diff options
| author |   Frederic Weisbecker <frederic@kernel.org> | 2022-02-08 17:16:35 +0100 |
|---|---|---|
| committer | Frederic Weisbecker <frederic@kernel.org> | 2022-03-07 23:53:50 +0100 |
| commit | f96272a90d9eaea9933aaab704ddbd258feb3841 (patch) | |
| tree | 95dcece73d404446f2a064227b55e07de0a8501d | |
| parent | tick/rcu: Stop allowing RCU_SOFTIRQ in idle (diff) | |
| download | wireguard-linux-f96272a90d9eaea9933aaab704ddbd258feb3841.tar.xz wireguard-linux-f96272a90d9eaea9933aaab704ddbd258feb3841.zip | |
lib/irq_poll: Declare IRQ_POLL softirq vector as ksoftirqd-parking safe
The following warning may appear while setting a CPU down:
NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #20!!!
The IRQ_POLL_SOFTIRQ vector can be raised during the hotplug cpu_down()
path after ksoftirqd is parked and before the CPU actually dies. However
this is handled afterward at the CPUHP_IRQ_POLL_DEAD stage where the
queue gets migrated.
Hence this warning can be considered spurious and the vector can join
the "hotplug-safe" list.
Reported-and-tested-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Paul Menzel <pmenzel@molgen.mpg.de>
| -rw-r--r-- | include/linux/interrupt.h | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 9613326d2f8a..f40754caaefa 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -580,12 +580,15 @@ enum }; /* - * Ignoring the RCU vector after ksoftirqd is parked is fine - * because: - * 1) rcutree_migrate_callbacks() takes care of the queue. + * The following vectors can be safely ignored after ksoftirqd is parked: + * + * _ RCU: + * 1) rcutree_migrate_callbacks() migrates the queue. * 2) rcu_report_dead() reports the final quiescent states. + * + * _ IRQ_POLL: irq_poll_cpu_dead() migrates the queue */ -#define SOFTIRQ_HOTPLUG_SAFE_MASK (BIT(RCU_SOFTIRQ)) +#define SOFTIRQ_HOTPLUG_SAFE_MASK (BIT(RCU_SOFTIRQ) | BIT(IRQ_POLL_SOFTIRQ)) /* map softirq index to softirq name. update 'softirq_to_name' in * kernel/softirq.c when adding a new softirq. |