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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 B0D82C0650F for ; Thu, 8 Aug 2019 08:46:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8FD8F217F4 for ; Thu, 8 Aug 2019 08:46:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731522AbfHHIq6 (ORCPT ); Thu, 8 Aug 2019 04:46:58 -0400 Received: from mail-wr1-f68.google.com ([209.85.221.68]:33864 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730305AbfHHIq6 (ORCPT ); Thu, 8 Aug 2019 04:46:58 -0400 Received: by mail-wr1-f68.google.com with SMTP id 31so94096054wrm.1 for ; Thu, 08 Aug 2019 01:46:56 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=a+nwCR321Fw3F7ZHJYZbloauI2zuYmZr88zjTNkWmUU=; b=LgSJ20cAT6EMerCEuprKXi7iRhRGBEujjr9VHoOCBm21mf10WylLDNmNg2+Zs+SZ6B Y913Sjm1aeYAoJNjl+AS9GPrdylaq2MINi6ic+avieX6dUlCrD/SGXzdWvKt6BGTTaPC 8gKYLk3EhMwnCqs5cEQqsHQlu8dVoVBWzCQ+6pTFz0t7Mg3E7SOEFy4+eZ6MKEUEh4eP 4tYx/5zmWX4FKdQQwKo2vBUEs4zb3+EIjVa4+sBE3j9oISLHsHdSVSh+z7AXiA//FCiM SOZv1kfv9304u8cm8hBpOk6N6dttxN5rfrpHVLyAbYMd1mASyOXZZ894H3W1wmxJnWZn xLlg== X-Gm-Message-State: APjAAAWlhzxupFciWENTL6JBXwd/f34U1y25+KYERvNbSMalzxn12eKi Mi3cmPggWHyoNoGiHQTZo9l5JQ== X-Google-Smtp-Source: APXvYqyBt+WdhlWEt3znn6hUHzN/Gq+9HthenRLR5HcaMpMEZqciUAFNTCbSKINw/qEd75FnkCokVA== X-Received: by 2002:a5d:6508:: with SMTP id x8mr16394221wru.310.1565254015829; Thu, 08 Aug 2019 01:46:55 -0700 (PDT) Received: from localhost.localdomain ([151.29.237.107]) by smtp.gmail.com with ESMTPSA id j16sm49857668wrp.62.2019.08.08.01.46.54 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 08 Aug 2019 01:46:54 -0700 (PDT) Date: Thu, 8 Aug 2019 10:46:52 +0200 From: Juri Lelli To: Dietmar Eggemann Cc: Peter Zijlstra , mingo@kernel.org, linux-kernel@vger.kernel.org, luca.abeni@santannapisa.it, bristot@redhat.com, balsini@android.com, dvyukov@google.com, tglx@linutronix.de, vpillai@digitalocean.com, rostedt@goodmis.org Subject: Re: [RFC][PATCH 12/13] sched/deadline: Introduce deadline servers Message-ID: <20190808084652.GG29310@localhost.localdomain> References: <20190726145409.947503076@infradead.org> <20190726161358.056107990@infradead.org> <34710762-f813-3913-0e55-fde7c91c6c2d@arm.com> <20190808075635.GB17205@worktop.programming.kicks-ass.net> <20cc05d3-0d0f-a558-2bbe-3b72527dd9bc@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20cc05d3-0d0f-a558-2bbe-3b72527dd9bc@arm.com> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/08/19 10:11, Dietmar Eggemann wrote: > On 8/8/19 9:56 AM, Peter Zijlstra wrote: > > On Wed, Aug 07, 2019 at 06:31:59PM +0200, Dietmar Eggemann wrote: > >> On 7/26/19 4:54 PM, Peter Zijlstra wrote: > >>> > >>> > >>> Signed-off-by: Peter Zijlstra (Intel) > >> > >> [...] > >> > >>> @@ -889,6 +891,8 @@ static void update_curr(struct cfs_rq *c > >>> trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime); > >>> cgroup_account_cputime(curtask, delta_exec); > >>> account_group_exec_runtime(curtask, delta_exec); > >>> + if (curtask->server) > >>> + dl_server_update(curtask->server, delta_exec); > >>> } > >> > >> I get a lockdep_assert_held(&rq->lock) related warning in start_dl_timer() > >> when running the full stack. > > > > That would seem to imply a stale curtask->server value; the hunk below: > > > > --- a/kernel/sched/core.c > > +++ b/kernel/sched/core.c > > @@ -3756,8 +3756,11 @@ pick_next_task(struct rq *rq, struct tas > > > > for_each_class(class) { > > p = class->pick_next_task(rq, NULL, NULL); > > - if (p) > > + if (p) { > > + if (p->sched_class == class && p->server) > > + p->server = NULL; > > return p; > > + } > > } > > > > > > Was supposed to clear p->server, but clearly something is going 'funny'. > > What about the fast path in pick_next_task()? > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index bffe849b5a42..f1ea6ae16052 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -3742,6 +3742,9 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) > if (unlikely(!p)) > p = idle_sched_class.pick_next_task(rq, prev, rf); > > + if (p->sched_class == &fair_sched_class && p->server) > + p->server = NULL; > + Hummm, but then who sets it back to the correct server. AFAIU update_curr() needs a ->server to do the correct DL accounting?