Index: base/memory/discardable_memory.h |
diff --git a/base/memory/discardable_memory.h b/base/memory/discardable_memory.h |
index ce0f0bbe75c7eff42006f8e299c8e8015c1d62bf..a0882ccc94e9ab280ef3a82b9492cd0525b1bb9a 100644 |
--- a/base/memory/discardable_memory.h |
+++ b/base/memory/discardable_memory.h |
@@ -5,26 +5,24 @@ |
#ifndef BASE_MEMORY_DISCARDABLE_MEMORY_H_ |
#define BASE_MEMORY_DISCARDABLE_MEMORY_H_ |
-#include <string> |
-#include <vector> |
- |
#include "base/base_export.h" |
#include "base/basictypes.h" |
#include "base/compiler_specific.h" |
-#include "base/memory/scoped_ptr.h" |
namespace base { |
-// Platform abstraction for discardable memory. DiscardableMemory is used to |
-// cache large objects without worrying about blowing out memory, both on mobile |
-// devices where there is no swap, and desktop devices where unused free memory |
-// should be used to help the user experience. This is preferable to releasing |
-// memory in response to an OOM signal because it is simpler, though it has less |
-// flexibility as to which objects get discarded. |
+// Discardable memory is used to cache large objects without worrying about |
+// blowing out memory, both on mobile devices where there is no swap, and |
+// desktop devices where unused free memory should be used to help the user |
+// experience. This is preferable to releasing memory in response to an OOM |
+// signal because it is simpler and provides system-wide management of |
+// purgable memory, though it has less flexibility as to which objects get |
+// discarded. |
// |
// Discardable memory has two states: locked and unlocked. While the memory is |
-// locked, it will not be discarded. Unlocking the memory allows the OS to |
-// reclaim it if needed. Locks do not nest. |
+// locked, it will not be discarded. Unlocking the memory allows the |
+// discardable memory system and the OS to reclaim it if needed. Locks do not |
+// nest. |
// |
// Notes: |
// - The paging behavior of memory while it is locked is not specified. While |
@@ -39,19 +37,10 @@ namespace base { |
// responsibility of users of discardable memory to ensure there are no |
// races. |
// |
-// References: |
-// - Linux: http://lwn.net/Articles/452035/ |
-// - Mac: http://trac.webkit.org/browser/trunk/Source/WebCore/platform/mac/PurgeableBufferMac.cpp |
-// the comment starting with "vm_object_purgable_control" at |
-// http://www.opensource.apple.com/source/xnu/xnu-792.13.8/osfmk/vm/vm_object.c |
-// |
-// Thread-safety: DiscardableMemory instances are not thread-safe. |
class BASE_EXPORT DiscardableMemory { |
public: |
- virtual ~DiscardableMemory() {} |
- |
- // Create a DiscardableMemory instance with |size|. |
- static scoped_ptr<DiscardableMemory> CreateLockedMemory(size_t size); |
+ DiscardableMemory(); |
+ virtual ~DiscardableMemory(); |
// Locks the memory so that it will not be purged by the system. Returns |
// true on success. If the return value is false then this object should be |