1959077 - Mark stack element ranges are unnecessarily updated after work is donated

Status: RESOLVED FIXED

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

Description

[Jon Coppeard (:jonco)]

We update object element ranges stored on the mark stack at the start and end of every slice to take account of the number of shifted elements to ensure we don't skip any marking, as the number of shifted elements may change between slices. Currently there is a bug where we also update element ranges after work is donated between marking theads as if we were starting a new slice.

This doesn't affect correctness but it can make us re-do some marking work unnecessarily.

Comment 1

[Jon Coppeard (:jonco)]

Attachment: Bug 1959077 - Update mark stack elements ranges only at the beginning and end of each slice when parallel marking r?sfink

This also adds some asserts when moving work that would have caught this.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/0d47139188e4
Update mark stack elements ranges only at the beginning and end of each slice when parallel marking r=sfink

Comment 3

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/0d47139188e4