1 // Copyright 2013 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #include "base/memory/discardable_memory_emulated.h"
7 #include "base/lazy_instance.h"
8 #include "base/memory/discardable_memory_manager.h"
13 // This is admittedly pretty magical.
14 const size_t kEmulatedMemoryLimit = 512 * 1024 * 1024;
15 const size_t kEmulatedSoftMemoryLimit = 32 * 1024 * 1024;
16 const size_t kEmulatedHardMemoryLimitExpirationTimeMs = 1000;
18 // internal::DiscardableMemoryManager has an explicit constructor that takes
19 // a number of memory limit parameters. The LeakyLazyInstanceTraits doesn't
20 // handle the case. Thus, we need our own class here.
21 struct DiscardableMemoryManagerLazyInstanceTraits {
22 // Leaky as discardable memory clients can use this after the exit handler
24 static const bool kRegisterOnExit = false;
26 static const bool kAllowedToAccessOnNonjoinableThread = true;
29 static internal::DiscardableMemoryManager* New(void* instance) {
30 return new (instance) internal::DiscardableMemoryManager(
32 kEmulatedSoftMemoryLimit,
33 TimeDelta::FromMilliseconds(kEmulatedHardMemoryLimitExpirationTimeMs));
35 static void Delete(internal::DiscardableMemoryManager* instance) {
36 instance->~DiscardableMemoryManager();
40 LazyInstance<internal::DiscardableMemoryManager,
41 DiscardableMemoryManagerLazyInstanceTraits>
42 g_manager = LAZY_INSTANCE_INITIALIZER;
48 DiscardableMemoryEmulated::DiscardableMemoryEmulated(size_t bytes)
51 g_manager.Pointer()->Register(this, bytes);
54 DiscardableMemoryEmulated::~DiscardableMemoryEmulated() {
57 g_manager.Pointer()->Unregister(this);
61 bool DiscardableMemoryEmulated::ReduceMemoryUsage() {
62 return g_manager.Pointer()->ReduceMemoryUsage();
66 void DiscardableMemoryEmulated::ReduceMemoryUsageUntilWithinLimit(
68 g_manager.Pointer()->ReduceMemoryUsageUntilWithinLimit(bytes);
72 void DiscardableMemoryEmulated::PurgeForTesting() {
73 g_manager.Pointer()->PurgeAll();
76 bool DiscardableMemoryEmulated::Initialize() {
77 return Lock() != DISCARDABLE_MEMORY_LOCK_STATUS_FAILED;
80 DiscardableMemoryLockStatus DiscardableMemoryEmulated::Lock() {
84 if (!g_manager.Pointer()->AcquireLock(this, &purged))
85 return DISCARDABLE_MEMORY_LOCK_STATUS_FAILED;
88 return purged ? DISCARDABLE_MEMORY_LOCK_STATUS_PURGED
89 : DISCARDABLE_MEMORY_LOCK_STATUS_SUCCESS;
92 void DiscardableMemoryEmulated::Unlock() {
94 g_manager.Pointer()->ReleaseLock(this);
98 void* DiscardableMemoryEmulated::Memory() const {
101 return memory_.get();
104 bool DiscardableMemoryEmulated::AllocateAndAcquireLock() {
108 memory_.reset(new uint8[bytes_]);
112 void DiscardableMemoryEmulated::Purge() {
116 bool DiscardableMemoryEmulated::IsMemoryResident() const {
120 } // namespace internal