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 ESMTP id A45276B0044 for ; Tue, 3 Nov 2009 15:24:09 -0500 (EST) Received: from zps19.corp.google.com (zps19.corp.google.com [172.25.146.19]) by smtp-out.google.com with ESMTP id nA3KO62s011800 for ; Tue, 3 Nov 2009 12:24:06 -0800 Received: from pwi12 (pwi12.prod.google.com [10.241.219.12]) by zps19.corp.google.com with ESMTP id nA3KLWld012756 for ; Tue, 3 Nov 2009 12:24:03 -0800 Received: by pwi12 with SMTP id 12so2994218pwi.25 for ; Tue, 03 Nov 2009 12:24:03 -0800 (PST) Date: Tue, 3 Nov 2009 12:24:01 -0800 (PST) From: David Rientjes Subject: Re: [RFC][-mm][PATCH 3/6] oom-killer: count lowmem rss In-Reply-To: <20091102162617.9d07e05f.kamezawa.hiroyu@jp.fujitsu.com> Message-ID: References: <20091102162244.9425e49b.kamezawa.hiroyu@jp.fujitsu.com> <20091102162617.9d07e05f.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, KOSAKI Motohiro , Andrea Arcangeli , Andrew Morton , minchan.kim@gmail.com, vedran.furac@gmail.com, Hugh Dickins List-ID: On Mon, 2 Nov 2009, KAMEZAWA Hiroyuki wrote: > From: KAMEZAWA Hiroyuki > > Count lowmem rss per mm_struct. Lowmem here means... > > for NUMA, pages in a zone < policy_zone. > for HIGHMEM x86, pages in NORMAL zone. > for others, all pages are lowmem. > > Now, lower_zone_protection[] works very well for protecting lowmem but > possiblity of lowmem-oom is not 0 even if under good protection in the kernel. > (As fact, it's can be configured by sysctl. When we keep it high, there > will be tons of not-for-use memory but system will be protected against > rare event of lowmem-oom.) Right, lowmem isn't addressed currently by the oom killer. Adding this constraint will probably make the heuristics much harder to write and understand. It's not always clear that we want to kill a task using lowmem just because another task needs some, for instance. Do you think we'll need a way to defer killing any task is no task is heuristically found to be hogging lowmem? -- 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