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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E6E9DC6FD1D for ; Tue, 21 Mar 2023 11:12:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230146AbjCULM2 (ORCPT ); Tue, 21 Mar 2023 07:12:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50728 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229497AbjCULMV (ORCPT ); Tue, 21 Mar 2023 07:12:21 -0400 Received: from mail-pj1-x1031.google.com (mail-pj1-x1031.google.com [IPv6:2607:f8b0:4864:20::1031]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 356553E1C9 for ; Tue, 21 Mar 2023 04:12:19 -0700 (PDT) Received: by mail-pj1-x1031.google.com with SMTP id o6-20020a17090a9f8600b0023f32869993so15886663pjp.1 for ; Tue, 21 Mar 2023 04:12:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1679397138; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=aFm2bVhMnmdLT8TBnJW2RkUaD0t/LuQwcgQAtupO00s=; b=LT3wPyTQyYRItyBqKfzpiKtfA/xZLZqwxUyX0U8pbX0KVlmbN2VaL+vO4VVw6Zqc8D JH0H5bubLUI0i1JNgc5/upC9JJ08iLIh4ClBxv8COcHYvaDe69n88ifPDHr7mmrdDM06 xN+BtkORi89bUBrfbq8qNQCjE1mzvZA6o9MSvUU9sTt0xcpq3hnT3IGjQPa5HSV+b2/L 6cpNH10oQAi3iRIHzspx6G4Miy7JkCIQUtXM2Nf6OI4j930MvYYDc8ZzjKpWACr9zqW+ lkE6PlPTFiMaZF8XNj3CZjKEDd05Ktruo8Hy45DaMHLzHbrbGl9Fa/nDbwwAh4HjQa8Z YKaA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679397138; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=aFm2bVhMnmdLT8TBnJW2RkUaD0t/LuQwcgQAtupO00s=; b=weS+v1V6L7CGW+Crqh3hR4c0yBA1ym4e9xhK+OOVlwRXIM7aN0eEhT5F5mkNkH3d3M mixl4fzLSJVO4CEQQSDH/gD2UmQiEUV4Dh010sYPDnXSVvl1ZvGRWgPbgh+3ZAvJ6nJx DxwLzvl1ZX4adNGOQFx8x9z5EpLqvpFFhzDOgMmrn3HfX3h7koMUhYA3lxtA5uhWM6Fe EKxCaAj7me9C5A/RanGbTBx25XKpqQ7wqBdIoh/0YEQD8TMVJ5SxiJzx6E0HpqiPYsn6 q1r991u1+uRBWPv+7Bv4xjLeB7bi7CP5feBiirbUPf87bPWSP+PE+TfV90CawMm9Nt+m TUPQ== X-Gm-Message-State: AO0yUKXZnyPHJCuzuAGMs2P832GoLGyj6sD2Ex0IaBfar4cpMo8CLY2m 1lA5Vge1KrnBfmiK8QNuexVn38HDEk2VioRwz3elxBuBacyRfc5sV6g= X-Google-Smtp-Source: AK7set8PPOXF3EsDqEpb+b5nkEUYnuYetnD8KL3lY4WY5ZprY/xpg5oTrUgZF6jT2PowFrbyJ8LGkHrBmqLyMVdvWi0= X-Received: by 2002:a17:903:2303:b0:1a0:5402:b17b with SMTP id d3-20020a170903230300b001a05402b17bmr750510plh.0.1679397138642; Tue, 21 Mar 2023 04:12:18 -0700 (PDT) MIME-Version: 1.0 References: <20230317160810.107988-1-vincent.guittot@linaro.org> <20230321100206.GE2234901@hirez.programming.kicks-ass.net> <7bba69e0-5261-9921-16b7-c8592b5d213b@arm.com> <20230321104949.GI2234901@hirez.programming.kicks-ass.net> In-Reply-To: <20230321104949.GI2234901@hirez.programming.kicks-ass.net> From: Vincent Guittot Date: Tue, 21 Mar 2023 12:12:07 +0100 Message-ID: Subject: Re: [PATCH v2] sched/fair: sanitize vruntime of entity being migrated To: Peter Zijlstra Cc: Dietmar Eggemann , mingo@redhat.com, juri.lelli@redhat.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, linux-kernel@vger.kernel.org, zhangqiao22@huawei.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 21 Mar 2023 at 11:50, Peter Zijlstra wrote: > > On Tue, Mar 21, 2023 at 11:29:13AM +0100, Dietmar Eggemann wrote: > > On 21/03/2023 11:02, Peter Zijlstra wrote: > > > On Fri, Mar 17, 2023 at 05:08:10PM +0100, Vincent Guittot wrote: > > >> Commit 829c1651e9c4 ("sched/fair: sanitize vruntime of entity being placed") > > >> fixes an overflowing bug, but ignore a case that se->exec_start is reset > > >> after a migration. > > >> > > >> For fixing this case, we delay the reset of se->exec_start after > > >> placing the entity which se->exec_start to detect long sleeping task. > > >> > > >> In order to take into account a possible divergence between the clock_task > > >> of 2 rqs, we increase the threshold to around 104 days. > > >> > > >> > > >> Fixes: 829c1651e9c4 ("sched/fair: sanitize vruntime of entity being placed") > > >> Signed-off-by: Zhang Qiao > > >> Signed-off-by: Vincent Guittot > > >> --- > > > > > > Blergh, this just isn't going to be nice. I'll go queue this for > > > sched/urgent and then we can forget about this for a little while. > > > > > > Thanks! > > > > Don't we miss setting `se->exec_start = 0` for fair task in > > move_queued_task()? ( ... and __migrate_swap_task()) > > > > https://lkml.kernel.org/r/df2cccda-1550-b06b-aa74-e0f054e9fb9d@arm.com > > Ah, I see what you mean now... When I read your and Vincent's replies > earlier today I though you mean to avoid the extra ENQUEUE_MIGRATED use, > but your actual goal was to capure more sites. > > Hmm, we could of course go add more ENQUEUE_MIGRATED, but you're right > in that TASK_ON_RQ_MIGRATING already captures that. > > An alternative is something like the below, that matches > deactivate_task(), but still uses ENQUEUE_MIGRATED to pass it down into > the class methods. > > Hmm? Yes, this seems to be the right way to set ENQUEUE_MIGRATED flags > > > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -2084,6 +2084,9 @@ static inline void dequeue_task(struct r > > void activate_task(struct rq *rq, struct task_struct *p, int flags) > { > + if (task_on_rq_migrating(p)) > + flags |= ENQUEUE_MIGRATED; > + > enqueue_task(rq, p, flags); > > p->on_rq = TASK_ON_RQ_QUEUED; > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -8726,7 +8726,7 @@ static void attach_task(struct rq *rq, s > lockdep_assert_rq_held(rq); > > WARN_ON_ONCE(task_rq(p) != rq); > - activate_task(rq, p, ENQUEUE_NOCLOCK | ENQUEUE_MIGRATED); > + activate_task(rq, p, ENQUEUE_NOCLOCK); > check_preempt_curr(rq, p, 0); > } >