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From: Glauber Costa <glommer@parallels.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: cgroups@vger.kernel.org, Li Zefan <lizefan@huawei.com>,
	Tejun Heo <tj@kernel.org>,
	devel@openvz.org, Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@suse.cz>, Linux MM <linux-mm@kvack.org>,
	Pavel Emelyanov <xemul@parallels.com>
Subject: Re: [RFC 5/7] use percpu_counters for res_counter usage
Date: Fri, 30 Mar 2012 15:53:16 +0200	[thread overview]
Message-ID: <4F75BACC.7050704@parallels.com> (raw)
In-Reply-To: <4F7583AB.3070304@jp.fujitsu.com>

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?




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  reply	other threads:[~2012-03-30 13:53 UTC|newest]

Thread overview: 26+ 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
2012-03-30  8:04 ` 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     ` Glauber Costa
2012-03-30  8:04   ` [RFC 2/7] consolidate all res_counter manipulation Glauber Costa
2012-03-30  8:04     ` 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     ` 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     ` Glauber Costa
2012-03-30  8:04   ` [RFC 5/7] use percpu_counters for res_counter usage Glauber Costa
2012-03-30  8:04     ` 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  9:33         ` KAMEZAWA Hiroyuki
2012-03-30  9:58         ` KAMEZAWA Hiroyuki
2012-03-30 13:53           ` Glauber Costa [this message]
     [not found]             ` <4F75BACC.7050704-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-04-09  1:48               ` KAMEZAWA Hiroyuki
2012-04-09  1:48                 ` KAMEZAWA Hiroyuki
     [not found]         ` <4F757DEB.4030006-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
2012-03-30 12:59           ` Glauber Costa
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     ` Glauber Costa
2012-03-30  8:04   ` [RFC 7/7] Global optimization Glauber Costa
2012-03-30  8:04     ` 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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