diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2024-10-04 14:46:58 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2024-11-05 12:55:38 +0100 |
| commit | 7c70cb94d29cd325fabe4a818c18613e3b9919a1 (patch) | |
| tree | 2c4d6b58f7e284778060e2aff70db2b87d7a977c /include/linux/preempt.h | |
| parent | 26baa1f1c4bdc34b8d698c1900b407d863ad0e69 (diff) | |
sched: Add Lazy preemption model
Change fair to use resched_curr_lazy(), which, when the lazy
preemption model is selected, will set TIF_NEED_RESCHED_LAZY.
This LAZY bit will be promoted to the full NEED_RESCHED bit on tick.
As such, the average delay between setting LAZY and actually
rescheduling will be TICK_NSEC/2.
In short, Lazy preemption will delay preemption for fair class but
will function as Full preemption for all the other classes, most
notably the realtime (RR/FIFO/DEADLINE) classes.
The goal is to bridge the performance gap with Voluntary, such that we
might eventually remove that option entirely.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lkml.kernel.org/r/20241007075055.331243614@infradead.org
Diffstat (limited to 'include/linux/preempt.h')
| -rw-r--r-- | include/linux/preempt.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/include/linux/preempt.h b/include/linux/preempt.h index ce76f1a45722..ca86235ac15c 100644 --- a/include/linux/preempt.h +++ b/include/linux/preempt.h @@ -486,6 +486,7 @@ DEFINE_LOCK_GUARD_0(migrate, migrate_disable(), migrate_enable()) extern bool preempt_model_none(void); extern bool preempt_model_voluntary(void); extern bool preempt_model_full(void); +extern bool preempt_model_lazy(void); #else @@ -502,6 +503,11 @@ static inline bool preempt_model_full(void) return IS_ENABLED(CONFIG_PREEMPT); } +static inline bool preempt_model_lazy(void) +{ + return IS_ENABLED(CONFIG_PREEMPT_LAZY); +} + #endif static inline bool preempt_model_rt(void) @@ -519,7 +525,7 @@ static inline bool preempt_model_rt(void) */ static inline bool preempt_model_preemptible(void) { - return preempt_model_full() || preempt_model_rt(); + return preempt_model_full() || preempt_model_lazy() || preempt_model_rt(); } #endif /* __LINUX_PREEMPT_H */ |