Bug 64388

Summary: COLLECT_ON_EVERY_ALLOCATION no longer works
Product: WebKit Reporter: Filip Pizlo <fpizlo>
Component: JavaScriptCoreAssignee: Nobody <webkit-unassigned>
Status: RESOLVED FIXED    
Severity: Normal CC: webkit.review.bot
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: All   
OS: All   
Attachments:
Description Flags
the patch
none
the patch (fix style) none

Filip Pizlo
Reported 2011-07-12 13:59:24 PDT
The GC allocation path breaks if COLLECT_ON_EVERY_ALLOCATION is set. This occurs for two reasons: 1) To collect we need JSGlobalData to be initialized, but to be initialized, JSGlobalData must perform allocations. 2) Even if this is side-stepped, the Heap::allocate() handles allocation slow cases by calling itself recursively, which always results in another forced collection if COLLECT_ON_EVERY_ALLOCATION is set. But allocating after a collection requires the slow path to be taken. Hence, COLLECT_ON_EVERY_ALLOCATION causes every allocation to recurse ad infinitum, invoking a full heap GC every time.
Attachments
the patch (5.62 KB, patch)
2011-07-12 15:00 PDT, Filip Pizlo 		no flags
DetailsFormatted DiffDiff
the patch (fix style) (5.61 KB, patch)
2011-07-12 15:06 PDT, Filip Pizlo 		no flags
DetailsFormatted DiffDiff
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.
Filip Pizlo
Comment 1 2011-07-12 15:00:22 PDT
Created attachment 100568 [details] the patch
WebKit Review Bot
Comment 2 2011-07-12 15:02:34 PDT
Attachment 100568 [details] did not pass style-queue: Failed to run "['Tools/Scripts/check-webkit-style', '--diff-files', u'Source/JavaScriptCore/ChangeLog', u'Source..." exit_code: 1 Source/JavaScriptCore/heap/Heap.h:139: The parameter name "sizeClass" adds no information, so it should be removed. [readability/parameter_name] [5] Total errors found: 1 in 4 files If any of these errors are false positives, please file a bug against check-webkit-style.
Filip Pizlo
Comment 3 2011-07-12 15:06:01 PDT
Created attachment 100571 [details] the patch (fix style)
WebKit Review Bot
Comment 4 2011-07-12 15:35:54 PDT
Comment on attachment 100571 [details] the patch (fix style) Clearing flags on attachment: 100571 Committed r90865: <http://trac.webkit.org/changeset/90865>
WebKit Review Bot
Comment 5 2011-07-12 15:35:58 PDT
All reviewed patches have been landed. Closing bug.
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