From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59E93C3F68F for ; Mon, 9 Dec 2019 23:17:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 310AC2068E for ; Mon, 9 Dec 2019 23:17:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726950AbfLIXRw (ORCPT ); Mon, 9 Dec 2019 18:17:52 -0500 Received: from mail105.syd.optusnet.com.au ([211.29.132.249]:35499 "EHLO mail105.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726592AbfLIXRw (ORCPT ); Mon, 9 Dec 2019 18:17:52 -0500 Received: from dread.disaster.area (pa49-195-139-249.pa.nsw.optusnet.com.au [49.195.139.249]) by mail105.syd.optusnet.com.au (Postfix) with ESMTPS id 9FDC93A1740; Tue, 10 Dec 2019 10:17:46 +1100 (AEDT) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1ieSHf-000609-Or; Tue, 10 Dec 2019 10:17:43 +1100 Date: Tue, 10 Dec 2019 10:17:43 +1100 From: Dave Chinner To: Srikar Dronamraju Cc: Peter Zijlstra , Phil Auld , Ming Lei , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org, Jeff Moyer , Dave Chinner , Eric Sandeen , Christoph Hellwig , Jens Axboe , Ingo Molnar , Tejun Heo , Vincent Guittot Subject: Re: single aio thread is migrated crazily by scheduler Message-ID: <20191209231743.GA19256@dread.disaster.area> References: <20191115010824.GC4847@ming.t460p> <20191115045634.GN4614@dread.disaster.area> <20191115070843.GA24246@ming.t460p> <20191115234005.GO4614@dread.disaster.area> <20191118092121.GV4131@hirez.programming.kicks-ass.net> <20191118204054.GV4614@dread.disaster.area> <20191120191636.GI4097@hirez.programming.kicks-ass.net> <20191120220313.GC18056@pauld.bos.csb> <20191121132937.GW4114@hirez.programming.kicks-ass.net> <20191209165122.GA27229@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191209165122.GA27229@linux.vnet.ibm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.3 cv=X6os11be c=1 sm=1 tr=0 a=KoypXv6BqLCQNZUs2nCMWg==:117 a=KoypXv6BqLCQNZUs2nCMWg==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=kj9zAlcOel0A:10 a=pxVhFHJ0LMsA:10 a=7-415B0cAAAA:8 a=-oRCy8-_WFT2JPw6eY8A:9 a=CjuIK1q_8ugA:10 a=biEYGPWJfzWAr4FL6Ov7:22 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Mon, Dec 09, 2019 at 10:21:22PM +0530, Srikar Dronamraju wrote: > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 44123b4d14e8..efd740aafa17 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -2664,7 +2664,12 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) > */ > int wake_up_process(struct task_struct *p) > { > - return try_to_wake_up(p, TASK_NORMAL, 0); > + int wake_flags = 0; > + > + if (is_per_cpu_kthread(p)) > + wake_flags = WF_KTHREAD; > + > + return try_to_wake_up(p, TASK_NORMAL, WF_KTHREAD); This is buggy. It always sets WF_KTHREAD, even for non-kernel processes. I think you meant: return try_to_wake_up(p, TASK_NORMAL, wake_flags); I suspect this bug invalidates the test results presented, too... -Dave. -- Dave Chinner david@fromorbit.com