From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id D23986B007B for ; Mon, 11 Jan 2010 23:48:37 -0500 (EST) Received: by pzk34 with SMTP id 34so14162644pzk.11 for ; Mon, 11 Jan 2010 20:48:36 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20100112042116.GA26035@localhost> References: <1263184634-15447-4-git-send-email-shijie8@gmail.com> <1263191277-30373-1-git-send-email-shijie8@gmail.com> <20100111153802.f3150117.minchan.kim@barrios-desktop> <20100112094708.d09b01ea.kamezawa.hiroyu@jp.fujitsu.com> <20100112022708.GA21621@localhost> <28c262361001112005s745e5ecj9fd6ae3d0d997477@mail.gmail.com> <20100112042116.GA26035@localhost> Date: Tue, 12 Jan 2010 13:48:36 +0900 Message-ID: <28c262361001112048n5e03670fx68dbc94209dbf3db@mail.gmail.com> Subject: Re: [PATCH 4/4] mm/page_alloc : relieve zone->lock's pressure for memory free From: Minchan Kim Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org To: Wu Fengguang Cc: KAMEZAWA Hiroyuki , Huang Shijie , "akpm@linux-foundation.org" , "mel@csn.ul.ie" , "kosaki.motohiro@jp.fujitsu.com" , "linux-mm@kvack.org" , Rik van Riel List-ID: On Tue, Jan 12, 2010 at 1:21 PM, Wu Fengguang wrot= e: >> Hmm. It's not atomic as Kame pointed out. >> >> Now, zone->flags have several bit. >> =C2=A0* ZONE_ALL_UNRECLAIMALBE >> =C2=A0* ZONE_RECLAIM_LOCKED >> =C2=A0* ZONE_OOM_LOCKED. >> >> I think this flags are likely to race when the memory pressure is high. >> If we don't prevent race, concurrent reclaim and killing could be happen= ed. >> So I think reset zone->flags outside of zone->lock would make our effort= s which >> prevent current reclaim and killing invalidate. > > zone_set_flag()/zone_clear_flag() calls set_bit()/clear_bit() which is > atomic. Do you mean more high level exclusion? No. I was wrong. I though it's not atomic operation. I confused it with __set_bit. :) Sorry for the noise. Thanks, Wu. :) --=20 Kind regards, Minchan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org