From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 19 Mar 2005 22:58:55 -0800 From: Andrew Morton Subject: Re: [Patch] cpusets policy kill no swap Message-Id: <20050319225855.475e4167.akpm@osdl.org> In-Reply-To: <20050320014847.16310.53697.sendpatchset@sam.engr.sgi.com> References: <20050320014847.16310.53697.sendpatchset@sam.engr.sgi.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: Paul Jackson Cc: mort@sgi.com, linux-mm@kvack.org, emery@sgi.com, bron@sgi.com, Simon.Derr@bull.net, linux-kernel@vger.kernel.org List-ID: Paul Jackson wrote: > > This mechanisms differs from a general purpose out-of-memory > killer in various ways, including: > > * An oom-killer tries to score the bad buy, to avoid shooting > the innocent little task that just happened to ask for one > page too many. > * The policy_kill_no_swap hook kills the current requester. > * It takes severe memory pressure to wake up an oom-killer. > * The policy_kill_no_swap hook triggers on the slightest > pressure that exceeds readily free memory. > * The oom-killer can be useful on a general purpose system. > * The policy_kill_no_swap hook is only useful for carefully > tuned apps running on dedicated nodes on large systems. > There are a lot of reasons why we would wake kswapd apart from starting swapout. Such as to reclaim clean pagecache or some dcache+icache. > In short - simple enough, but quite specialized. Way too specialised, I suspect. Is it not possible to have a little userspace daemon which monitors the long-running applications's rss and whacks it if the rss gets too large? The patch you have simply kills the process when all the eligible zones reach their upper watermark. Again, we can probably determine that state from userspace right now. If not, it would be simple enough to add the required info to /proc somewhere. -- 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: aart@kvack.org