nohz: Fix another inconsistency between CONFIG_NO_HZ=n and nohz=off
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>
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index a12df5a..ea20f7d 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -711,8 +711,10 @@
return false;
}
- 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 };
return false;
+ }
if (need_resched())
return false;