From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx176.postini.com [74.125.245.176]) by kanga.kvack.org (Postfix) with SMTP id AD17F6B0092 for ; Mon, 5 Mar 2012 15:07:42 -0500 (EST) Message-ID: <4F551CB6.5010209@redhat.com> Date: Mon, 05 Mar 2012 15:06:14 -0500 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH] mm: use global_dirty_limit in throttle_vm_writeout() References: <20120302061451.GA6468@localhost> In-Reply-To: <20120302061451.GA6468@localhost> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Fengguang Wu Cc: Andrew Morton , Johannes Weiner , Jan Kara , Greg Thelen , Ying Han , KAMEZAWA Hiroyuki , Mel Gorman , Minchan Kim , Linux Memory Management List , LKML On 03/02/2012 01:14 AM, Fengguang Wu wrote: > When starting a memory hog task, a desktop box w/o swap is found to go > unresponsive for a long time. It's solely caused by lots of congestion > waits in throttle_vm_writeout(): > > gnome-system-mo-4201 553.073384: congestion_wait: throttle_vm_writeout+0x70/0x7f shrink_mem_cgroup_zone+0x48f/0x4a1 > gnome-system-mo-4201 553.073386: writeback_congestion_wait: usec_timeout=100000 usec_delayed=100000 > gtali-4237 553.080377: congestion_wait: throttle_vm_writeout+0x70/0x7f shrink_mem_cgroup_zone+0x48f/0x4a1 > gtali-4237 553.080378: writeback_congestion_wait: usec_timeout=100000 usec_delayed=100000 > Xorg-3483 553.103375: congestion_wait: throttle_vm_writeout+0x70/0x7f shrink_mem_cgroup_zone+0x48f/0x4a1 > Xorg-3483 553.103377: writeback_congestion_wait: usec_timeout=100000 usec_delayed=100000 > > The root cause is, the dirty threshold is knocked down a lot by the > memory hog task. Fixed by using global_dirty_limit which decreases > gradually on such events and can guarantee we stay above (the also > decreasing) nr_dirty in the progress of following down to the new > dirty threshold. > > Signed-off-by: Fengguang Wu Reviewed-by: Rik van Riel -- 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