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From: Balbir Singh <balbir@linux.vnet.ibm.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
	"nishimura@mxp.nes.nec.co.jp" <nishimura@mxp.nes.nec.co.jp>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [RFC][PATCH] memcg remove css_get/put per pages v2
Date: Fri, 11 Jun 2010 11:41:02 +0530	[thread overview]
Message-ID: <20100611061102.GF5191@balbir.in.ibm.com> (raw)
In-Reply-To: <20100609155940.dd121130.kamezawa.hiroyu@jp.fujitsu.com>

* KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> [2010-06-09 15:59:40]:

> +		if (consume_stock(mem)) {
> +			/*
> +			 * It seems dagerous to access memcg without css_get().
> +			 * But considering how consume_stok works, it's not
> +			 * necessary. If consume_stock success, some charges
> +			 * from this memcg are cached on this cpu. So, we
> +			 * don't need to call css_get()/css_tryget() before
> +			 * calling consume_stock().
> +			 */
> +			rcu_read_unlock();
> +			goto done;
> +		}
> +		if (!css_tryget(&mem->css)) {

If tryget fails, can one assume that this due to a race and the mem is
about to be freed?


-- 
	Three Cheers,
	Balbir

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  parent reply	other threads:[~2010-06-11  7:03 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-06-08  3:19 [RFC][PATCH] memcg remove css_get/put per pages KAMEZAWA Hiroyuki
2010-06-08  5:40 ` Balbir Singh
2010-06-09  0:47   ` KAMEZAWA Hiroyuki
2010-06-09  5:14     ` KAMEZAWA Hiroyuki
2010-06-08  7:31 ` Daisuke Nishimura
2010-06-09  0:54   ` KAMEZAWA Hiroyuki
2010-06-09  2:05     ` Daisuke Nishimura
2010-06-09  6:59 ` [RFC][PATCH] memcg remove css_get/put per pages v2 KAMEZAWA Hiroyuki
2010-06-10  2:34   ` Daisuke Nishimura
2010-06-10  2:49     ` KAMEZAWA Hiroyuki
2010-06-11  4:37   ` Daisuke Nishimura
2010-06-11  4:52     ` KAMEZAWA Hiroyuki
2010-06-11  4:59       ` Daisuke Nishimura
2010-06-11  6:11   ` Balbir Singh [this message]
2010-06-11  6:21     ` KAMEZAWA Hiroyuki

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