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authorPeter Zijlstra <peterz@infradead.org>2010-06-17 18:02:37 +0200
committerThomas Gleixner <tglx@linutronix.de>2010-06-17 19:37:29 +0200
commit3310d4d38fbc514e7b18bd3b1eea8effdd63b5aa (patch)
tree14e2a5b6126c9b1341a3d4bf5299545ce4b1999a /kernel/time
parentLinux 2.6.35-rc3 (diff)
downloadlinux-3310d4d38fbc514e7b18bd3b1eea8effdd63b5aa.tar.xz
linux-3310d4d38fbc514e7b18bd3b1eea8effdd63b5aa.zip
nohz: Fix nohz ratelimit
Chris Wedgwood reports that 39c0cbe (sched: Rate-limit nohz) causes a serial console regression, unresponsiveness, and indeed it does. The reason is that the nohz code is skipped even when the tick was already stopped before the nohz_ratelimit(cpu) condition changed. Move the nohz_ratelimit() check to the other conditions which prevent long idle sleeps. 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> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Greg KH <gregkh@suse.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Jef Driesen <jefdriesen@telenet.be> LKML-Reference: <1276790557.27822.516.camel@twins> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/tick-sched.c5
1 files changed, 1 insertions, 4 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 1d7b9bc1c034..783fbadf2202 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 {