1575895 - Malloc allocations can trigger back-to-back GC slices

Status: RESOLVED FIXED

(Core :: JavaScript: GC, defect, P1)

Description

[Jon Coppeard (:jonco)]

Right now we always trigger an incremental slice in GCRuntime::maybeMallocTriggerZoneGC if we've exceeded the incremental threshold. This is different to what happens in maybeAllocTriggerZoneGC where we have a delay between triggering slices implemented with gcDelayBytes.

We don't check this threshold on every malloc allocation, but this could still result in us doing back-to-back slices, effectively a non-incremental GC.

Comment 1

[Jon Coppeard (:jonco)]

Attachment: Bug 1575895 - Don't start GC slices due to malloc allocation if we're already collecting the zone r?sfink

At some point we can think about triggering incremental slices here the way we do for the GC heap allocations but for now it's simplest to just not trigger any more slices if we're already allocating.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/7578290bed2a
Don't start GC slices due to malloc allocation if we're already collecting the zone r=sfink

Comment 3

[Daniel Varga [:dvarga]]

https://hg.mozilla.org/mozilla-central/rev/7578290bed2a