Simplify gray marking a little in preparation for making it incremental
Categories
(Core :: JavaScript: GC, task, P3)
Tracking
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| Tracking | Status | |
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| firefox94 | --- | fixed |
People
(Reporter: jonco, Assigned: jonco)
References
Details
Attachments
(2 files)
I've been looking into how we might mark gray roots incrementally. In preparation for that here are a couple of patches to simplify and tidy up the current gray root marking.
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Assignee | |
Comment 1•3 years ago
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We try to do as much black marking as possible before gray marking. Cross
compartment pointers between marking zones are followed when marking black, but
not when marking gray. Instead they are put on a list and we delay marking them
until we start gray marking their zone.
This code checked for any cross compartment pointers on the list whose souce
had become black due to gray unmarking, and marked their target black. This was
unnecessary because gray unmarking already results in marking the target black
since it invokes the standard barrier on targets in collecting zones.
The patch removes this code and adds an assertion that no black marking is
necessary when traversing this list.
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Assignee | |
Comment 2•3 years ago
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This splits the markGrayReferencesInCurrentGroup action into
markGrayRootsInCurrentGroup and markGray, which means we don't need the extra
state to check whether it's the first time it's called. Now
markGrayRootsInCurrentGroup will run once, and then markGray will run to
process the mark stack. If we exhast the budget, we will re-enter in markGray
and won't try to mark the roots again.
Depends on D124780
Pushed by jcoppeard@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/0c12e7b5aea2 We don't need to mark incoming cross compartment pointers black at the start of gray marking r=sfink https://hg.mozilla.org/integration/autoland/rev/fcf04373f799 Split gray marking into separate actions r=sfink
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Comment 4•3 years ago
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| bugherder | ||
https://hg.mozilla.org/mozilla-central/rev/0c12e7b5aea2
https://hg.mozilla.org/mozilla-central/rev/fcf04373f799
Description
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