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authorThomas Gleixner <tglx@linutronix.de>2013-11-29 12:18:13 +0100
committerBen Hutchings <ben@decadent.org.uk>2014-08-06 18:07:39 +0100
commitc4b4c3c5f8e6cbd1c0626a80b2ca8cd33aa0e50a (patch)
tree8971cfca34a7fac97ec2f33f4c92479f7f2a9ea4 /kernel
parentea43a736ef5810a2ff1755771cc00c367805b5bf (diff)
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/time/tick-sched.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index e9a45f1a34f..2695d72d68e 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;