Title: [89278] releases/WebKitGTK/webkit-1.4/Source/_javascript_Core
Revision
89278
Author
mrobin...@webkit.org
Date
2011-06-20 12:41:46 -0700 (Mon, 20 Jun 2011)

Log Message

Merging r86957

Modified Paths

Diff

Modified: releases/WebKitGTK/webkit-1.4/Source/_javascript_Core/ChangeLog (89277 => 89278)


--- releases/WebKitGTK/webkit-1.4/Source/_javascript_Core/ChangeLog	2011-06-20 19:39:45 UTC (rev 89277)
+++ releases/WebKitGTK/webkit-1.4/Source/_javascript_Core/ChangeLog	2011-06-20 19:41:46 UTC (rev 89278)
@@ -1,3 +1,17 @@
+2011-05-20  Xan Lopez  <xlo...@igalia.com>
+
+        Reviewed by Oliver Hunt.
+
+        JIT requires VM overcommit (particularly on x86-64), Linux does not by default support this without swap?
+        https://bugs.webkit.org/show_bug.cgi?id=42756
+
+        Use the MAP_NORESERVE flag for mmap on Linux to skip the kernel
+        check of the available memory. This should give us an
+        overcommit-like behavior in most systems, which is what we want.
+
+        * wtf/OSAllocatorPosix.cpp:
+        (WTF::OSAllocator::reserveAndCommit): pass MAP_NORSERVE to mmap.
+
 2011-06-04  Gustavo Noronha Silva  <g...@gnome.org>
 
         Unreviewed, MIPS build fix.

Modified: releases/WebKitGTK/webkit-1.4/Source/_javascript_Core/wtf/OSAllocatorPosix.cpp (89277 => 89278)


--- releases/WebKitGTK/webkit-1.4/Source/_javascript_Core/wtf/OSAllocatorPosix.cpp	2011-06-20 19:39:45 UTC (rev 89277)
+++ releases/WebKitGTK/webkit-1.4/Source/_javascript_Core/wtf/OSAllocatorPosix.cpp	2011-06-20 19:41:46 UTC (rev 89278)
@@ -54,6 +54,18 @@
 
     int flags = MAP_PRIVATE | MAP_ANON;
 
+#if OS(LINUX)
+    // Linux distros usually do not allow overcommit by default, so
+    // JSC's strategy of mmaping a large amount of memory upfront
+    // won't work very well on some systems. Fortunately there's a
+    // flag we can pass to mmap to disable the overcommit check for
+    // this particular call, so we can get away with it as long as the
+    // overcommit flag value in /proc/sys/vm/overcommit_memory is 0
+    // ('heuristic') and not 2 (always check). 0 is the usual default
+    // value, so this should work well in general.
+    flags |= MAP_NORESERVE;
+#endif
+
 #if OS(DARWIN) && !defined(BUILDING_ON_TIGER)
     int fd = usage;
 #else
_______________________________________________
webkit-changes mailing list
webkit-changes@lists.webkit.org
http://lists.webkit.org/mailman/listinfo.cgi/webkit-changes

Reply via email to