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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

 



WARNING: multiple messages have this Message-ID (diff)
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Glauber Costa <glommer@parallels.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: Mon, 09 Apr 2012 10:48:42 +0900	[thread overview]
Message-ID: <4F823FFA.8000401@jp.fujitsu.com> (raw)
In-Reply-To: <4F75BACC.7050704@parallels.com>

(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

 



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  parent reply	other threads:[~2012-04-09  1:48 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
     [not found]             ` <4F75BACC.7050704-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-04-09  1:48               ` KAMEZAWA Hiroyuki [this message]
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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