Reland "EGL: Refactor multifile blobcache"
This reverts commit 437354181694798af24038dd65455eeab06a329e.
Previous CL was reverted due to boot time regressions.
Main change from previous CL is removal of thread.join() if
the thread was not initialized. This was happening at boot
because a number of processes try to use the cache without
providing a location for the cache. In that case, both old
and new cache will not initialize.
Test: Boot (quickly)
Test: pubg_mobile_launch ANGLE trace
Test: /data/nativetest64/EGL_test/EGL_test
Test: /data/nativetest64/libEGL_test/libEGL_test
Bug: b/266725576
Change-Id: Ib9add1c8342278a46c2e629c919719f973f8c612
diff --git a/opengl/libs/EGL/MultifileBlobCache.cpp b/opengl/libs/EGL/MultifileBlobCache.cpp
new file mode 100644
index 0000000..99af299
--- /dev/null
+++ b/opengl/libs/EGL/MultifileBlobCache.cpp
@@ -0,0 +1,689 @@
+/*
+ ** Copyright 2022, 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.
+ */
+
+// #define LOG_NDEBUG 0
+
+#include "MultifileBlobCache.h"
+
+#include <dirent.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <log/log.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <time.h>
+#include <unistd.h>
+#include <utime.h>
+
+#include <algorithm>
+#include <chrono>
+#include <limits>
+#include <locale>
+
+#include <utils/JenkinsHash.h>
+
+using namespace std::literals;
+
+namespace {
+
+// Open the file and determine the size of the value it contains
+size_t getValueSizeFromFile(int fd, const std::string& entryPath) {
+ // Read the beginning of the file to get header
+ android::MultifileHeader header;
+ size_t result = read(fd, static_cast<void*>(&header), sizeof(android::MultifileHeader));
+ if (result != sizeof(android::MultifileHeader)) {
+ ALOGE("Error reading MultifileHeader from cache entry (%s): %s", entryPath.c_str(),
+ std::strerror(errno));
+ return 0;
+ }
+
+ return header.valueSize;
+}
+
+// Helper function to close entries or free them
+void freeHotCacheEntry(android::MultifileHotCache& entry) {
+ if (entry.entryFd != -1) {
+ // If we have an fd, then this entry was added to hot cache via INIT or GET
+ // We need to unmap and close the entry
+ munmap(entry.entryBuffer, entry.entrySize);
+ close(entry.entryFd);
+ } else {
+ // Otherwise, this was added to hot cache during SET, so it was never mapped
+ // and fd was only on the deferred thread.
+ delete[] entry.entryBuffer;
+ }
+}
+
+} // namespace
+
+namespace android {
+
+MultifileBlobCache::MultifileBlobCache(size_t maxTotalSize, size_t maxHotCacheSize,
+ const std::string& baseDir)
+ : mInitialized(false),
+ mMaxTotalSize(maxTotalSize),
+ mTotalCacheSize(0),
+ mHotCacheLimit(maxHotCacheSize),
+ mHotCacheSize(0),
+ mWorkerThreadIdle(true) {
+ if (baseDir.empty()) {
+ ALOGV("INIT: no baseDir provided in MultifileBlobCache constructor, returning early.");
+ return;
+ }
+
+ // Establish the name of our multifile directory
+ mMultifileDirName = baseDir + ".multifile";
+
+ // Set a limit for max key and value, ensuring at least one entry can always fit in hot cache
+ mMaxKeySize = mHotCacheLimit / 4;
+ mMaxValueSize = mHotCacheLimit / 2;
+
+ ALOGV("INIT: Initializing multifile blobcache with maxKeySize=%zu and maxValueSize=%zu",
+ mMaxKeySize, mMaxValueSize);
+
+ // Initialize our cache with the contents of the directory
+ mTotalCacheSize = 0;
+
+ // Create the worker thread
+ mTaskThread = std::thread(&MultifileBlobCache::processTasks, this);
+
+ // See if the dir exists, and initialize using its contents
+ struct stat st;
+ if (stat(mMultifileDirName.c_str(), &st) == 0) {
+ // Read all the files and gather details, then preload their contents
+ DIR* dir;
+ struct dirent* entry;
+ if ((dir = opendir(mMultifileDirName.c_str())) != nullptr) {
+ while ((entry = readdir(dir)) != nullptr) {
+ if (entry->d_name == "."s || entry->d_name == ".."s) {
+ continue;
+ }
+
+ std::string entryName = entry->d_name;
+ std::string fullPath = mMultifileDirName + "/" + entryName;
+
+ // The filename is the same as the entryHash
+ uint32_t entryHash = static_cast<uint32_t>(strtoul(entry->d_name, nullptr, 10));
+
+ ALOGV("INIT: Checking entry %u", entryHash);
+
+ // Look up the details of the file
+ struct stat st;
+ if (stat(fullPath.c_str(), &st) != 0) {
+ ALOGE("Failed to stat %s", fullPath.c_str());
+ return;
+ }
+
+ // Open the file so we can read its header
+ int fd = open(fullPath.c_str(), O_RDONLY);
+ if (fd == -1) {
+ ALOGE("Cache error - failed to open fullPath: %s, error: %s", fullPath.c_str(),
+ std::strerror(errno));
+ return;
+ }
+
+ // Look up the details we track about each file
+ size_t valueSize = getValueSizeFromFile(fd, fullPath);
+
+ // If the cache entry is damaged or no good, remove it
+ // TODO: Perform any other checks
+ if (valueSize <= 0 || st.st_size <= 0 || st.st_atime <= 0) {
+ ALOGV("INIT: Entry %u has a problem! Removing.", entryHash);
+ if (remove(fullPath.c_str()) != 0) {
+ ALOGE("Error removing %s: %s", fullPath.c_str(), std::strerror(errno));
+ }
+ continue;
+ }
+
+ ALOGV("INIT: Entry %u is good, tracking it now.", entryHash);
+
+ // Note: Converting from off_t (signed) to size_t (unsigned)
+ size_t fileSize = static_cast<size_t>(st.st_size);
+ time_t accessTime = st.st_atime;
+
+ // Track details for rapid lookup later
+ trackEntry(entryHash, valueSize, fileSize, accessTime);
+
+ // Track the total size
+ increaseTotalCacheSize(fileSize);
+
+ // Preload the entry for fast retrieval
+ if ((mHotCacheSize + fileSize) < mHotCacheLimit) {
+ // Memory map the file
+ uint8_t* mappedEntry = reinterpret_cast<uint8_t*>(
+ mmap(nullptr, fileSize, PROT_READ, MAP_PRIVATE, fd, 0));
+ if (mappedEntry == MAP_FAILED) {
+ ALOGE("Failed to mmap cacheEntry, error: %s", std::strerror(errno));
+ }
+
+ ALOGV("INIT: Populating hot cache with fd = %i, cacheEntry = %p for "
+ "entryHash %u",
+ fd, mappedEntry, entryHash);
+
+ // Track the details of the preload so they can be retrieved later
+ if (!addToHotCache(entryHash, fd, mappedEntry, fileSize)) {
+ ALOGE("INIT Failed to add %u to hot cache", entryHash);
+ munmap(mappedEntry, fileSize);
+ close(fd);
+ return;
+ }
+ } else {
+ close(fd);
+ }
+ }
+ closedir(dir);
+ } else {
+ ALOGE("Unable to open filename: %s", mMultifileDirName.c_str());
+ }
+ } else {
+ // If the multifile directory does not exist, create it and start from scratch
+ if (mkdir(mMultifileDirName.c_str(), 0755) != 0 && (errno != EEXIST)) {
+ ALOGE("Unable to create directory (%s), errno (%i)", mMultifileDirName.c_str(), errno);
+ }
+ }
+
+ mInitialized = true;
+}
+
+MultifileBlobCache::~MultifileBlobCache() {
+ if (!mInitialized) {
+ return;
+ }
+
+ // Inform the worker thread we're done
+ ALOGV("DESCTRUCTOR: Shutting down worker thread");
+ DeferredTask task(TaskCommand::Exit);
+ queueTask(std::move(task));
+
+ // Wait for it to complete
+ ALOGV("DESCTRUCTOR: Waiting for worker thread to complete");
+ waitForWorkComplete();
+ if (mTaskThread.joinable()) {
+ mTaskThread.join();
+ }
+}
+
+// Set will add the entry to hot cache and start a deferred process to write it to disk
+void MultifileBlobCache::set(const void* key, EGLsizeiANDROID keySize, const void* value,
+ EGLsizeiANDROID valueSize) {
+ if (!mInitialized) {
+ return;
+ }
+
+ // Ensure key and value are under their limits
+ if (keySize > mMaxKeySize || valueSize > mMaxValueSize) {
+ ALOGV("SET: keySize (%lu vs %zu) or valueSize (%lu vs %zu) too large", keySize, mMaxKeySize,
+ valueSize, mMaxValueSize);
+ return;
+ }
+
+ // Generate a hash of the key and use it to track this entry
+ uint32_t entryHash = android::JenkinsHashMixBytes(0, static_cast<const uint8_t*>(key), keySize);
+
+ size_t fileSize = sizeof(MultifileHeader) + keySize + valueSize;
+
+ // If we're going to be over the cache limit, kick off a trim to clear space
+ if (getTotalSize() + fileSize > mMaxTotalSize) {
+ ALOGV("SET: Cache is full, calling trimCache to clear space");
+ trimCache(mMaxTotalSize);
+ }
+
+ ALOGV("SET: Add %u to cache", entryHash);
+
+ uint8_t* buffer = new uint8_t[fileSize];
+
+ // Write the key and value after the header
+ android::MultifileHeader header = {keySize, valueSize};
+ memcpy(static_cast<void*>(buffer), static_cast<const void*>(&header),
+ sizeof(android::MultifileHeader));
+ memcpy(static_cast<void*>(buffer + sizeof(MultifileHeader)), static_cast<const void*>(key),
+ keySize);
+ memcpy(static_cast<void*>(buffer + sizeof(MultifileHeader) + keySize),
+ static_cast<const void*>(value), valueSize);
+
+ std::string fullPath = mMultifileDirName + "/" + std::to_string(entryHash);
+
+ // Track the size and access time for quick recall
+ trackEntry(entryHash, valueSize, fileSize, time(0));
+
+ // Update the overall cache size
+ increaseTotalCacheSize(fileSize);
+
+ // Keep the entry in hot cache for quick retrieval
+ ALOGV("SET: Adding %u to hot cache.", entryHash);
+
+ // Sending -1 as the fd indicates we don't have an fd for this
+ if (!addToHotCache(entryHash, -1, buffer, fileSize)) {
+ ALOGE("GET: Failed to add %u to hot cache", entryHash);
+ return;
+ }
+
+ // Track that we're creating a pending write for this entry
+ // Include the buffer to handle the case when multiple writes are pending for an entry
+ mDeferredWrites.insert(std::make_pair(entryHash, buffer));
+
+ // Create deferred task to write to storage
+ ALOGV("SET: Adding task to queue.");
+ DeferredTask task(TaskCommand::WriteToDisk);
+ task.initWriteToDisk(entryHash, fullPath, buffer, fileSize);
+ queueTask(std::move(task));
+}
+
+// Get will check the hot cache, then load it from disk if needed
+EGLsizeiANDROID MultifileBlobCache::get(const void* key, EGLsizeiANDROID keySize, void* value,
+ EGLsizeiANDROID valueSize) {
+ if (!mInitialized) {
+ return 0;
+ }
+
+ // Ensure key and value are under their limits
+ if (keySize > mMaxKeySize || valueSize > mMaxValueSize) {
+ ALOGV("GET: keySize (%lu vs %zu) or valueSize (%lu vs %zu) too large", keySize, mMaxKeySize,
+ valueSize, mMaxValueSize);
+ return 0;
+ }
+
+ // Generate a hash of the key and use it to track this entry
+ uint32_t entryHash = android::JenkinsHashMixBytes(0, static_cast<const uint8_t*>(key), keySize);
+
+ // See if we have this file
+ if (!contains(entryHash)) {
+ ALOGV("GET: Cache MISS - cache does not contain entry: %u", entryHash);
+ return 0;
+ }
+
+ // Look up the data for this entry
+ MultifileEntryStats entryStats = getEntryStats(entryHash);
+
+ size_t cachedValueSize = entryStats.valueSize;
+ if (cachedValueSize > valueSize) {
+ ALOGV("GET: Cache MISS - valueSize not large enough (%lu) for entry %u, returning required"
+ "size (%zu)",
+ valueSize, entryHash, cachedValueSize);
+ return cachedValueSize;
+ }
+
+ // We have the file and have enough room to write it out, return the entry
+ ALOGV("GET: Cache HIT - cache contains entry: %u", entryHash);
+
+ // Look up the size of the file
+ size_t fileSize = entryStats.fileSize;
+ if (keySize > fileSize) {
+ ALOGW("keySize (%lu) is larger than entrySize (%zu). This is a hash collision or modified "
+ "file",
+ keySize, fileSize);
+ return 0;
+ }
+
+ std::string fullPath = mMultifileDirName + "/" + std::to_string(entryHash);
+
+ // Open the hashed filename path
+ uint8_t* cacheEntry = 0;
+
+ // Check hot cache
+ if (mHotCache.find(entryHash) != mHotCache.end()) {
+ ALOGV("GET: HotCache HIT for entry %u", entryHash);
+ cacheEntry = mHotCache[entryHash].entryBuffer;
+ } else {
+ ALOGV("GET: HotCache MISS for entry: %u", entryHash);
+
+ if (mDeferredWrites.find(entryHash) != mDeferredWrites.end()) {
+ // Wait for writes to complete if there is an outstanding write for this entry
+ ALOGV("GET: Waiting for write to complete for %u", entryHash);
+ waitForWorkComplete();
+ }
+
+ // Open the entry file
+ int fd = open(fullPath.c_str(), O_RDONLY);
+ if (fd == -1) {
+ ALOGE("Cache error - failed to open fullPath: %s, error: %s", fullPath.c_str(),
+ std::strerror(errno));
+ return 0;
+ }
+
+ // Memory map the file
+ cacheEntry =
+ reinterpret_cast<uint8_t*>(mmap(nullptr, fileSize, PROT_READ, MAP_PRIVATE, fd, 0));
+ if (cacheEntry == MAP_FAILED) {
+ ALOGE("Failed to mmap cacheEntry, error: %s", std::strerror(errno));
+ close(fd);
+ return 0;
+ }
+
+ ALOGV("GET: Adding %u to hot cache", entryHash);
+ if (!addToHotCache(entryHash, fd, cacheEntry, fileSize)) {
+ ALOGE("GET: Failed to add %u to hot cache", entryHash);
+ return 0;
+ }
+
+ cacheEntry = mHotCache[entryHash].entryBuffer;
+ }
+
+ // Ensure the header matches
+ MultifileHeader* header = reinterpret_cast<MultifileHeader*>(cacheEntry);
+ if (header->keySize != keySize || header->valueSize != valueSize) {
+ ALOGW("Mismatch on keySize(%ld vs. cached %ld) or valueSize(%ld vs. cached %ld) compared "
+ "to cache header values for fullPath: %s",
+ keySize, header->keySize, valueSize, header->valueSize, fullPath.c_str());
+ removeFromHotCache(entryHash);
+ return 0;
+ }
+
+ // Compare the incoming key with our stored version (the beginning of the entry)
+ uint8_t* cachedKey = cacheEntry + sizeof(MultifileHeader);
+ int compare = memcmp(cachedKey, key, keySize);
+ if (compare != 0) {
+ ALOGW("Cached key and new key do not match! This is a hash collision or modified file");
+ removeFromHotCache(entryHash);
+ return 0;
+ }
+
+ // Remaining entry following the key is the value
+ uint8_t* cachedValue = cacheEntry + (keySize + sizeof(MultifileHeader));
+ memcpy(value, cachedValue, cachedValueSize);
+
+ return cachedValueSize;
+}
+
+void MultifileBlobCache::finish() {
+ if (!mInitialized) {
+ return;
+ }
+
+ // Wait for all deferred writes to complete
+ ALOGV("FINISH: Waiting for work to complete.");
+ waitForWorkComplete();
+
+ // Close all entries in the hot cache
+ for (auto hotCacheIter = mHotCache.begin(); hotCacheIter != mHotCache.end();) {
+ uint32_t entryHash = hotCacheIter->first;
+ MultifileHotCache entry = hotCacheIter->second;
+
+ ALOGV("FINISH: Closing hot cache entry for %u", entryHash);
+ freeHotCacheEntry(entry);
+
+ mHotCache.erase(hotCacheIter++);
+ }
+}
+
+void MultifileBlobCache::trackEntry(uint32_t entryHash, EGLsizeiANDROID valueSize, size_t fileSize,
+ time_t accessTime) {
+ mEntries.insert(entryHash);
+ mEntryStats[entryHash] = {valueSize, fileSize, accessTime};
+}
+
+bool MultifileBlobCache::contains(uint32_t hashEntry) const {
+ return mEntries.find(hashEntry) != mEntries.end();
+}
+
+MultifileEntryStats MultifileBlobCache::getEntryStats(uint32_t entryHash) {
+ return mEntryStats[entryHash];
+}
+
+void MultifileBlobCache::increaseTotalCacheSize(size_t fileSize) {
+ mTotalCacheSize += fileSize;
+}
+
+void MultifileBlobCache::decreaseTotalCacheSize(size_t fileSize) {
+ mTotalCacheSize -= fileSize;
+}
+
+bool MultifileBlobCache::addToHotCache(uint32_t newEntryHash, int newFd, uint8_t* newEntryBuffer,
+ size_t newEntrySize) {
+ ALOGV("HOTCACHE(ADD): Adding %u to hot cache", newEntryHash);
+
+ // Clear space if we need to
+ if ((mHotCacheSize + newEntrySize) > mHotCacheLimit) {
+ ALOGV("HOTCACHE(ADD): mHotCacheSize (%zu) + newEntrySize (%zu) is to big for "
+ "mHotCacheLimit "
+ "(%zu), freeing up space for %u",
+ mHotCacheSize, newEntrySize, mHotCacheLimit, newEntryHash);
+
+ // Wait for all the files to complete writing so our hot cache is accurate
+ waitForWorkComplete();
+
+ // Free up old entries until under the limit
+ for (auto hotCacheIter = mHotCache.begin(); hotCacheIter != mHotCache.end();) {
+ uint32_t oldEntryHash = hotCacheIter->first;
+ MultifileHotCache oldEntry = hotCacheIter->second;
+
+ // Move our iterator before deleting the entry
+ hotCacheIter++;
+ if (!removeFromHotCache(oldEntryHash)) {
+ ALOGE("HOTCACHE(ADD): Unable to remove entry %u", oldEntryHash);
+ return false;
+ }
+
+ // Clear at least half the hot cache
+ if ((mHotCacheSize + newEntrySize) <= mHotCacheLimit / 2) {
+ ALOGV("HOTCACHE(ADD): Freed enough space for %zu", mHotCacheSize);
+ break;
+ }
+ }
+ }
+
+ // Track it
+ mHotCache[newEntryHash] = {newFd, newEntryBuffer, newEntrySize};
+ mHotCacheSize += newEntrySize;
+
+ ALOGV("HOTCACHE(ADD): New hot cache size: %zu", mHotCacheSize);
+
+ return true;
+}
+
+bool MultifileBlobCache::removeFromHotCache(uint32_t entryHash) {
+ if (mHotCache.find(entryHash) != mHotCache.end()) {
+ ALOGV("HOTCACHE(REMOVE): Removing %u from hot cache", entryHash);
+
+ // Wait for all the files to complete writing so our hot cache is accurate
+ waitForWorkComplete();
+
+ ALOGV("HOTCACHE(REMOVE): Closing hot cache entry for %u", entryHash);
+ MultifileHotCache entry = mHotCache[entryHash];
+ freeHotCacheEntry(entry);
+
+ // Delete the entry from our tracking
+ mHotCacheSize -= entry.entrySize;
+ mHotCache.erase(entryHash);
+
+ return true;
+ }
+
+ return false;
+}
+
+bool MultifileBlobCache::applyLRU(size_t cacheLimit) {
+ // Walk through our map of sorted last access times and remove files until under the limit
+ for (auto cacheEntryIter = mEntryStats.begin(); cacheEntryIter != mEntryStats.end();) {
+ uint32_t entryHash = cacheEntryIter->first;
+
+ ALOGV("LRU: Removing entryHash %u", entryHash);
+
+ // Track the overall size
+ MultifileEntryStats entryStats = getEntryStats(entryHash);
+ decreaseTotalCacheSize(entryStats.fileSize);
+
+ // Remove it from hot cache if present
+ removeFromHotCache(entryHash);
+
+ // Remove it from the system
+ std::string entryPath = mMultifileDirName + "/" + std::to_string(entryHash);
+ if (remove(entryPath.c_str()) != 0) {
+ ALOGE("LRU: Error removing %s: %s", entryPath.c_str(), std::strerror(errno));
+ return false;
+ }
+
+ // Increment the iterator before clearing the entry
+ cacheEntryIter++;
+
+ // Delete the entry from our tracking
+ size_t count = mEntryStats.erase(entryHash);
+ if (count != 1) {
+ ALOGE("LRU: Failed to remove entryHash (%u) from mEntryStats", entryHash);
+ return false;
+ }
+
+ // See if it has been reduced enough
+ size_t totalCacheSize = getTotalSize();
+ if (totalCacheSize <= cacheLimit) {
+ // Success
+ ALOGV("LRU: Reduced cache to %zu", totalCacheSize);
+ return true;
+ }
+ }
+
+ ALOGV("LRU: Cache is emptry");
+ return false;
+}
+
+// When removing files, what fraction of the overall limit should be reached when removing files
+// A divisor of two will decrease the cache to 50%, four to 25% and so on
+constexpr uint32_t kCacheLimitDivisor = 2;
+
+// Calculate the cache size and remove old entries until under the limit
+void MultifileBlobCache::trimCache(size_t cacheByteLimit) {
+ // Start with the value provided by egl_cache
+ size_t limit = cacheByteLimit;
+
+ // Wait for all deferred writes to complete
+ waitForWorkComplete();
+
+ size_t size = getTotalSize();
+
+ // If size is larger than the threshold, remove files using LRU
+ if (size > limit) {
+ ALOGV("TRIM: Multifile cache size is larger than %zu, removing old entries",
+ cacheByteLimit);
+ if (!applyLRU(limit / kCacheLimitDivisor)) {
+ ALOGE("Error when clearing multifile shader cache");
+ return;
+ }
+ }
+}
+
+// This function performs a task. It only knows how to write files to disk,
+// but it could be expanded if needed.
+void MultifileBlobCache::processTask(DeferredTask& task) {
+ switch (task.getTaskCommand()) {
+ case TaskCommand::Exit: {
+ ALOGV("DEFERRED: Shutting down");
+ return;
+ }
+ case TaskCommand::WriteToDisk: {
+ uint32_t entryHash = task.getEntryHash();
+ std::string& fullPath = task.getFullPath();
+ uint8_t* buffer = task.getBuffer();
+ size_t bufferSize = task.getBufferSize();
+
+ // Create the file or reset it if already present, read+write for user only
+ int fd = open(fullPath.c_str(), O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
+ if (fd == -1) {
+ ALOGE("Cache error in SET - failed to open fullPath: %s, error: %s",
+ fullPath.c_str(), std::strerror(errno));
+ return;
+ }
+
+ ALOGV("DEFERRED: Opened fd %i from %s", fd, fullPath.c_str());
+
+ ssize_t result = write(fd, buffer, bufferSize);
+ if (result != bufferSize) {
+ ALOGE("Error writing fileSize to cache entry (%s): %s", fullPath.c_str(),
+ std::strerror(errno));
+ return;
+ }
+
+ ALOGV("DEFERRED: Completed write for: %s", fullPath.c_str());
+ close(fd);
+
+ // Erase the entry from mDeferredWrites
+ // Since there could be multiple outstanding writes for an entry, find the matching one
+ typedef std::multimap<uint32_t, uint8_t*>::iterator entryIter;
+ std::pair<entryIter, entryIter> iterPair = mDeferredWrites.equal_range(entryHash);
+ for (entryIter it = iterPair.first; it != iterPair.second; ++it) {
+ if (it->second == buffer) {
+ ALOGV("DEFERRED: Marking write complete for %u at %p", it->first, it->second);
+ mDeferredWrites.erase(it);
+ break;
+ }
+ }
+
+ return;
+ }
+ default: {
+ ALOGE("DEFERRED: Unhandled task type");
+ return;
+ }
+ }
+}
+
+// This function will wait until tasks arrive, then execute them
+// If the exit command is submitted, the loop will terminate
+void MultifileBlobCache::processTasksImpl(bool* exitThread) {
+ while (true) {
+ std::unique_lock<std::mutex> lock(mWorkerMutex);
+ if (mTasks.empty()) {
+ ALOGV("WORKER: No tasks available, waiting");
+ mWorkerThreadIdle = true;
+ mWorkerIdleCondition.notify_all();
+ // Only wake if notified and command queue is not empty
+ mWorkAvailableCondition.wait(lock, [this] { return !mTasks.empty(); });
+ }
+
+ ALOGV("WORKER: Task available, waking up.");
+ mWorkerThreadIdle = false;
+ DeferredTask task = std::move(mTasks.front());
+ mTasks.pop();
+
+ if (task.getTaskCommand() == TaskCommand::Exit) {
+ ALOGV("WORKER: Exiting work loop.");
+ *exitThread = true;
+ mWorkerThreadIdle = true;
+ mWorkerIdleCondition.notify_one();
+ return;
+ }
+
+ lock.unlock();
+ processTask(task);
+ }
+}
+
+// Process tasks until the exit task is submitted
+void MultifileBlobCache::processTasks() {
+ while (true) {
+ bool exitThread = false;
+ processTasksImpl(&exitThread);
+ if (exitThread) {
+ break;
+ }
+ }
+}
+
+// Add a task to the queue to be processed by the worker thread
+void MultifileBlobCache::queueTask(DeferredTask&& task) {
+ std::lock_guard<std::mutex> queueLock(mWorkerMutex);
+ mTasks.emplace(std::move(task));
+ mWorkAvailableCondition.notify_one();
+}
+
+// Wait until all tasks have been completed
+void MultifileBlobCache::waitForWorkComplete() {
+ std::unique_lock<std::mutex> lock(mWorkerMutex);
+ mWorkerIdleCondition.wait(lock, [this] { return (mTasks.empty() && mWorkerThreadIdle); });
+}
+
+}; // namespace android
\ No newline at end of file