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Message-ID: <1276790557.27822.516.camel@twins>
Date: Thu, 17 Jun 2010 18:02:37 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Brian Bloniarz <bmb@...enacr.com>
Cc: Mike Galbraith <efault@....de>, Jiri Kosina <jkosina@...e.cz>,
Chris Wedgwood <cw@...f.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Greg KH <gregkh@...e.de>, Alan Cox <alan@...rguk.ukuu.org.uk>,
OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>,
Jef Driesen <jefdriesen@...enet.be>,
linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...e.hu>,
Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH] nohz: Fix nohz ratelimit
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@...f.org>
Tested-by: Brian Bloniarz <bmb@...enacr.com>
Signed-off-by: Mike Galbraith <efault@....de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.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 {
--
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