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=-15.9 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_IN_DEF_DKIM_WL 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 974ECC2D0E4 for ; Thu, 19 Nov 2020 09:18:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E5192224D for ; Thu, 19 Nov 2020 09:18:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="SiGcoM1Z" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726407AbgKSJS0 (ORCPT ); Thu, 19 Nov 2020 04:18:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44074 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726182AbgKSJS0 (ORCPT ); Thu, 19 Nov 2020 04:18:26 -0500 Received: from mail-wr1-x42f.google.com (mail-wr1-x42f.google.com [IPv6:2a00:1450:4864:20::42f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EB0B9C0613CF for ; Thu, 19 Nov 2020 01:18:25 -0800 (PST) Received: by mail-wr1-x42f.google.com with SMTP id m6so5607097wrg.7 for ; Thu, 19 Nov 2020 01:18:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=IdO73wPUtO91VkHNoPsos+au3LYwQYAXfz1yiydAPjw=; b=SiGcoM1Z7UHzA4JfGM1ADc64LSJObWD3rK3mEabHpVq+qsFkyqIgfWSUClkF7e3P0a mKFhGum+0JZb1YcCdG5O/7uy/cMY9n3BY4b9FtY9fAi/OUtd/2O9UfKfYNjDU3lfk1Vv CoNWUnbPdfiklG0Ba6yHoigcezvm5licw9EJO29W6jBElMQmLtDXKCS3blMZdf01ZrfY vqsf9SnELgTdAgJN6Ce32HjjQvSFCGOVbK81+ZgDWGGPvCxUiSuQNEcPZpyXeyUb/HxR xO/UDT0W53dW8agM2LrCrqtWsc6aG5p8xK6BGQr/Xj0LwEgvuha5uXQuwSA3mqO6k4J9 ZKqw== 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; bh=IdO73wPUtO91VkHNoPsos+au3LYwQYAXfz1yiydAPjw=; b=OoSH7NzXxOqHLryxeIXdni0ZvT9NUr1lBaw/5CF2HP9Y3UzAc+QIEO1lHSdfn/jmZI 0TXwxvlsFLQ0xDraT2Gn78WnSV55bkwXnXa7qWcBqoHTf9rkyM+r5jJ0URMIN/LKYZrd 7VdXNNztNPmU5xxxc8ItExj/jVohhR6WHpXZNkDsPnYsUJPOMySKNtc9i/yeQDPeMwnG 7EeNFdhcxgQFMg2MexptHOEcRrd9X01TefHdjwcjLoI1NoDeuzwHfhcgaJOgbZDzaACt ZZUjhwClLfBRyJR/xj7XnZd5u542kP+nTCf6hJTszQ1W1OcFFoZlOi87wcLKteB4PBLP rhdw== X-Gm-Message-State: AOAM532P1kO0OzgHzuJUL0qrc6m4A6D3jjrEb1X5C76FZ0fBkDXQQb8H f5nWYRYaViI63g4h+baeLbQxjhmsok4ENA== X-Google-Smtp-Source: ABdhPJy9KoqPyLqdoPK1EXUPy9/Ro5D0jFmed6OXcjS8SVZViEddXqKt96daQmNhCN5uascZH3UUww== X-Received: by 2002:adf:d18a:: with SMTP id v10mr8830619wrc.325.1605777504496; Thu, 19 Nov 2020 01:18:24 -0800 (PST) Received: from google.com ([2a00:79e0:d:210:f693:9fff:fef4:a7ef]) by smtp.gmail.com with ESMTPSA id a128sm8935236wmf.5.2020.11.19.01.18.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Nov 2020 01:18:23 -0800 (PST) Date: Thu, 19 Nov 2020 09:18:20 +0000 From: Quentin Perret To: Will Deacon Cc: linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Catalin Marinas , Marc Zyngier , Greg Kroah-Hartman , Peter Zijlstra , Morten Rasmussen , Qais Yousef , Suren Baghdasaryan , Tejun Heo , Li Zefan , Johannes Weiner , Ingo Molnar , Juri Lelli , Vincent Guittot , kernel-team@android.com Subject: Re: [PATCH v3 07/14] sched: Introduce restrict_cpus_allowed_ptr() to limit task CPU affinity Message-ID: <20201119091820.GA2416649@google.com> References: <20201113093720.21106-1-will@kernel.org> <20201113093720.21106-8-will@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201113093720.21106-8-will@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org Hey Will, On Friday 13 Nov 2020 at 09:37:12 (+0000), Will Deacon wrote: > -static int __set_cpus_allowed_ptr(struct task_struct *p, > - const struct cpumask *new_mask, bool check) > +static int __set_cpus_allowed_ptr_locked(struct task_struct *p, > + const struct cpumask *new_mask, > + bool check, > + struct rq *rq, > + struct rq_flags *rf) > { > const struct cpumask *cpu_valid_mask = cpu_active_mask; > unsigned int dest_cpu; > - struct rq_flags rf; > - struct rq *rq; > int ret = 0; Should we have a lockdep assertion here? > - rq = task_rq_lock(p, &rf); > update_rq_clock(rq); > > if (p->flags & PF_KTHREAD) { > @@ -1929,7 +1923,7 @@ static int __set_cpus_allowed_ptr(struct task_struct *p, > if (task_running(rq, p) || p->state == TASK_WAKING) { > struct migration_arg arg = { p, dest_cpu }; > /* Need help from migration thread: drop lock and wait. */ > - task_rq_unlock(rq, p, &rf); > + task_rq_unlock(rq, p, rf); > stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); > return 0; > } else if (task_on_rq_queued(p)) { > @@ -1937,20 +1931,69 @@ static int __set_cpus_allowed_ptr(struct task_struct *p, > * OK, since we're going to drop the lock immediately > * afterwards anyway. > */ > - rq = move_queued_task(rq, &rf, p, dest_cpu); > + rq = move_queued_task(rq, rf, p, dest_cpu); > } > out: > - task_rq_unlock(rq, p, &rf); > + task_rq_unlock(rq, p, rf); And that's a little odd to have here no? Can we move it back on the caller's side? > return ret; > } Thanks, Quentin