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| author | Thomas Gleixner <tglx@linutronix.de> | 2013-11-29 12:18:13 +0100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-08-06 18:07:39 +0100 |
| commit | c4b4c3c5f8e6cbd1c0626a80b2ca8cd33aa0e50a (patch) | |
| tree | 8971cfca34a7fac97ec2f33f4c92479f7f2a9ea4 | |
| parent | ea43a736ef5810a2ff1755771cc00c367805b5bf (diff) | |
| download | lwn-c4b4c3c5f8e6cbd1c0626a80b2ca8cd33aa0e50a.tar.gz lwn-c4b4c3c5f8e6cbd1c0626a80b2ca8cd33aa0e50a.zip | |
nohz: Fix another inconsistency between CONFIG_NO_HZ=n and nohz=off
commit 0e576acbc1d9600cf2d9b4a141a2554639959d50 upstream.
If CONFIG_NO_HZ=n tick_nohz_get_sleep_length() returns NSEC_PER_SEC/HZ.
If CONFIG_NO_HZ=y and the nohz functionality is disabled via the
command line option "nohz=off" or not enabled due to missing hardware
support, then tick_nohz_get_sleep_length() returns 0. That happens
because ts->sleep_length is never set in that case.
Set it to NSEC_PER_SEC/HZ when the NOHZ mode is inactive.
Reported-by: Michal Hocko <mhocko@suse.cz>
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | kernel/time/tick-sched.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index e9a45f1a34f5..2695d72d68ec 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -325,8 +325,10 @@ void tick_nohz_stop_sched_tick(int inidle) tick_do_timer_cpu = TICK_DO_TIMER_NONE; } - if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE)) + if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE)) { + ts->sleep_length = (ktime_t) { .tv64 = NSEC_PER_SEC/HZ }; goto end; + } if (need_resched()) goto end; |