base/memory/discardable_memory_android.cc

   1 // Copyright (c) 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.
   4
   5 #include "base/memory/discardable_memory.h"
   6
   7 #include "base/basictypes.h"
   8 #include "base/compiler_specific.h"
   9 #include "base/lazy_instance.h"
  10 #include "base/logging.h"
  11 #include "base/memory/discardable_memory_ashmem.h"
  12 #include "base/memory/discardable_memory_ashmem_allocator.h"
  13 #include "base/memory/discardable_memory_emulated.h"
  14 #include "base/memory/discardable_memory_shmem.h"
  15 #include "base/sys_info.h"
  16
  17 namespace base {
  18 namespace {
  19
  20 const char kAshmemAllocatorName[] = "DiscardableMemoryAshmemAllocator";
  21
  22 // For Ashmem, have the DiscardableMemoryManager trigger userspace eviction
  23 // when address space usage gets too high (e.g. 512 MBytes).
  24 const size_t kAshmemMemoryLimit = 512 * 1024 * 1024;
  25
  26 size_t GetOptimalAshmemRegionSizeForAllocator() {
  27   // Note that this may do some I/O (without hitting the disk though) so it
  28   // should not be called on the critical path.
  29   return base::SysInfo::AmountOfPhysicalMemory() / 8;
  30 }
  31
  32 // Holds the shared state used for allocations.
  33 struct SharedState {
  34   SharedState()
  35       : manager(kAshmemMemoryLimit, kAshmemMemoryLimit, TimeDelta::Max()),
  36         allocator(kAshmemAllocatorName,
  37                   GetOptimalAshmemRegionSizeForAllocator()) {}
  38
  39   internal::DiscardableMemoryManager manager;
  40   internal::DiscardableMemoryAshmemAllocator allocator;
  41 };
  42 LazyInstance<SharedState>::Leaky g_shared_state = LAZY_INSTANCE_INITIALIZER;
  43
  44 }  // namespace
  45
  46 // static
  47 bool DiscardableMemory::ReduceMemoryUsage() {
  48   return internal::DiscardableMemoryEmulated::ReduceMemoryUsage();
  49 }
  50
  51 // static
  52 void DiscardableMemory::GetSupportedTypes(
  53     std::vector<DiscardableMemoryType>* types) {
  54   const DiscardableMemoryType supported_types[] = {
  55     DISCARDABLE_MEMORY_TYPE_SHMEM,
  56     DISCARDABLE_MEMORY_TYPE_ASHMEM,
  57     DISCARDABLE_MEMORY_TYPE_EMULATED
  58   };
  59   types->assign(supported_types, supported_types + arraysize(supported_types));
  60 }
  61
  62 // static
  63 scoped_ptr<DiscardableMemory> DiscardableMemory::CreateLockedMemoryWithType(
  64     DiscardableMemoryType type, size_t size) {
  65   switch (type) {
  66     case DISCARDABLE_MEMORY_TYPE_ASHMEM: {
  67       SharedState* const shared_state = g_shared_state.Pointer();
  68       scoped_ptr<internal::DiscardableMemoryAshmem> memory(
  69           new internal::DiscardableMemoryAshmem(
  70               size, &shared_state->allocator, &shared_state->manager));
  71       if (!memory->Initialize())
  72         return nullptr;
  73
  74       return memory.Pass();
  75     }
  76     case DISCARDABLE_MEMORY_TYPE_EMULATED: {
  77       scoped_ptr<internal::DiscardableMemoryEmulated> memory(
  78           new internal::DiscardableMemoryEmulated(size));
  79       if (!memory->Initialize())
  80         return nullptr;
  81
  82       return memory.Pass();
  83     }
  84     case DISCARDABLE_MEMORY_TYPE_SHMEM: {
  85       scoped_ptr<internal::DiscardableMemoryShmem> memory(
  86           new internal::DiscardableMemoryShmem(size));
  87       if (!memory->Initialize())
  88         return nullptr;
  89
  90       return memory.Pass();
  91     }
  92     case DISCARDABLE_MEMORY_TYPE_NONE:
  93     case DISCARDABLE_MEMORY_TYPE_MACH:
  94       NOTREACHED();
  95       return nullptr;
  96   }
  97
  98   NOTREACHED();
  99   return nullptr;
 100 }
 101
 102 }  // namespace base