Helpers for replacement repeating patterns: 1)raw_spin_unlock_irq(lock); schedule(); 2)raw_spin_unlock_irqrestore(lock, flags); schedule();
(The same for spinlock_t) They allow to prevent excess preempt_schedule(), which can happen on preemptible kernel. Signed-off-by: Kirill Tkhai <[email protected]> CC: Steven Rostedt <[email protected]> CC: Ingo Molnar <[email protected]> CC: Peter Zijlstra <[email protected]> --- include/linux/sched.h | 20 ++++++++++++++++++++ kernel/sched/core.c | 24 ++++++++++++++++++++++++ 2 files changed, 44 insertions(+), 0 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 8b10339..0ae79f3 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -310,6 +310,26 @@ extern signed long schedule_timeout_uninterruptible(signed long timeout); asmlinkage void schedule(void); extern void schedule_preempt_disabled(void); +#ifdef CONFIG_PREEMPT +extern void schedule_raw_spin_unlock(raw_spinlock_t *lock); +/* See comment for schedule_raw_spin_unlock() */ +static inline void schedule_spin_unlock(spinlock_t *lock) +{ + schedule_raw_spin_unlock(&lock->rlock); +} +#else +static inline void schedule_raw_spin_unlock(raw_spinlock_t *lock) +{ + raw_spin_unlock_irq(lock); + schedule(); +} +static inline void schedule_spin_unlock(spinlock_t *lock) +{ + spin_unlock_irq(lock); + schedule(); +} +#endif + struct nsproxy; struct user_namespace; diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 58453b8..381e493 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3125,6 +3125,30 @@ asmlinkage void __sched preempt_schedule_irq(void) exception_exit(prev_state); } +/* + * schedule_raw_spin_unlock - unlock raw_spinlock and call schedule() + * + * Should be used instead of the constructions + * 1) raw_spin_unlock_irq(lock); + * schedule(); + * or + * 2) raw_spin_unlock_irqrestore(lock, flags); + * schedule(); + * where they have to be. + * + * It helps to prevent excess preempt_schedule() during the unlocking, + * which can be called on preemptible kernel. + * Returns with irqs enabled. + */ +void __sched schedule_raw_spin_unlock(raw_spinlock_t *lock) +{ + preempt_disable(); + raw_spin_unlock_irq(lock); + sched_preempt_enable_no_resched(); + schedule(); +} +EXPORT_SYMBOL(schedule_raw_spin_unlock); + #endif /* CONFIG_PREEMPT */ int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
