Changeset 41660 in webkit for trunk/JavaScriptCore/wtf/FastMalloc.cpp

Timestamp:

Mar 12, 2009, 8:33:27 PM (16 years ago)

Author:

[email protected]

Message:

<rdar://problem/6548446> TCMalloc_SystemRelease should use madvise rather than re-mmaping span of pages

• wtf/FastMalloc.cpp:

(WTF::mergeDecommittedStates): If either of the spans has been released to the system, release the other
span as well so that the flag in the merged span is accurate.

• wtf/Platform.h:
• wtf/TCSystemAlloc.cpp: Track decommitted spans when using MADV_FREE_REUSABLE / MADV_FREE_REUSE.

(TCMalloc_SystemRelease): Use madvise with MADV_FREE_REUSABLE when it is available.
(TCMalloc_SystemCommit): Use madvise with MADV_FREE_REUSE when it is available.

• wtf/TCSystemAlloc.h:

File:

• trunk/JavaScriptCore/wtf/FastMalloc.cpp (modified) (2 diffs)

trunk/JavaScriptCore/wtf/FastMalloc.cpp

@@ -95 +95 @@
 #endif
 
-#define TCMALLOC_TRACK_DECOMMITED_SPANS (HAVE(VIRTUALALLOC))
+#define TCMALLOC_TRACK_DECOMMITED_SPANS (HAVE(VIRTUALALLOC) || HAVE(MADV_FREE_REUSE))
 
 #ifndef NDEBUG
@@ -1404 +1404 @@
 static ALWAYS_INLINE void mergeDecommittedStates(Span* destination, Span* other)
 {
-    if (other->decommitted)
+    if (destination->decommitted && !other->decommitted) {
+        TCMalloc_SystemRelease(reinterpret_cast<void*>(other->start << kPageShift),
+                               static_cast<size_t>(other->length << kPageShift));
+    } else if (other->decommitted && !destination->decommitted) {
+        TCMalloc_SystemRelease(reinterpret_cast<void*>(destination->start << kPageShift),
+                               static_cast<size_t>(destination->length << kPageShift));
         destination->decommitted = true;
+    }
 }
 #endif