From patchwork Thu Sep 27 09:04:05 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Viresh Kumar X-Patchwork-Id: 11751 Return-Path: X-Original-To: patchwork@peony.canonical.com Delivered-To: patchwork@peony.canonical.com Received: from fiordland.canonical.com (fiordland.canonical.com [91.189.94.145]) by peony.canonical.com (Postfix) with ESMTP id 0754824146 for ; Thu, 27 Sep 2012 09:04:52 +0000 (UTC) Received: from mail-ie0-f180.google.com (mail-ie0-f180.google.com [209.85.223.180]) by fiordland.canonical.com (Postfix) with ESMTP id A0F56A1842A for ; Thu, 27 Sep 2012 09:04:51 +0000 (UTC) Received: by mail-ie0-f180.google.com with SMTP id e10so3623563iej.11 for ; Thu, 27 Sep 2012 02:04:51 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=x-forwarded-to:x-forwarded-for:delivered-to:received-spf:from:to:cc :subject:date:message-id:x-mailer:in-reply-to:references:in-reply-to :references:x-originalarrivaltime:x-mc-unique:content-type :content-transfer-encoding:x-gm-message-state; bh=sFAk2V8kwOkS7ClwZ3QDfXE3lIPsXVYSUPnfMlnVIr4=; b=fu087j9Jb4JgzOvVNOToeklFOSXYA1Q5mpaTguvJDSJXCHK1bw6z2hV9e+0qhqI35a rjuyMkSleS23/0TIjJ9p95FMkVxNNMGhK5T6lxMLR5KiBCOQTphD/cEgIgvJayDurB89 pglNp7x5hEslKMP1vHE7fcpFyRX2ZfLpuMsCPJyFJny+PwD/WGeLSMPb0AVLXPQBloQe qU8LfPXCBbIB+8gxVmnhierrEnXh5gC7+p4kALxsn7liGE1qbKUzGExkvTLgwaUNfTc2 G+DkEnlwxsJbNWuzTz5ZcKuVG4dDtNwD+jvnvJ13Ugxu+JRAAnJPkNeR/8muA5pXB+Pj ablw== Received: by 10.50.150.198 with SMTP id uk6mr2938321igb.43.1348736691427; Thu, 27 Sep 2012 02:04:51 -0700 (PDT) X-Forwarded-To: linaro-patchwork@canonical.com X-Forwarded-For: patch@linaro.org linaro-patchwork@canonical.com Delivered-To: patches@linaro.org Received: by 10.50.184.232 with SMTP id ex8csp404056igc; Thu, 27 Sep 2012 02:04:50 -0700 (PDT) Received: by 10.216.144.69 with SMTP id m47mr1104254wej.183.1348736689690; Thu, 27 Sep 2012 02:04:49 -0700 (PDT) Received: from service87.mimecast.com (service87.mimecast.com. [91.220.42.44]) by mx.google.com with ESMTP id k29si3020498weo.140.2012.09.27.02.04.49; Thu, 27 Sep 2012 02:04:49 -0700 (PDT) Received-SPF: pass (google.com: domain of viresh.kumar2@arm.com designates 91.220.42.44 as permitted sender) client-ip=91.220.42.44; Authentication-Results: mx.google.com; spf=pass (google.com: domain of viresh.kumar2@arm.com designates 91.220.42.44 as permitted sender) smtp.mail=viresh.kumar2@arm.com Received: from cam-owa1.Emea.Arm.com (fw-tnat.cambridge.arm.com [217.140.96.21]) by service87.mimecast.com; Thu, 27 Sep 2012 10:04:39 +0100 Received: from localhost ([10.1.255.212]) by cam-owa1.Emea.Arm.com with Microsoft SMTPSVC(6.0.3790.0); Thu, 27 Sep 2012 10:04:18 +0100 From: Viresh Kumar To: linux-kernel@vger.kernel.org Cc: pjt@google.com, paul.mckenney@linaro.org, tglx@linutronix.de, tj@kernel.org, suresh.b.siddha@intel.com, venki@google.com, mingo@redhat.com, peterz@infradead.org, robin.randhawa@arm.com, Steve.Bannister@arm.com, Arvind.Chauhan@arm.com, amit.kucheria@linaro.org, vincent.guittot@linaro.org, linaro-dev@lists.linaro.org, patches@linaro.org, Viresh Kumar Subject: [PATCH V2 3/3] workqueue: Schedule work on non-idle cpu instead of current one Date: Thu, 27 Sep 2012 14:34:05 +0530 Message-Id: <7d5c2cac08134446583624cc124d46d9726bdb2d.1348736069.git.viresh.kumar@linaro.org> X-Mailer: git-send-email 1.7.12.rc2.18.g61b472e In-Reply-To: References: In-Reply-To: References: X-OriginalArrivalTime: 27 Sep 2012 09:04:18.0833 (UTC) FILETIME=[13B27010:01CD9C8F] X-MC-Unique: 112092710043928601 X-Gm-Message-State: ALoCoQlx4ePxfdBOIIQlor0qELeF5XDpDosBo2swoyR/FoCTLG4lmk8M+iw8pHodVlWVcUWFFLHC Workqueues queues work on current cpu, if the caller haven't passed a preferred cpu. This may wake up an idle CPU, which is actually not required. This work can be processed by any CPU and so we must select a non-idle CPU here. This patch adds in support in workqueue framework to get preferred CPU details from the scheduler, instead of using current CPU. Most of the time when a work is queued, the current cpu isn't idle and so we will choose it only. There are cases when a cpu is idle when it queues some work. For example, consider following scenario: - A cpu has programmed a timer and is IDLE now. - CPU gets into interrupt handler due to timer and queues a work. As the CPU is currently IDLE, we can queue this work to some other CPU. Signed-off-by: Viresh Kumar --- kernel/workqueue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 143fd8c..5fa4ba4 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1238,7 +1238,7 @@ static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, struct global_cwq *last_gcwq; if (cpu == WORK_CPU_UNBOUND) - cpu = raw_smp_processor_id(); + cpu = sched_select_cpu(0); /* * It's multi cpu. If @work was previously on a different