1110514 - Update |jemalloc_free_dirty_pages_impl| to use |arena.<i>.purge|

Status: RESOLVED FIXED

(Core :: Memory Allocator, defect)

Description

[Eric Rahm [:erahm]]

|jemalloc_free_dirty_pages_imp| [1] currently uses "arenas.purge" which is obsolete:
> "arena.<i>.purge" (unsigned) -- Purge unused dirty pages for arena <i>, or for
> all arenas if <i> equals "arenas.narenas".

[1] http://dxr.mozilla.org/mozilla-central/source/memory/build/mozjemalloc_compat.c#107

Comment 1

[Guilherme Gonçalves [:ggp]]

Attachment: Use arena.<i>.purge to free jemalloc3's dirty pages.

Comment 2

[Mike Hommey [:glandium]]

Comment on attachment 8536830 [details] [diff] [review]
Use arena.<i>.purge to free jemalloc3's dirty pages.

Review of attachment 8536830 [details] [diff] [review]:
-----------------------------------------------------------------

::: memory/build/mozjemalloc_compat.c
@@ +160,5 @@
> +
> +  je_(mallctl)("arenas.narenas", &narenas, &sz, NULL, 0);
> +  je_(mallctlnametomib)("arena.0.purge", mib, &miblen);
> +  mib[1] = narenas;
> +  je_(mallctlbymib)(mib, miblen, NULL, NULL, NULL, 0);

Just use CTL_GET and CTL_I_GET that are defined in this file and used in jemalloc_stats_impl.

Comment 3

[Mike Hommey [:glandium]]

(In reply to Mike Hommey [:glandium] from comment #2)
> Just use CTL_GET and CTL_I_GET that are defined in this file and used in
> jemalloc_stats_impl.

You'll need to factor the fact that it's mib[1] in this case and mib[2] in CTL_I_GET. I wouldn't mind making CTL_I_GET more generic.

Comment 4

[Guilherme Gonçalves [:ggp]]

(In reply to Mike Hommey [:glandium] from comment #3)
> You'll need to factor the fact that it's mib[1] in this case and mib[2] in
> CTL_I_GET. I wouldn't mind making CTL_I_GET more generic.

Not only that, but jemalloc also demands that every pointer passed to this ctl be NULL: https://github.com/jemalloc/jemalloc/blob/dev/src/ctl.c#L1453. Given how peculiar this ctl is, do you still think I should modify CTL_I_GET to accommodate for that as well, or is it ok to just leave the explicit je_(mallctlbymib)?

(I'm completely fine with using CTL_GET for narenas though)

Comment 5

[Guilherme Gonçalves [:ggp]]

Attachment: Use arena.<i>.purge to free jemalloc3's dirty pages.

As discussed on IRC, this should be enough. Patch updated.

Comment 6

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/866eedaf819c

Comment 7

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/866eedaf819c