Lets factorize all preempt_count operations to the __schedule() callers. This way we spare two preempt count changes in __schedule() when it's called by preemption APIs.
Suggested-by: Linus Torvalds <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Peter Zijlstra <[email protected]> Signed-off-by: Frederic Weisbecker <[email protected]> --- kernel/sched/core.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 89b165f..1c0e5b1 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2760,7 +2760,6 @@ static void __sched __schedule(void) struct rq *rq; int cpu; - preempt_disable(); cpu = smp_processor_id(); rq = cpu_rq(cpu); rcu_note_context_switch(); @@ -2822,8 +2821,6 @@ static void __sched __schedule(void) raw_spin_unlock_irq(&rq->lock); post_schedule(rq); - - sched_preempt_enable_no_resched(); } static inline void sched_submit_work(struct task_struct *tsk) @@ -2844,7 +2841,9 @@ asmlinkage __visible void __sched schedule(void) sched_submit_work(tsk); do { + preempt_disable(); __schedule(); + sched_preempt_enable_no_resched(); } while (need_resched()); } EXPORT_SYMBOL(schedule); @@ -2883,9 +2882,9 @@ void __sched schedule_preempt_disabled(void) static void preempt_schedule_common(void) { do { - preempt_count_add(PREEMPT_ACTIVE); + preempt_count_add(PREEMPT_ACTIVE + PREEMPT_CHECK_OFFSET); __schedule(); - preempt_count_sub(PREEMPT_ACTIVE); + preempt_count_sub(PREEMPT_ACTIVE + PREEMPT_CHECK_OFFSET); /* * Check again in case we missed a preemption opportunity @@ -2938,7 +2937,7 @@ asmlinkage __visible void __sched notrace preempt_schedule_context(void) return; do { - preempt_count_add(PREEMPT_ACTIVE); + preempt_count_add(PREEMPT_ACTIVE + PREEMPT_CHECK_OFFSET); /* * Needs preempt disabled in case user_exit() is traced * and the tracer calls preempt_enable_notrace() causing @@ -2947,8 +2946,7 @@ asmlinkage __visible void __sched notrace preempt_schedule_context(void) prev_ctx = exception_enter(); __schedule(); exception_exit(prev_ctx); - - preempt_count_sub(PREEMPT_ACTIVE); + preempt_count_sub(PREEMPT_ACTIVE + PREEMPT_CHECK_OFFSET); barrier(); } while (need_resched()); } @@ -2973,11 +2971,11 @@ asmlinkage __visible void __sched preempt_schedule_irq(void) prev_state = exception_enter(); do { - preempt_count_add(PREEMPT_ACTIVE); + preempt_count_add(PREEMPT_ACTIVE + PREEMPT_CHECK_OFFSET); local_irq_enable(); __schedule(); local_irq_disable(); - preempt_count_sub(PREEMPT_ACTIVE); + preempt_count_sub(PREEMPT_ACTIVE + PREEMPT_CHECK_OFFSET); /* * Check again in case we missed a preemption opportunity -- 2.1.4 -- 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/
