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| author | Peter Zijlstra <peterz@infradead.org> | 2010-06-17 18:02:37 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2010-06-17 19:37:29 +0200 |
| commit | 3310d4d38fbc514e7b18bd3b1eea8effdd63b5aa (patch) | |
| tree | 14e2a5b6126c9b1341a3d4bf5299545ce4b1999a /kernel | |
| parent | 7e27d6e778cd87b6f2415515d7127eba53fe5d02 (diff) | |
| download | lwn-3310d4d38fbc514e7b18bd3b1eea8effdd63b5aa.tar.gz lwn-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')
| -rw-r--r-- | 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 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 { |