From mboxrd@z Thu Jan 1 00:00:00 1970 From: KOSAKI Motohiro Subject: Re: [PATCH] mm: disallow direct reclaim page writeback Date: Thu, 15 Apr 2010 13:35:17 +0900 (JST) Message-ID: <20100415133332.D183.A69D9226@jp.fujitsu.com> References: <20100415013436.GO2493@dastard> <20100415130212.D16E.A69D9226@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Cc: kosaki.motohiro@jp.fujitsu.com, Mel Gorman , Chris Mason , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org To: Dave Chinner Return-path: In-Reply-To: <20100415130212.D16E.A69D9226@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org > Hi >=20 > > How about this? For now, we stop direct reclaim from doing writeback > > only on order zero allocations, but allow it for higher order > > allocations. That will prevent the majority of situations where > > direct reclaim blows the stack and interferes with background > > writeout, but won't cause lumpy reclaim to change behaviour. > > This reduces the scope of impact and hence testing and validation > > the needs to be done. >=20 > Tend to agree. but I would proposed slightly different algorithm for > avoind incorrect oom. >=20 > for high order allocation > allow to use lumpy reclaim and pageout() for both kswapd and direct re= claim >=20 > for low order allocation > - kswapd: always delegate io to flusher thread > - direct reclaim: delegate io to flusher thread only if vm pressure i= s low >=20 > This seems more safely. I mean Who want see incorrect oom regression? > I've made some pathes for this. I'll post it as another mail. Now, kernel compile and/or backup operation seems keep nr_vmscan_write=3D= =3D0. Dave, can you please try to run your pageout annoying workload? -- 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