From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <472801DC.6050802@us.ibm.com> Date: Tue, 30 Oct 2007 21:17:32 -0700 From: Badari MIME-Version: 1.0 Subject: Re: [RFC] oom notifications via /dev/oom_notify References: <20071030191827.GB31038@dmt> <1193781568.8904.33.camel@dyn9047017100.beaverton.ibm.com> <20071030171209.0caae1d5@cuia.boston.redhat.com> In-Reply-To: <20071030171209.0caae1d5@cuia.boston.redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel Cc: Marcelo Tosatti , linux-mm , drepper@redhat.com, Andrew Morton , mbligh@mbligh.org, balbir@linux.vnet.ibm.com List-ID: Rik van Riel wrote: > On Tue, 30 Oct 2007 13:59:28 -0800 > Badari Pulavarty wrote: > > >> Interesting.. Our database folks wanted some kind of notification when >> there is memory pressure and we are about to kill the biggest consumer >> (in most cases, the most useful application :(). What actually they >> want is a way to get notified, so that they can shrink their memory >> footprint in response. Just notifying before OOM may not help, since >> they don't have time to react. How does this notification help ? Are >> they supposed to monitor swapping activity and decide ? >> > > Marcelo's code monitors swapping activity and will let userspace > programs (that poll/select the device node) know when they should > shrink their memory footprint. > > This is not "OOM" in the sense of "no more memory or swap", but > in the sense of "we're low on memory - if you don't free something > we'll slow you down by swapping stuff". > > I think having this kind of OOM notification is a decent start. But any applications that wants to know notifications, would be more interested if kernel is swapping out any of its data, than overall system swapping events. I guess, making it per-process or per-cgroup may be logical extension. I am not sure if its really practical , though... Thanks, Badari -- 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