1847019 - Optimize marking atoms used by uncollected zones

Status: RESOLVED FIXED

(Core :: JavaScript: GC, enhancement, P3)

Description

[Jon Coppeard (:jonco)]

I noticed a couple of small improvements that could be made to atom marking in AtomMarkingRuntime::markAtomsUsedByUncollectedZones.

Currently we always allocate a bitmap to hold the union of mark bits from uncollected zones even though this is only useful when there is more than one uncollected zone. If there's only one zone we don't need the intermediate bitmap, and if there are no zones then there is no work to do at all.

Comment 1

[Jon Coppeard (:jonco)]

Attachment: Bug 1847019 - Skip unnecessary atom marking work r?sfink

This patch skips marking atoms unsed by uncollected zones if there are no
uncollected zones. Also it skips allocating a bitmap for the union of atoms to
mark if there's only one zone.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/df89b6fec938
Skip unnecessary atom marking work r=sfink

Comment 3

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/df89b6fec938