[whatwg] Low Memory Event

Glenn Maynard glenn at zewt.org
Sat Jan 1 16:48:43 PST 2011

On Sat, Jan 1, 2011 at 7:35 PM, Ryosuke Niwa <rniwa at webkit.org> wrote:
> What I don't understand about this proposal is how web apps are supposed to
> free memory.  In my understanding, ES5 doesn't allow you to manually free
> memory (unlike Objective-C), and it's up to GC implementor to decide how and
> when (most of) resources are freed.

"Freeing memory" in the context of Javascript means "make available to
the collector to be freed", eg. drop references.  Actually collecting
any resulting objects as a result of that is up to the implementation:
presumably a thorough GC pass would be forced after sending this
message, to actually free memory that the application released.

(That seems simple enough on mobile browsers, but on desktop systems
doing such a collection pass might force everything to be paged back
into memory, and to incorrectly hint the OS that everything is active
and shouldn't be paged back out quickly, so it's probably not that
simple in practice.)

Glenn Maynard

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