// Copyright (c) 2012 The Chromium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #include "net/disk_cache/backend_impl.h" #include "base/bind.h" #include "base/bind_helpers.h" #include "base/file_util.h" #include "base/files/file_path.h" #include "base/hash.h" #include "base/message_loop/message_loop.h" #include "base/metrics/field_trial.h" #include "base/metrics/histogram.h" #include "base/metrics/stats_counters.h" #include "base/rand_util.h" #include "base/strings/string_util.h" #include "base/strings/stringprintf.h" #include "base/sys_info.h" #include "base/threading/thread_restrictions.h" #include "base/time/time.h" #include "base/timer/timer.h" #include "net/base/net_errors.h" #include "net/disk_cache/cache_util.h" #include "net/disk_cache/entry_impl.h" #include "net/disk_cache/errors.h" #include "net/disk_cache/experiments.h" #include "net/disk_cache/file.h" // This has to be defined before including histogram_macros.h from this file. #define NET_DISK_CACHE_BACKEND_IMPL_CC_ #include "net/disk_cache/histogram_macros.h" using base::Time; using base::TimeDelta; using base::TimeTicks; namespace { const char* kIndexName = "index"; // Seems like ~240 MB correspond to less than 50k entries for 99% of the people. // Note that the actual target is to keep the index table load factor under 55% // for most users. const int k64kEntriesStore = 240 * 1000 * 1000; const int kBaseTableLen = 64 * 1024; const int kDefaultCacheSize = 80 * 1024 * 1024; // Avoid trimming the cache for the first 5 minutes (10 timer ticks). const int kTrimDelay = 10; int DesiredIndexTableLen(int32 storage_size) { if (storage_size <= k64kEntriesStore) return kBaseTableLen; if (storage_size <= k64kEntriesStore * 2) return kBaseTableLen * 2; if (storage_size <= k64kEntriesStore * 4) return kBaseTableLen * 4; if (storage_size <= k64kEntriesStore * 8) return kBaseTableLen * 8; // The biggest storage_size for int32 requires a 4 MB table. return kBaseTableLen * 16; } int MaxStorageSizeForTable(int table_len) { return table_len * (k64kEntriesStore / kBaseTableLen); } size_t GetIndexSize(int table_len) { size_t table_size = sizeof(disk_cache::CacheAddr) * table_len; return sizeof(disk_cache::IndexHeader) + table_size; } } // namespace // ------------------------------------------------------------------------ namespace disk_cache { BackendImpl::BackendImpl(const base::FilePath& path, base::MessageLoopProxy* cache_thread, net::NetLog* net_log) : background_queue_(this, cache_thread), path_(path), block_files_(path), mask_(0), max_size_(0), up_ticks_(0), cache_type_(net::DISK_CACHE), uma_report_(0), user_flags_(0), init_(false), restarted_(false), unit_test_(false), read_only_(false), disabled_(false), new_eviction_(false), first_timer_(true), user_load_(false), net_log_(net_log), done_(true, false), ptr_factory_(this) { } BackendImpl::BackendImpl(const base::FilePath& path, uint32 mask, base::MessageLoopProxy* cache_thread, net::NetLog* net_log) : background_queue_(this, cache_thread), path_(path), block_files_(path), mask_(mask), max_size_(0), up_ticks_(0), cache_type_(net::DISK_CACHE), uma_report_(0), user_flags_(kMask), init_(false), restarted_(false), unit_test_(false), read_only_(false), disabled_(false), new_eviction_(false), first_timer_(true), user_load_(false), net_log_(net_log), done_(true, false), ptr_factory_(this) { } BackendImpl::~BackendImpl() { if (user_flags_ & kNoRandom) { // This is a unit test, so we want to be strict about not leaking entries // and completing all the work. background_queue_.WaitForPendingIO(); } else { // This is most likely not a test, so we want to do as little work as // possible at this time, at the price of leaving dirty entries behind. background_queue_.DropPendingIO(); } if (background_queue_.BackgroundIsCurrentThread()) { // Unit tests may use the same thread for everything. CleanupCache(); } else { background_queue_.background_thread()->PostTask( FROM_HERE, base::Bind(&FinalCleanupCallback, base::Unretained(this))); // http://crbug.com/74623 base::ThreadRestrictions::ScopedAllowWait allow_wait; done_.Wait(); } } int BackendImpl::Init(const CompletionCallback& callback) { background_queue_.Init(callback); return net::ERR_IO_PENDING; } // ------------------------------------------------------------------------ int BackendImpl::OpenPrevEntry(void** iter, Entry** prev_entry, const CompletionCallback& callback) { DCHECK(!callback.is_null()); background_queue_.OpenPrevEntry(iter, prev_entry, callback); return net::ERR_IO_PENDING; } bool BackendImpl::SetMaxSize(int max_bytes) { COMPILE_ASSERT(sizeof(max_bytes) == sizeof(max_size_), unsupported_int_model); if (max_bytes < 0) return false; // Zero size means use the default. if (!max_bytes) return true; // Avoid a DCHECK later on. if (max_bytes >= kint32max - kint32max / 10) max_bytes = kint32max - kint32max / 10 - 1; user_flags_ |= kMaxSize; max_size_ = max_bytes; return true; } void BackendImpl::SetType(net::CacheType type) { DCHECK_NE(net::MEMORY_CACHE, type); cache_type_ = type; } bool BackendImpl::CreateBlock(FileType block_type, int block_count, Addr* block_address) { return block_files_.CreateBlock(block_type, block_count, block_address); } void BackendImpl::UpdateRank(EntryImpl* entry, bool modified) { if (read_only_ || (!modified && cache_type() == net::SHADER_CACHE)) return; eviction_.UpdateRank(entry, modified); } void BackendImpl::InternalDoomEntry(EntryImpl* entry) { uint32 hash = entry->GetHash(); std::string key = entry->GetKey(); Addr entry_addr = entry->entry()->address(); bool error; EntryImpl* parent_entry = MatchEntry(key, hash, true, entry_addr, &error); CacheAddr child(entry->GetNextAddress()); Trace("Doom entry 0x%p", entry); if (!entry->doomed()) { // We may have doomed this entry from within MatchEntry. eviction_.OnDoomEntry(entry); entry->InternalDoom(); if (!new_eviction_) { DecreaseNumEntries(); } stats_.OnEvent(Stats::DOOM_ENTRY); } if (parent_entry) { parent_entry->SetNextAddress(Addr(child)); parent_entry->Release(); } else if (!error) { data_->table[hash & mask_] = child; } FlushIndex(); } void BackendImpl::OnEntryDestroyBegin(Addr address) { EntriesMap::iterator it = open_entries_.find(address.value()); if (it != open_entries_.end()) open_entries_.erase(it); } void BackendImpl::OnEntryDestroyEnd() { DecreaseNumRefs(); if (data_->header.num_bytes > max_size_ && !read_only_ && (up_ticks_ > kTrimDelay || user_flags_ & kNoRandom)) eviction_.TrimCache(false); } EntryImpl* BackendImpl::GetOpenEntry(CacheRankingsBlock* rankings) const { DCHECK(rankings->HasData()); EntriesMap::const_iterator it = open_entries_.find(rankings->Data()->contents); if (it != open_entries_.end()) { // We have this entry in memory. return it->second; } return NULL; } int BackendImpl::MaxFileSize() const { return max_size_ / 8; } void BackendImpl::ModifyStorageSize(int32 old_size, int32 new_size) { if (disabled_ || old_size == new_size) return; if (old_size > new_size) SubstractStorageSize(old_size - new_size); else AddStorageSize(new_size - old_size); FlushIndex(); // Update the usage statistics. stats_.ModifyStorageStats(old_size, new_size); } void BackendImpl::TooMuchStorageRequested(int32 size) { stats_.ModifyStorageStats(0, size); } bool BackendImpl::IsAllocAllowed(int current_size, int new_size) { DCHECK_GT(new_size, current_size); if (user_flags_ & kNoBuffering) return false; int to_add = new_size - current_size; if (buffer_bytes_ + to_add > MaxBuffersSize()) return false; buffer_bytes_ += to_add; CACHE_UMA(COUNTS_50000, "BufferBytes", 0, buffer_bytes_ / 1024); return true; } void BackendImpl::BufferDeleted(int size) { buffer_bytes_ -= size; DCHECK_GE(size, 0); } bool BackendImpl::IsLoaded() const { CACHE_UMA(COUNTS, "PendingIO", 0, num_pending_io_); if (user_flags_ & kNoLoadProtection) return false; return (num_pending_io_ > 5 || user_load_); } std::string BackendImpl::HistogramName(const char* name, int experiment) const { if (!experiment) return base::StringPrintf("DiskCache.%d.%s", cache_type_, name); return base::StringPrintf("DiskCache.%d.%s_%d", cache_type_, name, experiment); } base::WeakPtr BackendImpl::GetWeakPtr() { return ptr_factory_.GetWeakPtr(); } // We want to remove biases from some histograms so we only send data once per // week. bool BackendImpl::ShouldReportAgain() { if (uma_report_) return uma_report_ == 2; uma_report_++; int64 last_report = stats_.GetCounter(Stats::LAST_REPORT); Time last_time = Time::FromInternalValue(last_report); if (!last_report || (Time::Now() - last_time).InDays() >= 7) { stats_.SetCounter(Stats::LAST_REPORT, Time::Now().ToInternalValue()); uma_report_++; return true; } return false; } void BackendImpl::FirstEviction() { DCHECK(data_->header.create_time); if (!GetEntryCount()) return; // This is just for unit tests. Time create_time = Time::FromInternalValue(data_->header.create_time); CACHE_UMA(AGE, "FillupAge", 0, create_time); int64 use_time = stats_.GetCounter(Stats::TIMER); CACHE_UMA(HOURS, "FillupTime", 0, static_cast(use_time / 120)); CACHE_UMA(PERCENTAGE, "FirstHitRatio", 0, stats_.GetHitRatio()); if (!use_time) use_time = 1; CACHE_UMA(COUNTS_10000, "FirstEntryAccessRate", 0, static_cast(data_->header.num_entries / use_time)); CACHE_UMA(COUNTS, "FirstByteIORate", 0, static_cast((data_->header.num_bytes / 1024) / use_time)); int avg_size = data_->header.num_bytes / GetEntryCount(); CACHE_UMA(COUNTS, "FirstEntrySize", 0, avg_size); int large_entries_bytes = stats_.GetLargeEntriesSize(); int large_ratio = large_entries_bytes * 100 / data_->header.num_bytes; CACHE_UMA(PERCENTAGE, "FirstLargeEntriesRatio", 0, large_ratio); if (new_eviction_) { CACHE_UMA(PERCENTAGE, "FirstResurrectRatio", 0, stats_.GetResurrectRatio()); CACHE_UMA(PERCENTAGE, "FirstNoUseRatio", 0, data_->header.lru.sizes[0] * 100 / data_->header.num_entries); CACHE_UMA(PERCENTAGE, "FirstLowUseRatio", 0, data_->header.lru.sizes[1] * 100 / data_->header.num_entries); CACHE_UMA(PERCENTAGE, "FirstHighUseRatio", 0, data_->header.lru.sizes[2] * 100 / data_->header.num_entries); } stats_.ResetRatios(); } void BackendImpl::OnEvent(Stats::Counters an_event) { stats_.OnEvent(an_event); } void BackendImpl::OnRead(int32 bytes) { DCHECK_GE(bytes, 0); byte_count_ += bytes; if (byte_count_ < 0) byte_count_ = kint32max; } void BackendImpl::OnWrite(int32 bytes) { // We use the same implementation as OnRead... just log the number of bytes. OnRead(bytes); } void BackendImpl::OnStatsTimer() { stats_.OnEvent(Stats::TIMER); int64 time = stats_.GetCounter(Stats::TIMER); int64 current = stats_.GetCounter(Stats::OPEN_ENTRIES); // OPEN_ENTRIES is a sampled average of the number of open entries, avoiding // the bias towards 0. if (num_refs_ && (current != num_refs_)) { int64 diff = (num_refs_ - current) / 50; if (!diff) diff = num_refs_ > current ? 1 : -1; current = current + diff; stats_.SetCounter(Stats::OPEN_ENTRIES, current); stats_.SetCounter(Stats::MAX_ENTRIES, max_refs_); } CACHE_UMA(COUNTS, "NumberOfReferences", 0, num_refs_); CACHE_UMA(COUNTS_10000, "EntryAccessRate", 0, entry_count_); CACHE_UMA(COUNTS, "ByteIORate", 0, byte_count_ / 1024); // These values cover about 99.5% of the population (Oct 2011). user_load_ = (entry_count_ > 300 || byte_count_ > 7 * 1024 * 1024); entry_count_ = 0; byte_count_ = 0; up_ticks_++; if (!data_) first_timer_ = false; if (first_timer_) { first_timer_ = false; if (ShouldReportAgain()) ReportStats(); } // Save stats to disk at 5 min intervals. if (time % 10 == 0) StoreStats(); } void BackendImpl::SetUnitTestMode() { user_flags_ |= kUnitTestMode; unit_test_ = true; } void BackendImpl::SetUpgradeMode() { user_flags_ |= kUpgradeMode; read_only_ = true; } void BackendImpl::SetNewEviction() { user_flags_ |= kNewEviction; new_eviction_ = true; } void BackendImpl::SetFlags(uint32 flags) { user_flags_ |= flags; } int BackendImpl::FlushQueueForTest(const CompletionCallback& callback) { background_queue_.FlushQueue(callback); return net::ERR_IO_PENDING; } void BackendImpl::TrimForTest(bool empty) { eviction_.SetTestMode(); eviction_.TrimCache(empty); } void BackendImpl::TrimDeletedListForTest(bool empty) { eviction_.SetTestMode(); eviction_.TrimDeletedList(empty); } int BackendImpl::SelfCheck() { if (!init_) { LOG(ERROR) << "Init failed"; return ERR_INIT_FAILED; } int num_entries = rankings_.SelfCheck(); if (num_entries < 0) { LOG(ERROR) << "Invalid rankings list, error " << num_entries; #if !defined(NET_BUILD_STRESS_CACHE) return num_entries; #endif } if (num_entries != data_->header.num_entries) { LOG(ERROR) << "Number of entries mismatch"; #if !defined(NET_BUILD_STRESS_CACHE) return ERR_NUM_ENTRIES_MISMATCH; #endif } return CheckAllEntries(); } // ------------------------------------------------------------------------ net::CacheType BackendImpl::GetCacheType() const { return cache_type_; } int32 BackendImpl::GetEntryCount() const { if (!index_.get() || disabled_) return 0; // num_entries includes entries already evicted. int32 not_deleted = data_->header.num_entries - data_->header.lru.sizes[Rankings::DELETED]; if (not_deleted < 0) { NOTREACHED(); not_deleted = 0; } return not_deleted; } EntryImpl* BackendImpl::OpenEntryImpl(const std::string& key) { if (disabled_) return NULL; TimeTicks start = TimeTicks::Now(); uint32 hash = base::Hash(key); Trace("Open hash 0x%x", hash); bool error; EntryImpl* cache_entry = MatchEntry(key, hash, false, Addr(), &error); if (cache_entry && ENTRY_NORMAL != cache_entry->entry()->Data()->state) { // The entry was already evicted. cache_entry->Release(); cache_entry = NULL; } int current_size = data_->header.num_bytes / (1024 * 1024); int64 total_hours = stats_.GetCounter(Stats::TIMER) / 120; int64 no_use_hours = stats_.GetCounter(Stats::LAST_REPORT_TIMER) / 120; int64 use_hours = total_hours - no_use_hours; if (!cache_entry) { CACHE_UMA(AGE_MS, "OpenTime.Miss", 0, start); CACHE_UMA(COUNTS_10000, "AllOpenBySize.Miss", 0, current_size); CACHE_UMA(HOURS, "AllOpenByTotalHours.Miss", 0, total_hours); CACHE_UMA(HOURS, "AllOpenByUseHours.Miss", 0, use_hours); stats_.OnEvent(Stats::OPEN_MISS); return NULL; } eviction_.OnOpenEntry(cache_entry); entry_count_++; Trace("Open hash 0x%x end: 0x%x", hash, cache_entry->entry()->address().value()); CACHE_UMA(AGE_MS, "OpenTime", 0, start); CACHE_UMA(COUNTS_10000, "AllOpenBySize.Hit", 0, current_size); CACHE_UMA(HOURS, "AllOpenByTotalHours.Hit", 0, total_hours); CACHE_UMA(HOURS, "AllOpenByUseHours.Hit", 0, use_hours); stats_.OnEvent(Stats::OPEN_HIT); SIMPLE_STATS_COUNTER("disk_cache.hit"); return cache_entry; } EntryImpl* BackendImpl::CreateEntryImpl(const std::string& key) { if (disabled_ || key.empty()) return NULL; TimeTicks start = TimeTicks::Now(); Trace("Create hash 0x%x", hash); scoped_refptr parent; Addr entry_address(data_->table[hash & mask_]); if (entry_address.is_initialized()) { // We have an entry already. It could be the one we are looking for, or just // a hash conflict. bool error; EntryImpl* old_entry = MatchEntry(key, hash, false, Addr(), &error); if (old_entry) return ResurrectEntry(old_entry); EntryImpl* parent_entry = MatchEntry(key, hash, true, Addr(), &error); DCHECK(!error); if (parent_entry) { parent.swap(&parent_entry); } else if (data_->table[hash & mask_]) { // We should have corrected the problem. NOTREACHED(); return NULL; } } // The general flow is to allocate disk space and initialize the entry data, // followed by saving that to disk, then linking the entry though the index // and finally through the lists. If there is a crash in this process, we may // end up with: // a. Used, unreferenced empty blocks on disk (basically just garbage). // b. Used, unreferenced but meaningful data on disk (more garbage). // c. A fully formed entry, reachable only through the index. // d. A fully formed entry, also reachable through the lists, but still dirty. // // Anything after (b) can be automatically cleaned up. We may consider saving // the current operation (as we do while manipulating the lists) so that we // can detect and cleanup (a) and (b). int num_blocks = EntryImpl::NumBlocksForEntry(key.size()); if (!block_files_.CreateBlock(BLOCK_256, num_blocks, &entry_address)) { LOG(ERROR) << "Create entry failed " << key.c_str(); stats_.OnEvent(Stats::CREATE_ERROR); return NULL; } Addr node_address(0); if (!block_files_.CreateBlock(RANKINGS, 1, &node_address)) { block_files_.DeleteBlock(entry_address, false); LOG(ERROR) << "Create entry failed " << key.c_str(); stats_.OnEvent(Stats::CREATE_ERROR); return NULL; } scoped_refptr cache_entry( new EntryImpl(this, entry_address, false)); IncreaseNumRefs(); if (!cache_entry->CreateEntry(node_address, key, hash)) { block_files_.DeleteBlock(entry_address, false); block_files_.DeleteBlock(node_address, false); LOG(ERROR) << "Create entry failed " << key.c_str(); stats_.OnEvent(Stats::CREATE_ERROR); return NULL; } cache_entry->BeginLogging(net_log_, true); // We are not failing the operation; let's add this to the map. open_entries_[entry_address.value()] = cache_entry.get(); // Save the entry. cache_entry->entry()->Store(); cache_entry->rankings()->Store(); IncreaseNumEntries(); entry_count_++; // Link this entry through the index. if (parent.get()) { parent->SetNextAddress(entry_address); } else { data_->table[hash & mask_] = entry_address.value(); } // Link this entry through the lists. eviction_.OnCreateEntry(cache_entry.get()); CACHE_UMA(AGE_MS, "CreateTime", 0, start); stats_.OnEvent(Stats::CREATE_HIT); SIMPLE_STATS_COUNTER("disk_cache.miss"); Trace("create entry hit "); FlushIndex(); cache_entry->AddRef(); return cache_entry.get(); } int BackendImpl::SyncDoomEntry(const std::string& key) { if (disabled_) return net::ERR_FAILED; EntryImpl* entry = OpenEntryImpl(key); if (!entry) return net::ERR_FAILED; entry->DoomImpl(); entry->Release(); return net::OK; } int BackendImpl::SyncDoomAllEntries() { // This is not really an error, but it is an interesting condition. ReportError(ERR_CACHE_DOOMED); stats_.OnEvent(Stats::DOOM_CACHE); if (!num_refs_) { RestartCache(false); return disabled_ ? net::ERR_FAILED : net::OK; } else { if (disabled_) return net::ERR_FAILED; eviction_.TrimCache(true); return net::OK; } } int BackendImpl::SyncDoomEntriesBetween(const base::Time initial_time, const base::Time end_time) { DCHECK_NE(net::APP_CACHE, cache_type_); if (end_time.is_null()) return SyncDoomEntriesSince(initial_time); DCHECK(end_time >= initial_time); if (disabled_) return net::ERR_FAILED; EntryImpl* node; void* iter = NULL; EntryImpl* next = OpenNextEntryImpl(&iter); if (!next) return net::OK; while (next) { node = next; next = OpenNextEntryImpl(&iter); if (node->GetLastUsed() >= initial_time && node->GetLastUsed() < end_time) { node->DoomImpl(); } else if (node->GetLastUsed() < initial_time) { if (next) next->Release(); next = NULL; SyncEndEnumeration(iter); } node->Release(); } return net::OK; } // We use OpenNextEntryImpl to retrieve elements from the cache, until we get // entries that are too old. int BackendImpl::SyncDoomEntriesSince(const base::Time initial_time) { DCHECK_NE(net::APP_CACHE, cache_type_); if (disabled_) return net::ERR_FAILED; stats_.OnEvent(Stats::DOOM_RECENT); for (;;) { void* iter = NULL; EntryImpl* entry = OpenNextEntryImpl(&iter); if (!entry) return net::OK; if (initial_time > entry->GetLastUsed()) { entry->Release(); SyncEndEnumeration(iter); return net::OK; } entry->DoomImpl(); entry->Release(); SyncEndEnumeration(iter); // Dooming the entry invalidates the iterator. } } int BackendImpl::OpenNextEntry(void** iter, Entry** next_entry, const CompletionCallback& callback) { DCHECK(!callback.is_null()); background_queue_.OpenNextEntry(iter, next_entry, callback); return net::ERR_IO_PENDING; } void BackendImpl::EndEnumeration(void** iter) { background_queue_.EndEnumeration(*iter); *iter = NULL; } void BackendImpl::GetStats(StatsItems* stats) { if (disabled_) return; std::pair item; item.first = "Entries"; item.second = base::StringPrintf("%d", data_->header.num_entries); stats->push_back(item); item.first = "Pending IO"; item.second = base::StringPrintf("%d", num_pending_io_); stats->push_back(item); item.first = "Max size"; item.second = base::StringPrintf("%d", max_size_); stats->push_back(item); item.first = "Current size"; item.second = base::StringPrintf("%d", data_->header.num_bytes); stats->push_back(item); item.first = "Cache type"; item.second = "Blockfile Cache"; stats->push_back(item); stats_.GetItems(stats); } void BackendImpl::SyncOnExternalCacheHit(const std::string& key) { if (disabled_) return; uint32 hash = base::Hash(key); bool error; EntryImpl* cache_entry = MatchEntry(key, hash, false, Addr(), &error); if (cache_entry) { if (ENTRY_NORMAL == cache_entry->entry()->Data()->state) { UpdateRank(cache_entry, cache_type() == net::SHADER_CACHE); } cache_entry->Release(); } } // ------------------------------------------------------------------------ // The maximum cache size will be either set explicitly by the caller, or // calculated by this code. void BackendImpl::AdjustMaxCacheSize(int table_len) { if (max_size_) return; // If table_len is provided, the index file exists. DCHECK(!table_len || data_->header.magic); // The user is not setting the size, let's figure it out. int64 available = base::SysInfo::AmountOfFreeDiskSpace(path_); if (available < 0) { max_size_ = kDefaultCacheSize; return; } if (table_len) available += data_->header.num_bytes; max_size_ = PreferedCacheSize(available); // Let's not use more than the default size while we tune-up the performance // of bigger caches. TODO(rvargas): remove this limit. if (max_size_ > kDefaultCacheSize * 4) max_size_ = kDefaultCacheSize * 4; if (!table_len) return; // If we already have a table, adjust the size to it. int current_max_size = MaxStorageSizeForTable(table_len); if (max_size_ > current_max_size) max_size_= current_max_size; } bool BackendImpl::InitStats() { Addr address(data_->header.stats); int size = stats_.StorageSize(); if (!address.is_initialized()) { FileType file_type = Addr::RequiredFileType(size); DCHECK_NE(file_type, EXTERNAL); int num_blocks = Addr::RequiredBlocks(size, file_type); if (!CreateBlock(file_type, num_blocks, &address)) return false; return stats_.Init(NULL, 0, address); } if (!address.is_block_file()) { NOTREACHED(); return false; } // Load the required data. size = address.num_blocks() * address.BlockSize(); MappedFile* file = File(address); if (!file) return false; scoped_ptr data(new char[size]); size_t offset = address.start_block() * address.BlockSize() + kBlockHeaderSize; if (!file->Read(data.get(), size, offset)) return false; if (!stats_.Init(data.get(), size, address)) return false; if (cache_type_ == net::DISK_CACHE && ShouldReportAgain()) stats_.InitSizeHistogram(); return true; } void BackendImpl::StoreStats() { int size = stats_.StorageSize(); scoped_ptr data(new char[size]); Addr address; size = stats_.SerializeStats(data.get(), size, &address); DCHECK(size); if (!address.is_initialized()) return; MappedFile* file = File(address); if (!file) return; size_t offset = address.start_block() * address.BlockSize() + kBlockHeaderSize; file->Write(data.get(), size, offset); // ignore result. } void BackendImpl::RestartCache(bool failure) { int64 errors = stats_.GetCounter(Stats::FATAL_ERROR); int64 full_dooms = stats_.GetCounter(Stats::DOOM_CACHE); int64 partial_dooms = stats_.GetCounter(Stats::DOOM_RECENT); int64 last_report = stats_.GetCounter(Stats::LAST_REPORT); PrepareForRestart(); if (failure) { DCHECK(!num_refs_); DCHECK(!open_entries_.size()); DelayedCacheCleanup(path_); } else { DeleteCache(path_, false); } // Don't call Init() if directed by the unit test: we are simulating a failure // trying to re-enable the cache. if (unit_test_) init_ = true; // Let the destructor do proper cleanup. else if (SyncInit() == net::OK) { stats_.SetCounter(Stats::FATAL_ERROR, errors); stats_.SetCounter(Stats::DOOM_CACHE, full_dooms); stats_.SetCounter(Stats::DOOM_RECENT, partial_dooms); stats_.SetCounter(Stats::LAST_REPORT, last_report); } } void BackendImpl::PrepareForRestart() { // Reset the mask_ if it was not given by the user. if (!(user_flags_ & kMask)) mask_ = 0; if (!(user_flags_ & kNewEviction)) new_eviction_ = false; disabled_ = true; data_->header.crash = 0; index_->Flush(); index_ = NULL; data_ = NULL; block_files_.CloseFiles(); rankings_.Reset(); init_ = false; restarted_ = true; } void BackendImpl::CleanupCache() { Trace("Backend Cleanup"); eviction_.Stop(); timer_.reset(); if (init_) { StoreStats(); if (data_) data_->header.crash = 0; if (user_flags_ & kNoRandom) { // This is a net_unittest, verify that we are not 'leaking' entries. File::WaitForPendingIO(&num_pending_io_); DCHECK(!num_refs_); } else { File::DropPendingIO(); } } block_files_.CloseFiles(); FlushIndex(); index_ = NULL; ptr_factory_.InvalidateWeakPtrs(); done_.Signal(); } int BackendImpl::NewEntry(Addr address, EntryImpl** entry) { EntriesMap::iterator it = open_entries_.find(address.value()); if (it != open_entries_.end()) { // Easy job. This entry is already in memory. EntryImpl* this_entry = it->second; this_entry->AddRef(); *entry = this_entry; return 0; } STRESS_DCHECK(block_files_.IsValid(address)); if (!address.SanityCheckForEntry()) { LOG(WARNING) << "Wrong entry address."; STRESS_NOTREACHED(); return ERR_INVALID_ADDRESS; } scoped_refptr cache_entry( new EntryImpl(this, address, read_only_)); IncreaseNumRefs(); *entry = NULL; TimeTicks start = TimeTicks::Now(); if (!cache_entry->entry()->Load()) return ERR_READ_FAILURE; if (IsLoaded()) { CACHE_UMA(AGE_MS, "LoadTime", 0, start); } if (!cache_entry->SanityCheck()) { LOG(WARNING) << "Messed up entry found."; STRESS_NOTREACHED(); return ERR_INVALID_ENTRY; } STRESS_DCHECK(block_files_.IsValid( Addr(cache_entry->entry()->Data()->rankings_node))); if (!cache_entry->LoadNodeAddress()) return ERR_READ_FAILURE; if (!rankings_.SanityCheck(cache_entry->rankings(), false)) { STRESS_NOTREACHED(); cache_entry->SetDirtyFlag(0); // Don't remove this from the list (it is not linked properly). Instead, // break the link back to the entry because it is going away, and leave the // rankings node to be deleted if we find it through a list. rankings_.SetContents(cache_entry->rankings(), 0); } else if (!rankings_.DataSanityCheck(cache_entry->rankings(), false)) { STRESS_NOTREACHED(); cache_entry->SetDirtyFlag(0); rankings_.SetContents(cache_entry->rankings(), address.value()); } if (!cache_entry->DataSanityCheck()) { LOG(WARNING) << "Messed up entry found."; cache_entry->SetDirtyFlag(0); cache_entry->FixForDelete(); } // Prevent overwriting the dirty flag on the destructor. cache_entry->SetDirtyFlag(GetCurrentEntryId()); if (cache_entry->dirty()) { Trace("Dirty entry 0x%p 0x%x", reinterpret_cast(cache_entry.get()), address.value()); } open_entries_[address.value()] = cache_entry.get(); cache_entry->BeginLogging(net_log_, false); cache_entry.swap(entry); return 0; } // This is the actual implementation for OpenNextEntry and OpenPrevEntry. EntryImpl* BackendImpl::OpenFollowingEntry(bool forward, void** iter) { if (disabled_) return NULL; DCHECK(iter); const int kListsToSearch = 3; scoped_refptr entries[kListsToSearch]; scoped_ptr iterator( reinterpret_cast(*iter)); *iter = NULL; if (!iterator.get()) { iterator.reset(new Rankings::Iterator(&rankings_)); bool ret = false; // Get an entry from each list. for (int i = 0; i < kListsToSearch; i++) { EntryImpl* temp = NULL; ret |= OpenFollowingEntryFromList(forward, static_cast(i), &iterator->nodes[i], &temp); entries[i].swap(&temp); // The entry was already addref'd. } if (!ret) return NULL; } else { // Get the next entry from the last list, and the actual entries for the // elements on the other lists. for (int i = 0; i < kListsToSearch; i++) { EntryImpl* temp = NULL; if (iterator->list == i) { OpenFollowingEntryFromList(forward, iterator->list, &iterator->nodes[i], &temp); } else { temp = GetEnumeratedEntry(iterator->nodes[i], static_cast(i)); } entries[i].swap(&temp); // The entry was already addref'd. } } int newest = -1; int oldest = -1; Time access_times[kListsToSearch]; for (int i = 0; i < kListsToSearch; i++) { if (entries[i].get()) { access_times[i] = entries[i]->GetLastUsed(); if (newest < 0) { DCHECK_LT(oldest, 0); newest = oldest = i; continue; } if (access_times[i] > access_times[newest]) newest = i; if (access_times[i] < access_times[oldest]) oldest = i; } } if (newest < 0 || oldest < 0) return NULL; EntryImpl* next_entry; if (forward) { next_entry = entries[newest].get(); iterator->list = static_cast(newest); } else { next_entry = entries[oldest].get(); iterator->list = static_cast(oldest); } *iter = iterator.release(); next_entry->AddRef(); return next_entry; } void BackendImpl::AddStorageSize(int32 bytes) { data_->header.num_bytes += bytes; DCHECK_GE(data_->header.num_bytes, 0); } void BackendImpl::SubstractStorageSize(int32 bytes) { data_->header.num_bytes -= bytes; DCHECK_GE(data_->header.num_bytes, 0); } void BackendImpl::IncreaseNumRefs() { num_refs_++; if (max_refs_ < num_refs_) max_refs_ = num_refs_; } void BackendImpl::DecreaseNumRefs() { DCHECK(num_refs_); num_refs_--; if (!num_refs_ && disabled_) base::MessageLoop::current()->PostTask( FROM_HERE, base::Bind(&BackendImpl::RestartCache, GetWeakPtr(), true)); } void BackendImpl::IncreaseNumEntries() { data_->header.num_entries++; DCHECK_GT(data_->header.num_entries, 0); } void BackendImpl::DecreaseNumEntries() { data_->header.num_entries--; if (data_->header.num_entries < 0) { NOTREACHED(); data_->header.num_entries = 0; } } int BackendImpl::SyncInit() { #if defined(NET_BUILD_STRESS_CACHE) // Start evictions right away. up_ticks_ = kTrimDelay * 2; #endif DCHECK(!init_); if (init_) return net::ERR_FAILED; bool create_files = false; if (!InitBackingStore(&create_files)) { ReportError(ERR_STORAGE_ERROR); return net::ERR_FAILED; } num_refs_ = num_pending_io_ = max_refs_ = 0; entry_count_ = byte_count_ = 0; if (!restarted_) { buffer_bytes_ = 0; trace_object_ = TraceObject::GetTraceObject(); // Create a recurrent timer of 30 secs. int timer_delay = unit_test_ ? 1000 : 30000; timer_.reset(new base::RepeatingTimer()); timer_->Start(FROM_HERE, TimeDelta::FromMilliseconds(timer_delay), this, &BackendImpl::OnStatsTimer); } init_ = true; Trace("Init"); if (data_->header.experiment != NO_EXPERIMENT && cache_type_ != net::DISK_CACHE) { // No experiment for other caches. return net::ERR_FAILED; } if (!(user_flags_ & kNoRandom)) { // The unit test controls directly what to test. new_eviction_ = (cache_type_ == net::DISK_CACHE); } if (!CheckIndex()) { ReportError(ERR_INIT_FAILED); return net::ERR_FAILED; } if (!restarted_ && (create_files || !data_->header.num_entries)) ReportError(ERR_CACHE_CREATED); if (!(user_flags_ & kNoRandom) && cache_type_ == net::DISK_CACHE && !InitExperiment(&data_->header, create_files)) { return net::ERR_FAILED; } // We don't care if the value overflows. The only thing we care about is that // the id cannot be zero, because that value is used as "not dirty". // Increasing the value once per second gives us many years before we start // having collisions. data_->header.this_id++; if (!data_->header.this_id) data_->header.this_id++; bool previous_crash = (data_->header.crash != 0); data_->header.crash = 1; if (!block_files_.Init(create_files)) return net::ERR_FAILED; // We want to minimize the changes to cache for an AppCache. if (cache_type() == net::APP_CACHE) { DCHECK(!new_eviction_); read_only_ = true; } else if (cache_type() == net::SHADER_CACHE) { DCHECK(!new_eviction_); } eviction_.Init(this); // stats_ and rankings_ may end up calling back to us so we better be enabled. disabled_ = false; if (!InitStats()) return net::ERR_FAILED; disabled_ = !rankings_.Init(this, new_eviction_); #if defined(STRESS_CACHE_EXTENDED_VALIDATION) trace_object_->EnableTracing(false); int sc = SelfCheck(); if (sc < 0 && sc != ERR_NUM_ENTRIES_MISMATCH) NOTREACHED(); trace_object_->EnableTracing(true); #endif if (previous_crash) { ReportError(ERR_PREVIOUS_CRASH); } else if (!restarted_) { ReportError(ERR_NO_ERROR); } FlushIndex(); return disabled_ ? net::ERR_FAILED : net::OK; } EntryImpl* BackendImpl::ResurrectEntry(EntryImpl* deleted_entry) { if (ENTRY_NORMAL == deleted_entry->entry()->Data()->state) { deleted_entry->Release(); stats_.OnEvent(Stats::CREATE_MISS); Trace("create entry miss "); return NULL; } // We are attempting to create an entry and found out that the entry was // previously deleted. eviction_.OnCreateEntry(deleted_entry); entry_count_++; stats_.OnEvent(Stats::RESURRECT_HIT); Trace("Resurrect entry hit "); return deleted_entry; } EntryImpl* BackendImpl::CreateEntryImpl(const std::string& key) { if (disabled_ || key.empty()) return NULL; TimeTicks start = TimeTicks::Now(); Trace("Create hash 0x%x", hash); scoped_refptr parent; Addr entry_address(data_->table[hash & mask_]); if (entry_address.is_initialized()) { // We have an entry already. It could be the one we are looking for, or just // a hash conflict. bool error; EntryImpl* old_entry = MatchEntry(key, hash, false, Addr(), &error); if (old_entry) return ResurrectEntry(old_entry); EntryImpl* parent_entry = MatchEntry(key, hash, true, Addr(), &error); DCHECK(!error); if (parent_entry) { parent.swap(&parent_entry); } else if (data_->table[hash & mask_]) { // We should have corrected the problem. NOTREACHED(); return NULL; } } // The general flow is to allocate disk space and initialize the entry data, // followed by saving that to disk, then linking the entry though the index // and finally through the lists. If there is a crash in this process, we may // end up with: // a. Used, unreferenced empty blocks on disk (basically just garbage). // b. Used, unreferenced but meaningful data on disk (more garbage). // c. A fully formed entry, reachable only through the index. // d. A fully formed entry, also reachable through the lists, but still dirty. // // Anything after (b) can be automatically cleaned up. We may consider saving // the current operation (as we do while manipulating the lists) so that we // can detect and cleanup (a) and (b). int num_blocks = EntryImpl::NumBlocksForEntry(key.size()); if (!block_files_.CreateBlock(BLOCK_256, num_blocks, &entry_address)) { LOG(ERROR) << "Create entry failed " << key.c_str(); stats_.OnEvent(Stats::CREATE_ERROR); return NULL; } Addr node_address(0); if (!block_files_.CreateBlock(RANKINGS, 1, &node_address)) { block_files_.DeleteBlock(entry_address, false); LOG(ERROR) << "Create entry failed " << key.c_str(); stats_.OnEvent(Stats::CREATE_ERROR); return NULL; } scoped_refptr cache_entry( new EntryImpl(this, entry_address, false)); IncreaseNumRefs(); if (!cache_entry->CreateEntry(node_address, key, hash)) { block_files_.DeleteBlock(entry_address, false); block_files_.DeleteBlock(node_address, false); LOG(ERROR) << "Create entry failed " << key.c_str(); stats_.OnEvent(Stats::CREATE_ERROR); return NULL; } cache_entry->BeginLogging(net_log_, true); // We are not failing the operation; let's add this to the map. open_entries_[entry_address.value()] = cache_entry; // Save the entry. cache_entry->entry()->Store(); cache_entry->rankings()->Store(); IncreaseNumEntries(); entry_count_++; // Link this entry through the index. if (parent.get()) { parent->SetNextAddress(entry_address); } else { data_->table[hash & mask_] = entry_address.value(); } // Link this entry through the lists. eviction_.OnCreateEntry(cache_entry); CACHE_UMA(AGE_MS, "CreateTime", 0, start); stats_.OnEvent(Stats::CREATE_HIT); SIMPLE_STATS_COUNTER("disk_cache.miss"); Trace("create entry hit "); FlushIndex(); cache_entry->AddRef(); return cache_entry.get(); } void BackendImpl::LogStats() { StatsItems stats; GetStats(&stats); for (size_t index = 0; index < stats.size(); index++) VLOG(1) << stats[index].first << ": " << stats[index].second; } void BackendImpl::ReportStats() { CACHE_UMA(COUNTS, "Entries", 0, data_->header.num_entries); int current_size = data_->header.num_bytes / (1024 * 1024); int max_size = max_size_ / (1024 * 1024); int hit_ratio_as_percentage = stats_.GetHitRatio(); CACHE_UMA(COUNTS_10000, "Size2", 0, current_size); // For any bin in HitRatioBySize2, the hit ratio of caches of that size is the // ratio of that bin's total count to the count in the same bin in the Size2 // histogram. if (base::RandInt(0, 99) < hit_ratio_as_percentage) CACHE_UMA(COUNTS_10000, "HitRatioBySize2", 0, current_size); CACHE_UMA(COUNTS_10000, "MaxSize2", 0, max_size); if (!max_size) max_size++; CACHE_UMA(PERCENTAGE, "UsedSpace", 0, current_size * 100 / max_size); CACHE_UMA(COUNTS_10000, "AverageOpenEntries2", 0, static_cast(stats_.GetCounter(Stats::OPEN_ENTRIES))); CACHE_UMA(COUNTS_10000, "MaxOpenEntries2", 0, static_cast(stats_.GetCounter(Stats::MAX_ENTRIES))); stats_.SetCounter(Stats::MAX_ENTRIES, 0); CACHE_UMA(COUNTS_10000, "TotalFatalErrors", 0, static_cast(stats_.GetCounter(Stats::FATAL_ERROR))); CACHE_UMA(COUNTS_10000, "TotalDoomCache", 0, static_cast(stats_.GetCounter(Stats::DOOM_CACHE))); CACHE_UMA(COUNTS_10000, "TotalDoomRecentEntries", 0, static_cast(stats_.GetCounter(Stats::DOOM_RECENT))); stats_.SetCounter(Stats::FATAL_ERROR, 0); stats_.SetCounter(Stats::DOOM_CACHE, 0); stats_.SetCounter(Stats::DOOM_RECENT, 0); int64 total_hours = stats_.GetCounter(Stats::TIMER) / 120; if (!data_->header.create_time || !data_->header.lru.filled) { int cause = data_->header.create_time ? 0 : 1; if (!data_->header.lru.filled) cause |= 2; CACHE_UMA(CACHE_ERROR, "ShortReport", 0, cause); CACHE_UMA(HOURS, "TotalTimeNotFull", 0, static_cast(total_hours)); return; } // This is an up to date client that will report FirstEviction() data. After // that event, start reporting this: CACHE_UMA(HOURS, "TotalTime", 0, static_cast(total_hours)); // For any bin in HitRatioByTotalTime, the hit ratio of caches of that total // time is the ratio of that bin's total count to the count in the same bin in // the TotalTime histogram. if (base::RandInt(0, 99) < hit_ratio_as_percentage) CACHE_UMA(HOURS, "HitRatioByTotalTime", 0, implicit_cast(total_hours)); int64 use_hours = stats_.GetCounter(Stats::LAST_REPORT_TIMER) / 120; stats_.SetCounter(Stats::LAST_REPORT_TIMER, stats_.GetCounter(Stats::TIMER)); // We may see users with no use_hours at this point if this is the first time // we are running this code. if (use_hours) use_hours = total_hours - use_hours; if (!use_hours || !GetEntryCount() || !data_->header.num_bytes) return; CACHE_UMA(HOURS, "UseTime", 0, static_cast(use_hours)); // For any bin in HitRatioByUseTime, the hit ratio of caches of that use time // is the ratio of that bin's total count to the count in the same bin in the // UseTime histogram. if (base::RandInt(0, 99) < hit_ratio_as_percentage) CACHE_UMA(HOURS, "HitRatioByUseTime", 0, implicit_cast(use_hours)); CACHE_UMA(PERCENTAGE, "HitRatio", 0, hit_ratio_as_percentage); int64 trim_rate = stats_.GetCounter(Stats::TRIM_ENTRY) / use_hours; CACHE_UMA(COUNTS, "TrimRate", 0, static_cast(trim_rate)); int avg_size = data_->header.num_bytes / GetEntryCount(); CACHE_UMA(COUNTS, "EntrySize", 0, avg_size); CACHE_UMA(COUNTS, "EntriesFull", 0, data_->header.num_entries); CACHE_UMA(PERCENTAGE, "IndexLoad", 0, data_->header.num_entries * 100 / (mask_ + 1)); int large_entries_bytes = stats_.GetLargeEntriesSize(); int large_ratio = large_entries_bytes * 100 / data_->header.num_bytes; CACHE_UMA(PERCENTAGE, "LargeEntriesRatio", 0, large_ratio); if (new_eviction_) { CACHE_UMA(PERCENTAGE, "ResurrectRatio", 0, stats_.GetResurrectRatio()); CACHE_UMA(PERCENTAGE, "NoUseRatio", 0, data_->header.lru.sizes[0] * 100 / data_->header.num_entries); CACHE_UMA(PERCENTAGE, "LowUseRatio", 0, data_->header.lru.sizes[1] * 100 / data_->header.num_entries); CACHE_UMA(PERCENTAGE, "HighUseRatio", 0, data_->header.lru.sizes[2] * 100 / data_->header.num_entries); CACHE_UMA(PERCENTAGE, "DeletedRatio", 0, data_->header.lru.sizes[4] * 100 / data_->header.num_entries); } stats_.ResetRatios(); stats_.SetCounter(Stats::TRIM_ENTRY, 0); if (cache_type_ == net::DISK_CACHE) block_files_.ReportStats(); } void BackendImpl::ReportError(int error) { STRESS_DCHECK(!error || error == ERR_PREVIOUS_CRASH || error == ERR_CACHE_CREATED); // We transmit positive numbers, instead of direct error codes. DCHECK_LE(error, 0); CACHE_UMA(CACHE_ERROR, "Error", 0, error * -1); } bool BackendImpl::CheckIndex() { DCHECK(data_); size_t current_size = index_->GetLength(); if (current_size < sizeof(Index)) { LOG(ERROR) << "Corrupt Index file"; return false; } if (new_eviction_) { // We support versions 2.0 and 2.1, upgrading 2.0 to 2.1. if (kIndexMagic != data_->header.magic || kCurrentVersion >> 16 != data_->header.version >> 16) { LOG(ERROR) << "Invalid file version or magic"; return false; } if (kCurrentVersion == data_->header.version) { // We need file version 2.1 for the new eviction algorithm. UpgradeTo2_1(); } } else { if (kIndexMagic != data_->header.magic || kCurrentVersion != data_->header.version) { LOG(ERROR) << "Invalid file version or magic"; return false; } } if (!data_->header.table_len) { LOG(ERROR) << "Invalid table size"; return false; } if (current_size < GetIndexSize(data_->header.table_len) || data_->header.table_len & (kBaseTableLen - 1)) { LOG(ERROR) << "Corrupt Index file"; return false; } AdjustMaxCacheSize(data_->header.table_len); #if !defined(NET_BUILD_STRESS_CACHE) if (data_->header.num_bytes < 0 || (max_size_ < kint32max - kDefaultCacheSize && data_->header.num_bytes > max_size_ + kDefaultCacheSize)) { LOG(ERROR) << "Invalid cache (current) size"; return false; } #endif if (data_->header.num_entries < 0) { LOG(ERROR) << "Invalid number of entries"; return false; } if (!mask_) mask_ = data_->header.table_len - 1; // Load the table into memory with a single read. scoped_ptr buf(new char[current_size]); return index_->Read(buf.get(), current_size, 0); } int BackendImpl::CheckAllEntries() { int num_dirty = 0; int num_entries = 0; DCHECK(mask_ < kuint32max); for (unsigned int i = 0; i <= mask_; i++) { Addr address(data_->table[i]); if (!address.is_initialized()) continue; for (;;) { EntryImpl* tmp; int ret = NewEntry(address, &tmp); if (ret) { STRESS_NOTREACHED(); return ret; } scoped_refptr cache_entry; cache_entry.swap(&tmp); if (cache_entry->dirty()) num_dirty++; else if (CheckEntry(cache_entry.get())) num_entries++; else return ERR_INVALID_ENTRY; DCHECK_EQ(i, cache_entry->entry()->Data()->hash & mask_); address.set_value(cache_entry->GetNextAddress()); if (!address.is_initialized()) break; } } Trace("CheckAllEntries End"); if (num_entries + num_dirty != data_->header.num_entries) { LOG(ERROR) << "Number of entries " << num_entries << " " << num_dirty << " " << data_->header.num_entries; DCHECK_LT(num_entries, data_->header.num_entries); return ERR_NUM_ENTRIES_MISMATCH; } return num_dirty; } bool BackendImpl::CheckEntry(EntryImpl* cache_entry) { bool ok = block_files_.IsValid(cache_entry->entry()->address()); ok = ok && block_files_.IsValid(cache_entry->rankings()->address()); EntryStore* data = cache_entry->entry()->Data(); for (size_t i = 0; i < arraysize(data->data_addr); i++) { if (data->data_addr[i]) { Addr address(data->data_addr[i]); if (address.is_block_file()) ok = ok && block_files_.IsValid(address); } } return ok && cache_entry->rankings()->VerifyHash(); } int BackendImpl::MaxBuffersSize() { static int64 total_memory = base::SysInfo::AmountOfPhysicalMemory(); static bool done = false; if (!done) { const int kMaxBuffersSize = 30 * 1024 * 1024; // We want to use up to 2% of the computer's memory. total_memory = total_memory * 2 / 100; if (total_memory > kMaxBuffersSize || total_memory <= 0) total_memory = kMaxBuffersSize; done = true; } return static_cast(total_memory); } } // namespace disk_cache