1562550 - Be more mindful of how much memory we touch during nursery poisoning.

Status: RESOLVED FIXED

(Core :: JavaScript: GC, enhancement, P2)

Description

[Paul Bone [:pbone]]

When the nursery is initalised we poison the entire nursery chunk with the initalisation pattern. Although poisoning is only used during testing and on Nightly, this will affect the memory usage telemetry we're seeing from Nightly. Let's avoid touching that memory so we get telemetry that represents better what we'll achieve in release.

Comment 2

[Paul Bone [:pbone]]

I've made Bug 1562551 a duplicate and will also fix another case of over-poisoning with this bug.

Comment 3

[Paul Bone [:pbone]]

Attachment: Bug 1562550 - (part 1) Add a poisonRange method to NurseryChunk r=jonco

Comment 4

[Paul Bone [:pbone]]

Attachment: Bug 1562550 - (part 2) Don't poison memory unnecessarily during Nursery::init r=jonco

Depends on D36875

Comment 5

[Paul Bone [:pbone]]

Attachment: Bug 1562550 - (part 3) Poison the unused part of a nursery chunk

This poisoning happens eventually when the chunk is decommitted, but it's
important to do it synchronously to catch more bugs. Unlike the other
patches on this bug this one increases the amount of poisoning done.

Depends on D36876

Comment 6

[Paul Bone [:pbone]]

Attachment: Bug 1562550 - (part 5) Avoid unnecessary poisoning between GCs r=jonco

Depends on D36877

Comment 7

[Paul Bone [:pbone]]

Attachment: Bug 1562550 - (part 3) Poison unused memory when we shrink the nursery r=jonco

When we shrink the nursery below one chunk, poison and mark as inaccessible
the now unused part of that chunk.

This is the only patch in this patch series that adds extra memory poisoning.

Depends on D36876

Comment 8

[Paul Bone [:pbone]]

Attachment: Bug 1562550 - (part 4) We don't need to poison the start chunk here r=jonco

Depends on D36878

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/9c274e3d473b
(part 1) Add a poisonRange method to NurseryChunk r=jonco
https://hg.mozilla.org/integration/autoland/rev/111838e2b22f
(part 2) Don't poison memory unnecessarily during Nursery::init r=jonco
https://hg.mozilla.org/integration/autoland/rev/0e662f79db6c
(part 3) Poison unused memory when we shrink the nursery r=jonco
https://hg.mozilla.org/integration/autoland/rev/89feefb6541e
(part 4) We don't need to poison the start chunk here r=jonco
https://hg.mozilla.org/integration/autoland/rev/6cc26a5b9fe2
(part 5) Avoid unnecessary poisoning between GCs r=jonco

Comment 10

[Oana Pop-Rus]

https://hg.mozilla.org/mozilla-central/rev/9c274e3d473b
https://hg.mozilla.org/mozilla-central/rev/111838e2b22f
https://hg.mozilla.org/mozilla-central/rev/0e662f79db6c
https://hg.mozilla.org/mozilla-central/rev/89feefb6541e
https://hg.mozilla.org/mozilla-central/rev/6cc26a5b9fe2