From: KAMEZAWA Hiroyuki <kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
To: Glauber Costa <glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>,
Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
devel-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org,
Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>,
Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>,
Linux MM <linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org>,
Pavel Emelyanov <xemul-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
Subject: Re: [RFC 5/7] use percpu_counters for res_counter usage
Date: Mon, 09 Apr 2012 10:48:42 +0900 [thread overview]
Message-ID: <4F823FFA.8000401@jp.fujitsu.com> (raw)
In-Reply-To: <4F75BACC.7050704-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
(2012/03/30 22:53), Glauber Costa wrote:
> On 03/30/2012 11:58 AM, KAMEZAWA Hiroyuki wrote:
>> ==
>>
>> Now, we do consume 'reserved' usage, we can avoid css_get(), an heavy atomic
>> ops. You may need to move this code as
>>
>> rcu_read_lock()
>> ....
>> res_counter_charge()
>> if (failure) {
>> css_tryget()
>> rcu_read_unlock()
>> } else {
>> rcu_read_unlock()
>> return success;
>> }
>>
>> to compare performance. This css_get() affects performance very very much.
>
> thanks for the tip.
>
> But one thing:
>
> To be sure: it effectively mean that we are drawing from a dead memcg
> (because we pre-allocated, right?
Cached stock is consumed by the current task. It blocks removal of memcg.
It's not dead.
Thanks,
-Kame
next prev parent reply other threads:[~2012-04-09 1:48 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-30 8:04 [RFC 0/7] Initial proposal for faster res_counter updates Glauber Costa
[not found] ` <1333094685-5507-1-git-send-email-glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-03-30 8:04 ` [RFC 1/7] split percpu_counter_sum Glauber Costa
2012-03-30 8:04 ` [RFC 2/7] consolidate all res_counter manipulation Glauber Costa
2012-03-30 8:04 ` [RFC 3/7] bundle a percpu counter into res_counters and use its lock Glauber Costa
2012-03-30 8:04 ` [RFC 4/7] move res_counter_set limit to res_counter.c Glauber Costa
2012-03-30 8:04 ` [RFC 5/7] use percpu_counters for res_counter usage Glauber Costa
[not found] ` <1333094685-5507-6-git-send-email-glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-03-30 9:33 ` KAMEZAWA Hiroyuki
2012-03-30 9:58 ` KAMEZAWA Hiroyuki
2012-03-30 13:53 ` Glauber Costa
[not found] ` <4F75BACC.7050704-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-04-09 1:48 ` KAMEZAWA Hiroyuki [this message]
[not found] ` <4F757DEB.4030006-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
2012-03-30 12:59 ` Glauber Costa
2012-03-30 8:04 ` [RFC 6/7] Add min and max statistics to percpu_counter Glauber Costa
2012-03-30 8:04 ` [RFC 7/7] Global optimization Glauber Costa
2012-03-30 8:32 ` [RFC 0/7] Initial proposal for faster res_counter updates KAMEZAWA Hiroyuki
2012-03-30 10:46 ` Glauber Costa
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