diff options
| author | Frederic Weisbecker <frederic@kernel.org> | 2019-07-24 15:22:59 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-05-17 11:13:22 +0200 |
| commit | fe2ae32a7ec9fa64f61993b808f25315b9996b03 (patch) | |
| tree | 0d935deff423125cff3fd29e26c29128c2c47aab /include/trace | |
| parent | c6989314fd809c5eaf4980d6fa474f19fc653d6c (diff) | |
nohz: Add TICK_DEP_BIT_RCU
[ Upstream commit 01b4c39901e087ceebae2733857248de81476bd8 ]
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>
Stable-dep-of: 58d766824264 ("tick/nohz: Fix cpu_is_hotpluggable() by checking with nohz subsystem")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'include/trace')
| -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 a57e4ee989d6..350b046e7576 100644 --- a/include/trace/events/timer.h +++ b/include/trace/events/timer.h @@ -362,7 +362,8 @@ 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 |