists(const std::string& module_name) {
     auto deps = GetDependencies(module_name);
-    if (blacklist_enabled && module_blacklist_.count(module_name)) {
+    if (blocklist_enabled && module_blocklist_.count(module_name)) {
         return false;
     }
     if (deps.empty()) {
diff --git a/libmodprobe/libmodprobe_test.cpp b/libmodprobe/libmodprobe_test.cpp
index eea0abd..5919c49 100644
--- a/libmodprobe/libmodprobe_test.cpp
+++ b/libmodprobe/libmodprobe_test.cpp
@@ -113,9 +113,9 @@
             "options test9.ko param_x=1 param_y=2 param_z=3\n"
             "options test100.ko param_1=1\n";
 
-    const std::string modules_blacklist =
-            "blacklist test9.ko\n"
-            "blacklist test3.ko\n";
+    const std::string modules_blocklist =
+            "blocklist test9.ko\n"
+            "blocklist test3.ko\n";
 
     const std::string modules_load =
             "test4.ko\n"
@@ -139,7 +139,7 @@
                                                  0600, getuid(), getgid()));
     ASSERT_TRUE(android::base::WriteStringToFile(modules_load, dir_path + "/modules.load", 0600,
                                                  getuid(), getgid()));
-    ASSERT_TRUE(android::base::WriteStringToFile(modules_blacklist, dir_path + "/modules.blacklist",
+    ASSERT_TRUE(android::base::WriteStringToFile(modules_blocklist, dir_path + "/modules.blocklist",
                                                  0600, getuid(), getgid()));
 
     for (auto i = test_modules.begin(); i != test_modules.end(); ++i) {
@@ -176,6 +176,6 @@
 
     EXPECT_TRUE(modules_loaded == expected_after_remove);
 
-    m.EnableBlacklist(true);
+    m.EnableBlocklist(true);
     EXPECT_FALSE(m.LoadWithAliases("test4", true));
 }
diff --git a/llkd/README.md b/llkd/README.md
index 191f988..6f92f14 100644
--- a/llkd/README.md
+++ b/llkd/README.md
@@ -1,199 +1,237 @@
-Android Live-LocK Daemon
-========================
+<!--
+Project: /_project.yaml
+Book: /_book.yaml
 
-Introduction
-------------
+{% include "_versions.html" %}
+-->
 
-Android Live-LocK Daemon (llkd) is used to catch kernel deadlocks and mitigate.
+<!--
+  Copyright 2020 The Android Open Source Project
 
-Code is structured to allow integration into another service as either as part
-of the main loop, or spun off as a thread should that be necessary.  A default
-standalone implementation is provided by llkd component.
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
 
-The 'C' interface from libllkd component is thus:
+      http://www.apache.org/licenses/LICENSE-2.0
 
-    #include "llkd.h"
-    bool llkInit(const char* threadname) /* return true if enabled */
-    unsigned llkCheckMillseconds(void)   /* ms to sleep for next check */
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+-->
 
-If a threadname is provided, a thread will be automatically spawned, otherwise
-caller must call llkCheckMilliseconds in its main loop.  Function will return
-the period of time before the next expected call to this handler.
+# Android Live-LocK Daemon (llkd)
 
-Operations
-----------
+Android 10 <!-- {{ androidQVersionNumber }} --> includes the Android Live-LocK Daemon
+(`llkd`), which is designed to catch and mitigate kernel deadlocks. The `llkd`
+component provides a default standalone implementation, but you can
+alternatively integrate the `llkd` code into another service, either as part of
+the main loop or as a separate thread.
 
-There are two detection scenarios. Persistent D or Z state, and persistent
+## Detection scenarios <!-- {:#detection-scenarios} -->
+
+The `llkd` has two detection scenarios: Persistent D or Z state, and persistent
 stack signature.
 
-If a thread is in D or Z state with no forward progress for longer than
-ro.llk.timeout_ms, or ro.llk.[D|Z].timeout_ms, kill the process or parent
-process respectively.  If another scan shows the same process continues to
-exist, then have a confirmed live-lock condition and need to panic.  Panic
-the kernel in a manner to provide the greatest bugreporting details as to the
-condition.  Add a alarm self watchdog should llkd ever get locked up that is
-double the expected time to flow through the mainloop.  Sampling is every
-ro.llk_sample_ms.
+### Persistent D or Z state <!-- {:#persistent-d-or-z-state} -->
 
-For usedebug releases only, persistent stack signature checking is enabled.
-If a thread in any state but Z, has a persistent listed ro.llk.stack kernel
-symbol always being reported, even if there is forward scheduling progress, for
-longer than ro.llk.timeout_ms, or ro.llk.stack.timeout_ms, then issue a kill
-to the process.  If another scan shows the same process continues to exist,
-then have a confirmed live-lock condition and need to panic.  There is no
-ABA detection since forward scheduling progress is allowed, thus the condition
-for the symbols are:
+If a thread is in D (uninterruptible sleep) or Z (zombie) state with no forward
+progress for longer than `ro.llk.timeout_ms or ro.llk.[D|Z].timeout_ms`, the
+`llkd` kills the process (or parent process). If a subsequent scan shows the
+same process continues to exist, the `llkd` confirms a live-lock condition and
+panics the kernel in a manner that provides the most detailed bug report for the
+condition.
 
-- Check is looking for " __symbol__+0x" or " __symbol__.cfi+0x" in
-  /proc/__pid__/stack.
-- The __symbol__ should be rare and short lived enough that on a typical
-  system the function is seen at most only once in a sample over the timeout
-  period of ro.llk.stack.timeout_ms, samples occur every ro.llk.check_ms. This
-  can be the only way to prevent a false trigger as there is no ABA protection.
-- Persistent continuously when the live lock condition exists.
-- Should be just below the function that is calling the lock that could
-  contend, because if the lock is below or in the symbol function, the
-  symbol will show in all affected processes, not just the one that
-  caused the lockup.
+The `llkd` includes a self watchdog that alarms if `llkd` locks up; watchdog is
+double the expected time to flow through the mainloop and sampling is every
+`ro.llk_sample_ms`.
 
-Default will not monitor init, or [kthreadd] and all that [kthreadd] spawns.
-This reduces the effectiveness of llkd by limiting its coverage.  If there is
-value in covering [kthreadd] spawned threads, the requirement will be that
-the drivers not remain in a persistent 'D' state, or that they have mechanisms
-to recover the thread should it be killed externally (this is good driver
-coding hygiene, a common request to add such to publicly reviewed kernel.org
-maintained drivers).  For instance use wait_event_interruptible() instead of
-wait_event().  The blacklists can be adjusted accordingly if these
-conditions are met to cover kernel components.  For the stack symbol checking,
-there is an additional process blacklist so that we do not incide sepolicy
-violations on services that block ptrace operations.
+### Persistent stack signature <!-- {:#persistent-stack-signature} -->
 
-An accompanying gTest set have been added, and will setup a persistent D or Z
-process, with and without forward progress, but not in a live-lock state
-because that would require a buggy kernel, or a module or kernel modification
-to stimulate.  The test will check that llkd will mitigate first by killing
-the appropriate process.  D state is setup by vfork() waiting for exec() in
-child process.  Z state is setup by fork() and an un-waited for child process.
-Should be noted that both of these conditions should never happen on Android
-on purpose, and llkd effectively sweeps up processes that create these
-conditions.  If the test can, it will reconfigure llkd to expedite the test
-duration by adjusting the ro.llk.* Android properties.  Tests run the D state
-with some scheduling progress to ensure that ABA checking prevents false
-triggers. If 100% reliable ABA on platform, then ro.llk.killtest can be
-set to false; however this will result in some of the unit tests to panic
-kernel instead of deal with more graceful kill operation.
+For userdebug releases, the `llkd` can detect kernel live-locks using persistent
+stack signature checking. If a thread in any state except Z has a persistent
+listed `ro.llk.stack` kernel symbol that is reported for longer than
+`ro.llk.timeout_ms` or `ro.llk.stack.timeout_ms`, the `llkd` kills the process
+(even if there is forward scheduling progress). If a subsequent scan shows the
+same process continues to exist, the `llkd` confirms a live-lock condition and
+panics the kernel in a manner that provides the most detailed bug report for the
+condition.
 
-Android Properties
-------------------
+Note: Because forward scheduling progress is allowed, the `llkd` does not
+perform [ABA detection](https://en.wikipedia.org/wiki/ABA_problem){:.external}.
 
-The following are the Android Properties llkd respond to.
-*prop*_ms named properties are in milliseconds.
-Properties that use comma (*,*) separator for lists, use a leading separator to
-preserve default and add or subtract entries with (*optional*) plus (*+*) and
-minus (*-*) prefixes respectively.
-For these lists, the string "*false*" is synonymous with an *empty* list,
-and *blank* or *missing* resorts to the specified *default* value.
+The `lldk` check persists continuously when the live lock condition exists and
+looks for the composed strings `" symbol+0x"` or `" symbol.cfi+0x"` in the
+`/proc/pid/stack` file on Linux. The list of symbols is in `ro.llk.stack` and
+defaults to the comma-separated list of
+"`cma_alloc,__get_user_pages,bit_wait_io,wait_on_page_bit_killable`".
 
-#### ro.config.low_ram
-device is configured with limited memory.
+Symbols should be rare and short-lived enough that on a typical system the
+function is seen only once in a sample over the timeout period of
+`ro.llk.stack.timeout_ms` (samples occur every `ro.llk.check_ms`). Due to lack
+of ABA protection, this is the only way to prevent a false trigger. The symbol
+function must appear below the function calling the lock that could contend. If
+the lock is below or in the symbol function, the symbol appears in all affected
+processes, not just the one that caused the lockup.
 
-#### ro.debuggable
-device is configured for userdebug or eng build.
+## Coverage <!-- {:#coverage} -->
 
-#### ro.llk.sysrq_t
-default not ro.config.low_ram, or ro.debuggable if property is "eng".
-if true do sysrq t (dump all threads).
+The default implementation of `llkd` does not monitor `init`, `[kthreadd]`, or
+`[kthreadd]` spawns. For the `llkd` to cover `[kthreadd]`-spawned threads:
 
-#### ro.llk.enable
-default false, allow live-lock daemon to be enabled.
+* Drivers must not remain in a persistent D state,
 
-#### llk.enable
-default ro.llk.enable, and evaluated for eng.
+OR
 
-#### ro.khungtask.enable
-default false, allow [khungtask] daemon to be enabled.
+* Drivers must have mechanisms to recover the thread should it be killed
+  externally. For example, use `wait_event_interruptible()` instead of
+  `wait_event()`.
 
-#### khungtask.enable
-default ro.khungtask.enable and evaluated for eng.
+If one of the above conditions is met, the `llkd` ignorelist can be adjusted to
+cover kernel components.  Stack symbol checking involves an additional process
+ignore list to prevent sepolicy violations on services that block `ptrace`
+operations.
 
-#### ro.llk.mlockall
-default false, enable call to mlockall().
+## Android properties <!-- {:#android-properties} -->
 
-#### ro.khungtask.timeout
-default value 12 minutes, [khungtask] maximum timelimit.
+The `llkd` responds to several Android properties (listed below).
 
-#### ro.llk.timeout_ms
-default 10 minutes, D or Z maximum timelimit, double this value and it sets
-the alarm watchdog for llkd.
+* Properties named `prop_ms` are in milliseconds.
+* Properties that use comma (,) separator for lists use a leading separator to
+  preserve the default entry, then add or subtract entries with optional plus
+  (+) and minus (-) prefixes respectively. For these lists, the string "false"
+  is synonymous with an empty list, and blank or missing entries resort to the
+  specified default value.
 
-#### ro.llk.D.timeout_ms
-default ro.llk.timeout_ms, D maximum timelimit.
+### ro.config.low_ram <!-- {:#ro-config-low-ram} -->
 
-#### ro.llk.Z.timeout_ms
-default ro.llk.timeout_ms, Z maximum timelimit.
+Device is configured with limited memory.
 
-#### ro.llk.stack.timeout_ms
-default ro.llk.timeout_ms,
-checking for persistent stack symbols maximum timelimit.
-Only active on userdebug or eng builds.
+### ro.debuggable <!-- {:#ro-debuggable} -->
 
-#### ro.llk.check_ms
-default 2 minutes samples of threads for D or Z.
+Device is configured for userdebug or eng build.
 
-#### ro.llk.stack
-default cma_alloc,__get_user_pages,bit_wait_io,wait_on_page_bit_killable
-comma separated list of kernel symbols.
-Look for kernel stack symbols that if ever persistently present can
-indicate a subsystem is locked up.
-Beware, check does not on purpose do forward scheduling ABA except by polling
-every ro.llk_check_ms over the period ro.llk.stack.timeout_ms, so stack symbol
-should be exceptionally rare and fleeting.
-One must be convinced that it is virtually *impossible* for symbol to show up
-persistently in all samples of the stack.
-Again, looks for a match for either " **symbol**+0x" or " **symbol**.cfi+0x"
-in stack expansion.
-Only available on userdebug or eng builds, limited privileges due to security
-concerns on user builds prevents this checking.
+### ro.llk.sysrq_t <!-- {:#ro-llk-sysrq-t} -->
 
-#### ro.llk.blacklist.process
-default 0,1,2 (kernel, init and [kthreadd]) plus process names
-init,[kthreadd],[khungtaskd],lmkd,llkd,watchdogd,
-[watchdogd],[watchdogd/0],...,[watchdogd/***get_nprocs**-1*].
-Do not watch these processes.  A process can be comm, cmdline or pid reference.
-NB: automated default here can be larger than the current maximum property
-size of 92.
-NB: false is a very very very unlikely process to want to blacklist.
+If property is "eng", the default is not `ro.config.low_ram` or `ro.debuggable`.
+If true, dump all threads (`sysrq t`).
 
-#### ro.llk.blacklist.parent
-default 0,2,adbd&[setsid] (kernel, [kthreadd] and adbd *only for zombie setsid*).
-Do not watch processes that have this parent.
-An ampersand (*&*) separator is used to specify that the parent is ignored
-only in combination with the target child process.
-Ampersand was selected because it is never part of a process name,
-however a setprop in the shell requires it to be escaped or quoted;
-init rc file where this is normally specified does not have this issue.
-A parent or target processes can be specified as comm, cmdline or pid reference.
+### ro.llk.enable <!-- {:#ro-llk-enable} -->
 
-#### ro.llk.blacklist.uid
-default *empty* or false, comma separated list of uid numbers or names.
-Do not watch processes that match this uid.
+Allow live-lock daemon to be enabled. Default is false.
 
-#### ro.llk.blacklist.process.stack
-default process names init,lmkd.llkd,llkd,keystore,ueventd,apexd,logd.
-This subset of processes are not monitored for live lock stack signatures.
-Also prevents the sepolicy violation associated with processes that block
-ptrace, as these can not be checked anyways.
-Only active on userdebug and eng builds.
+### llk.enable <!-- {:#llk-enable} -->
 
-Architectural Concerns
-----------------------
+Evaluated for eng builds. Default is `ro.llk.enable`.
 
-- built-in [khungtask] daemon is too generic and trips on driver code that
-  sits around in D state too much.  To switch to S instead makes the task(s)
-  killable, so the drivers should be able to resurrect them if needed.
-- Properties are limited to 92 characters.
-- Create kernel module and associated gTest to actually test panic.
-- Create gTest to test out blacklist (ro.llk.blacklist.*properties* generally
-  not be inputs).  Could require more test-only interfaces to libllkd.
-- Speed up gTest using something else than ro.llk.*properties*, which should
-  not be inputs as they should be baked into the product.
+### ro.khungtask.enable <!-- {:#ro-khungtask-enable} -->
+
+Allow `[khungtask]` daemon to be enabled. Default is false.
+
+### khungtask.enable <!-- {:#khungtask-enable} -->
+
+Evaluated for eng builds. Default is `ro.khungtask.enable`.
+
+### ro.llk.mlockall <!-- {:#ro-llk-mlockall} -->
+
+Enable call to `mlockall()`. Default is false.
+
+### ro.khungtask.timeout <!-- {:#ro-khungtask-timeout} -->
+
+`[khungtask]` maximum time limit. Default is 12 minutes.
+
+### ro.llk.timeout_ms <!-- {:#ro-llk-timeout-ms} -->
+
+D or Z maximum time limit. Default is 10 minutes. Double this value to set the
+alarm watchdog for `llkd`.
+
+### ro.llk.D.timeout_ms <!-- {:#ro-llk-D-timeout-ms} -->
+
+D maximum time limit. Default is `ro.llk.timeout_ms`.
+
+### ro.llk.Z.timeout_ms <!-- {:#ro-llk-Z-timeout-ms} -->
+
+Z maximum time limit. Default is `ro.llk.timeout_ms`.
+
+### ro.llk.stack.timeout_ms <!-- {:#ro-llk-stack-timeout-ms} -->
+
+Checks for persistent stack symbols maximum time limit. Default is
+`ro.llk.timeout_ms`. **Active only on userdebug or eng builds**.
+
+### ro.llk.check_ms <!-- {:#ro-llk-check-ms} -->
+
+Samples of threads for D or Z. Default is two minutes.
+
+### ro.llk.stack <!-- {:#ro-llk-stack} -->
+
+Checks for kernel stack symbols that if persistently present can indicate a
+subsystem is locked up. Default is
+`cma_alloc,__get_user_pages,bit_wait_io,wait_on_page_bit_killable`
+comma-separated list of kernel symbols. The check doesn't do forward scheduling
+ABA except by polling every `ro.llk_check_ms` over the period
+`ro.llk.stack.timeout_ms`, so stack symbols should be exceptionally rare and
+fleeting (it is highly unlikely for a symbol to show up persistently in all
+samples of the stack). Checks for a match for `" symbol+0x"` or
+`" symbol.cfi+0x"` in stack expansion. **Available only on userdebug or eng
+builds**; security concerns on user builds result in limited privileges that
+prevent this check.
+
+### ro.llk.ignorelist.process <!-- {:#ro-llk-ignorelist-process} -->
+
+The `llkd` does not watch the specified processes. Default is `0,1,2` (`kernel`,
+`init`, and `[kthreadd]`) plus process names
+`init,[kthreadd],[khungtaskd],lmkd,llkd,watchdogd, [watchdogd],[watchdogd/0],...,[watchdogd/get_nprocs-1]`.
+A process can be a `comm`, `cmdline`, or `pid` reference. An automated default
+can be larger than the current maximum property size of 92.
+
+Note: `false` is an extremely unlikely process to want to ignore.
+
+### ro.llk.ignorelist.parent <!-- {:#ro-llk-ignorelist-parent} -->
+
+The `llkd` does not watch processes that have the specified parent(s). Default
+is `0,2,adbd&[setsid]` (`kernel`, `[kthreadd]`, and `adbd` only for zombie
+`setsid`). An ampersand (&) separator specifies that the parent is ignored only
+in combination with the target child process. Ampersand was selected because it
+is never part of a process name; however, a `setprop` in the shell requires the
+ampersand to be escaped or quoted, although the `init rc` file where this is
+normally specified does not have this issue. A parent or target process can be a
+`comm`, `cmdline`, or `pid` reference.
+
+### ro.llk.ignorelist.uid <!-- {:#ro-llk-ignorelist-uid} -->
+
+The `llkd` does not watch processes that match the specified uid(s).
+Comma-separated list of uid numbers or names. Default is empty or false.
+
+### ro.llk.ignorelist.process.stack <!-- {:#ro-llk-ignorelist-process-stack} -->
+
+The `llkd` does not monitor the specified subset of processes for live lock stack
+signatures. Default is process names
+`init,lmkd.llkd,llkd,keystore,ueventd,apexd,logd`. Prevents the sepolicy
+violation associated with processes that block `ptrace` (as these can't be
+checked). **Active only on userdebug and eng builds**. For details on build
+types, refer to [Building Android](/setup/build/building#choose-a-target).
+
+## Architectural concerns <!-- {:#architectural-concerns} -->
+
+* Properties are limited to 92 characters.  However, this is not limited for
+  defaults defined in the `include/llkd.h` file in the sources.
+* The built-in `[khungtask]` daemon is too generic and trips on driver code that
+  sits around in D state too much. Switching drivers to sleep, or S state,
+  would make task(s) killable, and need to be resurrectable by drivers on an
+  as-need basis.
+
+## Library interface (optional) <!-- {:#library-interface-optional} -->
+
+You can optionally incorporate the `llkd` into another privileged daemon using
+the following C interface from the `libllkd` component:
+
+```
+#include "llkd.h"
+bool llkInit(const char* threadname) /* return true if enabled */
+unsigned llkCheckMillseconds(void)   /* ms to sleep for next check */
+```
+
+If a threadname is provided, a thread automatically spawns, otherwise the caller
+must call `llkCheckMilliseconds` in its main loop. The function returns the
+period of time before the next expected call to this handler.
diff --git a/llkd/include/llkd.h b/llkd/include/llkd.h
index 3586ca1..4b20a56 100644
--- a/llkd/include/llkd.h
+++ b/llkd/include/llkd.h
@@ -30,37 +30,37 @@
 unsigned llkCheckMilliseconds(void);
 
 /* clang-format off */
-#define LLK_ENABLE_WRITEABLE_PROPERTY  "llk.enable"
-#define LLK_ENABLE_PROPERTY            "ro." LLK_ENABLE_WRITEABLE_PROPERTY
-#define LLK_ENABLE_DEFAULT             false /* "eng" and userdebug true */
-#define KHT_ENABLE_WRITEABLE_PROPERTY  "khungtask.enable"
-#define KHT_ENABLE_PROPERTY            "ro." KHT_ENABLE_WRITEABLE_PROPERTY
-#define LLK_ENABLE_SYSRQ_T_PROPERTY    "ro.llk.sysrq_t"
-#define LLK_ENABLE_SYSRQ_T_DEFAULT     true
-#define LLK_MLOCKALL_PROPERTY          "ro.llk.mlockall"
-#define LLK_MLOCKALL_DEFAULT           true
-#define LLK_KILLTEST_PROPERTY          "ro.llk.killtest"
-#define LLK_KILLTEST_DEFAULT           true
-#define LLK_TIMEOUT_MS_PROPERTY        "ro.llk.timeout_ms"
-#define KHT_TIMEOUT_PROPERTY           "ro.khungtask.timeout"
-#define LLK_D_TIMEOUT_MS_PROPERTY      "ro.llk.D.timeout_ms"
-#define LLK_Z_TIMEOUT_MS_PROPERTY      "ro.llk.Z.timeout_ms"
-#define LLK_STACK_TIMEOUT_MS_PROPERTY  "ro.llk.stack.timeout_ms"
-#define LLK_CHECK_MS_PROPERTY          "ro.llk.check_ms"
+#define LLK_ENABLE_WRITEABLE_PROPERTY   "llk.enable"
+#define LLK_ENABLE_PROPERTY             "ro." LLK_ENABLE_WRITEABLE_PROPERTY
+#define LLK_ENABLE_DEFAULT              false /* "eng" and userdebug true */
+#define KHT_ENABLE_WRITEABLE_PROPERTY   "khungtask.enable"
+#define KHT_ENABLE_PROPERTY             "ro." KHT_ENABLE_WRITEABLE_PROPERTY
+#define LLK_ENABLE_SYSRQ_T_PROPERTY     "ro.llk.sysrq_t"
+#define LLK_ENABLE_SYSRQ_T_DEFAULT      true
+#define LLK_MLOCKALL_PROPERTY           "ro.llk.mlockall"
+#define LLK_MLOCKALL_DEFAULT            true
+#define LLK_KILLTEST_PROPERTY           "ro.llk.killtest"
+#define LLK_KILLTEST_DEFAULT            true
+#define LLK_TIMEOUT_MS_PROPERTY         "ro.llk.timeout_ms"
+#define KHT_TIMEOUT_PROPERTY            "ro.khungtask.timeout"
+#define LLK_D_TIMEOUT_MS_PROPERTY       "ro.llk.D.timeout_ms"
+#define LLK_Z_TIMEOUT_MS_PROPERTY       "ro.llk.Z.timeout_ms"
+#define LLK_STACK_TIMEOUT_MS_PROPERTY   "ro.llk.stack.timeout_ms"
+#define LLK_CHECK_MS_PROPERTY           "ro.llk.check_ms"
 /* LLK_CHECK_MS_DEFAULT = actual timeout_ms / LLK_CHECKS_PER_TIMEOUT_DEFAULT */
-#define LLK_CHECKS_PER_TIMEOUT_DEFAULT 5
-#define LLK_CHECK_STACK_PROPERTY       "ro.llk.stack"
-#define LLK_CHECK_STACK_DEFAULT        \
+#define LLK_CHECKS_PER_TIMEOUT_DEFAULT  5
+#define LLK_CHECK_STACK_PROPERTY        "ro.llk.stack"
+#define LLK_CHECK_STACK_DEFAULT         \
     "cma_alloc,__get_user_pages,bit_wait_io,wait_on_page_bit_killable"
-#define LLK_BLACKLIST_PROCESS_PROPERTY "ro.llk.blacklist.process"
-#define LLK_BLACKLIST_PROCESS_DEFAULT  \
+#define LLK_IGNORELIST_PROCESS_PROPERTY "ro.llk.ignorelist.process"
+#define LLK_IGNORELIST_PROCESS_DEFAULT  \
     "0,1,2,init,[kthreadd],[khungtaskd],lmkd,llkd,watchdogd,[watchdogd],[watchdogd/0]"
-#define LLK_BLACKLIST_PARENT_PROPERTY  "ro.llk.blacklist.parent"
-#define LLK_BLACKLIST_PARENT_DEFAULT   "0,2,[kthreadd],adbd&[setsid]"
-#define LLK_BLACKLIST_UID_PROPERTY     "ro.llk.blacklist.uid"
-#define LLK_BLACKLIST_UID_DEFAULT      ""
-#define LLK_BLACKLIST_STACK_PROPERTY   "ro.llk.blacklist.process.stack"
-#define LLK_BLACKLIST_STACK_DEFAULT    "init,lmkd.llkd,llkd,keystore,ueventd,apexd"
+#define LLK_IGNORELIST_PARENT_PROPERTY  "ro.llk.ignorelist.parent"
+#define LLK_IGNORELIST_PARENT_DEFAULT   "0,2,[kthreadd],adbd&[setsid]"
+#define LLK_IGNORELIST_UID_PROPERTY     "ro.llk.ignorelist.uid"
+#define LLK_IGNORELIST_UID_DEFAULT      ""
+#define LLK_IGNORELIST_STACK_PROPERTY   "ro.llk.ignorelist.process.stack"
+#define LLK_IGNORELIST_STACK_DEFAULT    "init,lmkd.llkd,llkd,keystore,ueventd,apexd"
 /* clang-format on */
 
 __END_DECLS
diff --git a/llkd/libllkd.cpp b/llkd/libllkd.cpp
index 8ad9900..a24d900 100644
--- a/llkd/libllkd.cpp
+++ b/llkd/libllkd.cpp
@@ -98,26 +98,26 @@
 std::unordered_set<std::string> llkCheckStackSymbols;
 #endif
 
-// Blacklist variables, initialized with comma separated lists of high false
+// Ignorelist variables, initialized with comma separated lists of high false
 // positive and/or dangerous references, e.g. without self restart, for pid,
 // ppid, name and uid:
 
 // list of pids, or tids or names to skip. kernel pid (0), init pid (1),
 // [kthreadd] pid (2), ourselves, "init", "[kthreadd]", "lmkd", "llkd" or
 // combinations of watchdogd in kernel and user space.
-std::unordered_set<std::string> llkBlacklistProcess;
+std::unordered_set<std::string> llkIgnorelistProcess;
 // list of parent pids, comm or cmdline names to skip. default:
 // kernel pid (0), [kthreadd] (2), or ourselves, enforced and implied
-std::unordered_set<std::string> llkBlacklistParent;
+std::unordered_set<std::string> llkIgnorelistParent;
 // list of parent and target processes to skip. default:
 // adbd *and* [setsid]
-std::unordered_map<std::string, std::unordered_set<std::string>> llkBlacklistParentAndChild;
+std::unordered_map<std::string, std::unordered_set<std::string>> llkIgnorelistParentAndChild;
 // list of uids, and uid names, to skip, default nothing
-std::unordered_set<std::string> llkBlacklistUid;
+std::unordered_set<std::string> llkIgnorelistUid;
 #ifdef __PTRACE_ENABLED__
 // list of names to skip stack checking. "init", "lmkd", "llkd", "keystore" or
 // "logd" (if not userdebug).
-std::unordered_set<std::string> llkBlacklistStack;
+std::unordered_set<std::string> llkIgnorelistStack;
 #endif
 
 class dir {
@@ -626,9 +626,9 @@
     return flag ? "true" : "false";
 }
 
-std::string llkFormat(const std::unordered_set<std::string>& blacklist) {
+std::string llkFormat(const std::unordered_set<std::string>& ignorelist) {
     std::string ret;
-    for (const auto& entry : blacklist) {
+    for (const auto& entry : ignorelist) {
         if (!ret.empty()) ret += ",";
         ret += entry;
     }
@@ -636,10 +636,10 @@
 }
 
 std::string llkFormat(
-        const std::unordered_map<std::string, std::unordered_set<std::string>>& blacklist,
+        const std::unordered_map<std::string, std::unordered_set<std::string>>& ignorelist,
         bool leading_comma = false) {
     std::string ret;
-    for (const auto& entry : blacklist) {
+    for (const auto& entry : ignorelist) {
         for (const auto& target : entry.second) {
             if (leading_comma || !ret.empty()) ret += ",";
             ret += entry.first + "&" + target;
@@ -699,61 +699,61 @@
 }
 
 bool llkSkipName(const std::string& name,
-                 const std::unordered_set<std::string>& blacklist = llkBlacklistProcess) {
-    if (name.empty() || blacklist.empty()) return false;
+                 const std::unordered_set<std::string>& ignorelist = llkIgnorelistProcess) {
+    if (name.empty() || ignorelist.empty()) return false;
 
-    return blacklist.find(name) != blacklist.end();
+    return ignorelist.find(name) != ignorelist.end();
 }
 
 bool llkSkipProc(proc* procp,
-                 const std::unordered_set<std::string>& blacklist = llkBlacklistProcess) {
+                 const std::unordered_set<std::string>& ignorelist = llkIgnorelistProcess) {
     if (!procp) return false;
-    if (llkSkipName(std::to_string(procp->pid), blacklist)) return true;
-    if (llkSkipName(procp->getComm(), blacklist)) return true;
-    if (llkSkipName(procp->getCmdline(), blacklist)) return true;
-    if (llkSkipName(android::base::Basename(procp->getCmdline()), blacklist)) return true;
+    if (llkSkipName(std::to_string(procp->pid), ignorelist)) return true;
+    if (llkSkipName(procp->getComm(), ignorelist)) return true;
+    if (llkSkipName(procp->getCmdline(), ignorelist)) return true;
+    if (llkSkipName(android::base::Basename(procp->getCmdline()), ignorelist)) return true;
     return false;
 }
 
 const std::unordered_set<std::string>& llkSkipName(
         const std::string& name,
-        const std::unordered_map<std::string, std::unordered_set<std::string>>& blacklist) {
+        const std::unordered_map<std::string, std::unordered_set<std::string>>& ignorelist) {
     static const std::unordered_set<std::string> empty;
-    if (name.empty() || blacklist.empty()) return empty;
-    auto found = blacklist.find(name);
-    if (found == blacklist.end()) return empty;
+    if (name.empty() || ignorelist.empty()) return empty;
+    auto found = ignorelist.find(name);
+    if (found == ignorelist.end()) return empty;
     return found->second;
 }
 
 bool llkSkipPproc(proc* pprocp, proc* procp,
                   const std::unordered_map<std::string, std::unordered_set<std::string>>&
-                          blacklist = llkBlacklistParentAndChild) {
-    if (!pprocp || !procp || blacklist.empty()) return false;
-    if (llkSkipProc(procp, llkSkipName(std::to_string(pprocp->pid), blacklist))) return true;
-    if (llkSkipProc(procp, llkSkipName(pprocp->getComm(), blacklist))) return true;
-    if (llkSkipProc(procp, llkSkipName(pprocp->getCmdline(), blacklist))) return true;
+                          ignorelist = llkIgnorelistParentAndChild) {
+    if (!pprocp || !procp || ignorelist.empty()) return false;
+    if (llkSkipProc(procp, llkSkipName(std::to_string(pprocp->pid), ignorelist))) return true;
+    if (llkSkipProc(procp, llkSkipName(pprocp->getComm(), ignorelist))) return true;
+    if (llkSkipProc(procp, llkSkipName(pprocp->getCmdline(), ignorelist))) return true;
     return llkSkipProc(procp,
-                       llkSkipName(android::base::Basename(pprocp->getCmdline()), blacklist));
+                       llkSkipName(android::base::Basename(pprocp->getCmdline()), ignorelist));
 }
 
 bool llkSkipPid(pid_t pid) {
-    return llkSkipName(std::to_string(pid), llkBlacklistProcess);
+    return llkSkipName(std::to_string(pid), llkIgnorelistProcess);
 }
 
 bool llkSkipPpid(pid_t ppid) {
-    return llkSkipName(std::to_string(ppid), llkBlacklistParent);
+    return llkSkipName(std::to_string(ppid), llkIgnorelistParent);
 }
 
 bool llkSkipUid(uid_t uid) {
     // Match by number?
-    if (llkSkipName(std::to_string(uid), llkBlacklistUid)) {
+    if (llkSkipName(std::to_string(uid), llkIgnorelistUid)) {
         return true;
     }
 
     // Match by name?
     auto pwd = ::getpwuid(uid);
     return (pwd != nullptr) && __predict_true(pwd->pw_name != nullptr) &&
-           __predict_true(pwd->pw_name[0] != '\0') && llkSkipName(pwd->pw_name, llkBlacklistUid);
+           __predict_true(pwd->pw_name[0] != '\0') && llkSkipName(pwd->pw_name, llkIgnorelistUid);
 }
 
 bool getValidTidDir(dirent* dp, std::string* piddir) {
@@ -811,7 +811,7 @@
     }
 
     // Don't check process that are known to block ptrace, save sepolicy noise.
-    if (llkSkipProc(procp, llkBlacklistStack)) return false;
+    if (llkSkipProc(procp, llkIgnorelistStack)) return false;
     auto kernel_stack = ReadFile(piddir + "/stack");
     if (kernel_stack.empty()) {
         LOG(VERBOSE) << piddir << "/stack empty comm=" << procp->getComm()
@@ -917,12 +917,12 @@
               << LLK_CHECK_MS_PROPERTY "=" << llkFormat(llkCheckMs) << "\n"
 #ifdef __PTRACE_ENABLED__
               << LLK_CHECK_STACK_PROPERTY "=" << llkFormat(llkCheckStackSymbols) << "\n"
-              << LLK_BLACKLIST_STACK_PROPERTY "=" << llkFormat(llkBlacklistStack) << "\n"
+              << LLK_IGNORELIST_STACK_PROPERTY "=" << llkFormat(llkIgnorelistStack) << "\n"
 #endif
-              << LLK_BLACKLIST_PROCESS_PROPERTY "=" << llkFormat(llkBlacklistProcess) << "\n"
-              << LLK_BLACKLIST_PARENT_PROPERTY "=" << llkFormat(llkBlacklistParent)
-              << llkFormat(llkBlacklistParentAndChild, true) << "\n"
-              << LLK_BLACKLIST_UID_PROPERTY "=" << llkFormat(llkBlacklistUid);
+              << LLK_IGNORELIST_PROCESS_PROPERTY "=" << llkFormat(llkIgnorelistProcess) << "\n"
+              << LLK_IGNORELIST_PARENT_PROPERTY "=" << llkFormat(llkIgnorelistParent)
+              << llkFormat(llkIgnorelistParentAndChild, true) << "\n"
+              << LLK_IGNORELIST_UID_PROPERTY "=" << llkFormat(llkIgnorelistUid);
 }
 
 void* llkThread(void* obj) {
@@ -932,14 +932,14 @@
 
     std::string name = std::to_string(::gettid());
     if (!llkSkipName(name)) {
-        llkBlacklistProcess.emplace(name);
+        llkIgnorelistProcess.emplace(name);
     }
     name = static_cast<const char*>(obj);
     prctl(PR_SET_NAME, name.c_str());
     if (__predict_false(!llkSkipName(name))) {
-        llkBlacklistProcess.insert(name);
+        llkIgnorelistProcess.insert(name);
     }
-    // No longer modifying llkBlacklistProcess.
+    // No longer modifying llkIgnorelistProcess.
     llkRunning = true;
     llkLogConfig();
     while (llkRunning) {
@@ -1122,12 +1122,12 @@
             }
             if (pprocp) {
                 if (llkSkipPproc(pprocp, procp)) break;
-                if (llkSkipProc(pprocp, llkBlacklistParent)) break;
+                if (llkSkipProc(pprocp, llkIgnorelistParent)) break;
             } else {
-                if (llkSkipName(std::to_string(ppid), llkBlacklistParent)) break;
+                if (llkSkipName(std::to_string(ppid), llkIgnorelistParent)) break;
             }
 
-            if ((llkBlacklistUid.size() != 0) && llkSkipUid(procp->getUid())) {
+            if ((llkIgnorelistUid.size() != 0) && llkSkipUid(procp->getUid())) {
                 continue;
             }
 
@@ -1320,29 +1320,29 @@
     if (debuggable) {
         llkCheckStackSymbols = llkSplit(LLK_CHECK_STACK_PROPERTY, LLK_CHECK_STACK_DEFAULT);
     }
-    std::string defaultBlacklistStack(LLK_BLACKLIST_STACK_DEFAULT);
-    if (!debuggable) defaultBlacklistStack += ",logd,/system/bin/logd";
-    llkBlacklistStack = llkSplit(LLK_BLACKLIST_STACK_PROPERTY, defaultBlacklistStack);
+    std::string defaultIgnorelistStack(LLK_IGNORELIST_STACK_DEFAULT);
+    if (!debuggable) defaultIgnorelistStack += ",logd,/system/bin/logd";
+    llkIgnorelistStack = llkSplit(LLK_IGNORELIST_STACK_PROPERTY, defaultIgnorelistStack);
 #endif
-    std::string defaultBlacklistProcess(
-        std::to_string(kernelPid) + "," + std::to_string(initPid) + "," +
-        std::to_string(kthreaddPid) + "," + std::to_string(::getpid()) + "," +
-        std::to_string(::gettid()) + "," LLK_BLACKLIST_PROCESS_DEFAULT);
+    std::string defaultIgnorelistProcess(
+            std::to_string(kernelPid) + "," + std::to_string(initPid) + "," +
+            std::to_string(kthreaddPid) + "," + std::to_string(::getpid()) + "," +
+            std::to_string(::gettid()) + "," LLK_IGNORELIST_PROCESS_DEFAULT);
     if (threadname) {
-        defaultBlacklistProcess += ","s + threadname;
+        defaultIgnorelistProcess += ","s + threadname;
     }
     for (int cpu = 1; cpu < get_nprocs_conf(); ++cpu) {
-        defaultBlacklistProcess += ",[watchdog/" + std::to_string(cpu) + "]";
+        defaultIgnorelistProcess += ",[watchdog/" + std::to_string(cpu) + "]";
     }
-    llkBlacklistProcess = llkSplit(LLK_BLACKLIST_PROCESS_PROPERTY, defaultBlacklistProcess);
+    llkIgnorelistProcess = llkSplit(LLK_IGNORELIST_PROCESS_PROPERTY, defaultIgnorelistProcess);
     if (!llkSkipName("[khungtaskd]")) {  // ALWAYS ignore as special
-        llkBlacklistProcess.emplace("[khungtaskd]");
+        llkIgnorelistProcess.emplace("[khungtaskd]");
     }
-    llkBlacklistParent = llkSplit(LLK_BLACKLIST_PARENT_PROPERTY,
-                                  std::to_string(kernelPid) + "," + std::to_string(kthreaddPid) +
-                                          "," LLK_BLACKLIST_PARENT_DEFAULT);
-    // derive llkBlacklistParentAndChild by moving entries with '&' from above
-    for (auto it = llkBlacklistParent.begin(); it != llkBlacklistParent.end();) {
+    llkIgnorelistParent = llkSplit(LLK_IGNORELIST_PARENT_PROPERTY,
+                                   std::to_string(kernelPid) + "," + std::to_string(kthreaddPid) +
+                                           "," LLK_IGNORELIST_PARENT_DEFAULT);
+    // derive llkIgnorelistParentAndChild by moving entries with '&' from above
+    for (auto it = llkIgnorelistParent.begin(); it != llkIgnorelistParent.end();) {
         auto pos = it->find('&');
         if (pos == std::string::npos) {
             ++it;
@@ -1350,18 +1350,18 @@
         }
         auto parent = it->substr(0, pos);
         auto child = it->substr(pos + 1);
-        it = llkBlacklistParent.erase(it);
+        it = llkIgnorelistParent.erase(it);
 
-        auto found = llkBlacklistParentAndChild.find(parent);
-        if (found == llkBlacklistParentAndChild.end()) {
-            llkBlacklistParentAndChild.emplace(std::make_pair(
+        auto found = llkIgnorelistParentAndChild.find(parent);
+        if (found == llkIgnorelistParentAndChild.end()) {
+            llkIgnorelistParentAndChild.emplace(std::make_pair(
                     std::move(parent), std::unordered_set<std::string>({std::move(child)})));
         } else {
             found->second.emplace(std::move(child));
         }
     }
 
-    llkBlacklistUid = llkSplit(LLK_BLACKLIST_UID_PROPERTY, LLK_BLACKLIST_UID_DEFAULT);
+    llkIgnorelistUid = llkSplit(LLK_IGNORELIST_UID_PROPERTY, LLK_IGNORELIST_UID_DEFAULT);
 
     // internal watchdog
     ::signal(SIGALRM, llkAlarmHandler);
diff --git a/logcat/logcat.cpp b/logcat/logcat.cpp
index 0056c80..cf98dad 100644
--- a/logcat/logcat.cpp
+++ b/logcat/logcat.cpp
@@ -333,14 +333,14 @@
                               This can individually control each buffer's size with -b.
   -S, --statistics            Output statistics.
                               --pid can be used to provide pid specific stats.
-  -p, --prune                 Print prune white and ~black list. Service is specified as UID,
-                              UID/PID or /PID. Weighed for quicker pruning if prefix with ~,
-                              otherwise weighed for longevity if unadorned. All other pruning
-                              activity is oldest first. Special case ~! represents an automatic
-                              quicker pruning for the noisiest UID as determined by the current
-                              statistics.
-  -P, --prune='<list> ...'    Set prune white and ~black list, using same format as listed above.
-                              Must be quoted.
+  -p, --prune                 Print prune rules. Each rule is specified as UID, UID/PID or /PID. A
+                              '~' prefix indicates that elements matching the rule should be pruned
+                              with higher priority otherwise they're pruned with lower priority. All
+                              other pruning activity is oldest first. Special case ~! represents an
+                              automatic pruning for the noisiest UID as determined by the current
+                              statistics.  Special case ~1000/! represents pruning of the worst PID
+                              within AID_SYSTEM when AID_SYSTEM is the noisiest UID.
+  -P, --prune='<list> ...'    Set prune rules, using same format as listed above. Must be quoted.
 
 Filtering:
   -s                          Set default filter to silent. Equivalent to filterspec '*:S'
diff --git a/logcat/tests/logcat_test.cpp b/logcat/tests/logcat_test.cpp
index a2daeb0..61aa938 100644
--- a/logcat/tests/logcat_test.cpp
+++ b/logcat/tests/logcat_test.cpp
@@ -1301,7 +1301,7 @@
 }
 #endif
 
-static bool get_white_black(char** list) {
+static bool get_prune_rules(char** list) {
     FILE* fp = popen(logcat_executable " -p 2>/dev/null", "r");
     if (fp == NULL) {
         fprintf(stderr, "ERROR: logcat -p 2>/dev/null\n");
@@ -1334,7 +1334,7 @@
     return *list != NULL;
 }
 
-static bool set_white_black(const char* list) {
+static bool set_prune_rules(const char* list) {
     char buffer[BIG_BUFFER];
     snprintf(buffer, sizeof(buffer), logcat_executable " -P '%s' 2>&1",
              list ? list : "");
@@ -1363,28 +1363,28 @@
     return pclose(fp) == 0;
 }
 
-TEST(logcat, white_black_adjust) {
+TEST(logcat, prune_rules_adjust) {
     char* list = NULL;
     char* adjust = NULL;
 
-    get_white_black(&list);
+    get_prune_rules(&list);
 
     static const char adjustment[] = "~! 300/20 300/25 2000 ~1000/5 ~1000/30";
-    ASSERT_EQ(true, set_white_black(adjustment));
-    ASSERT_EQ(true, get_white_black(&adjust));
+    ASSERT_EQ(true, set_prune_rules(adjustment));
+    ASSERT_EQ(true, get_prune_rules(&adjust));
     EXPECT_STREQ(adjustment, adjust);
     free(adjust);
     adjust = NULL;
 
     static const char adjustment2[] = "300/20 300/21 2000 ~1000";
-    ASSERT_EQ(true, set_white_black(adjustment2));
-    ASSERT_EQ(true, get_white_black(&adjust));
+    ASSERT_EQ(true, set_prune_rules(adjustment2));
+    ASSERT_EQ(true, get_prune_rules(&adjust));
     EXPECT_STREQ(adjustment2, adjust);
     free(adjust);
     adjust = NULL;
 
-    ASSERT_EQ(true, set_white_black(list));
-    get_white_black(&adjust);
+    ASSERT_EQ(true, set_prune_rules(list));
+    get_prune_rules(&adjust);
     EXPECT_STREQ(list ? list : "", adjust ? adjust : "");
     free(adjust);
     adjust = NULL;
diff --git a/logd/Android.bp b/logd/Android.bp
index 1f6ab34..036cb7e 100644
--- a/logd/Android.bp
+++ b/logd/Android.bp
@@ -31,7 +31,11 @@
 cc_defaults {
     name: "logd_defaults",
 
-    shared_libs: ["libbase"],
+    shared_libs: [
+        "libbase",
+        "libz",
+    ],
+    static_libs: ["libzstd"],
     cflags: [
         "-Wextra",
         "-Wthread-safety",
@@ -40,6 +44,7 @@
     lto: {
         thin: true,
     },
+    cpp_std: "experimental",
 }
 
 cc_library_static {
@@ -48,12 +53,16 @@
     host_supported: true,
     srcs: [
         "ChattyLogBuffer.cpp",
+        "CompressionEngine.cpp",
         "LogReaderList.cpp",
         "LogReaderThread.cpp",
         "LogBufferElement.cpp",
         "LogStatistics.cpp",
-        "LogWhiteBlackList.cpp",
         "LogTags.cpp",
+        "PruneList.cpp",
+        "SerializedFlushToState.cpp",
+        "SerializedLogBuffer.cpp",
+        "SerializedLogChunk.cpp",
         "SimpleLogBuffer.cpp",
     ],
     logtags: ["event.logtags"],
@@ -132,6 +141,8 @@
         "ChattyLogBufferTest.cpp",
         "logd_test.cpp",
         "LogBufferTest.cpp",
+        "SerializedLogChunkTest.cpp",
+        "SerializedFlushToStateTest.cpp",
     ],
 
     static_libs: [
@@ -140,6 +151,8 @@
         "liblog",
         "liblogd",
         "libselinux",
+        "libz",
+        "libzstd",
     ],
 }
 
diff --git a/logd/ChattyLogBuffer.cpp b/logd/ChattyLogBuffer.cpp
index f92fe65..fd183e4 100644
--- a/logd/ChattyLogBuffer.cpp
+++ b/logd/ChattyLogBuffer.cpp
@@ -298,36 +298,39 @@
 // invariably move the logs value down faster as less chatty sources would be
 // expired in the noise.
 //
-// The first loop performs blacklisting and worst offender pruning. Falling
-// through when there are no notable worst offenders and have not hit the
-// region lock preventing further worst offender pruning. This loop also looks
-// after managing the chatty log entries and merging to help provide
-// statistical basis for blame. The chatty entries are not a notification of
-// how much logs you may have, but instead represent how much logs you would
-// have had in a virtual log buffer that is extended to cover all the in-memory
-// logs without loss. They last much longer than the represented pruned logs
-// since they get multiplied by the gains in the non-chatty log sources.
+// The first pass prunes elements that match 3 possible rules:
+// 1) A high priority prune rule, for example ~100/20, which indicates elements from UID 100 and PID
+//    20 should be pruned in this first pass.
+// 2) The default chatty pruning rule, ~!.  This rule sums the total size spent on log messages for
+//    each UID this log buffer.  If the highest sum consumes more than 12.5% of the log buffer, then
+//    these elements from that UID are pruned.
+// 3) The default AID_SYSTEM pruning rule, ~1000/!.  This rule is a special case to 2), if
+//    AID_SYSTEM is the top consumer of the log buffer, then this rule sums the total size spent on
+//    log messages for each PID in AID_SYSTEM in this log buffer and prunes elements from the PID
+//    with the highest sum.
+// This pass reevaluates the sums for rules 2) and 3) for every log message pruned. It creates
+// 'chatty' entries for the elements that it prunes and merges related chatty entries together. It
+// completes when one of three conditions have been met:
+// 1) The requested element count has been pruned.
+// 2) There are no elements that match any of these rules.
+// 3) A reader is referencing the oldest element that would match these rules.
 //
-// The second loop get complicated because an algorithm of watermarks and
-// history is maintained to reduce the order and keep processing time
-// down to a minimum at scale. These algorithms can be costly in the face
-// of larger log buffers, or severly limited processing time granted to a
-// background task at lowest priority.
+// The second pass prunes elements starting from the beginning of the log.  It skips elements that
+// match any low priority prune rules.  It completes when one of three conditions have been met:
+// 1) The requested element count has been pruned.
+// 2) All elements except those mwatching low priority prune rules have been pruned.
+// 3) A reader is referencing the oldest element that would match these rules.
 //
-// This second loop does straight-up expiration from the end of the logs
-// (again, remember for the specified log buffer id) but does some whitelist
-// preservation. Thus whitelist is a Hail Mary low priority, blacklists and
-// spam filtration all take priority. This second loop also checks if a region
-// lock is causing us to buffer too much in the logs to help the reader(s),
-// and will tell the slowest reader thread to skip log entries, and if
-// persistent and hits a further threshold, kill the reader thread.
+// The final pass only happens if there are any low priority prune rules and if the first two passes
+// were unable to prune the requested number of elements.  It prunes elements all starting from the
+// beginning of the log, regardless of if they match any low priority prune rules.
 //
-// The third thread is optional, and only gets hit if there was a whitelist
-// and more needs to be pruned against the backstop of the region lock.
-//
+// If the requested number of logs was unable to be pruned, KickReader() is called to mitigate the
+// situation before the next call to Prune() and the function returns false.  Otherwise, if the
+// requested number of logs or all logs present in the buffer are pruned, in the case of Clear(),
+// it returns true.
 bool ChattyLogBuffer::Prune(log_id_t id, unsigned long pruneRows, uid_t caller_uid) {
     LogReaderThread* oldest = nullptr;
-    bool busy = false;
     bool clearAll = pruneRows == ULONG_MAX;
 
     auto reader_threads_lock = std::lock_guard{reader_list()->reader_threads_lock()};
@@ -359,21 +362,20 @@
             }
 
             if (oldest && oldest->start() <= element.sequence()) {
-                busy = true;
                 KickReader(oldest, id, pruneRows);
-                break;
+                return false;
             }
 
             it = Erase(it);
             if (--pruneRows == 0) {
-                break;
+                return true;
             }
         }
-        return busy;
+        return true;
     }
 
-    // prune by worst offenders; by blacklist, UID, and by PID of system UID
-    bool hasBlacklist = (id != LOG_ID_SECURITY) && prune_->naughty();
+    // First prune pass.
+    bool check_high_priority = id != LOG_ID_SECURITY && prune_->HasHighPriorityPruneRules();
     while (!clearAll && (pruneRows > 0)) {
         // recalculate the worst offender on every batched pass
         int worst = -1;  // not valid for uid() or getKey()
@@ -381,7 +383,7 @@
         size_t second_worst_sizes = 0;
         pid_t worstPid = 0;  // POSIX guarantees PID != 0
 
-        if (worstUidEnabledForLogid(id) && prune_->worstUidEnabled()) {
+        if (worstUidEnabledForLogid(id) && prune_->worst_uid_enabled()) {
             // Calculate threshold as 12.5% of available storage
             size_t threshold = max_size(id) / 8;
 
@@ -391,14 +393,14 @@
             } else {
                 stats()->WorstTwoUids(id, threshold, &worst, &worst_sizes, &second_worst_sizes);
 
-                if (worst == AID_SYSTEM && prune_->worstPidOfSystemEnabled()) {
+                if (worst == AID_SYSTEM && prune_->worst_pid_of_system_enabled()) {
                     stats()->WorstTwoSystemPids(id, worst_sizes, &worstPid, &second_worst_sizes);
                 }
             }
         }
 
-        // skip if we have neither worst nor naughty filters
-        if ((worst == -1) && !hasBlacklist) {
+        // skip if we have neither a worst UID or high priority prune rules
+        if (worst == -1 && !check_high_priority) {
             break;
         }
 
@@ -440,7 +442,6 @@
             LogBufferElement& element = *it;
 
             if (oldest && oldest->start() <= element.sequence()) {
-                busy = true;
                 // Do not let chatty eliding trigger any reader mitigation
                 break;
             }
@@ -467,7 +468,7 @@
             int key = (id == LOG_ID_EVENTS || id == LOG_ID_SECURITY) ? element.GetTag()
                                                                      : element.uid();
 
-            if (hasBlacklist && prune_->naughty(&element)) {
+            if (check_high_priority && prune_->IsHighPriority(&element)) {
                 last.clear(&element);
                 it = Erase(it);
                 if (dropped) {
@@ -560,15 +561,17 @@
         }
         last.clear();
 
-        if (!kick || !prune_->worstUidEnabled()) {
+        if (!kick || !prune_->worst_uid_enabled()) {
             break;  // the following loop will ask bad clients to skip/drop
         }
     }
 
-    bool whitelist = false;
-    bool hasWhitelist = (id != LOG_ID_SECURITY) && prune_->nice() && !clearAll;
+    // Second prune pass.
+    bool skipped_low_priority_prune = false;
+    bool check_low_priority =
+            id != LOG_ID_SECURITY && prune_->HasLowPriorityPruneRules() && !clearAll;
     it = GetOldest(id);
-    while ((pruneRows > 0) && (it != logs().end())) {
+    while (pruneRows > 0 && it != logs().end()) {
         LogBufferElement& element = *it;
 
         if (element.log_id() != id) {
@@ -577,14 +580,12 @@
         }
 
         if (oldest && oldest->start() <= element.sequence()) {
-            busy = true;
-            if (!whitelist) KickReader(oldest, id, pruneRows);
+            if (!skipped_low_priority_prune) KickReader(oldest, id, pruneRows);
             break;
         }
 
-        if (hasWhitelist && !element.dropped_count() && prune_->nice(&element)) {
-            // WhiteListed
-            whitelist = true;
+        if (check_low_priority && !element.dropped_count() && prune_->IsLowPriority(&element)) {
+            skipped_low_priority_prune = true;
             it++;
             continue;
         }
@@ -593,10 +594,10 @@
         pruneRows--;
     }
 
-    // Do not save the whitelist if we are reader range limited
-    if (whitelist && (pruneRows > 0)) {
+    // Third prune pass.
+    if (skipped_low_priority_prune && pruneRows > 0) {
         it = GetOldest(id);
-        while ((it != logs().end()) && (pruneRows > 0)) {
+        while (it != logs().end() && pruneRows > 0) {
             LogBufferElement& element = *it;
 
             if (element.log_id() != id) {
@@ -605,7 +606,6 @@
             }
 
             if (oldest && oldest->start() <= element.sequence()) {
-                busy = true;
                 KickReader(oldest, id, pruneRows);
                 break;
             }
@@ -615,5 +615,5 @@
         }
     }
 
-    return (pruneRows > 0) && busy;
+    return pruneRows == 0 || it == logs().end();
 }
diff --git a/logd/ChattyLogBuffer.h b/logd/ChattyLogBuffer.h
index 6f60272..ce3dc7b 100644
--- a/logd/ChattyLogBuffer.h
+++ b/logd/ChattyLogBuffer.h
@@ -33,8 +33,8 @@
 #include "LogReaderThread.h"
 #include "LogStatistics.h"
 #include "LogTags.h"
-#include "LogWhiteBlackList.h"
 #include "LogWriter.h"
+#include "PruneList.h"
 #include "SimpleLogBuffer.h"
 #include "rwlock.h"
 
diff --git a/logd/CommandListener.cpp b/logd/CommandListener.cpp
index 9764c44..2eeb0d9 100644
--- a/logd/CommandListener.cpp
+++ b/logd/CommandListener.cpp
@@ -82,7 +82,7 @@
         return 0;
     }
 
-    cli->sendMsg(buf()->Clear((log_id_t)id, uid) ? "busy" : "success");
+    cli->sendMsg(buf()->Clear((log_id_t)id, uid) ? "success" : "busy");
     return 0;
 }
 
@@ -215,15 +215,13 @@
     return 0;
 }
 
-int CommandListener::GetPruneListCmd::runCommand(SocketClient* cli,
-                                                 int /*argc*/, char** /*argv*/) {
+int CommandListener::GetPruneListCmd::runCommand(SocketClient* cli, int, char**) {
     setname();
-    cli->sendMsg(PackageString(prune()->format()).c_str());
+    cli->sendMsg(PackageString(prune()->Format()).c_str());
     return 0;
 }
 
-int CommandListener::SetPruneListCmd::runCommand(SocketClient* cli, int argc,
-                                                 char** argv) {
+int CommandListener::SetPruneListCmd::runCommand(SocketClient* cli, int argc, char** argv) {
     setname();
     if (!clientHasLogCredentials(cli)) {
         cli->sendMsg("Permission Denied");
@@ -238,15 +236,12 @@
         str += argv[i];
     }
 
-    int ret = prune()->init(str.c_str());
-
-    if (ret) {
+    if (!prune()->Init(str.c_str())) {
         cli->sendMsg("Invalid");
         return 0;
     }
 
     cli->sendMsg("success");
-
     return 0;
 }
 
@@ -301,7 +296,7 @@
 
     LOG(INFO) << "logd reinit";
     buf()->Init();
-    prune()->init(nullptr);
+    prune()->Init(nullptr);
 
     // This only works on userdebug and eng devices to re-read the
     // /data/misc/logd/event-log-tags file right after /data is mounted.
diff --git a/logd/CommandListener.h b/logd/CommandListener.h
index a55a393..c3080ab 100644
--- a/logd/CommandListener.h
+++ b/logd/CommandListener.h
@@ -23,7 +23,7 @@
 #include "LogListener.h"
 #include "LogStatistics.h"
 #include "LogTags.h"
-#include "LogWhiteBlackList.h"
+#include "PruneList.h"
 
 class CommandListener : public FrameworkListener {
   public:
diff --git a/logd/CompressionEngine.cpp b/logd/CompressionEngine.cpp
new file mode 100644
index 0000000..f9c5979
--- /dev/null
+++ b/logd/CompressionEngine.cpp
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "CompressionEngine.h"
+
+#include <limits>
+
+#include <android-base/logging.h>
+#include <zlib.h>
+#include <zstd.h>
+
+CompressionEngine& CompressionEngine::GetInstance() {
+    static CompressionEngine* engine = new ZstdCompressionEngine();
+    return *engine;
+}
+
+bool ZlibCompressionEngine::Compress(std::span<uint8_t> in, std::vector<uint8_t>& out) {
+    z_stream strm;
+    strm.zalloc = Z_NULL;
+    strm.zfree = Z_NULL;
+    strm.opaque = Z_NULL;
+    int ret = deflateInit(&strm, Z_DEFAULT_COMPRESSION);
+    if (ret != Z_OK) {
+        LOG(FATAL) << "deflateInit() failed";
+    }
+
+    CHECK_LE(in.size(), static_cast<int64_t>(std::numeric_limits<uint32_t>::max()));
+    uint32_t out_size = deflateBound(&strm, in.size());
+
+    out.resize(out_size);
+    strm.avail_in = in.size();
+    strm.next_in = const_cast<uint8_t*>(in.data());
+    strm.avail_out = out_size;
+    strm.next_out = out.data();
+    ret = deflate(&strm, Z_FINISH);
+    CHECK_EQ(ret, Z_STREAM_END);
+
+    uint32_t compressed_data_size = strm.total_out;
+    deflateEnd(&strm);
+    out.resize(compressed_data_size);
+
+    return true;
+}
+
+bool ZlibCompressionEngine::Decompress(const std::vector<uint8_t>& in, std::vector<uint8_t>& out,
+                                       size_t out_size) {
+    out.resize(out_size);
+
+    z_stream strm;
+    strm.zalloc = Z_NULL;
+    strm.zfree = Z_NULL;
+    strm.opaque = Z_NULL;
+    strm.avail_in = in.size();
+    strm.next_in = const_cast<uint8_t*>(in.data());
+    strm.avail_out = out.size();
+    strm.next_out = out.data();
+
+    inflateInit(&strm);
+    int ret = inflate(&strm, Z_NO_FLUSH);
+
+    CHECK_EQ(strm.avail_in, 0U);
+    CHECK_EQ(strm.avail_out, 0U);
+    CHECK_EQ(ret, Z_STREAM_END);
+    inflateEnd(&strm);
+
+    return true;
+}
+
+bool ZstdCompressionEngine::Compress(std::span<uint8_t> in, std::vector<uint8_t>& out) {
+    size_t out_size = ZSTD_compressBound(in.size());
+    out.resize(out_size);
+
+    out_size = ZSTD_compress(out.data(), out_size, in.data(), in.size(), 1);
+    if (ZSTD_isError(out_size)) {
+        LOG(FATAL) << "ZSTD_compress failed: " << ZSTD_getErrorName(out_size);
+    }
+    out.resize(out_size);
+
+    return true;
+}
+
+bool ZstdCompressionEngine::Decompress(const std::vector<uint8_t>& in, std::vector<uint8_t>& out,
+                                       size_t out_size) {
+    out.resize(out_size);
+    size_t result = ZSTD_decompress(out.data(), out.size(), in.data(), in.size());
+    if (ZSTD_isError(result)) {
+        LOG(FATAL) << "ZSTD_decompress failed: " << ZSTD_getErrorName(result);
+    }
+    CHECK_EQ(result, out.size());
+    return true;
+}
diff --git a/logd/CompressionEngine.h b/logd/CompressionEngine.h
new file mode 100644
index 0000000..d760cea
--- /dev/null
+++ b/logd/CompressionEngine.h
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <span>
+#include <vector>
+
+class CompressionEngine {
+  public:
+    static CompressionEngine& GetInstance();
+
+    virtual ~CompressionEngine(){};
+
+    virtual bool Compress(std::span<uint8_t> in, std::vector<uint8_t>& out) = 0;
+    // Decompress the contents of `in` into `out`.  `out_size` must be set to the decompressed size
+    // of the contents.
+    virtual bool Decompress(const std::vector<uint8_t>& in, std::vector<uint8_t>& out,
+                            size_t out_size) = 0;
+};
+
+class ZlibCompressionEngine : public CompressionEngine {
+  public:
+    bool Compress(std::span<uint8_t> in, std::vector<uint8_t>& out) override;
+    bool Decompress(const std::vector<uint8_t>& in, std::vector<uint8_t>& out,
+                    size_t out_size) override;
+};
+
+class ZstdCompressionEngine : public CompressionEngine {
+  public:
+    bool Compress(std::span<uint8_t> in, std::vector<uint8_t>& out) override;
+    bool Decompress(const std::vector<uint8_t>& in, std::vector<uint8_t>& out,
+                    size_t out_size) override;
+};
\ No newline at end of file
diff --git a/logd/LogBufferElement.cpp b/logd/LogBufferElement.cpp
index ef9f1cf..dd779f9 100644
--- a/logd/LogBufferElement.cpp
+++ b/logd/LogBufferElement.cpp
@@ -61,7 +61,7 @@
     }
 }
 
-LogBufferElement::LogBufferElement(LogBufferElement&& elem)
+LogBufferElement::LogBufferElement(LogBufferElement&& elem) noexcept
     : uid_(elem.uid_),
       pid_(elem.pid_),
       tid_(elem.tid_),
@@ -134,7 +134,7 @@
     char* retval = nullptr;
     char buffer[256];
     snprintf(buffer, sizeof(buffer), "/proc/%u/comm", tid);
-    int fd = open(buffer, O_RDONLY);
+    int fd = open(buffer, O_RDONLY | O_CLOEXEC);
     if (fd >= 0) {
         ssize_t ret = read(fd, buffer, sizeof(buffer));
         if (ret >= (ssize_t)sizeof(buffer)) {
diff --git a/logd/LogBufferElement.h b/logd/LogBufferElement.h
index fd5d88f..b263ca5 100644
--- a/logd/LogBufferElement.h
+++ b/logd/LogBufferElement.h
@@ -37,7 +37,7 @@
     LogBufferElement(log_id_t log_id, log_time realtime, uid_t uid, pid_t pid, pid_t tid,
                      uint64_t sequence, const char* msg, uint16_t len);
     LogBufferElement(const LogBufferElement& elem);
-    LogBufferElement(LogBufferElement&& elem);
+    LogBufferElement(LogBufferElement&& elem) noexcept;
     ~LogBufferElement();
 
     uint32_t GetTag() const;
diff --git a/logd/LogBufferTest.cpp b/logd/LogBufferTest.cpp
index e651b4f..47d2a2f 100644
--- a/logd/LogBufferTest.cpp
+++ b/logd/LogBufferTest.cpp
@@ -26,6 +26,7 @@
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
 
+#include "LogBuffer.h"
 #include "LogReaderThread.h"
 #include "LogWriter.h"
 
@@ -240,7 +241,7 @@
         std::unique_ptr<LogWriter> test_writer(new TestWriter(&read_log_messages, &released));
         std::unique_ptr<LogReaderThread> log_reader(
                 new LogReaderThread(log_buffer_.get(), &reader_list_, std::move(test_writer), true,
-                                    0, ~0, 0, {}, 1, {}));
+                                    0, kLogMaskAll, 0, {}, 1, {}));
         reader_list_.reader_threads().emplace_back(std::move(log_reader));
     }
 
@@ -314,7 +315,7 @@
         std::unique_ptr<LogWriter> test_writer(new TestWriter(&read_log_messages, &released));
         std::unique_ptr<LogReaderThread> log_reader(
                 new LogReaderThread(log_buffer_.get(), &reader_list_, std::move(test_writer), true,
-                                    0, ~0, 0, {}, 1, {}));
+                                    0, kLogMaskAll, 0, {}, 1, {}));
         reader_list_.reader_threads().emplace_back(std::move(log_reader));
     }
 
@@ -348,7 +349,7 @@
         std::unique_ptr<LogWriter> test_writer(new TestWriter(&read_log_messages, &released));
         std::unique_ptr<LogReaderThread> log_reader(
                 new LogReaderThread(log_buffer_.get(), &reader_list_, std::move(test_writer), true,
-                                    0, ~0, 0, {}, 3, {}));
+                                    0, kLogMaskAll, 0, {}, 3, {}));
         reader_list_.reader_threads().emplace_back(std::move(log_reader));
     }
 
@@ -363,4 +364,96 @@
     CompareLogMessages(expected_log_messages, read_log_messages);
 }
 
-INSTANTIATE_TEST_CASE_P(LogBufferTests, LogBufferTest, testing::Values("chatty", "simple"));
+TEST_P(LogBufferTest, clear_logs) {
+    // Log 3 initial logs.
+    std::vector<LogMessage> log_messages = {
+            {{.pid = 1, .tid = 2, .sec = 10000, .nsec = 20001, .lid = LOG_ID_MAIN, .uid = 0},
+             "first"},
+            {{.pid = 10, .tid = 2, .sec = 10000, .nsec = 20002, .lid = LOG_ID_MAIN, .uid = 0},
+             "second"},
+            {{.pid = 100, .tid = 2, .sec = 10000, .nsec = 20003, .lid = LOG_ID_MAIN, .uid = 0},
+             "third"},
+    };
+    FixupMessages(&log_messages);
+    LogMessages(log_messages);
+
+    std::vector<LogMessage> read_log_messages;
+    bool released = false;
+
+    // Connect a blocking reader.
+    {
+        auto lock = std::unique_lock{reader_list_.reader_threads_lock()};
+        std::unique_ptr<LogWriter> test_writer(new TestWriter(&read_log_messages, &released));
+        std::unique_ptr<LogReaderThread> log_reader(
+                new LogReaderThread(log_buffer_.get(), &reader_list_, std::move(test_writer), false,
+                                    0, kLogMaskAll, 0, {}, 1, {}));
+        reader_list_.reader_threads().emplace_back(std::move(log_reader));
+    }
+
+    // Wait up to 250ms for the reader to read the first 3 logs.
+    constexpr int kMaxRetryCount = 50;
+    int count = 0;
+    for (; count < kMaxRetryCount; ++count) {
+        usleep(5000);
+        auto lock = std::unique_lock{reader_list_.reader_threads_lock()};
+        if (reader_list_.reader_threads().back()->start() == 4) {
+            break;
+        }
+    }
+    ASSERT_LT(count, kMaxRetryCount);
+
+    // Clear the log buffer.
+    log_buffer_->Clear(LOG_ID_MAIN, 0);
+
+    // Log 3 more logs.
+    std::vector<LogMessage> after_clear_messages = {
+            {{.pid = 1, .tid = 2, .sec = 10000, .nsec = 20001, .lid = LOG_ID_MAIN, .uid = 0},
+             "4th"},
+            {{.pid = 10, .tid = 2, .sec = 10000, .nsec = 20002, .lid = LOG_ID_MAIN, .uid = 0},
+             "5th"},
+            {{.pid = 100, .tid = 2, .sec = 10000, .nsec = 20003, .lid = LOG_ID_MAIN, .uid = 0},
+             "6th"},
+    };
+    FixupMessages(&after_clear_messages);
+    LogMessages(after_clear_messages);
+
+    // Wait up to 250ms for the reader to read the 3 additional logs.
+    for (count = 0; count < kMaxRetryCount; ++count) {
+        usleep(5000);
+        auto lock = std::unique_lock{reader_list_.reader_threads_lock()};
+        if (reader_list_.reader_threads().back()->start() == 7) {
+            break;
+        }
+    }
+    ASSERT_LT(count, kMaxRetryCount);
+
+    // Release the reader, wait for it to get the signal then check that it has been deleted.
+    {
+        auto lock = std::unique_lock{reader_list_.reader_threads_lock()};
+        reader_list_.reader_threads().back()->release_Locked();
+    }
+    while (!released) {
+        usleep(5000);
+    }
+    {
+        auto lock = std::unique_lock{reader_list_.reader_threads_lock()};
+        EXPECT_EQ(0U, reader_list_.reader_threads().size());
+    }
+
+    // Check that we have read all 6 messages.
+    std::vector<LogMessage> expected_log_messages = log_messages;
+    expected_log_messages.insert(expected_log_messages.end(), after_clear_messages.begin(),
+                                 after_clear_messages.end());
+    CompareLogMessages(expected_log_messages, read_log_messages);
+
+    // Finally, call FlushTo and ensure that only the 3 logs after the clear remain in the buffer.
+    std::vector<LogMessage> read_log_messages_after_clear;
+    std::unique_ptr<LogWriter> test_writer(new TestWriter(&read_log_messages_after_clear, nullptr));
+    std::unique_ptr<FlushToState> flush_to_state = log_buffer_->CreateFlushToState(1, kLogMaskAll);
+    EXPECT_TRUE(log_buffer_->FlushTo(test_writer.get(), *flush_to_state, nullptr));
+    EXPECT_EQ(7ULL, flush_to_state->start());
+    CompareLogMessages(after_clear_messages, read_log_messages_after_clear);
+}
+
+INSTANTIATE_TEST_CASE_P(LogBufferTests, LogBufferTest,
+                        testing::Values("chatty", "serialized", "simple"));
diff --git a/logd/LogBufferTest.h b/logd/LogBufferTest.h
index f91a1b5..5d57ad1 100644
--- a/logd/LogBufferTest.h
+++ b/logd/LogBufferTest.h
@@ -25,7 +25,8 @@
 #include "LogReaderList.h"
 #include "LogStatistics.h"
 #include "LogTags.h"
-#include "LogWhiteBlackList.h"
+#include "PruneList.h"
+#include "SerializedLogBuffer.h"
 #include "SimpleLogBuffer.h"
 
 struct LogMessage {
@@ -67,6 +68,8 @@
     void SetUp() override {
         if (GetParam() == "chatty") {
             log_buffer_.reset(new ChattyLogBuffer(&reader_list_, &tags_, &prune_, &stats_));
+        } else if (GetParam() == "serialized") {
+            log_buffer_.reset(new SerializedLogBuffer(&reader_list_, &tags_, &stats_));
         } else if (GetParam() == "simple") {
             log_buffer_.reset(new SimpleLogBuffer(&reader_list_, &tags_, &stats_));
         } else {
diff --git a/logd/LogKlog.cpp b/logd/LogKlog.cpp
index 1ea87a9..dbdf7fd 100644
--- a/logd/LogKlog.cpp
+++ b/logd/LogKlog.cpp
@@ -665,10 +665,9 @@
         ((size == 2) && (isdigit(tag[0]) || isdigit(tag[1]))) ||
         // register names like x18 but not driver names like en0
         ((size == 3) && (isdigit(tag[1]) && isdigit(tag[2]))) ||
-        // blacklist
+        // ignore
         ((size == cpuLen) && !fastcmp<strncmp>(tag, cpu, cpuLen)) ||
-        ((size == warningLen) &&
-         !fastcmp<strncasecmp>(tag, warning, warningLen)) ||
+        ((size == warningLen) && !fastcmp<strncasecmp>(tag, warning, warningLen)) ||
         ((size == errorLen) && !fastcmp<strncasecmp>(tag, error, errorLen)) ||
         ((size == infoLen) && !fastcmp<strncasecmp>(tag, info, infoLen))) {
         p = start;
diff --git a/logd/LogListener.h b/logd/LogListener.h
index c114e38..566af5b 100644
--- a/logd/LogListener.h
+++ b/logd/LogListener.h
@@ -20,7 +20,7 @@
 
 class LogListener {
   public:
-    LogListener(LogBuffer* buf);
+    explicit LogListener(LogBuffer* buf);
     bool StartListener();
 
   private:
diff --git a/logd/LogPermissions.cpp b/logd/LogPermissions.cpp
index 8f02d5a..3fd0ea1 100644
--- a/logd/LogPermissions.cpp
+++ b/logd/LogPermissions.cpp
@@ -89,7 +89,7 @@
     //
     for (int retry = 3; !(ret = foundGid && foundUid && foundLog) && retry;
          --retry) {
-        FILE* file = fopen(filename, "r");
+        FILE* file = fopen(filename, "re");
         if (!file) {
             continue;
         }
diff --git a/logd/LogReader.cpp b/logd/LogReader.cpp
index f71133d..6c97693 100644
--- a/logd/LogReader.cpp
+++ b/logd/LogReader.cpp
@@ -127,7 +127,7 @@
     if (cp) {
         logMask = 0;
         cp += sizeof(_logIds) - 1;
-        while (*cp && *cp != '\0') {
+        while (*cp != '\0') {
             int val = 0;
             while (isdigit(*cp)) {
                 val = val * 10 + *cp - '0';
diff --git a/logd/LogReaderThread.cpp b/logd/LogReaderThread.cpp
index dc8582d..4a8be01 100644
--- a/logd/LogReaderThread.cpp
+++ b/logd/LogReaderThread.cpp
@@ -25,8 +25,6 @@
 #include "LogBuffer.h"
 #include "LogReaderList.h"
 
-using namespace std::placeholders;
-
 LogReaderThread::LogReaderThread(LogBuffer* log_buffer, LogReaderList* reader_list,
                                  std::unique_ptr<LogWriter> writer, bool non_block,
                                  unsigned long tail, LogMask log_mask, pid_t pid,
diff --git a/logd/LogReaderThread.h b/logd/LogReaderThread.h
index bf70b94..1855c0e 100644
--- a/logd/LogReaderThread.h
+++ b/logd/LogReaderThread.h
@@ -60,6 +60,7 @@
     std::string name() const { return writer_->name(); }
     uint64_t start() const { return flush_to_state_->start(); }
     std::chrono::steady_clock::time_point deadline() const { return deadline_; }
+    FlushToState& flush_to_state() { return *flush_to_state_; }
 
   private:
     void ThreadFunction();
diff --git a/logd/LogStatistics.cpp b/logd/LogStatistics.cpp
index d49982a..3cd8fde 100644
--- a/logd/LogStatistics.cpp
+++ b/logd/LogStatistics.cpp
@@ -88,7 +88,7 @@
     } else {
         char buffer[512];
         snprintf(buffer, sizeof(buffer), "/proc/%u/cmdline", pid);
-        int fd = open(buffer, O_RDONLY);
+        int fd = open(buffer, O_RDONLY | O_CLOEXEC);
         if (fd >= 0) {
             ssize_t ret = read(fd, buffer, sizeof(buffer));
             if (ret > 0) {
@@ -944,7 +944,7 @@
 uid_t pidToUid(pid_t pid) {
     char buffer[512];
     snprintf(buffer, sizeof(buffer), "/proc/%u/status", pid);
-    FILE* fp = fopen(buffer, "r");
+    FILE* fp = fopen(buffer, "re");
     if (fp) {
         while (fgets(buffer, sizeof(buffer), fp)) {
             int uid = AID_LOGD;
diff --git a/logd/LogStatistics.h b/logd/LogStatistics.h
index 200c228..5f55802 100644
--- a/logd/LogStatistics.h
+++ b/logd/LogStatistics.h
@@ -128,9 +128,9 @@
             if (++index < (ssize_t)len) {
                 size_t num = len - index - 1;
                 if (num) {
-                    memmove(&out_keys[index + 1], &out_keys[index], num * sizeof(out_keys[0]));
+                    memmove(&out_keys[index + 1], &out_keys[index], num * sizeof(const TKey*));
                     memmove(&out_entries[index + 1], &out_entries[index],
-                            num * sizeof(out_entries[0]));
+                            num * sizeof(const TEntry*));
                 }
                 out_keys[index] = &key;
                 out_entries[index] = &entry;
@@ -477,15 +477,15 @@
                       tagNameTable.sizeOf() +
                       (pidTable.size() * sizeof(pidTable_t::iterator)) +
                       (tagTable.size() * sizeof(tagTable_t::iterator));
-        for (auto it : pidTable) {
+        for (const auto& it : pidTable) {
             const char* name = it.second.name();
             if (name) size += strlen(name) + 1;
         }
-        for (auto it : tidTable) {
+        for (const auto& it : tidTable) {
             const char* name = it.second.name();
             if (name) size += strlen(name) + 1;
         }
-        for (auto it : tagNameTable) {
+        for (const auto& it : tagNameTable) {
             size += sizeof(std::string);
             size_t len = it.first.size();
             // Account for short string optimization: if the string's length is <= 22 bytes for 64
@@ -505,7 +505,7 @@
     }
 
   public:
-    LogStatistics(bool enable_statistics);
+    explicit LogStatistics(bool enable_statistics);
 
     void AddTotal(log_id_t log_id, uint16_t size) EXCLUDES(lock_);
     void Add(const LogStatisticsElement& entry) EXCLUDES(lock_);
diff --git a/logd/LogWhiteBlackList.cpp b/logd/LogWhiteBlackList.cpp
deleted file mode 100644
index 88a3bdc..0000000
--- a/logd/LogWhiteBlackList.cpp
+++ /dev/null
@@ -1,265 +0,0 @@
-/*
- * Copyright (C) 2014 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include <ctype.h>
-
-#include <android-base/properties.h>
-#include <android-base/stringprintf.h>
-
-#include "LogWhiteBlackList.h"
-
-Prune::Prune(uid_t uid, pid_t pid) : mUid(uid), mPid(pid) {
-}
-
-int Prune::cmp(uid_t uid, pid_t pid) const {
-    if ((mUid == uid_all) || (mUid == uid)) {
-        if (mPid == pid_all) {
-            return 0;
-        }
-        return pid - mPid;
-    }
-    return uid - mUid;
-}
-
-std::string Prune::format() {
-    if (mUid != uid_all) {
-        if (mPid != pid_all) {
-            return android::base::StringPrintf("%u/%u", mUid, mPid);
-        }
-        return android::base::StringPrintf("%u", mUid);
-    }
-    if (mPid != pid_all) {
-        return android::base::StringPrintf("/%u", mPid);
-    }
-    // NB: mPid == pid_all can not happen if mUid == uid_all
-    return std::string("/");
-}
-
-PruneList::PruneList() {
-    init(nullptr);
-}
-
-PruneList::~PruneList() {
-    PruneCollection::iterator it;
-    for (it = mNice.begin(); it != mNice.end();) {
-        it = mNice.erase(it);
-    }
-    for (it = mNaughty.begin(); it != mNaughty.end();) {
-        it = mNaughty.erase(it);
-    }
-}
-
-int PruneList::init(const char* str) {
-    mWorstUidEnabled = true;
-    mWorstPidOfSystemEnabled = true;
-    PruneCollection::iterator it;
-    for (it = mNice.begin(); it != mNice.end();) {
-        it = mNice.erase(it);
-    }
-    for (it = mNaughty.begin(); it != mNaughty.end();) {
-        it = mNaughty.erase(it);
-    }
-
-    // default here means take ro.logd.filter, persist.logd.filter then
-    // internal default in that order.
-    if (str && !strcmp(str, "default")) {
-        str = nullptr;
-    }
-    if (str && !strcmp(str, "disable")) {
-        str = "";
-    }
-
-    std::string filter;
-
-    if (str) {
-        filter = str;
-    } else {
-        filter = android::base::GetProperty("ro.logd.filter", "default");
-        auto persist_filter = android::base::GetProperty("persist.logd.filter", "default");
-        // default here means take ro.logd.filter
-        if (persist_filter != "default") {
-            filter = persist_filter;
-        }
-    }
-
-    // default here means take internal default.
-    if (filter == "default") {
-        // See README.property for description of filter format
-        filter = "~! ~1000/!";
-    }
-    if (filter == "disable") {
-        filter = "";
-    }
-
-    mWorstUidEnabled = false;
-    mWorstPidOfSystemEnabled = false;
-
-    for (str = filter.c_str(); *str; ++str) {
-        if (isspace(*str)) {
-            continue;
-        }
-
-        PruneCollection* list;
-        if ((*str == '~') || (*str == '!')) {  // ~ supported, ! undocumented
-            ++str;
-            // special case, translates to worst UID at priority in blacklist
-            if (*str == '!') {
-                mWorstUidEnabled = true;
-                ++str;
-                if (!*str) {
-                    break;
-                }
-                if (!isspace(*str)) {
-                    return 1;
-                }
-                continue;
-            }
-            // special case, translated to worst PID of System at priority
-            static const char worstPid[] = "1000/!";
-            if (!strncmp(str, worstPid, sizeof(worstPid) - 1)) {
-                mWorstPidOfSystemEnabled = true;
-                str += sizeof(worstPid) - 1;
-                if (!*str) {
-                    break;
-                }
-                if (!isspace(*str)) {
-                    return 1;
-                }
-                continue;
-            }
-            if (!*str) {
-                return 1;
-            }
-            list = &mNaughty;
-        } else {
-            list = &mNice;
-        }
-
-        uid_t uid = Prune::uid_all;
-        if (isdigit(*str)) {
-            uid = 0;
-            do {
-                uid = uid * 10 + *str++ - '0';
-            } while (isdigit(*str));
-        }
-
-        pid_t pid = Prune::pid_all;
-        if (*str == '/') {
-            ++str;
-            if (isdigit(*str)) {
-                pid = 0;
-                do {
-                    pid = pid * 10 + *str++ - '0';
-                } while (isdigit(*str));
-            }
-        }
-
-        if ((uid == Prune::uid_all) && (pid == Prune::pid_all)) {
-            return 1;
-        }
-
-        if (*str && !isspace(*str)) {
-            return 1;
-        }
-
-        // insert sequentially into list
-        PruneCollection::iterator it = list->begin();
-        while (it != list->end()) {
-            Prune& p = *it;
-            int m = uid - p.mUid;
-            if (m == 0) {
-                if (p.mPid == p.pid_all) {
-                    break;
-                }
-                if ((pid == p.pid_all) && (p.mPid != p.pid_all)) {
-                    it = list->erase(it);
-                    continue;
-                }
-                m = pid - p.mPid;
-            }
-            if (m <= 0) {
-                if (m < 0) {
-                    list->insert(it, Prune(uid, pid));
-                }
-                break;
-            }
-            ++it;
-        }
-        if (it == list->end()) {
-            list->push_back(Prune(uid, pid));
-        }
-        if (!*str) {
-            break;
-        }
-    }
-
-    return 0;
-}
-
-std::string PruneList::format() {
-    static const char nice_format[] = " %s";
-    const char* fmt = nice_format + 1;
-
-    std::string string;
-
-    if (mWorstUidEnabled) {
-        string = "~!";
-        fmt = nice_format;
-        if (mWorstPidOfSystemEnabled) {
-            string += " ~1000/!";
-        }
-    }
-
-    PruneCollection::iterator it;
-
-    for (it = mNice.begin(); it != mNice.end(); ++it) {
-        string += android::base::StringPrintf(fmt, (*it).format().c_str());
-        fmt = nice_format;
-    }
-
-    static const char naughty_format[] = " ~%s";
-    fmt = naughty_format + (*fmt != ' ');
-    for (it = mNaughty.begin(); it != mNaughty.end(); ++it) {
-        string += android::base::StringPrintf(fmt, (*it).format().c_str());
-        fmt = naughty_format;
-    }
-
-    return string;
-}
-
-// ToDo: Lists are in sorted order, Prune->cmp() returns + or -
-// If there is scaling issues, resort to a better algorithm than linear
-// based on these assumptions.
-
-bool PruneList::naughty(LogBufferElement* element) {
-    PruneCollection::iterator it;
-    for (it = mNaughty.begin(); it != mNaughty.end(); ++it) {
-        if (!(*it).cmp(element)) {
-            return true;
-        }
-    }
-    return false;
-}
-
-bool PruneList::nice(LogBufferElement* element) {
-    PruneCollection::iterator it;
-    for (it = mNice.begin(); it != mNice.end(); ++it) {
-        if (!(*it).cmp(element)) {
-            return true;
-        }
-    }
-    return false;
-}
diff --git a/logd/LogWhiteBlackList.h b/logd/LogWhiteBlackList.h
deleted file mode 100644
index 447ab87..0000000
--- a/logd/LogWhiteBlackList.h
+++ /dev/null
@@ -1,81 +0,0 @@
-/*
- * Copyright (C) 2014 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#pragma once
-
-#include <sys/types.h>
-
-#include <string.h>
-#include <list>
-
-#include "LogBufferElement.h"
-
-class Prune {
-    friend class PruneList;
-
-    const uid_t mUid;
-    const pid_t mPid;
-    int cmp(uid_t uid, pid_t pid) const;
-
-   public:
-    static const uid_t uid_all = (uid_t)-1;
-    static const pid_t pid_all = (pid_t)-1;
-
-    Prune(uid_t uid, pid_t pid);
-
-    uid_t getUid() const {
-        return mUid;
-    }
-    pid_t getPid() const {
-        return mPid;
-    }
-
-    int cmp(LogBufferElement* e) const { return cmp(e->uid(), e->pid()); }
-
-    std::string format();
-};
-
-typedef std::list<Prune> PruneCollection;
-
-class PruneList {
-    PruneCollection mNaughty;
-    PruneCollection mNice;
-    bool mWorstUidEnabled;
-    bool mWorstPidOfSystemEnabled;
-
-   public:
-    PruneList();
-    ~PruneList();
-
-    int init(const char* str);
-
-    bool naughty(LogBufferElement* element);
-    bool naughty(void) {
-        return !mNaughty.empty();
-    }
-    bool nice(LogBufferElement* element);
-    bool nice(void) {
-        return !mNice.empty();
-    }
-    bool worstUidEnabled() const {
-        return mWorstUidEnabled;
-    }
-    bool worstPidOfSystemEnabled() const {
-        return mWorstPidOfSystemEnabled;
-    }
-
-    std::string format();
-};
diff --git a/logd/PruneList.cpp b/logd/PruneList.cpp
new file mode 100644
index 0000000..c3859f3
--- /dev/null
+++ b/logd/PruneList.cpp
@@ -0,0 +1,201 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "PruneList.h"
+
+#include <ctype.h>
+
+#include <android-base/logging.h>
+#include <android-base/properties.h>
+#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
+
+bool Prune::Matches(LogBufferElement* element) const {
+    return (uid_ == UID_ALL || uid_ == element->uid()) &&
+           (pid_ == PID_ALL || pid_ == element->pid());
+}
+
+std::string Prune::Format() const {
+    if (uid_ != UID_ALL) {
+        if (pid_ != PID_ALL) {
+            return android::base::StringPrintf("%u/%u", uid_, pid_);
+        }
+        return android::base::StringPrintf("%u", uid_);
+    }
+    if (pid_ != PID_ALL) {
+        return android::base::StringPrintf("/%u", pid_);
+    }
+    // NB: pid_ == PID_ALL can not happen if uid_ == UID_ALL
+    return std::string("/");
+}
+
+PruneList::PruneList() {
+    Init(nullptr);
+}
+
+bool PruneList::Init(const char* str) {
+    high_priority_prune_.clear();
+    low_priority_prune_.clear();
+
+    // default here means take ro.logd.filter, persist.logd.filter then internal default in order.
+    if (str && !strcmp(str, "default")) {
+        str = nullptr;
+    }
+    if (str && !strcmp(str, "disable")) {
+        str = "";
+    }
+
+    std::string filter;
+
+    if (str) {
+        filter = str;
+    } else {
+        filter = android::base::GetProperty("ro.logd.filter", "default");
+        auto persist_filter = android::base::GetProperty("persist.logd.filter", "default");
+        // default here means take ro.logd.filter
+        if (persist_filter != "default") {
+            filter = persist_filter;
+        }
+    }
+
+    // default here means take internal default.
+    if (filter == "default") {
+        filter = "~! ~1000/!";
+    }
+    if (filter == "disable") {
+        filter = "";
+    }
+
+    worst_uid_enabled_ = false;
+    worst_pid_of_system_enabled_ = false;
+
+    for (str = filter.c_str(); *str; ++str) {
+        if (isspace(*str)) {
+            continue;
+        }
+
+        std::list<Prune>* list;
+        if (*str == '~' || *str == '!') {  // ~ supported, ! undocumented
+            ++str;
+            // special case, prune the worst UID of those using at least 1/8th of the buffer.
+            if (*str == '!') {
+                worst_uid_enabled_ = true;
+                ++str;
+                if (!*str) {
+                    break;
+                }
+                if (!isspace(*str)) {
+                    LOG(ERROR) << "Nothing expected after '~!', but found '" << str << "'";
+                    return false;
+                }
+                continue;
+            }
+            // special case, translated to worst PID of System at priority
+            static const char WORST_SYSTEM_PID[] = "1000/!";
+            if (!strncmp(str, WORST_SYSTEM_PID, sizeof(WORST_SYSTEM_PID) - 1)) {
+                worst_pid_of_system_enabled_ = true;
+                str += sizeof(WORST_SYSTEM_PID) - 1;
+                if (!*str) {
+                    break;
+                }
+                if (!isspace(*str)) {
+                    LOG(ERROR) << "Nothing expected after '~1000/!', but found '" << str << "'";
+                    return false;
+                }
+                continue;
+            }
+            if (!*str) {
+                LOG(ERROR) << "Expected UID or PID after '~', but found nothing";
+                return false;
+            }
+            list = &high_priority_prune_;
+        } else {
+            list = &low_priority_prune_;
+        }
+
+        uid_t uid = Prune::UID_ALL;
+        if (isdigit(*str)) {
+            uid = 0;
+            do {
+                uid = uid * 10 + *str++ - '0';
+            } while (isdigit(*str));
+        }
+
+        pid_t pid = Prune::PID_ALL;
+        if (*str == '/') {
+            ++str;
+            if (isdigit(*str)) {
+                pid = 0;
+                do {
+                    pid = pid * 10 + *str++ - '0';
+                } while (isdigit(*str));
+            }
+        }
+
+        if (uid == Prune::UID_ALL && pid == Prune::PID_ALL) {
+            LOG(ERROR) << "Expected UID/PID combination, but found none";
+            return false;
+        }
+
+        if (*str && !isspace(*str)) {
+            LOG(ERROR) << "Nothing expected after UID/PID combination, but found '" << str << "'";
+            return false;
+        }
+
+        list->emplace_back(uid, pid);
+        if (!*str) {
+            break;
+        }
+    }
+
+    return true;
+}
+
+std::string PruneList::Format() const {
+    std::vector<std::string> prune_rules;
+
+    if (worst_uid_enabled_) {
+        prune_rules.emplace_back("~!");
+    }
+    if (worst_pid_of_system_enabled_) {
+        prune_rules.emplace_back("~1000/!");
+    }
+    for (const auto& rule : low_priority_prune_) {
+        prune_rules.emplace_back(rule.Format());
+    }
+    for (const auto& rule : high_priority_prune_) {
+        prune_rules.emplace_back("~" + rule.Format());
+    }
+    return android::base::Join(prune_rules, " ");
+}
+
+bool PruneList::IsHighPriority(LogBufferElement* element) const {
+    for (const auto& rule : high_priority_prune_) {
+        if (rule.Matches(element)) {
+            return true;
+        }
+    }
+    return false;
+}
+
+bool PruneList::IsLowPriority(LogBufferElement* element) const {
+    for (const auto& rule : low_priority_prune_) {
+        if (rule.Matches(element)) {
+            return true;
+        }
+    }
+    return false;
+}
diff --git a/logd/PruneList.h b/logd/PruneList.h
new file mode 100644
index 0000000..94de5c5
--- /dev/null
+++ b/logd/PruneList.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <sys/types.h>
+
+#include <string.h>
+#include <list>
+
+#include "LogBufferElement.h"
+
+class Prune {
+  public:
+    static const uid_t UID_ALL = (uid_t)-1;
+    static const pid_t PID_ALL = (pid_t)-1;
+
+    Prune(uid_t uid, pid_t pid) : uid_(uid), pid_(pid) {}
+
+    bool Matches(LogBufferElement* element) const;
+    std::string Format() const;
+
+    uid_t uid() const { return uid_; }
+    pid_t pid() const { return pid_; }
+
+  private:
+    const uid_t uid_;
+    const pid_t pid_;
+};
+
+class PruneList {
+  public:
+    PruneList();
+
+    bool Init(const char* str);
+    std::string Format() const;
+
+    bool IsHighPriority(LogBufferElement* element) const;
+    bool IsLowPriority(LogBufferElement* element) const;
+
+    bool HasHighPriorityPruneRules() const { return !high_priority_prune_.empty(); }
+    bool HasLowPriorityPruneRules() const { return !low_priority_prune_.empty(); }
+
+    bool worst_uid_enabled() const { return worst_uid_enabled_; }
+    bool worst_pid_of_system_enabled() const { return worst_pid_of_system_enabled_; }
+
+  private:
+    std::list<Prune> high_priority_prune_;
+    std::list<Prune> low_priority_prune_;
+
+    bool worst_uid_enabled_;
+    bool worst_pid_of_system_enabled_;
+};
diff --git a/logd/README.property b/logd/README.property
index 6a9369a..ab9c4d4 100644
--- a/logd/README.property
+++ b/logd/README.property
@@ -65,8 +65,8 @@
 - number - support multipliers (K or M) for convenience. Range is limited
   to between 64K and 256M for log buffer sizes. Individual log buffer ids
   such as main, system, ... override global default.
-- Pruning filter is of form of a space-separated list of [~][UID][/PID]
-  references, where '~' prefix means to blacklist otherwise whitelist. For
-  blacklisting, UID or PID may be a '!' to instead reference the chattiest
-  client, with the restriction that the PID must be in the UID group 1000
-  (system or AID_SYSTEM).
+- Pruning filter rules are specified as UID, UID/PID or /PID. A '~' prefix indicates that elements
+  matching the rule should be pruned with higher priority otherwise they're pruned with lower
+  priority. All other pruning activity is oldest first. Special case ~! represents an automatic
+  pruning for the noisiest UID as determined by the current statistics.  Special case ~1000/!
+  represents pruning of the worst PID within AID_SYSTEM when AID_SYSTEM is the noisiest UID.
diff --git a/logd/SerializedFlushToState.cpp b/logd/SerializedFlushToState.cpp
new file mode 100644
index 0000000..6e2e8b0
--- /dev/null
+++ b/logd/SerializedFlushToState.cpp
@@ -0,0 +1,158 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "SerializedFlushToState.h"
+
+#include <android-base/logging.h>
+
+SerializedFlushToState::SerializedFlushToState(uint64_t start, LogMask log_mask)
+    : FlushToState(start, log_mask) {
+    log_id_for_each(i) {
+        if (((1 << i) & log_mask) == 0) {
+            continue;
+        }
+        logs_needed_from_next_position_[i] = true;
+    }
+}
+
+SerializedFlushToState::~SerializedFlushToState() {
+    log_id_for_each(i) {
+        if (log_positions_[i]) {
+            log_positions_[i]->buffer_it->DecReaderRefCount(true);
+        }
+    }
+}
+
+void SerializedFlushToState::CreateLogPosition(log_id_t log_id) {
+    CHECK(!logs_[log_id].empty());
+    LogPosition log_position;
+    auto it = logs_[log_id].begin();
+    while (it != logs_[log_id].end() && start() > it->highest_sequence_number()) {
+        ++it;
+    }
+    if (it == logs_[log_id].end()) {
+        --it;
+    }
+    it->IncReaderRefCount();
+    log_position.buffer_it = it;
+
+    // Find the offset of the first log with sequence number >= start().
+    int read_offset = 0;
+    while (read_offset < it->write_offset()) {
+        const auto* entry = it->log_entry(read_offset);
+        if (entry->sequence() >= start()) {
+            break;
+        }
+        read_offset += entry->total_len();
+    }
+    log_position.read_offset = read_offset;
+
+    log_positions_[log_id].emplace(log_position);
+}
+
+void SerializedFlushToState::AddMinHeapEntry(log_id_t log_id) {
+    auto& buffer_it = log_positions_[log_id]->buffer_it;
+    auto read_offset = log_positions_[log_id]->read_offset;
+
+    // If there is another log to read in this buffer, add it to the min heap.
+    if (read_offset < buffer_it->write_offset()) {
+        auto* entry = buffer_it->log_entry(read_offset);
+        min_heap_.emplace(log_id, entry);
+    } else if (read_offset == buffer_it->write_offset()) {
+        // If there are no more logs to read in this buffer and it's the last buffer, then
+        // set logs_needed_from_next_position_ to wait until more logs get logged.
+        if (buffer_it == std::prev(logs_[log_id].end())) {
+            logs_needed_from_next_position_[log_id] = true;
+        } else {
+            // Otherwise, if there is another buffer piece, move to that and do the same check.
+            buffer_it->DecReaderRefCount(true);
+            ++buffer_it;
+            buffer_it->IncReaderRefCount();
+            log_positions_[log_id]->read_offset = 0;
+            if (buffer_it->write_offset() == 0) {
+                logs_needed_from_next_position_[log_id] = true;
+            } else {
+                auto* entry = buffer_it->log_entry(0);
+                min_heap_.emplace(log_id, entry);
+            }
+        }
+    } else {
+        // read_offset > buffer_it->write_offset() should never happen.
+        CHECK(false);
+    }
+}
+
+void SerializedFlushToState::CheckForNewLogs() {
+    log_id_for_each(i) {
+        if (!logs_needed_from_next_position_[i]) {
+            continue;
+        }
+        if (!log_positions_[i]) {
+            if (logs_[i].empty()) {
+                continue;
+            }
+            CreateLogPosition(i);
+        }
+        logs_needed_from_next_position_[i] = false;
+        // If it wasn't possible to insert, logs_needed_from_next_position will be set back to true.
+        AddMinHeapEntry(i);
+    }
+}
+
+MinHeapElement SerializedFlushToState::PopNextUnreadLog() {
+    auto top = min_heap_.top();
+    min_heap_.pop();
+
+    auto* entry = top.entry;
+    auto log_id = top.log_id;
+
+    log_positions_[log_id]->read_offset += entry->total_len();
+
+    AddMinHeapEntry(log_id);
+
+    return top;
+}
+
+void SerializedFlushToState::Prune(log_id_t log_id,
+                                   const std::list<SerializedLogChunk>::iterator& buffer_it) {
+    // If we don't have a position for this log or if we're not referencing buffer_it, ignore.
+    if (!log_positions_[log_id].has_value() || log_positions_[log_id]->buffer_it != buffer_it) {
+        return;
+    }
+
+    // // Decrease the ref count since we're deleting our reference.
+    buffer_it->DecReaderRefCount(false);
+
+    // Delete in the reference.
+    log_positions_[log_id].reset();
+
+    // Remove the MinHeapElement referencing log_id, if it exists, but retain the others.
+    std::vector<MinHeapElement> old_elements;
+    while (!min_heap_.empty()) {
+        auto& element = min_heap_.top();
+        if (element.log_id != log_id) {
+            old_elements.emplace_back(element);
+        }
+        min_heap_.pop();
+    }
+    for (auto&& element : old_elements) {
+        min_heap_.emplace(element);
+    }
+
+    // Finally set logs_needed_from_next_position_, so CheckForNewLogs() will re-create the
+    // log_position_ object during the next read.
+    logs_needed_from_next_position_[log_id] = true;
+}
diff --git a/logd/SerializedFlushToState.h b/logd/SerializedFlushToState.h
new file mode 100644
index 0000000..74b3de5
--- /dev/null
+++ b/logd/SerializedFlushToState.h
@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <bitset>
+#include <list>
+#include <queue>
+
+#include "LogBuffer.h"
+#include "SerializedLogChunk.h"
+#include "SerializedLogEntry.h"
+
+struct LogPosition {
+    std::list<SerializedLogChunk>::iterator buffer_it;
+    int read_offset;
+};
+
+struct MinHeapElement {
+    MinHeapElement(log_id_t log_id, const SerializedLogEntry* entry)
+        : log_id(log_id), entry(entry) {}
+    log_id_t log_id;
+    const SerializedLogEntry* entry;
+    // The change of comparison operators is intentional, std::priority_queue uses operator<() to
+    // compare but creates a max heap.  Since we want a min heap, we return the opposite result.
+    bool operator<(const MinHeapElement& rhs) const {
+        return entry->sequence() > rhs.entry->sequence();
+    }
+};
+
+// This class tracks the specific point where a FlushTo client has read through the logs.  It
+// directly references the std::list<> iterators from the parent SerializedLogBuffer and the offset
+// into each log chunk where it has last read.  All interactions with this class, except for its
+// construction, must be done with SerializedLogBuffer::lock_ held.  No log chunks that it
+// references may be pruned, which is handled by ensuring prune does not touch any log chunk with
+// highest sequence number greater or equal to start().
+class SerializedFlushToState : public FlushToState {
+  public:
+    // Initializes this state object.  For each log buffer set in log_mask, this sets
+    // logs_needed_from_next_position_.
+    SerializedFlushToState(uint64_t start, LogMask log_mask);
+
+    // Decrease the reference of all referenced logs.  This happens when a reader is disconnected.
+    ~SerializedFlushToState() override;
+
+    // We can't hold SerializedLogBuffer::lock_ in the constructor, so we must initialize logs here.
+    void InitializeLogs(std::list<SerializedLogChunk>* logs) {
+        if (logs_ == nullptr) logs_ = logs;
+    }
+
+    // Checks to see if any log buffers set in logs_needed_from_next_position_ have new logs and
+    // calls AddMinHeapEntry() if so.
+    void CheckForNewLogs();
+
+    bool HasUnreadLogs() { return !min_heap_.empty(); }
+
+    // Pops the next unread log from the min heap.  Add the next log for that log_id to the min heap
+    // if one is available otherwise set logs_needed_from_next_position_ to indicate that we're
+    // waiting for more logs.
+    MinHeapElement PopNextUnreadLog();
+
+    // If the parent log buffer prunes logs, the reference that this class contains may become
+    // invalid, so this must be called first to drop the reference to buffer_it, if any.
+    void Prune(log_id_t log_id, const std::list<SerializedLogChunk>::iterator& buffer_it);
+
+  private:
+    // If there is a log in the serialized log buffer for `log_id` at the read_offset, add it to the
+    // min heap for reading, otherwise set logs_needed_from_next_position_ to indicate that we're
+    // waiting for the next log.
+    void AddMinHeapEntry(log_id_t log_id);
+
+    // Create a LogPosition object for the given log_id by searching through the log chunks for the
+    // first chunk and then first log entry within that chunk that is greater or equal to start().
+    void CreateLogPosition(log_id_t log_id);
+
+    std::list<SerializedLogChunk>* logs_ = nullptr;
+    // An optional structure that contains an iterator to the serialized log buffer and offset into
+    // it that this logger should handle next.
+    std::optional<LogPosition> log_positions_[LOG_ID_MAX];
+    // A bit for each log that is set if a given log_id has no logs or if this client has read all
+    // of its logs. In order words: `logs_[i].empty() || (buffer_it == std::prev(logs_.end) &&
+    // next_log_position == logs_write_position_)`.  These will be re-checked in each
+    // loop in case new logs came in.
+    std::bitset<LOG_ID_MAX> logs_needed_from_next_position_ = {};
+    // A min heap that has up to one entry per log buffer, sorted by sequence number, of the next
+    // element that this reader should read.
+    std::priority_queue<MinHeapElement> min_heap_;
+};
diff --git a/logd/SerializedFlushToStateTest.cpp b/logd/SerializedFlushToStateTest.cpp
new file mode 100644
index 0000000..a1d21ac
--- /dev/null
+++ b/logd/SerializedFlushToStateTest.cpp
@@ -0,0 +1,254 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "SerializedFlushToState.h"
+
+#include <map>
+
+#include <android-base/logging.h>
+#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
+#include <gtest/gtest.h>
+
+using android::base::Join;
+using android::base::StringPrintf;
+
+constexpr size_t kChunkSize = 3 * 4096;
+
+class SerializedFlushToStateTest : public testing::Test {
+  protected:
+    void SetUp() override {
+        // This test spams many unneeded INFO logs, so we suppress them.
+        old_log_severity_ = android::base::SetMinimumLogSeverity(android::base::WARNING);
+    }
+    void TearDown() override { android::base::SetMinimumLogSeverity(old_log_severity_); }
+
+    std::string TestReport(const std::vector<uint64_t>& expected,
+                           const std::vector<uint64_t>& read) {
+        auto sequence_to_log_id = [&](uint64_t sequence) -> int {
+            for (const auto& [log_id, sequences] : sequence_numbers_per_buffer_) {
+                if (std::find(sequences.begin(), sequences.end(), sequence) != sequences.end()) {
+                    return log_id;
+                }
+            }
+            return -1;
+        };
+
+        std::map<int, std::vector<uint64_t>> missing_sequences;
+        std::vector<uint64_t> missing_expected;
+        std::set_difference(expected.begin(), expected.end(), read.begin(), read.end(),
+                            std::back_inserter(missing_expected));
+        for (uint64_t sequence : missing_expected) {
+            int log_id = sequence_to_log_id(sequence);
+            missing_sequences[log_id].emplace_back(sequence);
+        }
+
+        std::map<int, std::vector<uint64_t>> extra_sequences;
+        std::vector<uint64_t> extra_read;
+        std::set_difference(read.begin(), read.end(), expected.begin(), expected.end(),
+                            std::back_inserter(extra_read));
+        for (uint64_t sequence : extra_read) {
+            int log_id = sequence_to_log_id(sequence);
+            extra_sequences[log_id].emplace_back(sequence);
+        }
+
+        std::vector<std::string> errors;
+        for (const auto& [log_id, sequences] : missing_sequences) {
+            errors.emplace_back(
+                    StringPrintf("Log id %d missing %zu sequences", log_id, sequences.size()));
+        }
+
+        for (const auto& [log_id, sequences] : extra_sequences) {
+            errors.emplace_back(
+                    StringPrintf("Log id %d has extra %zu sequences", log_id, sequences.size()));
+        }
+
+        return Join(errors, ", ");
+    }
+
+    // Read sequence numbers in order from SerializedFlushToState for every mask combination and all
+    // sequence numbers from 0 through the highest logged sequence number + 1.
+    // This assumes that all of the logs have already been written.
+    void TestAllReading() {
+        uint64_t max_sequence = sequence_ + 1;
+        uint32_t max_mask = (1 << LOG_ID_MAX) - 1;
+        for (uint64_t sequence = 0; sequence < max_sequence; ++sequence) {
+            for (uint32_t mask = 0; mask < max_mask; ++mask) {
+                auto state = SerializedFlushToState{sequence, mask};
+                state.InitializeLogs(log_chunks_);
+                state.CheckForNewLogs();
+                TestReading(sequence, mask, state);
+            }
+        }
+    }
+
+    // Similar to TestAllReading() except that it doesn't assume any logs are in the buffer, instead
+    // it calls write_logs() in a loop for sequence/mask combination.  It clears log_chunks_ and
+    // sequence_numbers_per_buffer_ between calls, such that only the sequence numbers written in
+    // the previous call to write_logs() are expected.
+    void TestAllReadingWithFutureMessages(const std::function<bool(int)>& write_logs) {
+        uint64_t max_sequence = sequence_ + 1;
+        uint32_t max_mask = (1 << LOG_ID_MAX) - 1;
+        for (uint64_t sequence = 1; sequence < max_sequence; ++sequence) {
+            for (uint32_t mask = 1; mask < max_mask; ++mask) {
+                log_id_for_each(i) { log_chunks_[i].clear(); }
+                auto state = SerializedFlushToState{sequence, mask};
+                state.InitializeLogs(log_chunks_);
+                int loop_count = 0;
+                while (write_logs(loop_count++)) {
+                    state.CheckForNewLogs();
+                    TestReading(sequence, mask, state);
+                    sequence_numbers_per_buffer_.clear();
+                }
+            }
+        }
+    }
+
+    void TestReading(uint64_t start, LogMask log_mask, SerializedFlushToState& state) {
+        std::vector<uint64_t> expected_sequence;
+        log_id_for_each(i) {
+            if (((1 << i) & log_mask) == 0) {
+                continue;
+            }
+            for (const auto& sequence : sequence_numbers_per_buffer_[i]) {
+                if (sequence >= start) {
+                    expected_sequence.emplace_back(sequence);
+                }
+            }
+        }
+        std::sort(expected_sequence.begin(), expected_sequence.end());
+
+        std::vector<uint64_t> read_sequence;
+
+        while (state.HasUnreadLogs()) {
+            auto top = state.PopNextUnreadLog();
+            read_sequence.emplace_back(top.entry->sequence());
+        }
+
+        EXPECT_TRUE(std::is_sorted(read_sequence.begin(), read_sequence.end()));
+
+        EXPECT_EQ(expected_sequence.size(), read_sequence.size());
+
+        EXPECT_EQ(expected_sequence, read_sequence)
+                << "start: " << start << " log_mask: " << log_mask << " "
+                << TestReport(expected_sequence, read_sequence);
+    }
+
+    // Add a chunk with the given messages to the a given log buffer.  Keep track of the sequence
+    // numbers for future validation.  Optionally mark the block as having finished writing.
+    void AddChunkWithMessages(int buffer, bool finish_writing,
+                              const std::vector<std::string>& messages) {
+        auto chunk = SerializedLogChunk{kChunkSize};
+        for (const auto& message : messages) {
+            auto sequence = sequence_++;
+            sequence_numbers_per_buffer_[buffer].emplace_back(sequence);
+            ASSERT_TRUE(chunk.CanLog(message.size() + 1));
+            chunk.Log(sequence, log_time(), 0, 1, 1, message.c_str(), message.size() + 1);
+        }
+        if (finish_writing) {
+            chunk.FinishWriting();
+        }
+        log_chunks_[buffer].emplace_back(std::move(chunk));
+    }
+
+    android::base::LogSeverity old_log_severity_;
+    std::map<int, std::vector<uint64_t>> sequence_numbers_per_buffer_;
+    std::list<SerializedLogChunk> log_chunks_[LOG_ID_MAX];
+    uint64_t sequence_ = 1;
+};
+
+// 0: multiple chunks, with variable number of entries, with/without finishing writing
+// 1: 1 chunk with 1 log and finished writing
+// 2: 1 chunk with 1 log and not finished writing
+// 3: 1 chunk with 0 logs and not finished writing
+// 4: 1 chunk with 0 logs and finished writing (impossible, but SerializedFlushToState handles it)
+// 5-7: 0 chunks
+TEST_F(SerializedFlushToStateTest, smoke) {
+    AddChunkWithMessages(true, 0, {"1st", "2nd"});
+    AddChunkWithMessages(true, 1, {"3rd"});
+    AddChunkWithMessages(false, 0, {"4th"});
+    AddChunkWithMessages(true, 0, {"4th", "5th", "more", "even", "more", "go", "here"});
+    AddChunkWithMessages(false, 2, {"6th"});
+    AddChunkWithMessages(true, 0, {"7th"});
+    AddChunkWithMessages(false, 3, {});
+    AddChunkWithMessages(true, 4, {});
+
+    TestAllReading();
+}
+
+TEST_F(SerializedFlushToStateTest, random) {
+    srand(1);
+    for (int count = 0; count < 20; ++count) {
+        unsigned int num_messages = 1 + rand() % 15;
+        auto messages = std::vector<std::string>{num_messages, "same message"};
+
+        bool compress = rand() % 2;
+        int buf = rand() % LOG_ID_MAX;
+
+        AddChunkWithMessages(compress, buf, messages);
+    }
+
+    TestAllReading();
+}
+
+// Same start as smoke, but we selectively write logs to the buffers and ensure they're read.
+TEST_F(SerializedFlushToStateTest, future_writes) {
+    auto write_logs = [&](int loop_count) {
+        switch (loop_count) {
+            case 0:
+                // Initial writes.
+                AddChunkWithMessages(true, 0, {"1st", "2nd"});
+                AddChunkWithMessages(true, 1, {"3rd"});
+                AddChunkWithMessages(false, 0, {"4th"});
+                AddChunkWithMessages(true, 0, {"4th", "5th", "more", "even", "more", "go", "here"});
+                AddChunkWithMessages(false, 2, {"6th"});
+                AddChunkWithMessages(true, 0, {"7th"});
+                AddChunkWithMessages(false, 3, {});
+                AddChunkWithMessages(true, 4, {});
+                break;
+            case 1:
+                // Smoke test, add a simple chunk.
+                AddChunkWithMessages(true, 0, {"1st", "2nd"});
+                break;
+            case 2:
+                // Add chunks to all but one of the logs.
+                AddChunkWithMessages(true, 0, {"1st", "2nd"});
+                AddChunkWithMessages(true, 1, {"1st", "2nd"});
+                AddChunkWithMessages(true, 2, {"1st", "2nd"});
+                AddChunkWithMessages(true, 3, {"1st", "2nd"});
+                AddChunkWithMessages(true, 4, {"1st", "2nd"});
+                AddChunkWithMessages(true, 5, {"1st", "2nd"});
+                AddChunkWithMessages(true, 6, {"1st", "2nd"});
+                break;
+            case 3:
+                // Finally add chunks to all logs.
+                AddChunkWithMessages(true, 0, {"1st", "2nd"});
+                AddChunkWithMessages(true, 1, {"1st", "2nd"});
+                AddChunkWithMessages(true, 2, {"1st", "2nd"});
+                AddChunkWithMessages(true, 3, {"1st", "2nd"});
+                AddChunkWithMessages(true, 4, {"1st", "2nd"});
+                AddChunkWithMessages(true, 5, {"1st", "2nd"});
+                AddChunkWithMessages(true, 6, {"1st", "2nd"});
+                AddChunkWithMessages(true, 7, {"1st", "2nd"});
+                break;
+            default:
+                return false;
+        }
+        return true;
+    };
+
+    TestAllReadingWithFutureMessages(write_logs);
+}
diff --git a/logd/SerializedLogBuffer.cpp b/logd/SerializedLogBuffer.cpp
new file mode 100644
index 0000000..70b800f
--- /dev/null
+++ b/logd/SerializedLogBuffer.cpp
@@ -0,0 +1,352 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "SerializedLogBuffer.h"
+
+#include <limits>
+#include <thread>
+
+#include <android-base/logging.h>
+#include <android-base/scopeguard.h>
+
+#include "LogStatistics.h"
+#include "SerializedFlushToState.h"
+
+SerializedLogBuffer::SerializedLogBuffer(LogReaderList* reader_list, LogTags* tags,
+                                         LogStatistics* stats)
+    : reader_list_(reader_list), tags_(tags), stats_(stats) {
+    Init();
+}
+
+SerializedLogBuffer::~SerializedLogBuffer() {}
+
+void SerializedLogBuffer::Init() {
+    log_id_for_each(i) {
+        if (SetSize(i, __android_logger_get_buffer_size(i))) {
+            SetSize(i, LOG_BUFFER_MIN_SIZE);
+        }
+    }
+
+    // Release any sleeping reader threads to dump their current content.
+    auto reader_threads_lock = std::lock_guard{reader_list_->reader_threads_lock()};
+    for (const auto& reader_thread : reader_list_->reader_threads()) {
+        reader_thread->triggerReader_Locked();
+    }
+}
+
+bool SerializedLogBuffer::ShouldLog(log_id_t log_id, const char* msg, uint16_t len) {
+    if (log_id == LOG_ID_SECURITY) {
+        return true;
+    }
+
+    int prio = ANDROID_LOG_INFO;
+    const char* tag = nullptr;
+    size_t tag_len = 0;
+    if (IsBinary(log_id)) {
+        int32_t tag_int = MsgToTag(msg, len);
+        tag = tags_->tagToName(tag_int);
+        if (tag) {
+            tag_len = strlen(tag);
+        }
+    } else {
+        prio = *msg;
+        tag = msg + 1;
+        tag_len = strnlen(tag, len - 1);
+    }
+    return __android_log_is_loggable_len(prio, tag, tag_len, ANDROID_LOG_VERBOSE);
+}
+
+int SerializedLogBuffer::Log(log_id_t log_id, log_time realtime, uid_t uid, pid_t pid, pid_t tid,
+                             const char* msg, uint16_t len) {
+    if (log_id >= LOG_ID_MAX || len == 0) {
+        return -EINVAL;
+    }
+
+    if (!ShouldLog(log_id, msg, len)) {
+        stats_->AddTotal(log_id, len);
+        return -EACCES;
+    }
+
+    auto sequence = sequence_.fetch_add(1, std::memory_order_relaxed);
+
+    auto lock = std::lock_guard{lock_};
+
+    if (logs_[log_id].empty()) {
+        logs_[log_id].push_back(SerializedLogChunk(max_size_[log_id] / 4));
+    }
+
+    auto total_len = sizeof(SerializedLogEntry) + len;
+    if (!logs_[log_id].back().CanLog(total_len)) {
+        logs_[log_id].back().FinishWriting();
+        logs_[log_id].push_back(SerializedLogChunk(max_size_[log_id] / 4));
+    }
+
+    auto entry = logs_[log_id].back().Log(sequence, realtime, uid, pid, tid, msg, len);
+    stats_->Add(entry->ToLogStatisticsElement(log_id));
+
+    MaybePrune(log_id);
+
+    reader_list_->NotifyNewLog(1 << log_id);
+    return len;
+}
+
+void SerializedLogBuffer::MaybePrune(log_id_t log_id) {
+    auto get_total_size = [](const auto& buffer) {
+        size_t total_size = 0;
+        for (const auto& chunk : buffer) {
+            total_size += chunk.PruneSize();
+        }
+        return total_size;
+    };
+    size_t total_size = get_total_size(logs_[log_id]);
+    if (total_size > max_size_[log_id]) {
+        Prune(log_id, total_size - max_size_[log_id], 0);
+        LOG(INFO) << "Pruned Logs from log_id: " << log_id << ", previous size: " << total_size
+                  << " after size: " << get_total_size(logs_[log_id]);
+    }
+}
+
+// Decompresses the chunks, call LogStatistics::Subtract() on each entry, then delete the chunks and
+// the list.  Note that the SerializedLogChunk objects have been removed from logs_ and their
+// references have been deleted from any SerializedFlushToState objects, so this can be safely done
+// without holding lock_.  It is done in a separate thread to avoid delaying the writer thread.  The
+// lambda for the thread takes ownership of the 'chunks' list and thus when the thread ends and the
+// lambda is deleted, the objects are deleted.
+void SerializedLogBuffer::DeleteLogChunks(std::list<SerializedLogChunk>&& chunks, log_id_t log_id) {
+    auto delete_thread = std::thread{[chunks = std::move(chunks), log_id, this]() mutable {
+        for (auto& chunk : chunks) {
+            chunk.IncReaderRefCount();
+            int read_offset = 0;
+            while (read_offset < chunk.write_offset()) {
+                auto* entry = chunk.log_entry(read_offset);
+                stats_->Subtract(entry->ToLogStatisticsElement(log_id));
+                read_offset += entry->total_len();
+            }
+            chunk.DecReaderRefCount(false);
+        }
+    }};
+    delete_thread.detach();
+}
+
+void SerializedLogBuffer::NotifyReadersOfPrune(
+        log_id_t log_id, const std::list<SerializedLogChunk>::iterator& chunk) {
+    for (const auto& reader_thread : reader_list_->reader_threads()) {
+        auto& state = reinterpret_cast<SerializedFlushToState&>(reader_thread->flush_to_state());
+        state.Prune(log_id, chunk);
+    }
+}
+
+bool SerializedLogBuffer::Prune(log_id_t log_id, size_t bytes_to_free, uid_t uid) {
+    // Don't prune logs that are newer than the point at which any reader threads are reading from.
+    LogReaderThread* oldest = nullptr;
+    auto reader_threads_lock = std::lock_guard{reader_list_->reader_threads_lock()};
+    for (const auto& reader_thread : reader_list_->reader_threads()) {
+        if (!reader_thread->IsWatching(log_id)) {
+            continue;
+        }
+        if (!oldest || oldest->start() > reader_thread->start() ||
+            (oldest->start() == reader_thread->start() &&
+             reader_thread->deadline().time_since_epoch().count() != 0)) {
+            oldest = reader_thread.get();
+        }
+    }
+
+    auto& log_buffer = logs_[log_id];
+
+    std::list<SerializedLogChunk> chunks_to_prune;
+    auto prune_chunks = android::base::make_scope_guard([&chunks_to_prune, log_id, this] {
+        DeleteLogChunks(std::move(chunks_to_prune), log_id);
+    });
+
+    auto it = log_buffer.begin();
+    while (it != log_buffer.end()) {
+        if (oldest != nullptr && it->highest_sequence_number() >= oldest->start()) {
+            break;
+        }
+
+        // Increment ahead of time since we're going to splice this iterator from the list.
+        auto it_to_prune = it++;
+
+        // The sequence number check ensures that all readers have read all logs in this chunk, but
+        // they may still hold a reference to the chunk to track their last read log_position.
+        // Notify them to delete the reference.
+        NotifyReadersOfPrune(log_id, it_to_prune);
+
+        if (uid != 0) {
+            // Reorder the log buffer to remove logs from the given UID.  If there are no logs left
+            // in the buffer after the removal, delete it.
+            if (it_to_prune->ClearUidLogs(uid, log_id, stats_)) {
+                log_buffer.erase(it_to_prune);
+            }
+        } else {
+            size_t buffer_size = it_to_prune->PruneSize();
+            chunks_to_prune.splice(chunks_to_prune.end(), log_buffer, it_to_prune);
+            if (buffer_size >= bytes_to_free) {
+                return true;
+            }
+            bytes_to_free -= buffer_size;
+        }
+    }
+
+    // If we've deleted all buffers without bytes_to_free hitting 0, then we're called by Clear()
+    // and should return true.
+    if (it == log_buffer.end()) {
+        return true;
+    }
+
+    // Otherwise we are stuck due to a reader, so mitigate it.
+    CHECK(oldest != nullptr);
+    KickReader(oldest, log_id, bytes_to_free);
+    return false;
+}
+
+// If the selected reader is blocking our pruning progress, decide on
+// what kind of mitigation is necessary to unblock the situation.
+void SerializedLogBuffer::KickReader(LogReaderThread* reader, log_id_t id, size_t bytes_to_free) {
+    if (bytes_to_free >= max_size_[id]) {  // +100%
+        // A misbehaving or slow reader is dropped if we hit too much memory pressure.
+        LOG(WARNING) << "Kicking blocked reader, " << reader->name()
+                     << ", from LogBuffer::kickMe()";
+        reader->release_Locked();
+    } else if (reader->deadline().time_since_epoch().count() != 0) {
+        // Allow a blocked WRAP deadline reader to trigger and start reporting the log data.
+        reader->triggerReader_Locked();
+    } else {
+        // Tell slow reader to skip entries to catch up.
+        unsigned long prune_rows = bytes_to_free / 300;
+        LOG(WARNING) << "Skipping " << prune_rows << " entries from slow reader, " << reader->name()
+                     << ", from LogBuffer::kickMe()";
+        reader->triggerSkip_Locked(id, prune_rows);
+    }
+}
+
+std::unique_ptr<FlushToState> SerializedLogBuffer::CreateFlushToState(uint64_t start,
+                                                                      LogMask log_mask) {
+    return std::make_unique<SerializedFlushToState>(start, log_mask);
+}
+
+bool SerializedLogBuffer::FlushTo(
+        LogWriter* writer, FlushToState& abstract_state,
+        const std::function<FilterResult(log_id_t log_id, pid_t pid, uint64_t sequence,
+                                         log_time realtime)>& filter) {
+    auto lock = std::unique_lock{lock_};
+
+    auto& state = reinterpret_cast<SerializedFlushToState&>(abstract_state);
+    state.InitializeLogs(logs_);
+    state.CheckForNewLogs();
+
+    while (state.HasUnreadLogs()) {
+        MinHeapElement top = state.PopNextUnreadLog();
+        auto* entry = top.entry;
+        auto log_id = top.log_id;
+
+        if (entry->sequence() < state.start()) {
+            continue;
+        }
+        state.set_start(entry->sequence());
+
+        if (!writer->privileged() && entry->uid() != writer->uid()) {
+            continue;
+        }
+
+        if (filter) {
+            auto ret = filter(log_id, entry->pid(), entry->sequence(), entry->realtime());
+            if (ret == FilterResult::kSkip) {
+                continue;
+            }
+            if (ret == FilterResult::kStop) {
+                break;
+            }
+        }
+
+        lock.unlock();
+        // We never prune logs equal to or newer than any LogReaderThreads' `start` value, so the
+        // `entry` pointer is safe here without the lock
+        if (!entry->Flush(writer, log_id)) {
+            return false;
+        }
+        lock.lock();
+
+        // Since we released the log above, buffers that aren't in our min heap may now have had
+        // logs added, so re-check them.
+        state.CheckForNewLogs();
+    }
+
+    state.set_start(state.start() + 1);
+    return true;
+}
+
+bool SerializedLogBuffer::Clear(log_id_t id, uid_t uid) {
+    // Try three times to clear, then disconnect the readers and try one final time.
+    for (int retry = 0; retry < 3; ++retry) {
+        {
+            auto lock = std::lock_guard{lock_};
+            bool prune_success = Prune(id, ULONG_MAX, uid);
+            if (prune_success) {
+                return true;
+            }
+        }
+        sleep(1);
+    }
+    // Check if it is still busy after the sleep, we try to prune one entry, not another clear run,
+    // so we are looking for the quick side effect of the return value to tell us if we have a
+    // _blocked_ reader.
+    bool busy = false;
+    {
+        auto lock = std::lock_guard{lock_};
+        busy = !Prune(id, 1, uid);
+    }
+    // It is still busy, disconnect all readers.
+    if (busy) {
+        auto reader_threads_lock = std::lock_guard{reader_list_->reader_threads_lock()};
+        for (const auto& reader_thread : reader_list_->reader_threads()) {
+            if (reader_thread->IsWatching(id)) {
+                LOG(WARNING) << "Kicking blocked reader, " << reader_thread->name()
+                             << ", from LogBuffer::clear()";
+                reader_thread->release_Locked();
+            }
+        }
+    }
+    auto lock = std::lock_guard{lock_};
+    return Prune(id, ULONG_MAX, uid);
+}
+
+unsigned long SerializedLogBuffer::GetSize(log_id_t id) {
+    auto lock = std::lock_guard{lock_};
+    size_t retval = 2 * max_size_[id] / 3;  // See the comment in SetSize().
+    return retval;
+}
+
+// New SerializedLogChunk objects will be allocated according to the new size, but older one are
+// unchanged.  MaybePrune() is called on the log buffer to reduce it to an appropriate size if the
+// new size is lower.
+// ChattyLogBuffer/SimpleLogBuffer don't consider the 'Overhead' of LogBufferElement or the
+// std::list<> overhead as part of the log size.  SerializedLogBuffer does by its very nature, so
+// the 'size' metric is not compatible between them.  Their actual memory usage is between 1.5x and
+// 2x of what they claim to use, so we conservatively set our internal size as size + size / 2.
+int SerializedLogBuffer::SetSize(log_id_t id, unsigned long size) {
+    // Reasonable limits ...
+    if (!__android_logger_valid_buffer_size(size)) {
+        return -1;
+    }
+
+    auto lock = std::lock_guard{lock_};
+    max_size_[id] = size + size / 2;
+
+    MaybePrune(id);
+
+    return 0;
+}
diff --git a/logd/SerializedLogBuffer.h b/logd/SerializedLogBuffer.h
new file mode 100644
index 0000000..346f51f
--- /dev/null
+++ b/logd/SerializedLogBuffer.h
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <atomic>
+#include <bitset>
+#include <list>
+#include <mutex>
+#include <queue>
+#include <vector>
+
+#include <android-base/thread_annotations.h>
+
+#include "LogBuffer.h"
+#include "LogReaderList.h"
+#include "LogStatistics.h"
+#include "LogTags.h"
+#include "SerializedLogChunk.h"
+#include "SerializedLogEntry.h"
+#include "rwlock.h"
+
+class SerializedLogBuffer final : public LogBuffer {
+  public:
+    SerializedLogBuffer(LogReaderList* reader_list, LogTags* tags, LogStatistics* stats);
+    ~SerializedLogBuffer();
+    void Init() override;
+
+    int Log(log_id_t log_id, log_time realtime, uid_t uid, pid_t pid, pid_t tid, const char* msg,
+            uint16_t len) override;
+    std::unique_ptr<FlushToState> CreateFlushToState(uint64_t start, LogMask log_mask) override;
+    bool FlushTo(LogWriter* writer, FlushToState& state,
+                 const std::function<FilterResult(log_id_t log_id, pid_t pid, uint64_t sequence,
+                                                  log_time realtime)>& filter) override;
+
+    bool Clear(log_id_t id, uid_t uid) override;
+    unsigned long GetSize(log_id_t id) override;
+    int SetSize(log_id_t id, unsigned long size) override;
+
+    uint64_t sequence() const override { return sequence_.load(std::memory_order_relaxed); }
+
+  private:
+    bool ShouldLog(log_id_t log_id, const char* msg, uint16_t len);
+    void MaybePrune(log_id_t log_id) REQUIRES(lock_);
+    bool Prune(log_id_t log_id, size_t bytes_to_free, uid_t uid) REQUIRES(lock_);
+    void KickReader(LogReaderThread* reader, log_id_t id, size_t bytes_to_free)
+            REQUIRES_SHARED(lock_);
+    void NotifyReadersOfPrune(log_id_t log_id, const std::list<SerializedLogChunk>::iterator& chunk)
+            REQUIRES(reader_list_->reader_threads_lock());
+    void DeleteLogChunks(std::list<SerializedLogChunk>&& chunks, log_id_t log_id);
+
+    LogReaderList* reader_list_;
+    LogTags* tags_;
+    LogStatistics* stats_;
+
+    unsigned long max_size_[LOG_ID_MAX] GUARDED_BY(lock_) = {};
+    std::list<SerializedLogChunk> logs_[LOG_ID_MAX] GUARDED_BY(lock_);
+    RwLock lock_;
+
+    std::atomic<uint64_t> sequence_ = 1;
+};
diff --git a/logd/SerializedLogChunk.cpp b/logd/SerializedLogChunk.cpp
new file mode 100644
index 0000000..2516003
--- /dev/null
+++ b/logd/SerializedLogChunk.cpp
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "SerializedLogChunk.h"
+
+#include <android-base/logging.h>
+
+#include "CompressionEngine.h"
+
+SerializedLogChunk::~SerializedLogChunk() {
+    CHECK_EQ(reader_ref_count_, 0U);
+}
+
+void SerializedLogChunk::Compress() {
+    if (compressed_log_.empty()) {
+        CompressionEngine::GetInstance().Compress({contents_.data(), write_offset_},
+                                                  compressed_log_);
+        LOG(INFO) << "Compressed Log, buffer max size: " << contents_.size()
+                  << " size used: " << write_offset_
+                  << " compressed size: " << compressed_log_.size();
+    }
+    contents_.resize(0);
+}
+
+// TODO: Develop a better reference counting strategy to guard against the case where the writer is
+// much faster than the reader, and we needlessly compess / decompress the logs.
+void SerializedLogChunk::IncReaderRefCount() {
+    if (++reader_ref_count_ != 1 || writer_active_) {
+        return;
+    }
+    CompressionEngine::GetInstance().Decompress(compressed_log_, contents_, write_offset_);
+}
+
+void SerializedLogChunk::DecReaderRefCount(bool compress) {
+    CHECK_NE(reader_ref_count_, 0U);
+    if (--reader_ref_count_ != 0) {
+        return;
+    }
+    if (compress && !writer_active_) {
+        Compress();
+    }
+}
+
+bool SerializedLogChunk::ClearUidLogs(uid_t uid, log_id_t log_id, LogStatistics* stats) {
+    CHECK_EQ(reader_ref_count_, 0U);
+    if (write_offset_ == 0) {
+        return true;
+    }
+
+    IncReaderRefCount();
+
+    int read_offset = 0;
+    int new_write_offset = 0;
+    while (read_offset < write_offset_) {
+        const auto* entry = log_entry(read_offset);
+        if (entry->uid() == uid) {
+            read_offset += entry->total_len();
+            if (stats != nullptr) {
+                stats->Subtract(entry->ToLogStatisticsElement(log_id));
+            }
+            continue;
+        }
+        size_t entry_total_len = entry->total_len();
+        if (read_offset != new_write_offset) {
+            memmove(contents_.data() + new_write_offset, contents_.data() + read_offset,
+                    entry_total_len);
+        }
+        read_offset += entry_total_len;
+        new_write_offset += entry_total_len;
+    }
+
+    if (new_write_offset == 0) {
+        DecReaderRefCount(false);
+        return true;
+    }
+
+    // Clear the old compressed logs and set write_offset_ appropriately for DecReaderRefCount()
+    // to compress the new partially cleared log.
+    if (new_write_offset != write_offset_) {
+        compressed_log_.clear();
+        write_offset_ = new_write_offset;
+    }
+
+    DecReaderRefCount(true);
+
+    return false;
+}
+
+bool SerializedLogChunk::CanLog(size_t len) {
+    return write_offset_ + len <= contents_.size();
+}
+
+SerializedLogEntry* SerializedLogChunk::Log(uint64_t sequence, log_time realtime, uid_t uid,
+                                            pid_t pid, pid_t tid, const char* msg, uint16_t len) {
+    auto new_log_address = contents_.data() + write_offset_;
+    auto* entry = new (new_log_address) SerializedLogEntry(uid, pid, tid, sequence, realtime, len);
+    memcpy(entry->msg(), msg, len);
+    write_offset_ += entry->total_len();
+    highest_sequence_number_ = sequence;
+    return entry;
+}
\ No newline at end of file
diff --git a/logd/SerializedLogChunk.h b/logd/SerializedLogChunk.h
new file mode 100644
index 0000000..a8ac8cd
--- /dev/null
+++ b/logd/SerializedLogChunk.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <sys/types.h>
+
+#include <vector>
+
+#include "LogWriter.h"
+#include "SerializedLogEntry.h"
+
+class SerializedLogChunk {
+  public:
+    explicit SerializedLogChunk(size_t size) : contents_(size) {}
+    ~SerializedLogChunk();
+
+    void Compress();
+    void IncReaderRefCount();
+    // Decrease the reader ref count and compress the log if appropriate.  `compress` should only be
+    // set to false in the case that the log buffer will be deleted afterwards.
+    void DecReaderRefCount(bool compress);
+
+    // Must have no readers referencing this.  Return true if there are no logs left in this chunk.
+    bool ClearUidLogs(uid_t uid, log_id_t log_id, LogStatistics* stats);
+
+    bool CanLog(size_t len);
+    SerializedLogEntry* Log(uint64_t sequence, log_time realtime, uid_t uid, pid_t pid, pid_t tid,
+                            const char* msg, uint16_t len);
+
+    // If this buffer has been compressed, we only consider its compressed size when accounting for
+    // memory consumption for pruning.  This is since the uncompressed log is only by used by
+    // readers, and thus not a representation of how much these logs cost to keep in memory.
+    size_t PruneSize() const { return compressed_log_.size() ?: contents_.size(); }
+
+    void FinishWriting() {
+        writer_active_ = false;
+        if (reader_ref_count_ == 0) {
+            Compress();
+        }
+    }
+
+    const SerializedLogEntry* log_entry(int offset) const {
+        return reinterpret_cast<const SerializedLogEntry*>(data() + offset);
+    }
+    const uint8_t* data() const { return contents_.data(); }
+    int write_offset() const { return write_offset_; }
+    uint64_t highest_sequence_number() const { return highest_sequence_number_; }
+
+  private:
+    // The decompressed contents of this log buffer.  Deallocated when the ref_count reaches 0 and
+    // writer_active_ is false.
+    std::vector<uint8_t> contents_;
+    int write_offset_ = 0;
+    uint32_t reader_ref_count_ = 0;
+    bool writer_active_ = true;
+    uint64_t highest_sequence_number_ = 1;
+    std::vector<uint8_t> compressed_log_;
+};
diff --git a/logd/SerializedLogChunkTest.cpp b/logd/SerializedLogChunkTest.cpp
new file mode 100644
index 0000000..6572503
--- /dev/null
+++ b/logd/SerializedLogChunkTest.cpp
@@ -0,0 +1,284 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "SerializedLogChunk.h"
+
+#include <limits>
+
+#include <android-base/stringprintf.h>
+#include <android/log.h>
+#include <gtest/gtest.h>
+
+using android::base::StringPrintf;
+
+TEST(SerializedLogChunk, smoke) {
+    size_t chunk_size = 10 * 4096;
+    auto chunk = SerializedLogChunk{chunk_size};
+    EXPECT_EQ(chunk_size, chunk.PruneSize());
+
+    static const char log_message[] = "log message";
+    size_t expected_total_len = sizeof(SerializedLogEntry) + sizeof(log_message);
+    ASSERT_TRUE(chunk.CanLog(expected_total_len));
+    EXPECT_TRUE(chunk.CanLog(chunk_size));
+    EXPECT_FALSE(chunk.CanLog(chunk_size + 1));
+
+    log_time time(CLOCK_REALTIME);
+    auto* entry = chunk.Log(1234, time, 0, 1, 2, log_message, sizeof(log_message));
+    ASSERT_NE(nullptr, entry);
+
+    EXPECT_EQ(1234U, entry->sequence());
+    EXPECT_EQ(time, entry->realtime());
+    EXPECT_EQ(0U, entry->uid());
+    EXPECT_EQ(1, entry->pid());
+    EXPECT_EQ(2, entry->tid());
+    EXPECT_EQ(sizeof(log_message), entry->msg_len());
+    EXPECT_STREQ(log_message, entry->msg());
+    EXPECT_EQ(expected_total_len, entry->total_len());
+
+    EXPECT_FALSE(chunk.CanLog(chunk_size));
+    EXPECT_EQ(static_cast<int>(expected_total_len), chunk.write_offset());
+    EXPECT_EQ(1234U, chunk.highest_sequence_number());
+}
+
+TEST(SerializedLogChunk, fill_log_exactly) {
+    static const char log_message[] = "this is a log message";
+    size_t individual_message_size = sizeof(SerializedLogEntry) + sizeof(log_message);
+    size_t chunk_size = individual_message_size * 3;
+    auto chunk = SerializedLogChunk{chunk_size};
+    EXPECT_EQ(chunk_size, chunk.PruneSize());
+
+    ASSERT_TRUE(chunk.CanLog(individual_message_size));
+    EXPECT_NE(nullptr, chunk.Log(1, log_time(), 1000, 1, 1, log_message, sizeof(log_message)));
+
+    ASSERT_TRUE(chunk.CanLog(individual_message_size));
+    EXPECT_NE(nullptr, chunk.Log(2, log_time(), 1000, 2, 1, log_message, sizeof(log_message)));
+
+    ASSERT_TRUE(chunk.CanLog(individual_message_size));
+    EXPECT_NE(nullptr, chunk.Log(3, log_time(), 1000, 3, 1, log_message, sizeof(log_message)));
+
+    EXPECT_FALSE(chunk.CanLog(1));
+}
+
+TEST(SerializedLogChunk, three_logs) {
+    size_t chunk_size = 10 * 4096;
+    auto chunk = SerializedLogChunk{chunk_size};
+
+    chunk.Log(2, log_time(0x1234, 0x5678), 0x111, 0x222, 0x333, "initial message",
+              strlen("initial message"));
+    chunk.Log(3, log_time(0x2345, 0x6789), 0x444, 0x555, 0x666, "second message",
+              strlen("second message"));
+    auto uint64_t_max = std::numeric_limits<uint64_t>::max();
+    auto uint32_t_max = std::numeric_limits<uint32_t>::max();
+    chunk.Log(uint64_t_max, log_time(uint32_t_max, uint32_t_max), uint32_t_max, uint32_t_max,
+              uint32_t_max, "last message", strlen("last message"));
+
+    static const char expected_buffer_data[] =
+            "\x11\x01\x00\x00\x22\x02\x00\x00\x33\x03\x00\x00"  // UID PID TID
+            "\x02\x00\x00\x00\x00\x00\x00\x00"                  // Sequence
+            "\x34\x12\x00\x00\x78\x56\x00\x00"                  // Timestamp
+            "\x0F\x00initial message"                           // msg_len + message
+            "\x44\x04\x00\x00\x55\x05\x00\x00\x66\x06\x00\x00"  // UID PID TID
+            "\x03\x00\x00\x00\x00\x00\x00\x00"                  // Sequence
+            "\x45\x23\x00\x00\x89\x67\x00\x00"                  // Timestamp
+            "\x0E\x00second message"                            // msg_len + message
+            "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF"  // UID PID TID
+            "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF"                  // Sequence
+            "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF"                  // Timestamp
+            "\x0C\x00last message";                             // msg_len + message
+
+    for (size_t i = 0; i < chunk_size; ++i) {
+        if (i < sizeof(expected_buffer_data)) {
+            EXPECT_EQ(static_cast<uint8_t>(expected_buffer_data[i]), chunk.data()[i])
+                    << "position: " << i;
+        } else {
+            EXPECT_EQ(0, chunk.data()[i]) << "position: " << i;
+        }
+    }
+}
+
+// Check that the CHECK() in DecReaderRefCount() if the ref count goes bad is caught.
+TEST(SerializedLogChunk, catch_DecCompressedRef_CHECK) {
+    size_t chunk_size = 10 * 4096;
+    auto chunk = SerializedLogChunk{chunk_size};
+    EXPECT_DEATH({ chunk.DecReaderRefCount(true); }, "");
+    EXPECT_DEATH({ chunk.DecReaderRefCount(false); }, "");
+}
+
+// Check that the CHECK() in ClearUidLogs() if the ref count is greater than 0 is caught.
+TEST(SerializedLogChunk, catch_ClearUidLogs_CHECK) {
+    size_t chunk_size = 10 * 4096;
+    auto chunk = SerializedLogChunk{chunk_size};
+    chunk.IncReaderRefCount();
+    EXPECT_DEATH({ chunk.ClearUidLogs(1000, LOG_ID_MAIN, nullptr); }, "");
+    chunk.DecReaderRefCount(false);
+}
+
+class UidClearTest : public testing::TestWithParam<bool> {
+  protected:
+    template <typename Write, typename Check>
+    void Test(const Write& write, const Check& check, bool expected_result) {
+        write(chunk_);
+
+        bool finish_writing = GetParam();
+        if (finish_writing) {
+            chunk_.FinishWriting();
+        }
+        EXPECT_EQ(expected_result, chunk_.ClearUidLogs(kUidToClear, LOG_ID_MAIN, nullptr));
+        if (finish_writing) {
+            chunk_.IncReaderRefCount();
+        }
+
+        check(chunk_);
+
+        if (finish_writing) {
+            chunk_.DecReaderRefCount(false);
+        }
+    }
+
+    static constexpr size_t kChunkSize = 10 * 4096;
+    static constexpr uid_t kUidToClear = 1000;
+    static constexpr uid_t kOtherUid = 1234;
+
+    SerializedLogChunk chunk_{kChunkSize};
+};
+
+// Test that ClearUidLogs() is a no-op if there are no logs of that UID in the buffer.
+TEST_P(UidClearTest, no_logs_in_chunk) {
+    auto write = [](SerializedLogChunk&) {};
+    auto check = [](SerializedLogChunk&) {};
+
+    Test(write, check, true);
+}
+
+// Test that ClearUidLogs() is a no-op if there are no logs of that UID in the buffer.
+TEST_P(UidClearTest, no_logs_from_uid) {
+    static const char msg[] = "this is a log message";
+    auto write = [](SerializedLogChunk& chunk) {
+        chunk.Log(1, log_time(), kOtherUid, 1, 2, msg, sizeof(msg));
+    };
+
+    auto check = [](SerializedLogChunk& chunk) {
+        auto* entry = chunk.log_entry(0);
+        EXPECT_STREQ(msg, entry->msg());
+    };
+
+    Test(write, check, false);
+}
+
+// Test that ClearUidLogs() returns true if all logs in a given buffer correspond to the given UID.
+TEST_P(UidClearTest, all_single) {
+    static const char msg[] = "this is a log message";
+    auto write = [](SerializedLogChunk& chunk) {
+        chunk.Log(1, log_time(), kUidToClear, 1, 2, msg, sizeof(msg));
+    };
+    auto check = [](SerializedLogChunk&) {};
+
+    Test(write, check, true);
+}
+
+// Test that ClearUidLogs() returns true if all logs in a given buffer correspond to the given UID.
+TEST_P(UidClearTest, all_multiple) {
+    static const char msg[] = "this is a log message";
+    auto write = [](SerializedLogChunk& chunk) {
+        chunk.Log(2, log_time(), kUidToClear, 1, 2, msg, sizeof(msg));
+        chunk.Log(3, log_time(), kUidToClear, 1, 2, msg, sizeof(msg));
+        chunk.Log(4, log_time(), kUidToClear, 1, 2, msg, sizeof(msg));
+    };
+    auto check = [](SerializedLogChunk&) {};
+
+    Test(write, check, true);
+}
+
+static std::string MakePrintable(const uint8_t* in, size_t length) {
+    std::string result;
+    for (size_t i = 0; i < length; ++i) {
+        uint8_t c = in[i];
+        if (isprint(c)) {
+            result.push_back(c);
+        } else {
+            result.append(StringPrintf("\\%02x", static_cast<int>(c) & 0xFF));
+        }
+    }
+    return result;
+}
+
+// This test clears UID logs at the beginning and end of the buffer, as well as two back to back
+// logs in the interior.
+TEST_P(UidClearTest, clear_beginning_and_end) {
+    static const char msg1[] = "this is a log message";
+    static const char msg2[] = "non-cleared message";
+    static const char msg3[] = "back to back cleared messages";
+    static const char msg4[] = "second in a row gone";
+    static const char msg5[] = "but we save this one";
+    static const char msg6[] = "and this 1!";
+    static const char msg7[] = "the last one goes too";
+    auto write = [](SerializedLogChunk& chunk) {
+        ASSERT_NE(nullptr, chunk.Log(1, log_time(), kUidToClear, 1, 2, msg1, sizeof(msg1)));
+        ASSERT_NE(nullptr, chunk.Log(2, log_time(), kOtherUid, 1, 2, msg2, sizeof(msg2)));
+        ASSERT_NE(nullptr, chunk.Log(3, log_time(), kUidToClear, 1, 2, msg3, sizeof(msg3)));
+        ASSERT_NE(nullptr, chunk.Log(4, log_time(), kUidToClear, 1, 2, msg4, sizeof(msg4)));
+        ASSERT_NE(nullptr, chunk.Log(5, log_time(), kOtherUid, 1, 2, msg5, sizeof(msg5)));
+        ASSERT_NE(nullptr, chunk.Log(6, log_time(), kOtherUid, 1, 2, msg6, sizeof(msg6)));
+        ASSERT_NE(nullptr, chunk.Log(7, log_time(), kUidToClear, 1, 2, msg7, sizeof(msg7)));
+    };
+
+    auto check = [](SerializedLogChunk& chunk) {
+        size_t read_offset = 0;
+        auto* entry = chunk.log_entry(read_offset);
+        EXPECT_STREQ(msg2, entry->msg());
+        read_offset += entry->total_len();
+
+        entry = chunk.log_entry(read_offset);
+        EXPECT_STREQ(msg5, entry->msg());
+        read_offset += entry->total_len();
+
+        entry = chunk.log_entry(read_offset);
+        EXPECT_STREQ(msg6, entry->msg()) << MakePrintable(chunk.data(), chunk.write_offset());
+        read_offset += entry->total_len();
+
+        EXPECT_EQ(static_cast<int>(read_offset), chunk.write_offset());
+    };
+    Test(write, check, false);
+}
+
+// This tests the opposite case of beginning_and_end, in which we don't clear the beginning or end
+// logs.  There is a single log pruned in the middle instead of back to back logs.
+TEST_P(UidClearTest, save_beginning_and_end) {
+    static const char msg1[] = "saved first message";
+    static const char msg2[] = "cleared interior message";
+    static const char msg3[] = "last message stays";
+    auto write = [](SerializedLogChunk& chunk) {
+        ASSERT_NE(nullptr, chunk.Log(1, log_time(), kOtherUid, 1, 2, msg1, sizeof(msg1)));
+        ASSERT_NE(nullptr, chunk.Log(2, log_time(), kUidToClear, 1, 2, msg2, sizeof(msg2)));
+        ASSERT_NE(nullptr, chunk.Log(3, log_time(), kOtherUid, 1, 2, msg3, sizeof(msg3)));
+    };
+
+    auto check = [](SerializedLogChunk& chunk) {
+        size_t read_offset = 0;
+        auto* entry = chunk.log_entry(read_offset);
+        EXPECT_STREQ(msg1, entry->msg());
+        read_offset += entry->total_len();
+
+        entry = chunk.log_entry(read_offset);
+        EXPECT_STREQ(msg3, entry->msg());
+        read_offset += entry->total_len();
+
+        EXPECT_EQ(static_cast<int>(read_offset), chunk.write_offset());
+    };
+    Test(write, check, false);
+}
+
+INSTANTIATE_TEST_CASE_P(UidClearTests, UidClearTest, testing::Values(true, false));
diff --git a/logd/SerializedLogEntry.h b/logd/SerializedLogEntry.h
new file mode 100644
index 0000000..f599abe
--- /dev/null
+++ b/logd/SerializedLogEntry.h
@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <sys/types.h>
+
+#include <log/log.h>
+#include <log/log_read.h>
+
+#include "LogStatistics.h"
+#include "LogWriter.h"
+
+// These structs are packed into a single chunk of memory for each log type within a
+// SerializedLogChunk object.  Their message is contained immediately at the end of the struct.  The
+// address of the next log in the buffer is *this + sizeof(SerializedLogEntry) + msg_len_.  If that
+// value would overflow the chunk of memory associated with the SerializedLogChunk object, then a
+// new SerializedLogChunk must be allocated to contain the next SerializedLogEntry.
+class __attribute__((packed)) SerializedLogEntry {
+  public:
+    SerializedLogEntry(uid_t uid, pid_t pid, pid_t tid, uint64_t sequence, log_time realtime,
+                       uint16_t len)
+        : uid_(uid),
+          pid_(pid),
+          tid_(tid),
+          sequence_(sequence),
+          realtime_(realtime),
+          msg_len_(len) {}
+    SerializedLogEntry(const SerializedLogEntry& elem) = delete;
+    SerializedLogEntry& operator=(const SerializedLogEntry& elem) = delete;
+    ~SerializedLogEntry() {
+        // Never place anything in this destructor.  This class is in place constructed and never
+        // destructed.
+    }
+
+    LogStatisticsElement ToLogStatisticsElement(log_id_t log_id) const {
+        return LogStatisticsElement{
+                .uid = uid(),
+                .pid = pid(),
+                .tid = tid(),
+                .tag = IsBinary(log_id) ? MsgToTag(msg(), msg_len()) : 0,
+                .realtime = realtime(),
+                .msg = msg(),
+                .msg_len = msg_len(),
+                .dropped_count = 0,
+                .log_id = log_id,
+        };
+    }
+
+    bool Flush(LogWriter* writer, log_id_t log_id) const {
+        struct logger_entry entry = {};
+
+        entry.hdr_size = sizeof(struct logger_entry);
+        entry.lid = log_id;
+        entry.pid = pid();
+        entry.tid = tid();
+        entry.uid = uid();
+        entry.sec = realtime().tv_sec;
+        entry.nsec = realtime().tv_nsec;
+        entry.len = msg_len();
+
+        return writer->Write(entry, msg());
+    }
+
+    uid_t uid() const { return uid_; }
+    pid_t pid() const { return pid_; }
+    pid_t tid() const { return tid_; }
+    uint16_t msg_len() const { return msg_len_; }
+    uint64_t sequence() const { return sequence_; }
+    log_time realtime() const { return realtime_; }
+
+    char* msg() { return reinterpret_cast<char*>(this) + sizeof(*this); }
+    const char* msg() const { return reinterpret_cast<const char*>(this) + sizeof(*this); }
+    uint16_t total_len() const { return sizeof(*this) + msg_len_; }
+
+  private:
+    const uint32_t uid_;
+    const uint32_t pid_;
+    const uint32_t tid_;
+    const uint64_t sequence_;
+    const log_time realtime_;
+    const uint16_t msg_len_;
+};
diff --git a/logd/SimpleLogBuffer.cpp b/logd/SimpleLogBuffer.cpp
index 292a7e4..ec08d54 100644
--- a/logd/SimpleLogBuffer.cpp
+++ b/logd/SimpleLogBuffer.cpp
@@ -212,46 +212,38 @@
     return true;
 }
 
-// clear all rows of type "id" from the buffer.
 bool SimpleLogBuffer::Clear(log_id_t id, uid_t uid) {
-    bool busy = true;
-    // If it takes more than 4 tries (seconds) to clear, then kill reader(s)
-    for (int retry = 4;;) {
-        if (retry == 1) {  // last pass
-            // Check if it is still busy after the sleep, we say prune
-            // one entry, not another clear run, so we are looking for
-            // the quick side effect of the return value to tell us if
-            // we have a _blocked_ reader.
-            {
-                auto lock = std::lock_guard{lock_};
-                busy = Prune(id, 1, uid);
-            }
-            // It is still busy, blocked reader(s), lets kill them all!
-            // otherwise, lets be a good citizen and preserve the slow
-            // readers and let the clear run (below) deal with determining
-            // if we are still blocked and return an error code to caller.
-            if (busy) {
-                auto reader_threads_lock = std::lock_guard{reader_list_->reader_threads_lock()};
-                for (const auto& reader_thread : reader_list_->reader_threads()) {
-                    if (reader_thread->IsWatching(id)) {
-                        LOG(WARNING) << "Kicking blocked reader, " << reader_thread->name()
-                                     << ", from LogBuffer::clear()";
-                        reader_thread->release_Locked();
-                    }
-                }
-            }
-        }
+    // Try three times to clear, then disconnect the readers and try one final time.
+    for (int retry = 0; retry < 3; ++retry) {
         {
             auto lock = std::lock_guard{lock_};
-            busy = Prune(id, ULONG_MAX, uid);
+            if (Prune(id, ULONG_MAX, uid)) {
+                return true;
+            }
         }
-
-        if (!busy || !--retry) {
-            break;
-        }
-        sleep(1);  // Let reader(s) catch up after notification
+        sleep(1);
     }
-    return busy;
+    // Check if it is still busy after the sleep, we try to prune one entry, not another clear run,
+    // so we are looking for the quick side effect of the return value to tell us if we have a
+    // _blocked_ reader.
+    bool busy = false;
+    {
+        auto lock = std::lock_guard{lock_};
+        busy = !Prune(id, 1, uid);
+    }
+    // It is still busy, disconnect all readers.
+    if (busy) {
+        auto reader_threads_lock = std::lock_guard{reader_list_->reader_threads_lock()};
+        for (const auto& reader_thread : reader_list_->reader_threads()) {
+            if (reader_thread->IsWatching(id)) {
+                LOG(WARNING) << "Kicking blocked reader, " << reader_thread->name()
+                             << ", from LogBuffer::clear()";
+                reader_thread->release_Locked();
+            }
+        }
+    }
+    auto lock = std::lock_guard{lock_};
+    return Prune(id, ULONG_MAX, uid);
 }
 
 // get the total space allocated to "id"
@@ -313,16 +305,16 @@
 
         if (oldest && oldest->start() <= element.sequence()) {
             KickReader(oldest, id, prune_rows);
-            return true;
+            return false;
         }
 
         stats_->Subtract(element.ToLogStatisticsElement());
         it = Erase(it);
         if (--prune_rows == 0) {
-            return false;
+            return true;
         }
     }
-    return false;
+    return true;
 }
 
 std::list<LogBufferElement>::iterator SimpleLogBuffer::Erase(
diff --git a/logd/SimpleLogBuffer.h b/logd/SimpleLogBuffer.h
index 2172507..9f7d699 100644
--- a/logd/SimpleLogBuffer.h
+++ b/logd/SimpleLogBuffer.h
@@ -31,7 +31,7 @@
   public:
     SimpleLogBuffer(LogReaderList* reader_list, LogTags* tags, LogStatistics* stats);
     ~SimpleLogBuffer();
-    void Init() override;
+    void Init() override final;
 
     int Log(log_id_t log_id, log_time realtime, uid_t uid, pid_t pid, pid_t tid, const char* msg,
             uint16_t len) override;
@@ -42,7 +42,7 @@
 
     bool Clear(log_id_t id, uid_t uid) override;
     unsigned long GetSize(log_id_t id) override;
-    int SetSize(log_id_t id, unsigned long size) override;
+    int SetSize(log_id_t id, unsigned long size) override final;
 
     uint64_t sequence() const override { return sequence_.load(std::memory_order_relaxed); }
 
diff --git a/logd/fuzz/Android.bp b/logd/fuzz/Android.bp
index f65fbdf..9834ff0 100644
--- a/logd/fuzz/Android.bp
+++ b/logd/fuzz/Android.bp
@@ -26,6 +26,8 @@
         "liblogd",
         "libcutils",
         "libsysutils",
+        "libz",
+        "libzstd",
     ],
     cflags: ["-Werror"],
 }
diff --git a/logd/fuzz/log_buffer_log_fuzzer.cpp b/logd/fuzz/log_buffer_log_fuzzer.cpp
index b576ddf..a7a1792 100644
--- a/logd/fuzz/log_buffer_log_fuzzer.cpp
+++ b/logd/fuzz/log_buffer_log_fuzzer.cpp
@@ -97,7 +97,7 @@
     size_t data_left = size;
     const uint8_t** pdata = &data;
 
-    prune_list.init(nullptr);
+    prune_list.Init(nullptr);
     // We want to get pruning code to get called.
     log_id_for_each(i) { log_buffer->SetSize(i, 10000); }
 
diff --git a/logd/main.cpp b/logd/main.cpp
index 773ffb8..46b6567 100644
--- a/logd/main.cpp
+++ b/logd/main.cpp
@@ -58,6 +58,7 @@
 #include "LogStatistics.h"
 #include "LogTags.h"
 #include "LogUtils.h"
+#include "SerializedLogBuffer.h"
 #include "SimpleLogBuffer.h"
 
 #define KMSG_PRIORITY(PRI)                                 \
diff --git a/logd/rwlock.h b/logd/rwlock.h
index 2b27ff1..c37721e 100644
--- a/logd/rwlock.h
+++ b/logd/rwlock.h
@@ -43,7 +43,7 @@
 
 class SCOPED_CAPABILITY SharedLock {
   public:
-    SharedLock(RwLock& lock) ACQUIRE_SHARED(lock) : lock_(lock) { lock_.lock_shared(); }
+    explicit SharedLock(RwLock& lock) ACQUIRE_SHARED(lock) : lock_(lock) { lock_.lock_shared(); }
     ~SharedLock() RELEASE() { lock_.unlock(); }
 
     void lock_shared() ACQUIRE_SHARED() { lock_.lock_shared(); }
diff --git a/rootdir/init.rc b/rootdir/init.rc
index 427ac4b..01551e2 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -490,6 +490,9 @@
     chown root log /proc/slabinfo
     chmod 0440 /proc/slabinfo
 
+    chown root log /proc/pagetypeinfo
+    chmod 0440 /proc/pagetypeinfo
+
     #change permissions on kmsg & sysrq-trigger so bugreports can grab kthread stacks
     chown root system /proc/kmsg
     chmod 0440 /proc/kmsg
diff --git a/shell_and_utilities/Android.bp b/shell_and_utilities/Android.bp
index b5a5fb6..f83c43e 100644
--- a/shell_and_utilities/Android.bp
+++ b/shell_and_utilities/Android.bp
@@ -36,7 +36,7 @@
         "sh.recovery",
         "toolbox.recovery",
         "toybox.recovery",
-        "unzip.recovery",
+        "ziptool.recovery",
     ],
 }
 
diff --git a/toolbox/modprobe.cpp b/toolbox/modprobe.cpp
index 1b5f54e..3ffa74e 100644
--- a/toolbox/modprobe.cpp
+++ b/toolbox/modprobe.cpp
@@ -36,7 +36,7 @@
     std::cerr << "  modprobe [-alrqvsDb] [-d DIR] MODULE [symbol=value][...]" << std::endl;
     std::cerr << std::endl;
     std::cerr << "Options:" << std::endl;
-    std::cerr << "  -b: Apply blacklist to module names too" << std::endl;
+    std::cerr << "  -b: Apply blocklist to module names too" << std::endl;
     std::cerr << "  -d: Load modules from DIR, option may be used multiple times" << std::endl;
     std::cerr << "  -D: Print dependencies for modules only, do not load";
     std::cerr << "  -h: Print this help" << std::endl;
@@ -59,7 +59,7 @@
     std::string module_parameters;
     std::vector<std::string> mod_dirs;
     modprobe_mode mode = AddModulesMode;
-    bool blacklist = false;
+    bool blocklist = false;
     bool verbose = false;
     int rv = EXIT_SUCCESS;
 
@@ -72,7 +72,7 @@
                 check_mode();
                 break;
             case 'b':
-                blacklist = true;
+                blocklist = true;
                 break;
             case 'd':
                 mod_dirs.emplace_back(optarg);
@@ -151,8 +151,8 @@
 
     Modprobe m(mod_dirs);
     m.EnableVerbose(verbose);
-    if (blacklist) {
-        m.EnableBlacklist(true);
+    if (blocklist) {
+        m.EnableBlocklist(true);
     }
 
     for (const auto& module : modules) {
diff --git a/trusty/storage/proxy/rpmb.c b/trusty/storage/proxy/rpmb.c
index 7dfd0d0..d1ed649 100644
--- a/trusty/storage/proxy/rpmb.c
+++ b/trusty/storage/proxy/rpmb.c
@@ -231,7 +231,7 @@
 
     if (req->read_size) {
         /* Prepare SECURITY PROTOCOL IN command. */
-        out_cdb.length = __builtin_bswap32(req->read_size);
+        in_cdb.length = __builtin_bswap32(req->read_size);
         sg_io_hdr_t io_hdr;
         set_sg_io_hdr(&io_hdr, SG_DXFER_FROM_DEV, sizeof(in_cdb), sizeof(sense_buffer),
                       req->read_size, read_buf, (unsigned char*)&in_cdb, sense_buffer);