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| author | Thomas Gleixner <tglx@linutronix.de> | 2020-05-03 15:08:52 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-05-19 15:51:21 +0200 |
| commit | 8ae0ae6737ad449c8ae21e2bb01d9736f360a933 (patch) | |
| tree | 1143878ecb15a2eeb6790b837da31d14a96c0776 /include/linux/rcutiny.h | |
| parent | 9ea366f669ded353ae49754216c042e7d2f72ba6 (diff) | |
| download | lwn-8ae0ae6737ad449c8ae21e2bb01d9736f360a933.tar.gz lwn-8ae0ae6737ad449c8ae21e2bb01d9736f360a933.zip | |
rcu: Provide rcu_irq_exit_preempt()
Interrupts and exceptions invoke rcu_irq_enter() on entry and need to
invoke rcu_irq_exit() before they either return to the interrupted code or
invoke the scheduler due to preemption.
The general assumption is that RCU idle code has to have preemption
disabled so that a return from interrupt cannot schedule. So the return
from interrupt code invokes rcu_irq_exit() and preempt_schedule_irq().
If there is any imbalance in the rcu_irq/nmi* invocations or RCU idle code
had preemption enabled then this goes unnoticed until the CPU goes idle or
some other RCU check is executed.
Provide rcu_irq_exit_preempt() which can be invoked from the
interrupt/exception return code in case that preemption is enabled. It
invokes rcu_irq_exit() and contains a few sanity checks in case that
CONFIG_PROVE_RCU is enabled to catch such issues directly.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134904.364456424@linutronix.de
Diffstat (limited to 'include/linux/rcutiny.h')
| -rw-r--r-- | include/linux/rcutiny.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 3465ba704a11..980eb78751d9 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -71,6 +71,7 @@ static inline void rcu_irq_enter(void) { } static inline void rcu_irq_exit_irqson(void) { } static inline void rcu_irq_enter_irqson(void) { } static inline void rcu_irq_exit(void) { } +static inline void rcu_irq_exit_preempt(void) { } static inline void exit_rcu(void) { } static inline bool rcu_preempt_need_deferred_qs(struct task_struct *t) { |