From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx121.postini.com [74.125.245.121]) by kanga.kvack.org (Postfix) with SMTP id 030406B00EA for ; Tue, 8 May 2012 11:24:34 -0400 (EDT) Date: Tue, 8 May 2012 10:24:29 -0500 (CDT) From: Christoph Lameter Subject: Re: [PATCH v1 5/6] mm: make vmstat_update periodic run conditional In-Reply-To: Message-ID: References: <1336056962-10465-1-git-send-email-gilad@benyossef.com> <1336056962-10465-6-git-send-email-gilad@benyossef.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Gilad Ben-Yossef Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Tejun Heo , John Stultz , Andrew Morton , KOSAKI Motohiro , Mel Gorman , Mike Frysinger , David Rientjes , Hugh Dickins , Minchan Kim , Konstantin Khlebnikov , Chris Metcalf , Hakan Akkan , Max Krasnyansky , Frederic Weisbecker , linux-mm@kvack.org On Tue, 8 May 2012, Gilad Ben-Yossef wrote: > My line of thought was that if we explicitly choose a scapegoat cpu we > and the user need to manage this - such as worry about what happens if > the scapegoats is offlines and let the user explicitly designate the > scapegoat cpu thus creating another knob, and worrying about what > happens if the user designate such a cpu but then it goes offlines... The scapegoat can be chosen on boot. One can f.e. create a file in /sys/device/syste/cpu called "scapegoat" which contains the number of the processor chosen. Then one can even write a userspace daemon to automatize the moving of the processing elsewhere. Could be integrated into something horrible like irqbalance f.e. > I figured the user needs to worry about other unbounded work items > anyway if he cares about where such things are run in the general case, > but using isolcpus for example. True. So the scapegoat heuristic could be to pick the first unisolated cpu. > The same should be doable with cpusets, except that right now we mark > unbounded workqueue worker threads as pinned even though they aren't. If > I understood the discussion, the idea is exactly to stop users from > putting these threads in non root cpusets. I am not 100% sure why.. Not sure that cpusets is a good thing to bring in here because that is an optional feature of the kernel and tying basic functionality like this to cpuset support does not sound right to me. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org