1139983 - Do not fall back to tenured if we fail to allocate in the nursery when NoGC

Status: RESOLVED FIXED

(Core :: JavaScript: GC, defect)

Description

[Terrence Cole [:terrence]]

Attachment: dont_fallback_from_nursery_to_tenured_alloc_on_nogc-v0.diff

We have a hugely complicated infrastructure around allocation for the new object cache to allow us to clear the nursery when it fills up without clobbering the cache itself. This is dumb. Unlike with CanGC, where failure usually kills the script, when we're allocating with NoGC, we're already prepared to retry on failure, so making a best effort makes no sense. If we just return false on nursery alloc failure, we have an insubstantially lower hit rate, but we can dump the enormous complexity.

Try run looks green modulo 2 cgc failures -- a missing annotation in the previous patch -- and what looks like a random orange -- I've retriggered a few runs to check:
https://treeherder.mozilla.org/#/jobs?repo=try&revision=73c6c968bbb3

Comment 1

[Terrence Cole [:terrence]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=73c6c968bbb3
https://hg.mozilla.org/integration/mozilla-inbound/rev/9a2b3b8289ee

Comment 2

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/9a2b3b8289ee