base: Remove DiscardableMemoryMach.

Remove unused DiscardableMemory implementation.

BUG=442945,422953

Review URL: https://codereview.chromium.org/963233003

Cr-Commit-Position: refs/heads/master@{#320171}

base/BUILD.gn

@@ -733,10 +733,6 @@ component("base") {
 
   # Mac.
   if (is_mac) {
-    sources += [
-      "memory/discardable_memory_mach.cc",
-      "memory/discardable_memory_mach.h",
-    ]
     sources -= [
       "native_library_posix.cc",
       "strings/sys_string_conversions_posix.cc",

base/base.gypi

@@ -969,10 +969,6 @@
             ],
           }],
           ['(OS == "mac" or OS == "ios") and >(nacl_untrusted_build)==0', {
-            'sources': [
-              'memory/discardable_memory_mach.cc',
-              'memory/discardable_memory_mach.h',
-            ],
             'sources/': [
               ['exclude', '^files/file_path_watcher_stub\\.cc$'],
               ['exclude', '^base_paths_posix\\.cc$'],

base/memory/discardable_memory.cc

@@ -14,7 +14,6 @@ const struct TypeNamePair {
   DiscardableMemoryType type;
   const char* name;
 } kTypeNamePairs[] = {
-  { DISCARDABLE_MEMORY_TYPE_MACH, "mach" },
   { DISCARDABLE_MEMORY_TYPE_SHMEM, "shmem" }
 };
 

base/memory/discardable_memory.h

@@ -17,7 +17,6 @@ namespace base {
 
 enum DiscardableMemoryType {
   DISCARDABLE_MEMORY_TYPE_NONE,
-  DISCARDABLE_MEMORY_TYPE_MACH,
   DISCARDABLE_MEMORY_TYPE_SHMEM
 };
 

base/memory/discardable_memory_android.cc

@@ -31,7 +31,6 @@ scoped_ptr<DiscardableMemory> DiscardableMemory::CreateLockedMemoryWithType(
       return memory.Pass();
     }
     case DISCARDABLE_MEMORY_TYPE_NONE:
-    case DISCARDABLE_MEMORY_TYPE_MACH:
       NOTREACHED();
       return nullptr;
   }

base/memory/discardable_memory_linux.cc

@@ -31,7 +31,6 @@ scoped_ptr<DiscardableMemory> DiscardableMemory::CreateLockedMemoryWithType(
       return memory.Pass();
     }
     case DISCARDABLE_MEMORY_TYPE_NONE:
-    case DISCARDABLE_MEMORY_TYPE_MACH:
       NOTREACHED();
       return nullptr;
   }

base/memory/discardable_memory_mac.cc

@@ -5,8 +5,6 @@
 #include "base/memory/discardable_memory.h"
 
 #include "base/logging.h"
-#include "base/memory/discardable_memory_mach.h"
-#include "base/memory/discardable_memory_manager.h"
 #include "base/memory/discardable_memory_shmem.h"
 #include "base/memory/scoped_ptr.h"
 
@@ -16,8 +14,7 @@ namespace base {
 void DiscardableMemory::GetSupportedTypes(
     std::vector<DiscardableMemoryType>* types) {
   const DiscardableMemoryType supported_types[] = {
-    DISCARDABLE_MEMORY_TYPE_SHMEM,
-    DISCARDABLE_MEMORY_TYPE_MACH
+    DISCARDABLE_MEMORY_TYPE_SHMEM
   };
   types->assign(supported_types, supported_types + arraysize(supported_types));
 }
@@ -26,14 +23,6 @@ void DiscardableMemory::GetSupportedTypes(
 scoped_ptr<DiscardableMemory> DiscardableMemory::CreateLockedMemoryWithType(
     DiscardableMemoryType type, size_t size) {
   switch (type) {
-    case DISCARDABLE_MEMORY_TYPE_MACH: {
-      scoped_ptr<internal::DiscardableMemoryMach> memory(
-          new internal::DiscardableMemoryMach(size));
-      if (!memory->Initialize())
-        return nullptr;
-
-      return memory.Pass();
-    }
     case DISCARDABLE_MEMORY_TYPE_SHMEM: {
       scoped_ptr<internal::DiscardableMemoryShmem> memory(
           new internal::DiscardableMemoryShmem(size));

base/memory/discardable_memory_mach.cc

-// Copyright 2014 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 "base/memory/discardable_memory_mach.h"
-
-#include <mach/mach.h>
-
-#include "base/basictypes.h"
-#include "base/compiler_specific.h"
-#include "base/lazy_instance.h"
-#include "base/logging.h"
-#include "base/mac/mach_logging.h"
-
-namespace base {
-namespace {
-
-// For Mach, have the DiscardableMemoryManager trigger userspace eviction when
-// address space usage gets too high (e.g. 512 MBytes).
-const size_t kMachMemoryLimit = 512 * 1024 * 1024;
-
-// internal::DiscardableMemoryManager has an explicit constructor that takes
-// a number of memory limit parameters. The LeakyLazyInstanceTraits doesn't
-// handle the case. Thus, we need our own class here.
-struct DiscardableMemoryManagerLazyInstanceTraits {
-  // Leaky as discardable memory clients can use this after the exit handler
-  // has been called.
-  static const bool kRegisterOnExit = false;
-#ifndef NDEBUG
-  static const bool kAllowedToAccessOnNonjoinableThread = true;
-#endif
-
-  static internal::DiscardableMemoryManager* New(void* instance) {
-    return new (instance) internal::DiscardableMemoryManager(
-        kMachMemoryLimit, kMachMemoryLimit, TimeDelta::Max());
-  }
-  static void Delete(internal::DiscardableMemoryManager* instance) {
-    instance->~DiscardableMemoryManager();
-  }
-};
-
-LazyInstance<internal::DiscardableMemoryManager,
-             DiscardableMemoryManagerLazyInstanceTraits>
-    g_manager = LAZY_INSTANCE_INITIALIZER;
-
-// The VM subsystem allows tagging of memory and 240-255 is reserved for
-// application use (see mach/vm_statistics.h). Pick 252 (after chromium's atomic
-// weight of ~52).
-const int kDiscardableMemoryTag = VM_MAKE_TAG(252);
-
-}  // namespace
-
-namespace internal {
-
-DiscardableMemoryMach::DiscardableMemoryMach(size_t bytes)
-    : memory_(0, 0), bytes_(mach_vm_round_page(bytes)), is_locked_(false) {
-  g_manager.Pointer()->Register(this, bytes);
-}
-
-DiscardableMemoryMach::~DiscardableMemoryMach() {
-  if (is_locked_)
-    Unlock();
-  g_manager.Pointer()->Unregister(this);
-}
-
-bool DiscardableMemoryMach::Initialize() {
-  return Lock() != DISCARDABLE_MEMORY_LOCK_STATUS_FAILED;
-}
-
-DiscardableMemoryLockStatus DiscardableMemoryMach::Lock() {
-  DCHECK(!is_locked_);
-
-  bool purged = false;
-  if (!g_manager.Pointer()->AcquireLock(this, &purged))
-    return DISCARDABLE_MEMORY_LOCK_STATUS_FAILED;
-
-  is_locked_ = true;
-  return purged ? DISCARDABLE_MEMORY_LOCK_STATUS_PURGED
-                : DISCARDABLE_MEMORY_LOCK_STATUS_SUCCESS;
-}
-
-void DiscardableMemoryMach::Unlock() {
-  DCHECK(is_locked_);
-  g_manager.Pointer()->ReleaseLock(this);
-  is_locked_ = false;
-}
-
-void* DiscardableMemoryMach::Memory() const {
-  DCHECK(is_locked_);
-  return reinterpret_cast<void*>(memory_.address());
-}
-
-bool DiscardableMemoryMach::AllocateAndAcquireLock() {
-  kern_return_t ret;
-  bool persistent;
-  if (!memory_.size()) {
-    vm_address_t address = 0;
-    ret = vm_allocate(
-        mach_task_self(),
-        &address,
-        bytes_,
-        VM_FLAGS_ANYWHERE | VM_FLAGS_PURGABLE | kDiscardableMemoryTag);
-    MACH_CHECK(ret == KERN_SUCCESS, ret) << "vm_allocate";
-    memory_.reset(address, bytes_);
-
-    // When making a fresh allocation, it's impossible for |persistent| to
-    // be true.
-    persistent = false;
-  } else {
-    // |persistent| will be reset to false below if appropriate, but when
-    // reusing an existing allocation, it's possible for it to be true.
-    persistent = true;
-
-#if !defined(NDEBUG)
-    ret = vm_protect(mach_task_self(),
-                     memory_.address(),
-                     memory_.size(),
-                     FALSE,
-                     VM_PROT_DEFAULT);
-    MACH_DCHECK(ret == KERN_SUCCESS, ret) << "vm_protect";
-#endif
-  }
-
-  int state = VM_PURGABLE_NONVOLATILE;
-  ret = vm_purgable_control(
-      mach_task_self(), memory_.address(), VM_PURGABLE_SET_STATE, &state);
-  MACH_CHECK(ret == KERN_SUCCESS, ret) << "vm_purgable_control";
-  if (state & VM_PURGABLE_EMPTY)
-    persistent = false;
-
-  return persistent;
-}
-
-void DiscardableMemoryMach::ReleaseLock() {
-  int state = VM_PURGABLE_VOLATILE | VM_VOLATILE_GROUP_DEFAULT;
-  kern_return_t ret = vm_purgable_control(
-      mach_task_self(), memory_.address(), VM_PURGABLE_SET_STATE, &state);
-  MACH_CHECK(ret == KERN_SUCCESS, ret) << "vm_purgable_control";
-
-#if !defined(NDEBUG)
-  ret = vm_protect(
-      mach_task_self(), memory_.address(), memory_.size(), FALSE, VM_PROT_NONE);
-  MACH_DCHECK(ret == KERN_SUCCESS, ret) << "vm_protect";
-#endif
-}
-
-void DiscardableMemoryMach::Purge() {
-  memory_.reset();
-}
-
-}  // namespace internal
-}  // namespace base

base/memory/discardable_memory_mach.h

-// Copyright 2014 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.
-
-#ifndef BASE_MEMORY_DISCARDABLE_MEMORY_MACH_H_
-#define BASE_MEMORY_DISCARDABLE_MEMORY_MACH_H_
-
-#include "base/memory/discardable_memory.h"
-
-#include "base/mac/scoped_mach_vm.h"
-#include "base/memory/discardable_memory_manager.h"
-
-namespace base {
-namespace internal {
-
-class DiscardableMemoryMach
-    : public DiscardableMemory,
-      public internal::DiscardableMemoryManagerAllocation {
- public:
-  explicit DiscardableMemoryMach(size_t bytes);
-  ~DiscardableMemoryMach() override;
-
-  bool Initialize();
-
-  // Overridden from DiscardableMemory:
-  DiscardableMemoryLockStatus Lock() override;
-  void Unlock() override;
-  void* Memory() const override;
-
-  // Overridden from internal::DiscardableMemoryManagerAllocation:
-  bool AllocateAndAcquireLock() override;
-  void ReleaseLock() override;
-  void Purge() override;
-
- private:
-  mac::ScopedMachVM memory_;
-  const size_t bytes_;
-  bool is_locked_;
-
-  DISALLOW_COPY_AND_ASSIGN(DiscardableMemoryMach);
-};
-
-}  // namespace internal
-}  // namespace base
-
-#endif  // BASE_MEMORY_DISCARDABLE_MEMORY_MACH_H_

base/memory/discardable_memory_unittest.cc

@@ -38,12 +38,12 @@ TEST_P(DiscardableMemoryTest, IsNamed) {
 }
 
 bool IsNativeType(DiscardableMemoryType type) {
-  return
 #if defined(OS_ANDROID)
     // SHMEM is backed by native discardable memory on Android.
-    type == DISCARDABLE_MEMORY_TYPE_SHMEM ||
+  return type == DISCARDABLE_MEMORY_TYPE_SHMEM;
+#else
+  return false;
 #endif
-    type == DISCARDABLE_MEMORY_TYPE_MACH;
 }
 
 TEST_P(DiscardableMemoryTest, SupportedNatively) {

base/memory/discardable_memory_win.cc

@@ -31,7 +31,6 @@ scoped_ptr<DiscardableMemory> DiscardableMemory::CreateLockedMemoryWithType(
       return memory.Pass();
     }
     case DISCARDABLE_MEMORY_TYPE_NONE:
-    case DISCARDABLE_MEMORY_TYPE_MACH:
       NOTREACHED();
       return nullptr;
   }

build/common.gypi

@@ -778,7 +778,6 @@
         }],
 
         ['OS=="mac" or OS=="ios"', {
-          'native_discardable_memory%': 1,
           'native_memory_pressure_signals%': 1,
         }],