1980048 - Remove the tiny size class

Status: RESOLVED FIXED

(Core :: Memory Allocator, task, P1)

Description

[Paul Bone [:pbone]]

To implement Bug 1980047 we must ensure there are no more than 256 regions in a run. We must remove the tiny size class because it is too small and will exceed 256 regions per run for 4096-byte runs.

Comment 1

[Paul Bone [:pbone]]

Attachment: Bug 1980048 - Remove the tiny size class from mozjemalloc r=glandium

Comment 2

[Paul Bone [:pbone]]

Removing the tiny size class will slightly regress explicit memory, but resident memory is unaffected. This is good. it shows that we're trading external fragmentation (more unallocated slots in 8 and 16 byte size classes) for internal fragmentation (8 byte allocations being rounded up to 16). The explicit memory measurement will increase because it counts internal fragmentation, but I'm happy that resident memory usage is unaffected.

https://perf.compare/compare-results?baseRev=04d817974fc947759dd0f9894eccf421bb67ee02&baseRepo=try&newRev=874bfec2723fac4323c4da78573702b9ab365747&newRepo=try&framework=4

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/4f2ba1495969
https://hg.mozilla.org/integration/autoland/rev/36d9ebe99a8f
Remove the tiny size class from mozjemalloc r=glandium

Comment 4

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/36d9ebe99a8f