diff --git a/libmeminfo/tools/Android.bp b/libmeminfo/tools/Android.bp
index 715d63d..1f93494 100644
--- a/libmeminfo/tools/Android.bp
+++ b/libmeminfo/tools/Android.bp
@@ -13,11 +13,24 @@
 // limitations under the License.
 
 cc_binary {
+    name: "librank2",
+    cflags: [
+        "-Wall",
+        "-Werror",
+    ],
+
+    srcs: ["librank.cpp"],
+    shared_libs: [
+        "libbase",
+        "libmeminfo",
+    ],
+}
+
+cc_binary {
     name: "procmem2",
     cflags: [
         "-Wall",
         "-Werror",
-        "-Wno-unused-parameter",
     ],
 
     srcs: ["procmem.cpp"],
@@ -32,7 +45,6 @@
     cflags: [
         "-Wall",
         "-Werror",
-        "-Wno-unused-parameter",
     ],
 
     srcs: ["procrank.cpp"],
diff --git a/libmeminfo/tools/librank.cpp b/libmeminfo/tools/librank.cpp
new file mode 100644
index 0000000..7668640
--- /dev/null
+++ b/libmeminfo/tools/librank.cpp
@@ -0,0 +1,350 @@
+/*
+ * Copyright (C) 2018 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 <dirent.h>
+#include <errno.h>
+#include <error.h>
+#include <inttypes.h>
+#include <linux/kernel-page-flags.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <algorithm>
+#include <memory>
+#include <vector>
+
+#include <android-base/file.h>
+#include <android-base/parseint.h>
+#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
+
+#include <meminfo/procmeminfo.h>
+
+using ::android::meminfo::MemUsage;
+using ::android::meminfo::ProcMemInfo;
+using ::android::meminfo::Vma;
+
+[[noreturn]] static void usage(const char* myname, int exit_status) {
+    fprintf(stderr,
+            "Usage: %s [ -P | -L ] [ -v | -r | -p | -u | -s | -h ]\n"
+            "\n"
+            "Sort options:\n"
+            "    -v  Sort processes by VSS.\n"
+            "    -r  Sort processes by RSS.\n"
+            "    -p  Sort processes by PSS.\n"
+            "    -u  Sort processes by USS.\n"
+            "    -s  Sort processes by swap.\n"
+            "        (Default sort order is PSS.)\n"
+            "    -a  Show all mappings, including stack, heap and anon.\n"
+            "    -P /path  Limit libraries displayed to those in path.\n"
+            "    -R  Reverse sort order (default is descending).\n"
+            "    -m [r][w][x] Only list pages that exactly match permissions\n"
+            "    -c  Only show cached (storage backed) pages\n"
+            "    -C  Only show non-cached (ram/swap backed) pages\n"
+            "    -k  Only show pages collapsed by KSM\n"
+            "    -h  Display this help screen.\n",
+            myname);
+    exit(exit_status);
+}
+
+static void add_mem_usage(MemUsage* to, const MemUsage& from) {
+    to->vss += from.vss;
+    to->rss += from.rss;
+    to->pss += from.pss;
+    to->uss += from.uss;
+
+    to->swap += from.swap;
+
+    to->private_clean += from.private_clean;
+    to->private_dirty += from.private_dirty;
+
+    to->shared_clean += from.shared_clean;
+    to->shared_dirty += from.shared_dirty;
+}
+
+struct ProcessRecord {
+  public:
+    ProcessRecord(pid_t pid) : pid_(-1), cmdline_("") {
+        std::string fname = ::android::base::StringPrintf("/proc/%d/cmdline", pid);
+        std::string cmdline;
+        if (!::android::base::ReadFileToString(fname, &cmdline)) {
+            fprintf(stderr, "Failed to read cmdline from: %s\n", fname.c_str());
+            return;
+        }
+        // We deliberately don't read the proc/<pid>cmdline file directly into 'cmdline_'
+        // because of some processes showing up cmdlines that end with "0x00 0x0A 0x00"
+        // e.g. xtra-daemon, lowi-server
+        // The .c_str() assignment below then takes care of trimming the cmdline at the first
+        // 0x00. This is how original procrank worked (luckily)
+        cmdline_ = cmdline.c_str();
+        pid_ = pid;
+        usage_.clear();
+    }
+
+    ~ProcessRecord() = default;
+
+    bool valid() const { return pid_ != -1; }
+
+    // Getters
+    pid_t pid() const { return pid_; }
+    const std::string& cmdline() const { return cmdline_; }
+    const MemUsage& usage() const { return usage_; }
+
+    // Add to the usage
+    void AddUsage(const MemUsage& mem_usage) { add_mem_usage(&usage_, mem_usage); }
+
+  private:
+    pid_t pid_;
+    std::string cmdline_;
+    MemUsage usage_;
+};
+
+struct LibRecord {
+  public:
+    LibRecord(const std::string& name) : name_(name) {}
+    ~LibRecord() = default;
+
+    const std::string& name() const { return name_; }
+    const MemUsage& usage() const { return usage_; }
+    const std::vector<ProcessRecord>& processes() const { return procs_; }
+    uint64_t pss() const { return usage_.pss; }
+    void AddUsage(const ProcessRecord& proc, const MemUsage& mem_usage) {
+        auto process = std::find_if(procs_.begin(), procs_.end(),
+                                    [&](auto p) -> bool { return p.pid() == proc.pid(); });
+        if (process == procs_.end()) {
+            process = procs_.emplace(procs_.end(), proc.pid());
+        }
+        process->AddUsage(mem_usage);
+        add_mem_usage(&usage_, mem_usage);
+    }
+
+    void Sort(std::function<bool(const ProcessRecord&, const ProcessRecord&)>& sorter) {
+        std::sort(procs_.begin(), procs_.end(), sorter);
+    }
+
+  private:
+    std::string name_;
+    MemUsage usage_;
+    std::vector<ProcessRecord> procs_;
+};
+
+// List of every library / map
+static std::vector<LibRecord> g_libs;
+
+// List of library/map names that we don't want to show by default
+static const std::vector<std::string> g_blacklisted_libs = {"[heap]", "[stack]"};
+
+// Global flags affected by command line
+static uint64_t g_pgflags = 0;
+static uint64_t g_pgflags_mask = 0;
+static uint16_t g_mapflags_mask = 0;
+static bool g_all_libs = false;
+static bool g_has_swap = false;
+static bool g_reverse_sort = false;
+static std::string g_prefix_filter = "";
+
+static bool read_all_pids(std::function<bool(pid_t pid)> for_each_pid) {
+    std::unique_ptr<DIR, int (*)(DIR*)> procdir(opendir("/proc"), closedir);
+    if (!procdir) return false;
+
+    struct dirent* dir;
+    pid_t pid;
+    while ((dir = readdir(procdir.get()))) {
+        if (!::android::base::ParseInt(dir->d_name, &pid)) continue;
+        if (!for_each_pid(pid)) return false;
+    }
+
+    return true;
+}
+
+static bool scan_libs_per_process(pid_t pid) {
+    ProcMemInfo pmem(pid, false, g_pgflags, g_pgflags_mask);
+    const std::vector<Vma> maps = pmem.Maps();
+    if (maps.size() == 0) {
+        // nothing to do here, continue
+        return true;
+    }
+
+    ProcessRecord proc(pid);
+    if (!proc.valid()) {
+        fprintf(stderr, "Failed to create process record for process: %d\n", pid);
+        return false;
+    }
+
+    for (auto& map : maps) {
+        // skip library / map if prefix for the path doesn't match
+        if (!g_prefix_filter.empty() && !::android::base::StartsWith(map.name, g_prefix_filter)) {
+            continue;
+        }
+        // Skip maps based on map permissions
+        if (g_mapflags_mask &&
+            ((map.flags & (PROT_READ | PROT_WRITE | PROT_EXEC)) != g_mapflags_mask)) {
+            continue;
+        }
+
+        // skip blacklisted library / map names
+        if (!g_all_libs && (std::find(g_blacklisted_libs.begin(), g_blacklisted_libs.end(),
+                                      map.name) != g_blacklisted_libs.end())) {
+            continue;
+        }
+
+        auto lib = std::find_if(g_libs.begin(), g_libs.end(),
+                                [&](auto l) -> bool { return map.name == l.name(); });
+        if (lib == g_libs.end()) {
+            lib = g_libs.emplace(g_libs.end(), map.name);
+        }
+
+        lib->AddUsage(proc, map.usage);
+        if (!g_has_swap && map.usage.swap) {
+            g_has_swap = true;
+        }
+    }
+
+    return true;
+}
+
+static uint16_t parse_mapflags(const char* mapflags) {
+    uint16_t ret = 0;
+    for (const char* p = mapflags; *p; p++) {
+        switch (*p) {
+            case 'r':
+                ret |= PROT_READ;
+                break;
+            case 'w':
+                ret |= PROT_WRITE;
+                break;
+            case 'x':
+                ret |= PROT_EXEC;
+                break;
+            default:
+                error(EXIT_FAILURE, 0, "Invalid permissions string: %s, %s", mapflags, p);
+        }
+    }
+
+    return ret;
+}
+
+int main(int argc, char* argv[]) {
+    int opt;
+
+    auto pss_sort = [](const ProcessRecord& a, const ProcessRecord& b) {
+        return g_reverse_sort ? a.usage().pss < b.usage().pss : a.usage().pss > b.usage().pss;
+    };
+
+    auto uss_sort = [](const ProcessRecord& a, const ProcessRecord& b) {
+        return g_reverse_sort ? a.usage().uss < b.usage().uss : a.usage().uss > b.usage().uss;
+    };
+
+    auto vss_sort = [](const ProcessRecord& a, const ProcessRecord& b) {
+        return g_reverse_sort ? a.usage().vss < b.usage().vss : a.usage().vss > b.usage().vss;
+    };
+
+    auto rss_sort = [](const ProcessRecord& a, const ProcessRecord& b) {
+        return g_reverse_sort ? a.usage().rss < b.usage().rss : a.usage().rss > b.usage().rss;
+    };
+
+    auto swap_sort = [](const ProcessRecord& a, const ProcessRecord& b) {
+        return g_reverse_sort ? a.usage().swap < b.usage().swap : a.usage().swap > b.usage().swap;
+    };
+
+    std::function<bool(const ProcessRecord&, const ProcessRecord&)> sort_func = pss_sort;
+
+    while ((opt = getopt(argc, argv, "acChkm:pP:uvrsR")) != -1) {
+        switch (opt) {
+            case 'a':
+                g_all_libs = true;
+                break;
+            case 'c':
+                g_pgflags = 0;
+                g_pgflags_mask = (1 << KPF_SWAPBACKED);
+                break;
+            case 'C':
+                g_pgflags = g_pgflags_mask = (1 << KPF_SWAPBACKED);
+                break;
+            case 'h':
+                usage(argv[0], EXIT_SUCCESS);
+            case 'k':
+                g_pgflags = g_pgflags_mask = (1 << KPF_KSM);
+                break;
+            case 'm':
+                g_mapflags_mask = parse_mapflags(optarg);
+                break;
+            case 'p':
+                sort_func = pss_sort;
+                break;
+            case 'P':
+                g_prefix_filter = optarg;
+                break;
+            case 'u':
+                sort_func = uss_sort;
+                break;
+            case 'v':
+                sort_func = vss_sort;
+                break;
+            case 'r':
+                sort_func = rss_sort;
+                break;
+            case 's':
+                sort_func = swap_sort;
+                break;
+            case 'R':
+                g_reverse_sort = true;
+                break;
+            default:
+                usage(argv[0], EXIT_FAILURE);
+        }
+    }
+
+    if (!read_all_pids(scan_libs_per_process)) {
+        error(EXIT_FAILURE, 0, "Failed to read all pids from the system");
+    }
+
+    printf(" %6s   %7s   %6s   %6s   %6s  ", "RSStot", "VSS", "RSS", "PSS", "USS");
+    if (g_has_swap) {
+        printf(" %6s  ", "Swap");
+    }
+    printf("Name/PID\n");
+
+    // sort the libraries by their pss
+    std::sort(g_libs.begin(), g_libs.end(),
+              [](const LibRecord& l1, const LibRecord& l2) { return l1.pss() > l2.pss(); });
+
+    for (auto& lib : g_libs) {
+        printf("%6" PRIu64 "K   %7s   %6s   %6s   %6s  ", lib.pss() / 1024, "", "", "", "");
+        if (g_has_swap) {
+            printf(" %6s  ", "");
+        }
+        printf("%s\n", lib.name().c_str());
+
+        // sort all mappings first
+        lib.Sort(sort_func);
+
+        for (auto& p : lib.processes()) {
+            const MemUsage& usage = p.usage();
+            printf(" %6s  %7" PRIu64 "K  %6" PRIu64 "K  %6" PRIu64 "K  %6" PRIu64 "K  ", "",
+                   usage.vss / 1024, usage.rss / 1024, usage.pss / 1024, usage.uss / 1024);
+            if (g_has_swap) {
+                printf("%6" PRIu64 "K  ", usage.swap / 1024);
+            }
+            printf("  %s [%d]\n", p.cmdline().c_str(), p.pid());
+        }
+    }
+
+    return 0;
+}