Changeset 46511 in webkit for trunk/JavaScriptCore/wtf/TCSystemAlloc.cpp

Timestamp:

Jul 28, 2009, 6:09:02 PM (16 years ago)

Author:

[email protected]

Message:

Reviewed by Darin Adler.

​https://bugs.webkit.org/show_bug.cgi?id=27236

• Implement TCMalloc_SystemRelease and TCMalloc_SystemCommit for Windows.
• Use a background thread to periodically scavenge memory to release back to the system.

• wtf/FastMalloc.cpp: (WTF::TCMalloc_PageHeap::init): (WTF::TCMalloc_PageHeap::runScavengerThread): (WTF::TCMalloc_PageHeap::scavenge): (WTF::TCMalloc_PageHeap::shouldContinueScavenging): (WTF::TCMalloc_PageHeap::New): (WTF::TCMalloc_PageHeap::AllocLarge): (WTF::TCMalloc_PageHeap::Delete): (WTF::TCMalloc_PageHeap::GrowHeap): (WTF::sleep): (WTF::TCMalloc_PageHeap::scavengerThread):
• wtf/TCSystemAlloc.cpp: (TCMalloc_SystemRelease): (TCMalloc_SystemCommit):
• wtf/TCSystemAlloc.h:

File:

• trunk/JavaScriptCore/wtf/TCSystemAlloc.cpp (modified) (5 diffs)

trunk/JavaScriptCore/wtf/TCSystemAlloc.cpp

@@ -32 +32 @@
 
 #include "config.h"
+#include "TCSystemAlloc.h"
+
+#include <algorithm>
+#include <fcntl.h>
+#include "Assertions.h"
+#include "TCSpinLock.h"
+#include "UnusedParam.h"
+
 #if HAVE(STDINT_H)
 #include <stdint.h>
@@ -39 +47 @@
 #include <sys/types.h>
 #endif
+
 #if PLATFORM(WIN_OS)
 #include "windows.h"
@@ -46 +55 @@
 #include <sys/mman.h>
 #endif
-#include <fcntl.h>
-#include "Assertions.h"
-#include "TCSystemAlloc.h"
-#include "TCSpinLock.h"
-#include "UnusedParam.h"
 
 #ifndef MAP_ANONYMOUS
 #define MAP_ANONYMOUS MAP_ANON
 #endif
+
+using namespace std;
 
 // Structure for discovering alignment
@@ -442 +448 @@
 }
 
+#elif HAVE(VIRTUALALLOC)
+
+void TCMalloc_SystemRelease(void* start, size_t length)
+{
+    if (VirtualFree(start, length, MEM_DECOMMIT))
+        return;
+
+    // The decommit may fail if the memory region consists of allocations
+    // from more than one call to VirtualAlloc.  In this case, fall back to
+    // using VirtualQuery to retrieve the allocation boundaries and decommit
+    // them each individually.
+
+    char* ptr = static_cast<char*>(start);
+    char* end = ptr + length;
+    MEMORY_BASIC_INFORMATION info;
+    while (ptr < end) {
+        size_t resultSize = VirtualQuery(ptr, &info, sizeof(info));
+        ASSERT_UNUSED(resultSize, resultSize == sizeof(info));
+
+        size_t decommitSize = min<size_t>(info.RegionSize, end - ptr);
+        BOOL success = VirtualFree(ptr, decommitSize, MEM_DECOMMIT);
+        ASSERT_UNUSED(success, success);
+        ptr += decommitSize;
+    }
+}
+
 #else
 
@@ -458 +490 @@
 #elif HAVE(VIRTUALALLOC)
 
-void TCMalloc_SystemCommit(void*, size_t)
+void TCMalloc_SystemCommit(void* start, size_t length)
 {
+    if (VirtualAlloc(start, length, MEM_COMMIT, PAGE_READWRITE) == start)
+        return;
+
+    // The commit may fail if the memory region consists of allocations
+    // from more than one call to VirtualAlloc.  In this case, fall back to
+    // using VirtualQuery to retrieve the allocation boundaries and commit them
+    // each individually.
+
+    char* ptr = static_cast<char*>(start);
+    char* end = ptr + length;
+    MEMORY_BASIC_INFORMATION info;
+    while (ptr < end) {
+        size_t resultSize = VirtualQuery(ptr, &info, sizeof(info));
+        ASSERT_UNUSED(resultSize, resultSize == sizeof(info));
+
+        size_t commitSize = min<size_t>(info.RegionSize, end - ptr);
+        void* newAddress = VirtualAlloc(ptr, commitSize, MEM_COMMIT, PAGE_READWRITE);
+        ASSERT_UNUSED(newAddress, newAddress == ptr);
+        ptr += commitSize;
+    }
 }