From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id C83738D0040 for ; Mon, 28 Mar 2011 09:18:39 -0400 (EDT) Subject: Re: [PATCH 2/5] Revert "oom: give the dying task a higher priority" From: Peter Zijlstra In-Reply-To: <20110328131029.GN19007@uudg.org> References: <20110315153801.3526.A69D9226@jp.fujitsu.com> <20110322194721.B05E.A69D9226@jp.fujitsu.com> <20110322200657.B064.A69D9226@jp.fujitsu.com> <20110324152757.GC1938@barrios-desktop> <1301305896.4859.8.camel@twins> <20110328122125.GA1892@barrios-desktop> <1301315307.4859.13.camel@twins> <20110328124025.GC1892@barrios-desktop> <20110328131029.GN19007@uudg.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Date: Mon, 28 Mar 2011 15:18:13 +0200 Message-ID: <1301318293.4859.19.camel@twins> Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: "Luis Claudio R. Goncalves" Cc: Minchan Kim , KOSAKI Motohiro , linux-kernel@vger.kernel.org, Andrew Morton , David Rientjes , Linus Torvalds , Rik van Riel , Oleg Nesterov , linux-mm , Andrey Vagin , Hugh Dickins , KAMEZAWA Hiroyuki On Mon, 2011-03-28 at 10:10 -0300, Luis Claudio R. Goncalves wrote: > | There was meaningless code in there. I guess it was in there from CFS. > | Thanks for the explanation, Peter. >=20 > Yes, it was CFS related: >=20 > p =3D find_lock_task_mm(p); > ... > p->rt.time_slice =3D HZ; <<---- THIS CFS has never used rt.time_slice, that's always been a pure SCHED_RR thing. > Peter, would that be effective to boost the priority of the dying task? The thing you're currently doing, making it SCHED_FIFO ? > I mean, in the context of SCHED_OTHER tasks would it really help the dyin= g > task to be scheduled sooner to release its resources?=20 That very much depends on how all this stuff works, I guess if everybody serializes on OOM and only the first will actually kill a task and all the waiting tasks will try to allocate a page again before also doing the OOM thing, and the pending tasks are woken after the OOM target task has completed dying.. then I don't see much point in boosting things, since everybody interested in memory will block and eventually only the dying task will be left running. Its been a very long while since I stared at the OOM code.. > If so, as we remove > the code in commit 93b43fa5508 we should re-add that old code.=20 It doesn't make any sense to fiddle with rt.time_slice afaict. -- 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