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Unified Diff: base/memory/discardable_memory.h

Issue 17106004: Add discardable memory emulation for non-android/mac platforms (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/src
Patch Set: address review feedback Created 7 years, 2 months ago
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Index: base/memory/discardable_memory.h
diff --git a/base/memory/discardable_memory.h b/base/memory/discardable_memory.h
index d6e91b979d5a46fdd50e6ef07ab4f52a904bc042..5145373486915ae119f7b2d42f31b2f31b8b4830 100644
--- a/base/memory/discardable_memory.h
+++ b/base/memory/discardable_memory.h
@@ -8,9 +8,17 @@
#include "base/base_export.h"
#include "base/basictypes.h"
#include "base/compiler_specific.h"
+#if !defined(DISCARDABLE_MEMORY_ALWAYS_SUPPORTED_NATIVELY)
+#include "base/memory/scoped_ptr.h"
+#endif
+#include "base/threading/non_thread_safe.h"
namespace base {
+namespace internal {
+class DiscardableMemoryProvider;
+}
+
enum LockDiscardableMemoryStatus {
DISCARDABLE_MEMORY_FAILED = -1,
DISCARDABLE_MEMORY_PURGED = 0,
@@ -37,6 +45,9 @@ enum LockDiscardableMemoryStatus {
// - Because of memory alignment, the amount of memory allocated can be
// larger than the requested memory size. It is not very efficient for
// small allocations.
+// - A discardable memory instance is not thread safe. It is the
+// responsibility of users of discardable memory to ensure there are no
+// races.
//
// References:
// - Linux: http://lwn.net/Articles/452035/
@@ -51,8 +62,9 @@ class BASE_EXPORT DiscardableMemory {
// The opened file will also be closed after this.
~DiscardableMemory();
- // Check whether the system supports discardable memory.
- static bool Supported();
+ // Check whether the system supports discardable memory natively. Returns
+ // false if the support is emulated.
+ static bool SupportedNatively();
// Initialize the DiscardableMemory object. On success, this function returns
// true and the memory is locked. This should only be called once.
@@ -87,6 +99,10 @@ class BASE_EXPORT DiscardableMemory {
static void PurgeForTesting();
private:
+#if !defined(DISCARDABLE_MEMORY_ALWAYS_SUPPORTED_NATIVELY)
+ scoped_ptr<uint8, FreeDeleter> acquired_memory_;
+#endif
+
#if defined(OS_ANDROID)
// Maps the discardable memory into the caller's address space.
// Returns true on success, false otherwise.

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