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| author |   Frederic Weisbecker <frederic@kernel.org> | 2022-02-08 17:16:34 +0100 |
|---|---|---|
| committer | Frederic Weisbecker <frederic@kernel.org> | 2022-03-07 23:01:34 +0100 |
| commit | 0345691b24c076655ce8f0f4bfd24cba3467ccbd (patch) | |
| tree | e5db80c55f164e4e61de306e4542401b1043c3e0 /include/linux/interrupt.h | |
| parent | tick/rcu: Remove obsolete rcu_needs_cpu() parameters (diff) | |
| download | wireguard-linux-0345691b24c076655ce8f0f4bfd24cba3467ccbd.tar.xz wireguard-linux-0345691b24c076655ce8f0f4bfd24cba3467ccbd.zip | |
tick/rcu: Stop allowing RCU_SOFTIRQ in idle
RCU_SOFTIRQ used to be special in that it could be raised on purpose
within the idle path to prevent from stopping the tick. Some code still
prevents from unnecessary warnings related to this specific behaviour
while entering in dynticks-idle mode.
However the nohz layout has changed quite a bit in ten years, and the
removal of CONFIG_RCU_FAST_NO_HZ has been the final straw to this
safe-conduct. Now the RCU_SOFTIRQ vector is expected to be raised from
sane places.
A remaining corner case is admitted though when the vector is invoked
in fragile hotplug path.
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>
Diffstat (limited to 'include/linux/interrupt.h')
| -rw-r--r-- | include/linux/interrupt.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 9367f1cb2e3c..9613326d2f8a 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -579,7 +579,13 @@ enum NR_SOFTIRQS }; -#define SOFTIRQ_STOP_IDLE_MASK (~(1 << RCU_SOFTIRQ)) +/* + * Ignoring the RCU vector after ksoftirqd is parked is fine + * because: + * 1) rcutree_migrate_callbacks() takes care of the queue. + * 2) rcu_report_dead() reports the final quiescent states. + */ +#define SOFTIRQ_HOTPLUG_SAFE_MASK (BIT(RCU_SOFTIRQ)) /* map softirq index to softirq name. update 'softirq_to_name' in * kernel/softirq.c when adding a new softirq. |