From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with ESMTP id D9C938D0040 for ; Mon, 28 Mar 2011 09:48:18 -0400 (EDT) Received: by gyd8 with SMTP id 8so1476774gyd.14 for ; Mon, 28 Mar 2011 06:48:16 -0700 (PDT) Date: Mon, 28 Mar 2011 22:48:04 +0900 From: Minchan Kim Subject: Re: [PATCH 2/5] Revert "oom: give the dying task a higher priority" Message-ID: <20110328134804.GE1892@barrios-desktop> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110328131029.GN19007@uudg.org> Sender: owner-linux-mm@kvack.org List-ID: To: "Luis Claudio R. Goncalves" Cc: Peter Zijlstra , 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, Mar 28, 2011 at 10:10:29AM -0300, Luis Claudio R. Goncalves wrote: > On Mon, Mar 28, 2011 at 09:40:25PM +0900, Minchan Kim wrote: > | On Mon, Mar 28, 2011 at 02:28:27PM +0200, Peter Zijlstra wrote: > | > On Mon, 2011-03-28 at 21:21 +0900, Minchan Kim wrote: > | > > Hi Peter, > | > > > | > > On Mon, Mar 28, 2011 at 11:51:36AM +0200, Peter Zijlstra wrote: > | > > > On Fri, 2011-03-25 at 00:27 +0900, Minchan Kim wrote: > | > > > > > | > > > > At that time, I thought that routine is meaningless in non-RT scheduler. > | > > > > So I Cced Peter but don't get the answer. > | > > > > I just want to confirm it. > | > > > > | > > > Probably lost somewhere in the mess that is my inbox :/, what is the > | > > > full question? > | > > > | > > The question is we had a routine which change rt.time_slice with HZ to > | > > accelarate task exit. But when we applied 93b43fa5508, we found it isn't effective > | > > any more about normal task. So we removed it. Is it right? > | > > | > rt.time_slice is only relevant to SCHED_RR, since you seem to use > | > SCHED_FIFO (which runs for as long as the task is runnable), its > | > completely irrelevant. > | > > | > > And Kosaki is about to revert 93b43fa5508 to find out the problem of this thread > | > > and Luis said he has a another solution to replace 93b43fa5508. > | > > If rt.time_slice handleing is effective, we should restore it until Luis's patch > | > > will be merged. > | > > | > Right, so only SCHED_RR is affected by time_slice, it will be > | > decremented on tick (so anything that avoids ticks will also avoid the > | > decrement) and once it reaches 0 the task will be queued at the tail of > | > its static priority and reset the slice. If there is no other task on > | > that same priority we'll again schedule that task. > | > > | > In short, don't use SCHED_RR and don't worry about time_slice. > | > | There was meaningless code in there. I guess it was in there from CFS. > | Thanks for the explanation, Peter. > > Yes, it was CFS related: I think it wasn't related CFS but O(1). I guess as we changed O(1) with CFS, the fault was remained. -- Kind regards, Minchan Kim -- 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