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From: Peter Zijlstra <peterz@infradead.org>
To: Brian Bloniarz <bmb@athenacr.com>
Cc: Mike Galbraith <efault@gmx.de>, Jiri Kosina <jkosina@suse.cz>,
	Chris Wedgwood <cw@f00f.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Greg KH <gregkh@suse.de>, Alan Cox <alan@lxorguk.ukuu.org.uk>,
	OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>,
	Jef Driesen <jefdriesen@telenet.be>,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH] nohz: Fix nohz ratelimit
Date: Thu, 17 Jun 2010 18:02:37 +0200	[thread overview]
Message-ID: <1276790557.27822.516.camel@twins> (raw)
In-Reply-To: <4C1A378F.7070604@athenacr.com>

Chris Wedgwood reports that 39c0cbe (sched: Rate-limit nohz) causes a
serial console regression, unresponsiveness, and indeed it does. The
below fixes it by not skipping out when the tick has been stopped.

Reported-by: Chris Wedgwood <cw@f00f.org>
Tested-by: Brian Bloniarz <bmb@athenacr.com>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
 kernel/time/tick-sched.c |    5 +----
 1 files changed, 1 insertions(+), 4 deletions(-)

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 5f171f0..e0707ea 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -315,9 +315,6 @@ void tick_nohz_stop_sched_tick(int inidle)
 		goto end;
 	}
 
-	if (nohz_ratelimit(cpu))
-		goto end;
-
 	ts->idle_calls++;
 	/* Read jiffies and the time when jiffies were updated last */
 	do {
@@ -328,7 +325,7 @@ void tick_nohz_stop_sched_tick(int inidle)
 	} while (read_seqretry(&xtime_lock, seq));
 
 	if (rcu_needs_cpu(cpu) || printk_needs_cpu(cpu) ||
-	    arch_needs_cpu(cpu)) {
+	    arch_needs_cpu(cpu) || nohz_ratelimit(cpu)) {
 		next_jiffies = last_jiffies + 1;
 		delta_jiffies = 1;
 	} else {


  reply	other threads:[~2010-06-17 16:03 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-06-10 17:25 Slow pty's (was Re: libdivecomputer interfaces?) Linus Torvalds
2010-06-10 18:07 ` OGAWA Hirofumi
2010-06-10 18:10 ` Chris Wedgwood
2010-06-10 22:25   ` Brian Bloniarz
2010-06-10 22:30     ` Linus Torvalds
2010-06-16 15:03     ` Jiri Kosina
2010-06-16 15:16       ` Mike Galbraith
2010-06-17  6:39         ` Mike Galbraith
2010-06-17  7:00           ` Mike Galbraith
2010-06-17 10:50             ` Mike Galbraith
2010-06-17 13:24               ` Peter Zijlstra
2010-06-17 14:11                 ` Thomas Gleixner
2010-06-17 14:14                 ` Mike Galbraith
2010-06-17 14:56                 ` Brian Bloniarz
2010-06-17 16:02                   ` Peter Zijlstra [this message]
2010-06-17 17:39                     ` [tip:timers/urgent] nohz: Fix nohz ratelimit tip-bot for Peter Zijlstra
2010-11-12 18:45 ` Slow pty's (was Re: libdivecomputer interfaces?) Jef Driesen

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