Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755324AbbBUBL2 (ORCPT ); Fri, 20 Feb 2015 20:11:28 -0500 Received: from relais.videotron.ca ([24.201.245.36]:22617 "EHLO relais.videotron.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754796AbbBUBL1 (ORCPT ); Fri, 20 Feb 2015 20:11:27 -0500 X-Greylist: delayed 900 seconds by postgrey-1.27 at vger.kernel.org; Fri, 20 Feb 2015 20:11:27 EST MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: TEXT/PLAIN; CHARSET=US-ASCII Date: Fri, 20 Feb 2015 19:56:17 -0500 (EST) From: Nicolas Pitre To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, rjw@rjwysocki.net, tglx@linutronix.de Subject: Re: [PATCH 27/35] sched/idle: Use explicit broadcast oneshot control function In-reply-to: <20150216122413.591402191@infradead.org> Message-id: References: <20150216121435.203983131@infradead.org> <20150216122413.591402191@infradead.org> User-Agent: Alpine 2.11 (LFD 23 2013-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1980 Lines: 57 On Mon, 16 Feb 2015, Peter Zijlstra wrote: > From: Thomas Gleixner > > Replace the clockevents_notify() call with an explicit function call. > > Signed-off-by: Thomas Gleixner This patch makes my test system hang solid after letting it sit idle for 5 to 15 minutes. Reverting it and this issue goes away. The explicit function call is not an equivalent replacement. In clockevents_notify() the clockevents_lock is held across the call to tick_broadcast_enter() or tick_broadcast_exit(). This patch drops the locking. > --- > kernel/sched/idle.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > Index: linux/kernel/sched/idle.c > =================================================================== > --- linux.orig/kernel/sched/idle.c > +++ linux/kernel/sched/idle.c > @@ -143,8 +143,7 @@ use_default: > * is used from another cpu as a broadcast timer, this call may > * fail if it is not available > */ > - if (broadcast && > - clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu)) > + if (broadcast && tick_broadcast_enter()) > goto use_default; > > /* Take note of the planned idle state. */ > @@ -161,7 +160,7 @@ use_default: > idle_set_state(this_rq(), NULL); > > if (broadcast) > - clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &dev->cpu); > + tick_broadcast_exit(); > > /* > * Give the governor an opportunity to reflect on the outcome > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/