[webkit-reviews] review granted: [Bug 172186] [iOS] The Garbage Collector shouldn't rely on the bmalloc scavenger for up to date memory footprint info : [Attachment 310304] Patch

[bugzilla-daemon at webkit.org]

Filip Pizlo <fpizlo at apple.com> has granted Michael Saboff <msaboff at apple.com>'s
request for review:
Bug 172186: [iOS] The Garbage Collector shouldn't rely on the bmalloc scavenger
for up to date memory footprint info
https://bugs.webkit.org/show_bug.cgi?id=172186

Attachment 310304: Patch

https://bugs.webkit.org/attachment.cgi?id=310304&action=review




--- Comment #4 from Filip Pizlo <fpizlo at apple.com> ---
Comment on attachment 310304
  --> https://bugs.webkit.org/attachment.cgi?id=310304
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=310304&action=review

> Source/JavaScriptCore/heap/Heap.cpp:519
> -    if (bmalloc::api::percentAvailableMemoryInUse() >
Options::criticalGCMemoryThreshold())
> +    static unsigned memCalls = 0;
> +
> +    bmalloc::MemoryDataAge memoryDataAge =
bmalloc::MemoryDataAge::UseCached;
> +
> +    if (++memCalls >= 100) {
> +	   memoryDataAge = bmalloc::MemoryDataAge::GetCurrent;
> +	   memCalls = 0;
> +    }
> +
> +    if (bmalloc::api::percentAvailableMemoryInUse(memoryDataAge) >
Options::criticalGCMemoryThreshold())
>	   return true;

This is a nice heuristic!