base: Use DiscardableMemoryManager on MacOSX.

This limits the address space used for discardable memory on MacOSX
by using the DiscardableMemoryManager for userspace eviction.

Includes some minor refactoring to keep all code using
DiscardableMemoryManager consistent.

BUG=369246

Review URL: https://codereview.chromium.org/261993003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@269640 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 135 insertions, 83 deletions

diff --git a/base/memory/discardable_memory_android.cc b/base/memory/discardable_memory_android.cc
index 9043906..c3de3a3 100644
--- a/base/memory/discardable_memory_android.cc
+++ b/base/memory/discardable_memory_android.cc
@@ -19,31 +19,27 @@ namespace {
 
 const char kAshmemAllocatorName[] = "DiscardableMemoryAshmemAllocator";
 
-// When ashmem is used, have the DiscardableMemoryManager trigger userspace
-// eviction when address space usage gets too high (e.g. 512 MBytes).
-const size_t kAshmemMaxAddressSpaceUsage = 512 * 1024 * 1024;
-
-// Holds the state used for ashmem allocations.
-struct AshmemGlobalContext {
-  AshmemGlobalContext()
-      : allocator(kAshmemAllocatorName,
-                  GetOptimalAshmemRegionSizeForAllocator()) {
-    manager.SetMemoryLimit(kAshmemMaxAddressSpaceUsage);
-  }
+// For Ashmem, have the DiscardableMemoryManager trigger userspace eviction
+// when address space usage gets too high (e.g. 512 MBytes).
+const size_t kAshmemMemoryLimit = 512 * 1024 * 1024;
+
+size_t GetOptimalAshmemRegionSizeForAllocator() {
+  // Note that this may do some I/O (without hitting the disk though) so it
+  // should not be called on the critical path.
+  return base::android::SysUtils::AmountOfPhysicalMemoryKB() * 1024 / 8;
+}
 
-  internal::DiscardableMemoryAshmemAllocator allocator;
-  internal::DiscardableMemoryManager manager;
+// Holds the shared state used for allocations.
+struct SharedState {
+  SharedState()
+      : manager(kAshmemMemoryLimit, kAshmemMemoryLimit),
+        allocator(kAshmemAllocatorName,
+                  GetOptimalAshmemRegionSizeForAllocator()) {}
 
- private:
-  // Returns 64 MBytes for a 512 MBytes device, 128 MBytes for 1024 MBytes...
-  static size_t GetOptimalAshmemRegionSizeForAllocator() {
-    // Note that this may do some I/O (without hitting the disk though) so it
-    // should not be called on the critical path.
-    return base::android::SysUtils::AmountOfPhysicalMemoryKB() * 1024 / 8;
-  }
+  internal::DiscardableMemoryManager manager;
+  internal::DiscardableMemoryAshmemAllocator allocator;
 };
-
-LazyInstance<AshmemGlobalContext>::Leaky g_context = LAZY_INSTANCE_INITIALIZER;
+LazyInstance<SharedState>::Leaky g_shared_state = LAZY_INSTANCE_INITIALIZER;
 
 }  // namespace
 
@@ -76,10 +72,10 @@ scoped_ptr<DiscardableMemory> DiscardableMemory::CreateLockedMemoryWithType(
     case DISCARDABLE_MEMORY_TYPE_MAC:
       return scoped_ptr<DiscardableMemory>();
     case DISCARDABLE_MEMORY_TYPE_ASHMEM: {
-      AshmemGlobalContext* const global_context = g_context.Pointer();
+      SharedState* const shared_state = g_shared_state.Pointer();
       scoped_ptr<internal::DiscardableMemoryAshmem> memory(
           new internal::DiscardableMemoryAshmem(
-              size, &global_context->allocator, &global_context->manager));
+              size, &shared_state->allocator, &shared_state->manager));
       if (!memory->Initialize())
         return scoped_ptr<DiscardableMemory>();
 
@@ -109,7 +105,7 @@ scoped_ptr<DiscardableMemory> DiscardableMemory::CreateLockedMemoryWithType(
 
 // static
 void DiscardableMemory::PurgeForTesting() {
-  g_context.Pointer()->manager.PurgeAll();
+  g_shared_state.Pointer()->manager.PurgeAll();
   internal::DiscardableMemoryEmulated::PurgeForTesting();
 }
 
diff --git a/base/memory/discardable_memory_emulated.cc b/base/memory/discardable_memory_emulated.cc
index 415a451..2659f0f 100644
--- a/base/memory/discardable_memory_emulated.cc
+++ b/base/memory/discardable_memory_emulated.cc
@@ -10,8 +10,19 @@
 namespace base {
 namespace {
 
-base::LazyInstance<internal::DiscardableMemoryManager>::Leaky g_manager =
-    LAZY_INSTANCE_INITIALIZER;
+// This is admittedly pretty magical. It's approximately enough memory for eight
+// 2560x1600 images.
+const size_t kEmulatedMemoryLimit = 128 * 1024 * 1024;
+const size_t kEmulatedBytesToKeepUnderModeratePressure = 12 * 1024 * 1024;
+
+struct SharedState {
+  SharedState()
+      : manager(kEmulatedMemoryLimit,
+                kEmulatedBytesToKeepUnderModeratePressure) {}
+
+  internal::DiscardableMemoryManager manager;
+};
+LazyInstance<SharedState>::Leaky g_shared_state = LAZY_INSTANCE_INITIALIZER;
 
 }  // namespace
 
@@ -20,28 +31,28 @@ namespace internal {
 DiscardableMemoryEmulated::DiscardableMemoryEmulated(size_t bytes)
     : bytes_(bytes),
       is_locked_(false) {
-  g_manager.Pointer()->Register(this, bytes);
+  g_shared_state.Pointer()->manager.Register(this, bytes);
 }
 
 DiscardableMemoryEmulated::~DiscardableMemoryEmulated() {
   if (is_locked_)
     Unlock();
-  g_manager.Pointer()->Unregister(this);
+  g_shared_state.Pointer()->manager.Unregister(this);
 }
 
 // static
 void DiscardableMemoryEmulated::RegisterMemoryPressureListeners() {
-  g_manager.Pointer()->RegisterMemoryPressureListener();
+  g_shared_state.Pointer()->manager.RegisterMemoryPressureListener();
 }
 
 // static
 void DiscardableMemoryEmulated::UnregisterMemoryPressureListeners() {
-  g_manager.Pointer()->UnregisterMemoryPressureListener();
+  g_shared_state.Pointer()->manager.UnregisterMemoryPressureListener();
 }
 
 // static
 void DiscardableMemoryEmulated::PurgeForTesting() {
-  g_manager.Pointer()->PurgeAll();
+  g_shared_state.Pointer()->manager.PurgeAll();
 }
 
 bool DiscardableMemoryEmulated::Initialize() {
@@ -52,7 +63,7 @@ DiscardableMemoryLockStatus DiscardableMemoryEmulated::Lock() {
   DCHECK(!is_locked_);
 
   bool purged = false;
-  if (!g_manager.Pointer()->AcquireLock(this, &purged))
+  if (!g_shared_state.Pointer()->manager.AcquireLock(this, &purged))
     return DISCARDABLE_MEMORY_LOCK_STATUS_FAILED;
 
   is_locked_ = true;
@@ -62,7 +73,7 @@ DiscardableMemoryLockStatus DiscardableMemoryEmulated::Lock() {
 
 void DiscardableMemoryEmulated::Unlock() {
   DCHECK(is_locked_);
-  g_manager.Pointer()->ReleaseLock(this);
+  g_shared_state.Pointer()->manager.ReleaseLock(this);
   is_locked_ = false;
 }
 
diff --git a/base/memory/discardable_memory_mac.cc b/base/memory/discardable_memory_mac.cc
index 8cd5905..d7133f5 100644
--- a/base/memory/discardable_memory_mac.cc
+++ b/base/memory/discardable_memory_mac.cc
@@ -9,80 +9,123 @@
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
+#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/memory/discardable_memory_emulated.h"
 #include "base/memory/discardable_memory_malloc.h"
+#include "base/memory/discardable_memory_manager.h"
 #include "base/memory/scoped_ptr.h"
 
 namespace base {
 namespace {
 
+// For Mac, have the DiscardableMemoryManager trigger userspace eviction when
+// address space usage gets too high (e.g. 512 MBytes).
+const size_t kMacMemoryLimit = 512 * 1024 * 1024;
+
+struct SharedState {
+  SharedState() : manager(kMacMemoryLimit, kMacMemoryLimit) {}
+
+  internal::DiscardableMemoryManager manager;
+};
+LazyInstance<SharedState>::Leaky g_shared_state = 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);
 
-class DiscardableMemoryMac : public DiscardableMemory {
+class DiscardableMemoryMac
+    : public DiscardableMemory,
+      public internal::DiscardableMemoryManagerAllocation {
  public:
-  explicit DiscardableMemoryMac(size_t size)
-      : buffer_(0),
-        size_(size) {
+  explicit DiscardableMemoryMac(size_t bytes)
+      : buffer_(0), bytes_(bytes), is_locked_(false) {
+    g_shared_state.Pointer()->manager.Register(this, bytes);
   }
 
-  bool Initialize() {
-    kern_return_t ret = vm_allocate(mach_task_self(),
-                                    &buffer_,
-                                    size_,
-                                    VM_FLAGS_PURGABLE |
-                                    VM_FLAGS_ANYWHERE |
-                                    kDiscardableMemoryTag);
-    if (ret != KERN_SUCCESS) {
-      DLOG(ERROR) << "vm_allocate() failed";
-      return false;
-    }
-
-    return true;
-  }
+  bool Initialize() { return Lock() == DISCARDABLE_MEMORY_LOCK_STATUS_PURGED; }
 
   virtual ~DiscardableMemoryMac() {
+    if (is_locked_)
+      Unlock();
+    g_shared_state.Pointer()->manager.Unregister(this);
     if (buffer_)
-      vm_deallocate(mach_task_self(), buffer_, size_);
+      vm_deallocate(mach_task_self(), buffer_, bytes_);
   }
 
+  // Overridden from DiscardableMemory:
   virtual DiscardableMemoryLockStatus Lock() OVERRIDE {
-    DCHECK_EQ(0, mprotect(reinterpret_cast<void*>(buffer_),
-                          size_,
-                          PROT_READ | PROT_WRITE));
+    DCHECK(!is_locked_);
+
+    bool purged = false;
+    if (!g_shared_state.Pointer()->manager.AcquireLock(this, &purged))
+      return DISCARDABLE_MEMORY_LOCK_STATUS_FAILED;
+
+    is_locked_ = true;
+    return purged ? DISCARDABLE_MEMORY_LOCK_STATUS_PURGED
+                  : DISCARDABLE_MEMORY_LOCK_STATUS_SUCCESS;
+  }
+  virtual void Unlock() OVERRIDE {
+    DCHECK(is_locked_);
+    g_shared_state.Pointer()->manager.ReleaseLock(this);
+    is_locked_ = false;
+  }
+  virtual void* Memory() const OVERRIDE {
+    DCHECK(is_locked_);
+    return reinterpret_cast<void*>(buffer_);
+  }
+
+  // Overridden from internal::DiscardableMemoryManagerAllocation:
+  virtual bool AllocateAndAcquireLock() OVERRIDE {
+    bool persistent = true;
+    if (!buffer_) {
+      kern_return_t ret = vm_allocate(
+          mach_task_self(),
+          &buffer_,
+          bytes_,
+          VM_FLAGS_PURGABLE | VM_FLAGS_ANYWHERE | kDiscardableMemoryTag);
+      CHECK_EQ(KERN_SUCCESS, ret) << "wm_allocate() failed.";
+      persistent = false;
+    }
+#if !defined(NDEBUG)
+    int status = mprotect(
+        reinterpret_cast<void*>(buffer_), bytes_, PROT_READ | PROT_WRITE);
+    DCHECK_EQ(0, status);
+#endif
     int state = VM_PURGABLE_NONVOLATILE;
     kern_return_t ret = vm_purgable_control(mach_task_self(),
                                             buffer_,
                                             VM_PURGABLE_SET_STATE,
                                             &state);
-    if (ret != KERN_SUCCESS)
-      return DISCARDABLE_MEMORY_LOCK_STATUS_FAILED;
-
-    return state & VM_PURGABLE_EMPTY ? DISCARDABLE_MEMORY_LOCK_STATUS_PURGED
-                                     : DISCARDABLE_MEMORY_LOCK_STATUS_SUCCESS;
+    CHECK_EQ(KERN_SUCCESS, ret) << "Failed to lock memory.";
+    if (state & VM_PURGABLE_EMPTY)
+      persistent = false;
+    return persistent;
   }
-
-  virtual void Unlock() OVERRIDE {
+  virtual void ReleaseLock() OVERRIDE {
     int state = VM_PURGABLE_VOLATILE | VM_VOLATILE_GROUP_DEFAULT;
     kern_return_t ret = vm_purgable_control(mach_task_self(),
                                             buffer_,
                                             VM_PURGABLE_SET_STATE,
                                             &state);
-    DCHECK_EQ(0, mprotect(reinterpret_cast<void*>(buffer_), size_, PROT_NONE));
-    if (ret != KERN_SUCCESS)
-      DLOG(ERROR) << "Failed to unlock memory.";
+    CHECK_EQ(KERN_SUCCESS, ret) << "Failed to unlock memory.";
+#if !defined(NDEBUG)
+    int status = mprotect(reinterpret_cast<void*>(buffer_), bytes_, PROT_NONE);
+    DCHECK_EQ(0, status);
+#endif
   }
-
-  virtual void* Memory() const OVERRIDE {
-    return reinterpret_cast<void*>(buffer_);
+  virtual void Purge() OVERRIDE {
+    if (buffer_) {
+      vm_deallocate(mach_task_self(), buffer_, bytes_);
+      buffer_ = 0;
+    }
   }
 
  private:
   vm_address_t buffer_;
-  const size_t size_;
+  const size_t bytes_;
+  bool is_locked_;
 
   DISALLOW_COPY_AND_ASSIGN(DiscardableMemoryMac);
 };
diff --git a/base/memory/discardable_memory_manager.cc b/base/memory/discardable_memory_manager.cc
index 468690b..3e90d22 100644
--- a/base/memory/discardable_memory_manager.cc
+++ b/base/memory/discardable_memory_manager.cc
@@ -12,21 +12,15 @@
 
 namespace base {
 namespace internal {
-namespace {
 
-// This is admittedly pretty magical. It's approximately enough memory for eight
-// 2560x1600 images.
-static const size_t kDefaultMemoryLimit = 128 * 1024 * 1024;
-static const size_t kDefaultBytesToKeepUnderModeratePressure = 12 * 1024 * 1024;
-
-}  // namespace
-
-DiscardableMemoryManager::DiscardableMemoryManager()
+DiscardableMemoryManager::DiscardableMemoryManager(
+    size_t memory_limit,
+    size_t bytes_to_keep_under_moderate_pressure)
     : allocations_(AllocationMap::NO_AUTO_EVICT),
       bytes_allocated_(0),
-      memory_limit_(kDefaultMemoryLimit),
+      memory_limit_(memory_limit),
       bytes_to_keep_under_moderate_pressure_(
-          kDefaultBytesToKeepUnderModeratePressure) {
+          bytes_to_keep_under_moderate_pressure) {
   BytesAllocatedChanged();
 }
 
diff --git a/base/memory/discardable_memory_manager.h b/base/memory/discardable_memory_manager.h
index 3c9bd61..8297b81 100644
--- a/base/memory/discardable_memory_manager.h
+++ b/base/memory/discardable_memory_manager.h
@@ -67,7 +67,8 @@ class BASE_EXPORT_PRIVATE DiscardableMemoryManager {
  public:
   typedef DiscardableMemoryManagerAllocation Allocation;
 
-  DiscardableMemoryManager();
+  DiscardableMemoryManager(size_t memory_limit,
+                           size_t bytes_to_keep_under_moderate_pressure);
   ~DiscardableMemoryManager();
 
   // Call this to register memory pressure listener. Must be called on a thread
diff --git a/base/memory/discardable_memory_manager_unittest.cc b/base/memory/discardable_memory_manager_unittest.cc
index c59d82e..8b08cf6 100644
--- a/base/memory/discardable_memory_manager_unittest.cc
+++ b/base/memory/discardable_memory_manager_unittest.cc
@@ -42,9 +42,16 @@ class TestAllocationImpl : public internal::DiscardableMemoryManagerAllocation {
   bool is_locked_;
 };
 
+// Tests can assume that the default limit is at least 1024. Tests that rely on
+// something else needs to explicit set the limit.
+const size_t kDefaultMemoryLimit = 1024;
+const size_t kDefaultBytesToKeepUnderModeratePressure = kDefaultMemoryLimit;
+
 class DiscardableMemoryManagerTestBase {
  public:
-  DiscardableMemoryManagerTestBase() {
+  DiscardableMemoryManagerTestBase()
+      : manager_(kDefaultMemoryLimit,
+                 kDefaultBytesToKeepUnderModeratePressure) {
     manager_.RegisterMemoryPressureListener();
   }