// 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/disk_format.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;
// 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;
}
// ------------------------------------------------------------------------
// Sets group for the current experiment. Returns false if the files should be
// discarded.
bool InitExperiment(disk_cache::IndexHeader* header, bool cache_created) {
if (header->experiment == disk_cache::EXPERIMENT_OLD_FILE1 ||
header->experiment == disk_cache::EXPERIMENT_OLD_FILE2) {
// Discard current cache.
return false;
}
if (base::FieldTrialList::FindFullName("SimpleCacheTrial") ==
"ExperimentControl") {
if (cache_created) {
header->experiment = disk_cache::EXPERIMENT_SIMPLE_CONTROL;
return true;
}
return header->experiment == disk_cache::EXPERIMENT_SIMPLE_CONTROL;
}
header->experiment = disk_cache::NO_EXPERIMENT;
return true;
}
// A callback to perform final cleanup on the background thread.
void FinalCleanupCallback(disk_cache::BackendImpl* backend) {
backend->CleanupCache();
}
} // 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::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<BackendImpl>());
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;
}
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::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;
}
int BackendImpl::SyncOpenEntry(const std::string& key, Entry** entry) {
DCHECK(entry);
*entry = OpenEntryImpl(key);
return (*entry) ? net::OK : net::ERR_FAILED;
}
int BackendImpl::SyncCreateEntry(const std::string& key, Entry** entry) {
DCHECK(entry);
*entry = CreateEntryImpl(key);
return (*entry) ? net::OK : net::ERR_FAILED;
}
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::SyncOpenNextEntry(void** iter, Entry** next_entry) {
*next_entry = OpenNextEntryImpl(iter);
return (*next_entry) ? net::OK : net::ERR_FAILED;
}
int BackendImpl::SyncOpenPrevEntry(void** iter, Entry** prev_entry) {
*prev_entry = OpenPrevEntryImpl(iter);
return (*prev_entry) ? net::OK : net::ERR_FAILED;
}
void BackendImpl::SyncEndEnumeration(void* iter) {
scoped_ptr<Rankings::Iterator> iterator(
reinterpret_cast<Rankings::Iterator*>(iter));
}
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();
}
}
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();
uint32 hash = base::Hash(key);
Trace("Create hash 0x%x", hash);
scoped_refptr<EntryImpl> 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<EntryImpl> 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();
}
EntryImpl* BackendImpl::OpenNextEntryImpl(void** iter) {
return OpenFollowingEntry(true, iter);
}
EntryImpl* BackendImpl::OpenPrevEntryImpl(void** iter) {
return OpenFollowingEntry(false, iter);
}
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;
}
base::FilePath BackendImpl::GetFileName(Addr address) const {
if (!address.is_separate_file() || !address.is_initialized()) {
NOTREACHED();
return base::FilePath();
}
std::string tmp = base::StringPrintf("f_%06x", address.FileNumber());
return path_.AppendASCII(tmp);
}
MappedFile* BackendImpl::File(Addr address) {
if (disabled_)
return NULL;
return block_files_.GetFile(address);
}
base::WeakPtr<InFlightBackendIO> BackendImpl::GetBackgroundQueue() {
return background_queue_.GetWeakPtr();
}
bool BackendImpl::CreateExternalFile(Addr* address) {
int file_number = data_->header.last_file + 1;
Addr file_address(0);
bool success = false;
for (int i = 0; i < 0x0fffffff; i++, file_number++) {
if (!file_address.SetFileNumber(file_number)) {
file_number = 1;
continue;
}
base::FilePath name = GetFileName(file_address);
int flags = base::PLATFORM_FILE_READ |
base::PLATFORM_FILE_WRITE |
base::PLATFORM_FILE_CREATE |
base::PLATFORM_FILE_EXCLUSIVE_WRITE;
base::PlatformFileError error;
scoped_refptr<disk_cache::File> file(new disk_cache::File(
base::CreatePlatformFile(name, flags, NULL, &error)));
if (!file->IsValid()) {
if (error != base::PLATFORM_FILE_ERROR_EXISTS) {
LOG(ERROR) << "Unable to create file: " << error;
return false;
}
continue;
}
success = true;
break;
}
DCHECK(success);
if (!success)
return false;
data_->header.last_file = file_number;
address->set_value(file_address.value());
return true;
}
bool BackendImpl::CreateBlock(FileType block_type, int block_count,
Addr* block_address) {
return block_files_.CreateBlock(block_type, block_count, block_address);
}
void BackendImpl::DeleteBlock(Addr block_address, bool deep) {
block_files_.DeleteBlock(block_address, deep);
}
LruData* BackendImpl::GetLruData() {
return &data_->header.lru;
}
void BackendImpl::UpdateRank(EntryImpl* entry, bool modified) {
if (read_only_ || (!modified && cache_type() == net::SHADER_CACHE))
return;
eviction_.UpdateRank(entry, modified);
}
void BackendImpl::RecoveredEntry(CacheRankingsBlock* rankings) {
Addr address(rankings->Data()->contents);
EntryImpl* cache_entry = NULL;
if (NewEntry(address, &cache_entry)) {
STRESS_NOTREACHED();
return;
}
uint32 hash = cache_entry->GetHash();
cache_entry->Release();
// Anything on the table means that this entry is there.
if (data_->table[hash & mask_])
return;
data_->table[hash & mask_] = address.value();
FlushIndex();
}
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();
}
#if defined(NET_BUILD_STRESS_CACHE)
CacheAddr BackendImpl::GetNextAddr(Addr address) {
EntriesMap::iterator it = open_entries_.find(address.value());
if (it != open_entries_.end()) {
EntryImpl* this_entry = it->second;
return this_entry->GetNextAddress();
}
DCHECK(block_files_.IsValid(address));
DCHECK(!address.is_separate_file() && address.file_type() == BLOCK_256);
CacheEntryBlock entry(File(address), address);
CHECK(entry.Load());
return entry.Data()->next;
}
void BackendImpl::NotLinked(EntryImpl* entry) {
Addr entry_addr = entry->entry()->address();
uint32 i = entry->GetHash() & mask_;
Addr address(data_->table[i]);
if (!address.is_initialized())
return;
for (;;) {
DCHECK(entry_addr.value() != address.value());
address.set_value(GetNextAddr(address));
if (!address.is_initialized())
break;
}
}
#endif // NET_BUILD_STRESS_CACHE
// An entry may be linked on the DELETED list for a while after being doomed.
// This function is called when we want to remove it.
void BackendImpl::RemoveEntry(EntryImpl* entry) {
#if defined(NET_BUILD_STRESS_CACHE)
NotLinked(entry);
#endif
if (!new_eviction_)
return;
DCHECK_NE(ENTRY_NORMAL, entry->entry()->Data()->state);
Trace("Remove entry 0x%p", entry);
eviction_.OnDestroyEntry(entry);
DecreaseNumEntries();
}
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;
}
int32 BackendImpl::GetCurrentEntryId() const {
return data_->header.this_id;
}
int BackendImpl::MaxFileSize() const {
return cache_type() == net::PNACL_CACHE ? max_size_ : 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> 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<int>(use_time / 120));
CACHE_UMA(PERCENTAGE, "FirstHitRatio", 0, stats_.GetHitRatio());
if (!use_time)
use_time = 1;
CACHE_UMA(COUNTS_10000, "FirstEntryAccessRate", 0,
static_cast<int>(data_->header.num_entries / use_time));
CACHE_UMA(COUNTS, "FirstByteIORate", 0,
static_cast<int>((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::CriticalError(int error) {
STRESS_NOTREACHED();
LOG(ERROR) << "Critical error found " << error;
if (disabled_)
return;
stats_.OnEvent(Stats::FATAL_ERROR);
LogStats();
ReportError(error);
// Setting the index table length to an invalid value will force re-creation
// of the cache files.
data_->header.table_len = 1;
disabled_ = true;
if (!num_refs_)
base::MessageLoop::current()->PostTask(
FROM_HERE, base::Bind(&BackendImpl::RestartCache, GetWeakPtr(), true));
}
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);
}
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::IncrementIoCount() {
num_pending_io_++;
}
void BackendImpl::DecrementIoCount() {
num_pending_io_--;
}
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;
}
void BackendImpl::ClearRefCountForTest() {
num_refs_ = 0;
}
int BackendImpl::FlushQueueForTest(const CompletionCallback& callback) {
background_queue_.FlushQueue(callback);
return net::ERR_IO_PENDING;
}
int BackendImpl::RunTaskForTest(const base::Closure& task,
const CompletionCallback& callback) {
background_queue_.RunTask(task, 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();
}
void BackendImpl::FlushIndex() {
if (index_.get() && !disabled_)
index_->Flush();
}
// ------------------------------------------------------------------------
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;
}
int BackendImpl::OpenEntry(const std::string& key, Entry** entry,
const CompletionCallback& callback) {
DCHECK(!callback.is_null());
background_queue_.OpenEntry(key, entry, callback);
return net::ERR_IO_PENDING;
}
int BackendImpl::CreateEntry(const std::string& key, Entry** entry,
const CompletionCallback& callback) {
DCHECK(!callback.is_null());
background_queue_.CreateEntry(key, entry, callback);
return net::ERR_IO_PENDING;
}
int BackendImpl::DoomEntry(const std::string& key,
const CompletionCallback& callback) {
DCHECK(!callback.is_null());
background_queue_.DoomEntry(key, callback);
return net::ERR_IO_PENDING;
}
int BackendImpl::DoomAllEntries(const CompletionCallback& callback) {
DCHECK(!callback.is_null());
background_queue_.DoomAllEntries(callback);
return net::ERR_IO_PENDING;
}
int BackendImpl::DoomEntriesBetween(const base::Time initial_time,
const base::Time end_time,
const CompletionCallback& callback) {
DCHECK(!callback.is_null());
background_queue_.DoomEntriesBetween(initial_time, end_time, callback);
return net::ERR_IO_PENDING;
}
int BackendImpl::DoomEntriesSince(const base::Time initial_time,
const CompletionCallback& callback) {
DCHECK(!callback.is_null());
background_queue_.DoomEntriesSince(initial_time, callback);
return net::ERR_IO_PENDING;
}
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<std::string, std::string> 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::OnExternalCacheHit(const std::string& key) {
background_queue_.OnExternalCacheHit(key);
}
// ------------------------------------------------------------------------
// We just created a new file so we're going to write the header and set the
// file length to include the hash table (zero filled).
bool BackendImpl::CreateBackingStore(disk_cache::File* file) {
AdjustMaxCacheSize(0);
IndexHeader header;
header.table_len = DesiredIndexTableLen(max_size_);
// We need file version 2.1 for the new eviction algorithm.
if (new_eviction_)
header.version = 0x20001;
header.create_time = Time::Now().ToInternalValue();
if (!file->Write(&header, sizeof(header), 0))
return false;
return file->SetLength(GetIndexSize(header.table_len));
}
bool BackendImpl::InitBackingStore(bool* file_created) {
if (!base::CreateDirectory(path_))
return false;
base::FilePath index_name = path_.AppendASCII(kIndexName);
int flags = base::PLATFORM_FILE_READ |
base::PLATFORM_FILE_WRITE |
base::PLATFORM_FILE_OPEN_ALWAYS |
base::PLATFORM_FILE_EXCLUSIVE_WRITE;
scoped_refptr<disk_cache::File> file(new disk_cache::File(
base::CreatePlatformFile(index_name, flags, file_created, NULL)));
if (!file->IsValid())
return false;
bool ret = true;
if (*file_created)
ret = CreateBackingStore(file.get());
file = NULL;
if (!ret)
return false;
index_ = new MappedFile();
data_ = reinterpret_cast<Index*>(index_->Init(index_name, 0));
if (!data_) {
LOG(ERROR) << "Unable to map Index file";
return false;
}
if (index_->GetLength() < sizeof(Index)) {
// We verify this again on CheckIndex() but it's easier to make sure now
// that the header is there.
LOG(ERROR) << "Corrupt Index file";
return false;
}
return true;
}
// 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_ = PreferredCacheSize(available);
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;
data_->header.stats = address.value();
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<char[]> 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<char[]> 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;
}
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.SanityCheckForEntryV2()) {
LOG(WARNING) << "Wrong entry address.";
STRESS_NOTREACHED();
return ERR_INVALID_ADDRESS;
}
scoped_refptr<EntryImpl> 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<void*>(cache_entry.get()),
address.value());
}
open_entries_[address.value()] = cache_entry.get();
cache_entry->BeginLogging(net_log_, false);
cache_entry.swap(entry);
return 0;
}
EntryImpl* BackendImpl::MatchEntry(const std::string& key, uint32 hash,
bool find_parent, Addr entry_addr,
bool* match_error) {
Addr address(data_->table[hash & mask_]);
scoped_refptr<EntryImpl> cache_entry, parent_entry;
EntryImpl* tmp = NULL;
bool found = false;
std::set<CacheAddr> visited;
*match_error = false;
for (;;) {
if (disabled_)
break;
if (visited.find(address.value()) != visited.end()) {
// It's possible for a buggy version of the code to write a loop. Just
// break it.
Trace("Hash collision loop 0x%x", address.value());
address.set_value(0);
parent_entry->SetNextAddress(address);
}
visited.insert(address.value());
if (!address.is_initialized()) {
if (find_parent)
found = true;
break;
}
int error = NewEntry(address, &tmp);
cache_entry.swap(&tmp);
if (error || cache_entry->dirty()) {
// This entry is dirty on disk (it was not properly closed): we cannot
// trust it.
Addr child(0);
if (!error)
child.set_value(cache_entry->GetNextAddress());
if (parent_entry.get()) {
parent_entry->SetNextAddress(child);
parent_entry = NULL;
} else {
data_->table[hash & mask_] = child.value();
}
Trace("MatchEntry dirty %d 0x%x 0x%x", find_parent, entry_addr.value(),
address.value());
if (!error) {
// It is important to call DestroyInvalidEntry after removing this
// entry from the table.
DestroyInvalidEntry(cache_entry.get());
cache_entry = NULL;
} else {
Trace("NewEntry failed on MatchEntry 0x%x", address.value());
}
// Restart the search.
address.set_value(data_->table[hash & mask_]);
visited.clear();
continue;
}
DCHECK_EQ(hash & mask_, cache_entry->entry()->Data()->hash & mask_);
if (cache_entry->IsSameEntry(key, hash)) {
if (!cache_entry->Update())
cache_entry = NULL;
found = true;
if (find_parent && entry_addr.value() != address.value()) {
Trace("Entry not on the index 0x%x", address.value());
*match_error = true;
parent_entry = NULL;
}
break;
}
if (!cache_entry->Update())
cache_entry = NULL;
parent_entry = cache_entry;
cache_entry = NULL;
if (!parent_entry.get())
break;
address.set_value(parent_entry->GetNextAddress());
}
if (parent_entry.get() && (!find_parent || !found))
parent_entry = NULL;
if (find_parent && entry_addr.is_initialized() && !cache_entry.get()) {
*match_error = true;
parent_entry = NULL;
}
if (cache_entry.get() && (find_parent || !found))
cache_entry = NULL;
find_parent ? parent_entry.swap(&tmp) : cache_entry.swap(&tmp);
FlushIndex();
return tmp;
}
// 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<EntryImpl> entries[kListsToSearch];
scoped_ptr<Rankings::Iterator> iterator(
reinterpret_cast<Rankings::Iterator*>(*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<Rankings::List>(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<Rankings::List>(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<Rankings::List>(newest);
} else {
next_entry = entries[oldest].get();
iterator->list = static_cast<Rankings::List>(oldest);
}
*iter = iterator.release();
next_entry->AddRef();
return next_entry;
}
bool BackendImpl::OpenFollowingEntryFromList(bool forward, Rankings::List list,
CacheRankingsBlock** from_entry,
EntryImpl** next_entry) {
if (disabled_)
return false;
if (!new_eviction_ && Rankings::NO_USE != list)
return false;
Rankings::ScopedRankingsBlock rankings(&rankings_, *from_entry);
CacheRankingsBlock* next_block = forward ?
rankings_.GetNext(rankings.get(), list) :
rankings_.GetPrev(rankings.get(), list);
Rankings::ScopedRankingsBlock next(&rankings_, next_block);
*from_entry = NULL;
*next_entry = GetEnumeratedEntry(next.get(), list);
if (!*next_entry)
return false;
*from_entry = next.release();
return true;
}
EntryImpl* BackendImpl::GetEnumeratedEntry(CacheRankingsBlock* next,
Rankings::List list) {
if (!next || disabled_)
return NULL;
EntryImpl* entry;
int rv = NewEntry(Addr(next->Data()->contents), &entry);
if (rv) {
STRESS_NOTREACHED();
rankings_.Remove(next, list, false);
if (rv == ERR_INVALID_ADDRESS) {
// There is nothing linked from the index. Delete the rankings node.
DeleteBlock(next->address(), true);
}
return NULL;
}
if (entry->dirty()) {
// We cannot trust this entry.
InternalDoomEntry(entry);
entry->Release();
return NULL;
}
if (!entry->Update()) {
STRESS_NOTREACHED();
entry->Release();
return NULL;
}
// Note that it is unfortunate (but possible) for this entry to be clean, but
// not actually the real entry. In other words, we could have lost this entry
// from the index, and it could have been replaced with a newer one. It's not
// worth checking that this entry is "the real one", so we just return it and
// let the enumeration continue; this entry will be evicted at some point, and
// the regular path will work with the real entry. With time, this problem
// will disasappear because this scenario is just a bug.
// Make sure that we save the key for later.
entry->GetKey();
return entry;
}
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;
}
void BackendImpl::DestroyInvalidEntry(EntryImpl* entry) {
LOG(WARNING) << "Destroying invalid entry.";
Trace("Destroying invalid entry 0x%p", entry);
entry->SetPointerForInvalidEntry(GetCurrentEntryId());
eviction_.OnDoomEntry(entry);
entry->InternalDoom();
if (!new_eviction_)
DecreaseNumEntries();
stats_.OnEvent(Stats::INVALID_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;
}
}
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<int>(stats_.GetCounter(Stats::OPEN_ENTRIES)));
CACHE_UMA(COUNTS_10000, "MaxOpenEntries2", 0,
static_cast<int>(stats_.GetCounter(Stats::MAX_ENTRIES)));
stats_.SetCounter(Stats::MAX_ENTRIES, 0);
CACHE_UMA(COUNTS_10000, "TotalFatalErrors", 0,
static_cast<int>(stats_.GetCounter(Stats::FATAL_ERROR)));
CACHE_UMA(COUNTS_10000, "TotalDoomCache", 0,
static_cast<int>(stats_.GetCounter(Stats::DOOM_CACHE)));
CACHE_UMA(COUNTS_10000, "TotalDoomRecentEntries", 0,
static_cast<int>(stats_.GetCounter(Stats::DOOM_RECENT)));
stats_.SetCounter(Stats::FATAL_ERROR, 0);
stats_.SetCounter(Stats::DOOM_CACHE, 0);
stats_.SetCounter(Stats::DOOM_RECENT, 0);
int age = (Time::Now() -
Time::FromInternalValue(data_->header.create_time)).InHours();
if (age)
CACHE_UMA(HOURS, "FilesAge", 0, age);
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<int>(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<int>(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<int>(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<int>(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<int>(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<int>(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::UpgradeTo2_1() {
// 2.1 is basically the same as 2.0, except that new fields are actually
// updated by the new eviction algorithm.
DCHECK(0x20000 == data_->header.version);
data_->header.version = 0x20001;
data_->header.lru.sizes[Rankings::NO_USE] = data_->header.num_entries;
}
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<char[]> 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<EntryImpl> 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<int>(total_memory);
}
} // namespace disk_cache