From patchwork Tue Jun 8 18:03:01 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 12307867 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 5620CC4743D for ; Tue, 8 Jun 2021 18:09:11 +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 2AB8C61278 for ; Tue, 8 Jun 2021 18:09:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2AB8C61278 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=h+KW6Y9eIJzi2iW/aoDeaQH3gvCNp7D5ASp5nuvcrcQ=; b=XoaJQTjKrBNDIK mx1hCKC5pzxsSjrjSGUP1KFmqotbWY1Db1/Oy/PSCpGnr7qHfMYR7ccIVBHrecT522SwiJuKvi7sB 0F+kiEu2lQ+N358FQIhR5UnSvEsNtOkZzGiNvrBXAbHXFO+XABKdkfgMc7xObHeFIGnOFM11bBwIp CGYlyuiQygkjeVzNWtRXIlbsxK6vo7W+AjqrQmWszKJeJG8Pbds04qXGk8DCxitqFSr0SNe83XSSL qwtjDvjkWtozKF/ZtNHPYsXIBC6hVQ8HsRQ6YS7qzeDXtLDVJlAnUZKQ113HVQ3e5YGf2EStDPnk/ wOuG6MzJBmpjNwgfPb/A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lqg8K-009sgV-Vk; Tue, 08 Jun 2021 18:07:26 +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 1lqg52-009qsv-0B for linux-arm-kernel@lists.infradead.org; Tue, 08 Jun 2021 18:04:01 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2514E613AC; Tue, 8 Jun 2021 18:03:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1623175439; bh=oZQTnBoiNHmMNC/XIJ3JXCME+8MVXh/ggSl0RMjN068=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=A9Q8qMVTYoKsuiTNC8h7bdaRp9uK1gc6DHSdj6GU7DVpmWn7oyEA/f0rw+GcxQpiM 6cE99CRceMlCPcAM1UDTHEQ/am26QTPAxgUyN0uTe0hQguz0zx3skF2MkY5L1Vc3Nl X7Kx76qfnDevoq/FtL7fk/kBsgyNmFcSirqWBclSgjAtUQab+cDWCd0o2/tQ5opJfU 9tCH5VZPdNmYvoquAFZrdVPVsZ10616r13XbfNcDBwsSqnb9lXVQ57b30lCkfv/FMW bLBP1P5YrOO+2D68QmUYPKfQSqk49+ZN6QVeggPLQX+VAHb2njLg6Gv585uL95Gznu SE869rxRVEJjw== 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 Subject: [PATCH v9 08/20] cpuset: Cleanup cpuset_cpus_allowed_fallback() use in select_fallback_rq() Date: Tue, 8 Jun 2021 19:03:01 +0100 Message-Id: <20210608180313.11502-9-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_110400_116147_B2F6D929 X-CRM114-Status: GOOD ( 17.29 ) 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 select_fallback_rq() only needs to recheck for an allowed CPU if the affinity mask of the task has changed since the last check. Return a 'bool' from cpuset_cpus_allowed_fallback() to indicate whether the affinity mask was updated, and use this to elide the allowed check when the mask has been left alone. No functional change. Suggested-by: Valentin Schneider Signed-off-by: Will Deacon Reviewed-by: Valentin Schneider --- include/linux/cpuset.h | 5 +++-- kernel/cgroup/cpuset.c | 10 ++++++++-- kernel/sched/core.c | 3 +-- 3 files changed, 12 insertions(+), 6 deletions(-) diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h index 414a8e694413..d2b9c41c8edf 100644 --- a/include/linux/cpuset.h +++ b/include/linux/cpuset.h @@ -59,7 +59,7 @@ extern void cpuset_wait_for_hotplug(void); extern void cpuset_read_lock(void); extern void cpuset_read_unlock(void); extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask); -extern void cpuset_cpus_allowed_fallback(struct task_struct *p); +extern bool cpuset_cpus_allowed_fallback(struct task_struct *p); extern nodemask_t cpuset_mems_allowed(struct task_struct *p); #define cpuset_current_mems_allowed (current->mems_allowed) void cpuset_init_current_mems_allowed(void); @@ -188,8 +188,9 @@ static inline void cpuset_cpus_allowed(struct task_struct *p, cpumask_copy(mask, task_cpu_possible_mask(p)); } -static inline void cpuset_cpus_allowed_fallback(struct task_struct *p) +static inline bool cpuset_cpus_allowed_fallback(struct task_struct *p) { + return false; } static inline nodemask_t cpuset_mems_allowed(struct task_struct *p) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 4e7c271e3800..a6bab2259f98 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -3327,17 +3327,22 @@ void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask) * which will not contain a sane cpumask during cases such as cpu hotplugging. * This is the absolute last resort for the scheduler and it is only used if * _every_ other avenue has been traveled. + * + * Returns true if the affinity of @tsk was changed, false otherwise. **/ -void cpuset_cpus_allowed_fallback(struct task_struct *tsk) +bool cpuset_cpus_allowed_fallback(struct task_struct *tsk) { const struct cpumask *cs_mask; + bool changed = false; const struct cpumask *possible_mask = task_cpu_possible_mask(tsk); rcu_read_lock(); cs_mask = task_cs(tsk)->cpus_allowed; - if (is_in_v2_mode() && cpumask_subset(cs_mask, possible_mask)) + if (is_in_v2_mode() && cpumask_subset(cs_mask, possible_mask)) { do_set_cpus_allowed(tsk, cs_mask); + changed = true; + } rcu_read_unlock(); /* @@ -3357,6 +3362,7 @@ void cpuset_cpus_allowed_fallback(struct task_struct *tsk) * select_fallback_rq() will fix things ups and set cpu_possible_mask * if required. */ + return changed; } void __init cpuset_init_current_mems_allowed(void) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 0c1b6f1a6c91..9e75cb3fbc9c 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2779,8 +2779,7 @@ static int select_fallback_rq(int cpu, struct task_struct *p) /* No more Mr. Nice Guy. */ switch (state) { case cpuset: - if (IS_ENABLED(CONFIG_CPUSETS)) { - cpuset_cpus_allowed_fallback(p); + if (cpuset_cpus_allowed_fallback(p)) { state = possible; break; }