From patchwork Tue Jun 8 18:03:00 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 12307865 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=-17.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 63F23C47082 for ; Tue, 8 Jun 2021 18:08:20 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 30A0661246 for ; Tue, 8 Jun 2021 18:08:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 30A0661246 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=+3HUy0efYvuVSW+cnlAFxlb4PyS/DTI+oPy8r6n4X3A=; b=11FdVTtrj9P1Yk Y4fVROdpS4v5VbXPNDmbVOkMIg0ud6/yYtmlZfei9Sa99UQYO8nrdt04KteL+EZFs12mtl1Tuf150 EIBDkgN9WCBONRl3U6hvFtoB9GGO3TcK0pxUTr70lYIqgeD3fE771lqMP77cg/b2ECI3x8AMNDI08 Z16AsqvkI1p8g/2+1G7YMOOfa/ZezbI5aFRFpPMgSqOuUQeCcq40GdKYunF3BdK4j+JaN8dvbppCm fp035SRM/utjP+WGjGc/GQGR70p3SEFHM4a2M4gYFnCqhyTYgV0ZBI7qxbvFXtfQAOrzQvN+dV2xp jnNMZpEztOk7YgyzmwXw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lqg7Z-009sCV-W6; Tue, 08 Jun 2021 18:06:38 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1lqg4x-009qr3-V9 for linux-arm-kernel@lists.infradead.org; Tue, 08 Jun 2021 18:03:57 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id EE2F561376; Tue, 8 Jun 2021 18:03:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1623175435; bh=5sDhSy8Iq6M6yt1brsixZg6Zkbj8pJRMdMdyvPGuV1Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=siyWlODmpTUHHzEEiXWvcnK8i83NNJ+MZH7E9+pgKi/bAY6VNDkMWHWdL7+uk09nL WZCfhs8iQjJmBvmd0rTZSeIMLyU1R7kE6Fwwcv93zH/JAWgUjJwWzc4aHoiIkoiS9+ 1XGZ40/sK/CERo7HMNX0Ly1eHcQU3tbmX5Ke1WDT+rtkmuUrDnMsLgnFcVt06cYmJt Ooq8IXVwRZdgmEq6KhZGmC0DXd2U4JXiHl2uG2LpAaR4vVjwb5oT8PUCe15S4elHKr KF95gJbAC/j3MKb/tTkAE3Nse8v7PA9UX3UI59vf5dm+T28Ce9lIgX5nzCoF9Lyqev 5kz0LB2+X3U/g== From: Will Deacon To: linux-arm-kernel@lists.infradead.org Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Will Deacon , Catalin Marinas , Marc Zyngier , Greg Kroah-Hartman , Peter Zijlstra , Morten Rasmussen , Qais Yousef , Suren Baghdasaryan , Quentin Perret , Tejun Heo , Johannes Weiner , Ingo Molnar , Juri Lelli , Vincent Guittot , "Rafael J. Wysocki" , Dietmar Eggemann , Daniel Bristot de Oliveira , Valentin Schneider , Mark Rutland , kernel-team@android.com, Valentin Schneider Subject: [PATCH v9 07/20] cpuset: Honour task_cpu_possible_mask() in guarantee_online_cpus() Date: Tue, 8 Jun 2021 19:03:00 +0100 Message-Id: <20210608180313.11502-8-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210608180313.11502-1-will@kernel.org> References: <20210608180313.11502-1-will@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210608_110356_061778_B65FF650 X-CRM114-Status: GOOD ( 20.32 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Asymmetric systems may not offer the same level of userspace ISA support across all CPUs, meaning that some applications cannot be executed by some CPUs. As a concrete example, upcoming arm64 big.LITTLE designs do not feature support for 32-bit applications on both clusters. Modify guarantee_online_cpus() to take task_cpu_possible_mask() into account when trying to find a suitable set of online CPUs for a given task. This will avoid passing an invalid mask to set_cpus_allowed_ptr() during ->attach() and will subsequently allow the cpuset hierarchy to be taken into account when forcefully overriding the affinity mask for a task which requires migration to a compatible CPU. Cc: Tejun Heo Cc: Johannes Weiner Reviewed-by: Valentin Schneider Signed-off-by: Will Deacon --- include/linux/cpuset.h | 2 +- kernel/cgroup/cpuset.c | 43 +++++++++++++++++++++++++----------------- 2 files changed, 27 insertions(+), 18 deletions(-) diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h index ed6ec677dd6b..414a8e694413 100644 --- a/include/linux/cpuset.h +++ b/include/linux/cpuset.h @@ -185,7 +185,7 @@ static inline void cpuset_read_unlock(void) { } static inline void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask) { - cpumask_copy(mask, cpu_possible_mask); + cpumask_copy(mask, task_cpu_possible_mask(p)); } static inline void cpuset_cpus_allowed_fallback(struct task_struct *p) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 6ec7303d5b1f..4e7c271e3800 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -372,18 +372,29 @@ static inline bool is_in_v2_mode(void) } /* - * Return in pmask the portion of a cpusets's cpus_allowed that - * are online. If none are online, walk up the cpuset hierarchy - * until we find one that does have some online cpus. + * Return in pmask the portion of a task's cpusets's cpus_allowed that + * are online and are capable of running the task. If none are found, + * walk up the cpuset hierarchy until we find one that does have some + * appropriate cpus. * * One way or another, we guarantee to return some non-empty subset * of cpu_online_mask. * * Call with callback_lock or cpuset_mutex held. */ -static void guarantee_online_cpus(struct cpuset *cs, struct cpumask *pmask) +static void guarantee_online_cpus(struct task_struct *tsk, + struct cpumask *pmask) { - while (!cpumask_intersects(cs->effective_cpus, cpu_online_mask)) { + const struct cpumask *possible_mask = task_cpu_possible_mask(tsk); + struct cpuset *cs; + + if (WARN_ON(!cpumask_and(pmask, possible_mask, cpu_online_mask))) + cpumask_copy(pmask, cpu_online_mask); + + rcu_read_lock(); + cs = task_cs(tsk); + + while (!cpumask_intersects(cs->effective_cpus, pmask)) { cs = parent_cs(cs); if (unlikely(!cs)) { /* @@ -393,11 +404,13 @@ static void guarantee_online_cpus(struct cpuset *cs, struct cpumask *pmask) * cpuset's effective_cpus is on its way to be * identical to cpu_online_mask. */ - cpumask_copy(pmask, cpu_online_mask); - return; + goto out_unlock; } } - cpumask_and(pmask, cs->effective_cpus, cpu_online_mask); + cpumask_and(pmask, pmask, cs->effective_cpus); + +out_unlock: + rcu_read_unlock(); } /* @@ -2199,15 +2212,13 @@ static void cpuset_attach(struct cgroup_taskset *tset) percpu_down_write(&cpuset_rwsem); - /* prepare for attach */ - if (cs == &top_cpuset) - cpumask_copy(cpus_attach, cpu_possible_mask); - else - guarantee_online_cpus(cs, cpus_attach); - guarantee_online_mems(cs, &cpuset_attach_nodemask_to); cgroup_taskset_for_each(task, css, tset) { + if (cs != &top_cpuset) + guarantee_online_cpus(task, cpus_attach); + else + cpumask_copy(cpus_attach, task_cpu_possible_mask(task)); /* * can_attach beforehand should guarantee that this doesn't * fail. TODO: have a better way to handle failure here @@ -3302,9 +3313,7 @@ void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask) unsigned long flags; spin_lock_irqsave(&callback_lock, flags); - rcu_read_lock(); - guarantee_online_cpus(task_cs(tsk), pmask); - rcu_read_unlock(); + guarantee_online_cpus(tsk, pmask); spin_unlock_irqrestore(&callback_lock, flags); }