| // 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 CONTENT_COMMON_HOST_DISCARDABLE_SHARED_MEMORY_MANAGER_H_ |
| #define CONTENT_COMMON_HOST_DISCARDABLE_SHARED_MEMORY_MANAGER_H_ |
| |
| #include <vector> |
| |
| #include "base/memory/discardable_memory_shmem_allocator.h" |
| #include "base/memory/discardable_shared_memory.h" |
| #include "base/memory/linked_ptr.h" |
| #include "base/memory/memory_pressure_listener.h" |
| #include "base/memory/shared_memory.h" |
| #include "base/memory/weak_ptr.h" |
| #include "base/process/process_handle.h" |
| #include "base/synchronization/lock.h" |
| #include "content/common/content_export.h" |
| |
| namespace content { |
| |
| // Implementation of DiscardableMemoryShmemAllocator that allocates and |
| // manages discardable memory segments for the browser process and child |
| // processes. This class is thread-safe and instances can safely be used |
| // on any thread. |
| class CONTENT_EXPORT HostDiscardableSharedMemoryManager |
| : public base::DiscardableMemoryShmemAllocator { |
| public: |
| HostDiscardableSharedMemoryManager(); |
| ~HostDiscardableSharedMemoryManager() override; |
| |
| // Returns a singleton instance. |
| static HostDiscardableSharedMemoryManager* current(); |
| |
| // Overridden from base::DiscardableMemoryShmemAllocator: |
| scoped_ptr<base::DiscardableSharedMemory> |
| AllocateLockedDiscardableSharedMemory(size_t size) override; |
| |
| // This allocates a discardable memory segment for |process_handle|. |
| // A valid shared memory handle is returned on success. |
| void AllocateLockedDiscardableSharedMemoryForChild( |
| base::ProcessHandle process_handle, |
| size_t size, |
| base::SharedMemoryHandle* shared_memory_handle); |
| |
| // Call this to notify the manager that child process associated with |
| // |process_handle| has been removed. The manager will use this to release |
| // memory segments allocated for child process to the OS. |
| void ProcessRemoved(base::ProcessHandle process_handle); |
| |
| // The maximum number of bytes of memory that may be allocated. This will |
| // cause memory usage to be reduced if currently above |limit|. |
| void SetMemoryLimit(size_t limit); |
| |
| // Reduce memory usage if above current memory limit. |
| void EnforceMemoryPolicy(); |
| |
| private: |
| struct MemorySegment { |
| MemorySegment(linked_ptr<base::DiscardableSharedMemory> memory, |
| base::ProcessHandle process_handle); |
| ~MemorySegment(); |
| |
| linked_ptr<base::DiscardableSharedMemory> memory; |
| base::ProcessHandle process_handle; |
| }; |
| |
| static bool CompareMemoryUsageTime(const MemorySegment& a, |
| const MemorySegment& b) { |
| // In this system, LRU memory segment is evicted first. |
| return a.memory->last_known_usage() > b.memory->last_known_usage(); |
| } |
| |
| void OnMemoryPressure( |
| base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level); |
| void ReduceMemoryUsageUntilWithinMemoryLimit(); |
| void ReduceMemoryUsageUntilWithinLimit(size_t limit); |
| void BytesAllocatedChanged(size_t new_bytes_allocated) const; |
| |
| // Virtual for tests. |
| virtual base::Time Now() const; |
| virtual void ScheduleEnforceMemoryPolicy(); |
| |
| base::Lock lock_; |
| // Note: The elements in |segments_| are arranged in such a way that they form |
| // a heap. The LRU memory segment always first. |
| typedef std::vector<MemorySegment> MemorySegmentVector; |
| MemorySegmentVector segments_; |
| size_t memory_limit_; |
| size_t bytes_allocated_; |
| scoped_ptr<base::MemoryPressureListener> memory_pressure_listener_; |
| bool enforce_memory_policy_pending_; |
| base::WeakPtrFactory<HostDiscardableSharedMemoryManager> weak_ptr_factory_; |
| |
| DISALLOW_COPY_AND_ASSIGN(HostDiscardableSharedMemoryManager); |
| }; |
| |
| } // namespace content |
| |
| #endif // CONTENT_COMMON_HOST_DISCARDABLE_SHARED_MEMORY_MANAGER_H_ |