From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755003AbZCFOkQ (ORCPT ); Fri, 6 Mar 2009 09:40:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751221AbZCFOkB (ORCPT ); Fri, 6 Mar 2009 09:40:01 -0500 Received: from bombadil.infradead.org ([18.85.46.34]:43892 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750761AbZCFOkB (ORCPT ); Fri, 6 Mar 2009 09:40:01 -0500 Subject: [RFC][PATCH]: wait: don't resched in prepare_to_wait() From: Peter Zijlstra To: Ingo Molnar , Thomas Gleixner , Oleg Nesterov , Nick Piggin Cc: lkml Content-Type: text/plain Date: Fri, 06 Mar 2009 15:39:37 +0100 Message-Id: <1236350377.6326.389.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.25.92 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Does the below make sense? After prepare to wait, we either call schedule() or find !cond in which case we'll call finish_wait() which contains another preemption check. Not-signed-off-by: Peter Zijlstra --- kernel/wait.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/kernel/wait.c b/kernel/wait.c index 42a2dbc..7b866ab 100644 --- a/kernel/wait.c +++ b/kernel/wait.c @@ -73,7 +73,9 @@ prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state) if (list_empty(&wait->task_list)) __add_wait_queue(q, wait); set_current_state(state); + preempt_disable(); spin_unlock_irqrestore(&q->lock, flags); + preempt_enable_no_resched(); } EXPORT_SYMBOL(prepare_to_wait); @@ -87,7 +89,9 @@ prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state) if (list_empty(&wait->task_list)) __add_wait_queue_tail(q, wait); set_current_state(state); + preempt_disable(); spin_unlock_irqrestore(&q->lock, flags); + preempt_enable_no_resched(); } EXPORT_SYMBOL(prepare_to_wait_exclusive);