From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 25 Jun 2008 15:08:59 +0900 From: KOSAKI Motohiro Subject: Re: [RFC][PATCH] prevent incorrect oom under split_lru In-Reply-To: <28c262360806242259k3ac308c4n7cee29b72456e95b@mail.gmail.com> References: <20080624092824.4f0440ca@bree.surriel.com> <28c262360806242259k3ac308c4n7cee29b72456e95b@mail.gmail.com> Message-Id: <20080625150141.D845.KOSAKI.MOTOHIRO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: MinChan Kim Cc: kosaki.motohiro@jp.fujitsu.com, Rik van Riel , linux-mm , LKML , Lee Schermerhorn , akpm@linux-foundation.org, Takenori Nagano List-ID: Hi Kim-san, > >> So, if priority==0, We should try to reclaim all page for prevent OOM. > > > > You are absolutely right. Good catch. > > I have a concern about application latency. > If lru list have many pages, it take a very long time to scan pages. > More system have many ram, More many time to scan pages. No problem. priority==0 indicate emergency. it doesn't happend on typical workload. > Of course I know this is trade-off between memory efficiency VS latency. > But In embedded, some application think latency is more important > thing than memory efficiency. > We need some mechanism to cut off scanning time. > > I think Takenori Nagano's "memory reclaim more efficiently patch" is > proper to reduce application latency in this case If we modify some > code. I think this is off-topic. but Yes. both my page reclaim throttle and nagano-san's patch provide reclaim cut off mechanism. and more off-topic, nagano-san's patch improve only priority==12. So, typical embedded doesn't improve so big because embedded system does't have so large memory. -- 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