From patchwork Thu Sep 4 07:17:53 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuansheng Liu X-Patchwork-Id: 4843071 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id B9EF1C0338 for ; Thu, 4 Sep 2014 07:33:47 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id EF2542026D for ; Thu, 4 Sep 2014 07:33:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BDA7F2018A for ; Thu, 4 Sep 2014 07:33:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756603AbaIDHdm (ORCPT ); Thu, 4 Sep 2014 03:33:42 -0400 Received: from mga14.intel.com ([192.55.52.115]:53400 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756164AbaIDHdm (ORCPT ); Thu, 4 Sep 2014 03:33:42 -0400 Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga103.fm.intel.com with ESMTP; 04 Sep 2014 00:25:21 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,862,1389772800"; d="scan'208";a="381246196" Received: from shsibuild003.sh.intel.com ([10.239.146.212]) by FMSMGA003.fm.intel.com with ESMTP; 04 Sep 2014 00:28:57 -0700 From: Chuansheng Liu To: peterz@infradead.org, luto@amacapital.net, daniel.lezcano@linaro.org, rjw@rjwysocki.net, mingo@redhat.com Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, changcheng.liu@intel.com, xiaoming.wang@intel.com, souvik.k.chakravarty@intel.com, chuansheng.liu@intel.com Subject: [PATCH 1/3] sched: Add new API wake_up_if_idle() to wake up the idle cpu Date: Thu, 4 Sep 2014 15:17:53 +0800 Message-Id: <1409815075-4180-1-git-send-email-chuansheng.liu@intel.com> X-Mailer: git-send-email 1.7.9.5 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-8.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Implementing one new API wake_up_if_idle(), which is used to wake up the idle CPU. Suggested-by: Andy Lutomirski Signed-off-by: Chuansheng Liu Acked-by: Daniel Lezcano --- include/linux/sched.h | 1 + kernel/sched/core.c | 19 +++++++++++++++++++ 2 files changed, 20 insertions(+) diff --git a/include/linux/sched.h b/include/linux/sched.h index 857ba40..3f89ac1 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1024,6 +1024,7 @@ struct sched_domain_topology_level { extern struct sched_domain_topology_level *sched_domain_topology; extern void set_sched_topology(struct sched_domain_topology_level *tl); +extern void wake_up_if_idle(int cpu); #ifdef CONFIG_SCHED_DEBUG # define SD_INIT_NAME(type) .name = #type diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 1211575..b818548 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1620,6 +1620,25 @@ static void ttwu_queue_remote(struct task_struct *p, int cpu) } } +void wake_up_if_idle(int cpu) +{ + struct rq *rq = cpu_rq(cpu); + unsigned long flags; + + if (!is_idle_task(rq->curr)) + return; + + if (set_nr_if_polling(rq->idle)) { + trace_sched_wake_idle_without_ipi(cpu); + } else { + raw_spin_lock_irqsave(&rq->lock, flags); + if (is_idle_task(rq->curr)) + smp_send_reschedule(cpu); + /* Else cpu is not in idle, do nothing here */ + raw_spin_unlock_irqrestore(&rq->lock, flags); + } +} + bool cpus_share_cache(int this_cpu, int that_cpu) { return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu);