content/child/child_discardable_shared_memory_manager.h

   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 #ifndef CONTENT_CHILD_CHILD_DISCARDABLE_SHARED_MEMORY_MANAGER_H_
   6 #define CONTENT_CHILD_CHILD_DISCARDABLE_SHARED_MEMORY_MANAGER_H_
   7
   8 #include "base/memory/discardable_memory_allocator.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/synchronization/lock.h"
  11 #include "content/child/thread_safe_sender.h"
  12 #include "content/common/content_export.h"
  13 #include "content/common/discardable_shared_memory_heap.h"
  14 #include "content/common/host_discardable_shared_memory_manager.h"
  15
  16 namespace content {
  17
  18 // Implementation of DiscardableMemoryAllocator that allocates
  19 // discardable memory segments through the browser process.
  20 class CONTENT_EXPORT ChildDiscardableSharedMemoryManager
  21     : public base::DiscardableMemoryAllocator {
  22  public:
  23   explicit ChildDiscardableSharedMemoryManager(ThreadSafeSender* sender);
  24   ~ChildDiscardableSharedMemoryManager() override;
  25
  26   // Overridden from base::DiscardableMemoryAllocator:
  27   scoped_ptr<base::DiscardableMemory> AllocateLockedDiscardableMemory(
  28       size_t size) override;
  29
  30   // Release memory and associated resources that have been purged.
  31   void ReleaseFreeMemory();
  32
  33   bool LockSpan(DiscardableSharedMemoryHeap::Span* span);
  34   void UnlockSpan(DiscardableSharedMemoryHeap::Span* span);
  35   void ReleaseSpan(scoped_ptr<DiscardableSharedMemoryHeap::Span> span);
  36
  37  private:
  38   scoped_ptr<base::DiscardableSharedMemory>
  39   AllocateLockedDiscardableSharedMemory(size_t size,
  40                                         DiscardableSharedMemoryId id);
  41   void MemoryUsageChanged(size_t new_bytes_allocated,
  42                           size_t new_bytes_free) const;
  43
  44   mutable base::Lock lock_;
  45   DiscardableSharedMemoryHeap heap_;
  46   scoped_refptr<ThreadSafeSender> sender_;
  47
  48   DISALLOW_COPY_AND_ASSIGN(ChildDiscardableSharedMemoryManager);
  49 };
  50
  51 }  // namespace content
  52
  53 #endif  // CONTENT_CHILD_CHILD_DISCARDABLE_SHARED_MEMORY_MANAGER_H_