From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 15 Feb 2008 14:07:32 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [RFC] [PATCH 3/4] Reclaim from groups over their soft limit under memory pressure Message-Id: <20080215140732.8b2dc04e.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <47B51430.4090009@linux.vnet.ibm.com> References: <20080213151201.7529.53642.sendpatchset@localhost.localdomain> <20080213151242.7529.79924.sendpatchset@localhost.localdomain> <20080214163054.81deaf27.kamezawa.hiroyu@jp.fujitsu.com> <47B3F073.1070804@linux.vnet.ibm.com> <20080214174236.aa2aae9b.kamezawa.hiroyu@jp.fujitsu.com> <47B406E4.9060109@linux.vnet.ibm.com> <6599ad830802142017g7cdb1b9cid8bbc8cb97e2df68@mail.gmail.com> <47B51430.4090009@linux.vnet.ibm.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: balbir@linux.vnet.ibm.com Cc: Paul Menage , linux-mm@kvack.org, Hugh Dickins , Peter Zijlstra , YAMAMOTO Takashi , Lee Schermerhorn , Herbert Poetzl , "Eric W. Biederman" , David Rientjes , Pavel Emelianov , Nick Piggin , Rik Van Riel , Andrew Morton List-ID: On Fri, 15 Feb 2008 09:55:20 +0530 Balbir Singh wrote: > Paul Menage wrote: > > On Thu, Feb 14, 2008 at 1:16 AM, Balbir Singh wrote: > >> > Probably backgound-reclaim patch will be able to help this soft-limit situation, > >> > if a daemon can know it should reclaim or not. > >> > > >> > >> Yes, I agree. I might just need to schedule the daemon under memory pressure. > >> > > > > Can we also have a way to trigger a one-off reclaim (of a configurable > > magnitude) from userspace? Having a background daemon doing it may be > > fine as a default, but there will be cases when a userspace machine > > manager knows better than the kernel how frequently/hard to try to > > reclaim on a given cgroup. > > > > Paul > > We have that capability, but we cannot specify how much to reclaim. > There is a force_empty file that when written to, tries to reclaim all pages > from the cgroup. Depending on the need, it can be extended so that the number of > pages to be reclaimed can be specified. > Note: Now, force_empty doesn't try to free memory but just drops charges. We can free memory by just making memory.limit to smaller number. (This may cause OOM. If we added high-low watermark, making memory.high smaller can works well for memory freeing to some extent.) Thanks, -Kame -- 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