Re: [PATCH] memcg: remove unnecessary thp check at page stat accounting

[Ying Han]

On Tue, Jan 24, 2012 at 12:41 AM, Johannes Weiner <hannes@xxxxxxxxxxx> wrote:
> On Mon, Jan 23, 2012 at 12:11:11PM -0800, Ying Han wrote:
>> On Wed, Jan 18, 2012 at 11:14 PM, KAMEZAWA Hiroyuki
>> <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
>> > Thank you very much for reviewing previous RFC series.
>> > This is a patch against memcg-devel and linux-next (can by applied without HUNKs).
>> >
>> > ==
>> >
>> > From 64641b360839b029bb353fbd95f7554cc806ed05 Mon Sep 17 00:00:00 2001
>> > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
>> > Date: Thu, 12 Jan 2012 16:08:33 +0900
>> > Subject: [PATCH] memcg: remove unnecessary thp check in mem_cgroup_update_page_stat()
>> >
>> > commit 58b318ecf(memcg-devel)
>> >    memcg: make mem_cgroup_split_huge_fixup() more efficient
>> > removes move_lock_page_cgroup() in thp-split path.
>> >
>> > So, We do not have to check PageTransHuge in mem_cgroup_update_page_stat
>> > and fallback into the locked accounting because both move charge and thp
>> > split up are done with compound_lock so they cannot race. update vs.
>> > move is protected by the mem_cgroup_stealed sufficiently.
>>
>> Sorry, i don't see we changed the "move charge" to "move account" ?
>
> move_account() moves charges.  IMO, it's the function that is a
> misnomer and "moving charges" is less ambiguous since we account
> several different things in the memory controller.

Hmm, that works then.

Acked-by: Ying Han<yinghan@xxxxxxxxxx>

--Ying
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