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| 1 // Copyright 2014 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_mach.h" | |
| 6 | |
| 7 #include <mach/mach.h> | |
| 8 | |
| 9 #include "base/basictypes.h" | |
| 10 #include "base/compiler_specific.h" | |
| 11 #include "base/lazy_instance.h" | |
| 12 #include "base/logging.h" | |
| 13 #include "base/mac/mach_logging.h" | |
| 14 | |
| 15 namespace base { | |
| 16 namespace { | |
| 17 | |
| 18 // For Mach, have the DiscardableMemoryManager trigger userspace eviction when | |
| 19 // address space usage gets too high (e.g. 512 MBytes). | |
| 20 const size_t kMachMemoryLimit = 512 * 1024 * 1024; | |
| 21 | |
| 22 // internal::DiscardableMemoryManager has an explicit constructor that takes | |
| 23 // a number of memory limit parameters. The LeakyLazyInstanceTraits doesn't | |
| 24 // handle the case. Thus, we need our own class here. | |
| 25 struct DiscardableMemoryManagerLazyInstanceTraits { | |
| 26 // Leaky as discardable memory clients can use this after the exit handler | |
| 27 // has been called. | |
| 28 static const bool kRegisterOnExit = false; | |
| 29 #ifndef NDEBUG | |
| 30 static const bool kAllowedToAccessOnNonjoinableThread = true; | |
| 31 #endif | |
| 32 | |
| 33 static internal::DiscardableMemoryManager* New(void* instance) { | |
| 34 return new (instance) internal::DiscardableMemoryManager( | |
| 35 kMachMemoryLimit, kMachMemoryLimit, TimeDelta::Max()); | |
| 36 } | |
| 37 static void Delete(internal::DiscardableMemoryManager* instance) { | |
| 38 instance->~DiscardableMemoryManager(); | |
| 39 } | |
| 40 }; | |
| 41 | |
| 42 LazyInstance<internal::DiscardableMemoryManager, | |
| 43 DiscardableMemoryManagerLazyInstanceTraits> | |
| 44 g_manager = LAZY_INSTANCE_INITIALIZER; | |
| 45 | |
| 46 // The VM subsystem allows tagging of memory and 240-255 is reserved for | |
| 47 // application use (see mach/vm_statistics.h). Pick 252 (after chromium's atomic | |
| 48 // weight of ~52). | |
| 49 const int kDiscardableMemoryTag = VM_MAKE_TAG(252); | |
| 50 | |
| 51 } // namespace | |
| 52 | |
| 53 namespace internal { | |
| 54 | |
| 55 DiscardableMemoryMach::DiscardableMemoryMach(size_t bytes) | |
| 56 : memory_(0, 0), bytes_(mach_vm_round_page(bytes)), is_locked_(false) { | |
| 57 g_manager.Pointer()->Register(this, bytes); | |
| 58 } | |
| 59 | |
| 60 DiscardableMemoryMach::~DiscardableMemoryMach() { | |
| 61 if (is_locked_) | |
| 62 Unlock(); | |
| 63 g_manager.Pointer()->Unregister(this); | |
| 64 } | |
| 65 | |
| 66 bool DiscardableMemoryMach::Initialize() { | |
| 67 return Lock() != DISCARDABLE_MEMORY_LOCK_STATUS_FAILED; | |
| 68 } | |
| 69 | |
| 70 DiscardableMemoryLockStatus DiscardableMemoryMach::Lock() { | |
| 71 DCHECK(!is_locked_); | |
| 72 | |
| 73 bool purged = false; | |
| 74 if (!g_manager.Pointer()->AcquireLock(this, &purged)) | |
| 75 return DISCARDABLE_MEMORY_LOCK_STATUS_FAILED; | |
| 76 | |
| 77 is_locked_ = true; | |
| 78 return purged ? DISCARDABLE_MEMORY_LOCK_STATUS_PURGED | |
| 79 : DISCARDABLE_MEMORY_LOCK_STATUS_SUCCESS; | |
| 80 } | |
| 81 | |
| 82 void DiscardableMemoryMach::Unlock() { | |
| 83 DCHECK(is_locked_); | |
| 84 g_manager.Pointer()->ReleaseLock(this); | |
| 85 is_locked_ = false; | |
| 86 } | |
| 87 | |
| 88 void* DiscardableMemoryMach::Memory() const { | |
| 89 DCHECK(is_locked_); | |
| 90 return reinterpret_cast<void*>(memory_.address()); | |
| 91 } | |
| 92 | |
| 93 bool DiscardableMemoryMach::AllocateAndAcquireLock() { | |
| 94 kern_return_t ret; | |
| 95 bool persistent; | |
| 96 if (!memory_.size()) { | |
| 97 vm_address_t address = 0; | |
| 98 ret = vm_allocate( | |
| 99 mach_task_self(), | |
| 100 &address, | |
| 101 bytes_, | |
| 102 VM_FLAGS_ANYWHERE | VM_FLAGS_PURGABLE | kDiscardableMemoryTag); | |
| 103 MACH_CHECK(ret == KERN_SUCCESS, ret) << "vm_allocate"; | |
| 104 memory_.reset(address, bytes_); | |
| 105 | |
| 106 // When making a fresh allocation, it's impossible for |persistent| to | |
| 107 // be true. | |
| 108 persistent = false; | |
| 109 } else { | |
| 110 // |persistent| will be reset to false below if appropriate, but when | |
| 111 // reusing an existing allocation, it's possible for it to be true. | |
| 112 persistent = true; | |
| 113 | |
| 114 #if !defined(NDEBUG) | |
| 115 ret = vm_protect(mach_task_self(), | |
| 116 memory_.address(), | |
| 117 memory_.size(), | |
| 118 FALSE, | |
| 119 VM_PROT_DEFAULT); | |
| 120 MACH_DCHECK(ret == KERN_SUCCESS, ret) << "vm_protect"; | |
| 121 #endif | |
| 122 } | |
| 123 | |
| 124 int state = VM_PURGABLE_NONVOLATILE; | |
| 125 ret = vm_purgable_control( | |
| 126 mach_task_self(), memory_.address(), VM_PURGABLE_SET_STATE, &state); | |
| 127 MACH_CHECK(ret == KERN_SUCCESS, ret) << "vm_purgable_control"; | |
| 128 if (state & VM_PURGABLE_EMPTY) | |
| 129 persistent = false; | |
| 130 | |
| 131 return persistent; | |
| 132 } | |
| 133 | |
| 134 void DiscardableMemoryMach::ReleaseLock() { | |
| 135 int state = VM_PURGABLE_VOLATILE | VM_VOLATILE_GROUP_DEFAULT; | |
| 136 kern_return_t ret = vm_purgable_control( | |
| 137 mach_task_self(), memory_.address(), VM_PURGABLE_SET_STATE, &state); | |
| 138 MACH_CHECK(ret == KERN_SUCCESS, ret) << "vm_purgable_control"; | |
| 139 | |
| 140 #if !defined(NDEBUG) | |
| 141 ret = vm_protect( | |
| 142 mach_task_self(), memory_.address(), memory_.size(), FALSE, VM_PROT_NONE); | |
| 143 MACH_DCHECK(ret == KERN_SUCCESS, ret) << "vm_protect"; | |
| 144 #endif | |
| 145 } | |
| 146 | |
| 147 void DiscardableMemoryMach::Purge() { | |
| 148 memory_.reset(); | |
| 149 } | |
| 150 | |
| 151 } // namespace internal | |
| 152 } // namespace base | |
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Chromium Code Reviews
Issue 1001833005:
Update from https://crrev.com/320343 (Closed)
Base URL: git@github.com:domokit/mojo.git@master