diff options
| author | Frederic Weisbecker <frederic@kernel.org> | 2019-07-24 15:22:59 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2019-10-05 10:45:16 -0700 |
| commit | 01b4c39901e087ceebae2733857248de81476bd8 (patch) | |
| tree | 72bdea923f0fc822c57b1cc916c596d2bf6682b3 /include/trace/events/timer.h | |
| parent | 54ecb8f7028c5eb3d740bb82b0f1d90f2df63c5c (diff) | |
nohz: Add TICK_DEP_BIT_RCU
If a nohz_full CPU is looping in the kernel, the scheduling-clock tick
might nevertheless remain disabled. In !PREEMPT kernels, this can
prevent RCU's attempts to enlist the aid of that CPU's executions of
cond_resched(), which can in turn result in an arbitrarily delayed grace
period and thus an OOM. RCU therefore needs a way to enable a holdout
nohz_full CPU's scheduler-clock interrupt.
This commit therefore provides a new TICK_DEP_BIT_RCU value which RCU can
pass to tick_dep_set_cpu() and friends to force on the scheduler-clock
interrupt for a specified CPU or task. In some cases, rcutorture needs
to turn on the scheduler-clock tick, so this commit also exports the
relevant symbols to GPL-licensed modules.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'include/trace/events/timer.h')
| -rw-r--r-- | include/trace/events/timer.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/trace/events/timer.h b/include/trace/events/timer.h index b7a904825e7d..295517f109d7 100644 --- a/include/trace/events/timer.h +++ b/include/trace/events/timer.h @@ -367,7 +367,8 @@ TRACE_EVENT(itimer_expire, tick_dep_name(POSIX_TIMER) \ tick_dep_name(PERF_EVENTS) \ tick_dep_name(SCHED) \ - tick_dep_name_end(CLOCK_UNSTABLE) + tick_dep_name(CLOCK_UNSTABLE) \ + tick_dep_name_end(RCU) #undef tick_dep_name #undef tick_dep_mask_name |