From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756438Ab1CBAaT (ORCPT ); Tue, 1 Mar 2011 19:30:19 -0500 Received: from smtp-out.google.com ([74.125.121.67]:62721 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755799Ab1CBAaR (ORCPT ); Tue, 1 Mar 2011 19:30:17 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=google.com; s=beta; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; b=JvU7o0PDFyamsPqWFoTH4aSVZaIVzUgttjhTU5AGo+998aJZvOmuVaaPpzGvwqroK9 6cPX9cjAI/X5J+hbNKrA== From: Venkatesh Pallipadi To: Mike Galbraith , Rik van Riel , a.p.zijlstra@chello.nl Cc: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, mtosatti@redhat.com, tglx@linutronix.de, mingo@elte.hu, Venkatesh Pallipadi Subject: [PATCH] sched: resched proper CPU on yield_to Date: Tue, 1 Mar 2011 16:28:21 -0800 Message-Id: <1299025701-22168-1-git-send-email-venki@google.com> X-Mailer: git-send-email 1.7.3.1 In-Reply-To: <1298885189.9501.2.camel@marge.simson.net> References: <1298885189.9501.2.camel@marge.simson.net> X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org yield_to_task_fair() has code to resched the CPU of yielding task when the intention is to resched the CPU of the task that is being yielded to. Change here fixes the problem and also makes the resched conditional on rq != p_rq. I don't have a setup to test this code path. So, this is only compile tested right now. Signed-off-by: Venkatesh Pallipadi --- kernel/sched.c | 9 ++++++++- kernel/sched_fair.c | 4 ---- 2 files changed, 8 insertions(+), 5 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index 5fb5aa2..afdbd09 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5495,8 +5495,15 @@ again: goto out; yielded = curr->sched_class->yield_to_task(rq, p, preempt); - if (yielded) + if (yielded) { schedstat_inc(rq, yld_count); + /* + * Make p's CPU reschedule; pick_next_entity takes care of + * fairness. + */ + if (preempt && rq != p_rq) + resched_task(p_rq->curr); + } out: double_rq_unlock(rq, p_rq); diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 36e8f02..1b1c780 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -2001,10 +2001,6 @@ static bool yield_to_task_fair(struct rq *rq, struct task_struct *p, bool preemp /* Tell the scheduler that we'd really like pse to run next. */ set_next_buddy(se); - /* Make p's CPU reschedule; pick_next_entity takes care of fairness. */ - if (preempt) - resched_task(rq->curr); - yield_task_fair(rq); return true; -- 1.7.3.1