From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 644AB37141 for ; Fri, 15 Dec 2023 15:23:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ZP/OuKyj" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=PsuBt3Vxcjvct1x6GswH9qrfO3gP89Oemg6DFIds43o=; b=ZP/OuKyjnrqJ1cfREu6NHWOPBP byVZ318SPUj0MAHcz96U15upnAMKHUaELm3jrg1nO6Jw7HyVWIFS7hSLjr93uFnxfxtCKuso81Bh2 9jDseVlPNpAWFmVlOiXsyl9fVIhbTOc07FXswNGv3sLLSkop3AgpyauaunGpBk7g2bXXHTfYEsidc tr3a3VO7GDxMddeihm8Hs3BpClkbV9H17WzsfFHxWJ/WwkVPn1RxPOUPLa0CiDIz2G6bGyz0EnD5s tReWuuLLXsuSlcVz/OjJUTBlbs1LrzgAK9HsgqIYvl6qVrwt1Ou/A8Dp5sRB+mFaIPYgQSdZGPKUT GMl+ifsQ==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1rEA1v-009xag-37; Fri, 15 Dec 2023 15:23:12 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 9EA993005B2; Fri, 15 Dec 2023 16:23:11 +0100 (CET) Date: Fri, 15 Dec 2023 16:23:11 +0100 From: Peter Zijlstra To: Keisuke Nishimura Cc: Ingo Molnar , Abel Wu , Josh Don , Mel Gorman , Xunlei Pang , Dietmar Eggemann , Valentin Schneider , Julia Lawall , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] sched/fair: take into account scheduling domain in select_idle_core() Message-ID: <20231215152311.GL36716@noisy.programming.kicks-ass.net> References: <20231214175551.629945-1-keisuke.nishimura@inria.fr> <20231214175551.629945-2-keisuke.nishimura@inria.fr> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231214175551.629945-2-keisuke.nishimura@inria.fr> On Thu, Dec 14, 2023 at 06:55:51PM +0100, Keisuke Nishimura wrote: > When picking out a CPU on a task wakeup, select_idle_smt() has to take > into account the scheduling domain where the function looks for the CPU. > This is because cpusets and isolcpus can remove CPUs from the domain > to isolate them from other SMT siblings. Same question as before, when cpusets, the cpu should also be unset from p->cpus_ptr. So I'm thinking you're one of those isolcpus users I wish that would go away ;-) > This change replaces the set of CPUs allowed to run the task from > p->cpus_ptr by the intersection of p->cpus_ptr and sched_domain_span(sd) > which is stored in the cpus argument provided by select_idle_cpu. > > Fixes: 9fe1f127b913 ("sched/fair: Merge select_idle_core/cpu()") > Signed-off-by: Keisuke Nishimura > Signed-off-by: Julia Lawall > --- > kernel/sched/fair.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 71306b48cf68..3b7d32632674 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -7262,7 +7262,7 @@ static int select_idle_core(struct task_struct *p, int core, struct cpumask *cpu > if (!available_idle_cpu(cpu)) { > idle = false; > if (*idle_cpu == -1) { > - if (sched_idle_cpu(cpu) && cpumask_test_cpu(cpu, p->cpus_ptr)) { > + if (sched_idle_cpu(cpu) && cpumask_test_cpu(cpu, cpus)) { > *idle_cpu = cpu; > break; > } > @@ -7270,7 +7270,7 @@ static int select_idle_core(struct task_struct *p, int core, struct cpumask *cpu > } > break; > } > - if (*idle_cpu == -1 && cpumask_test_cpu(cpu, p->cpus_ptr)) > + if (*idle_cpu == -1 && cpumask_test_cpu(cpu, cpus)) > *idle_cpu = cpu; > } Aside of that, the actual patch seems to be fine, just the rationale needs work.