1131233 - Remove off-main-thread GC trigger checks

Status: RESOLVED INVALID

(Core :: JavaScript: GC, defect)

Description

[Terrence Cole [:terrence]]

The ExclusiveContext has full access to the Zone, so I think the only thing blocking this is concurrent access to rt->gc.incrementalGCState.

Comment 1

[Terrence Cole [:terrence]]

Actually, I don't think it makes sense to trigger any GCs from off-main-thread. I was under the impression that if we OOM'd we'd retry the parse on the main thread, so triggering a GC would streamline the next on-thread alloc. This is not the case, instead we just report the OOM. Moreover, the one trigger that is safely checked off-thread -- maybeTriggerZoneGC -- is not actually effectual when run off-thread because triggerZoneGC explicitly bails if we try. Further, we can't even pause the off-thread for the main thread to do a GC here since we'd certainly deadlock.

Given that we're fine with the current situation and there's nothing we can do anyway, I think the right answer is to just simplify all of this code and only bother checking for GC on the main thread.

Comment 3

[Terrence Cole [:terrence]]

And we really don't do this. Hopefully, it's even clear in the new allocator that this is the case.