From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751745Ab0AKGiX (ORCPT ); Mon, 11 Jan 2010 01:38:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751424Ab0AKGiX (ORCPT ); Mon, 11 Jan 2010 01:38:23 -0500 Received: from mail-px0-f174.google.com ([209.85.216.174]:53399 "EHLO mail-px0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750809Ab0AKGiW (ORCPT ); Mon, 11 Jan 2010 01:38:22 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:cc:content-type; b=wnZ9vWOtXkUwEsm7eMtiHaL2JAuvf2sfpJ2eZCcP+6A9DlbrneS+0ySCGCvqspzbd0 Cz7w+lmDTfJ+QpXwypMl/9+HpOnUpA+/D0F/ixF4o/G/A3N8oEo8R3Kvu7ZJgG4405y0 HHReIjuI40j+5Z+F2wMmoLi0k+vNuGuYngXIk= MIME-Version: 1.0 Date: Mon, 11 Jan 2010 14:38:21 +0800 Message-ID: <2674af741001102238w7b0ddcadref00d345e2181d11@mail.gmail.com> Subject: [PATCH] sched: reassign prev and switch_count when reacquire_kernel_lock() fail From: Yong Zhang To: linux-kernel Cc: Ingo Molnar , Peter Zijlstra , Thomas Gleixner Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>From 4c04fbbd43f3fef7a3b9471a0000c399c2e045ed Mon Sep 17 00:00:00 2001 From: Yong Zhang Date: Mon, 11 Jan 2010 14:21:25 +0800 Subject: [PATCH] sched: reassign prev and switch_count when reacquire_kernel_lock() fail Assume A->B schedule is processing, if B have acquired BKL before and it need reschedule this time. Then on B's context, it will go to need_resched_nonpreemptible for reschedule. But at this time, prev and switch_count are related to A. It's wrong and will lead to incorrect scheduler statistics. Signed-off-by: Yong Zhang --- kernel/sched.c | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index c535cc4..4508fe7 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5530,8 +5530,11 @@ need_resched_nonpreemptible: post_schedule(rq); - if (unlikely(reacquire_kernel_lock(current) < 0)) + if (unlikely(reacquire_kernel_lock(current) < 0)) { + prev = rq->curr; + switch_count = &prev->nivcsw; goto need_resched_nonpreemptible; + } preempt_enable_no_resched(); if (need_resched()) -- 1.6.3.3