diff options
Diffstat (limited to 'kernel/sched')
-rw-r--r-- | kernel/sched/core.c | 45 | ||||
-rw-r--r-- | kernel/sched/features.h | 7 |
2 files changed, 0 insertions, 52 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 67d04651f44b..42053547e0f5 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2999,51 +2999,6 @@ void __sched schedule_preempt_disabled(void) preempt_disable(); } -#ifdef CONFIG_MUTEX_SPIN_ON_OWNER - -static inline bool owner_running(struct mutex *lock, struct task_struct *owner) -{ - if (lock->owner != owner) - return false; - - /* - * Ensure we emit the owner->on_cpu, dereference _after_ checking - * lock->owner still matches owner, if that fails, owner might - * point to free()d memory, if it still matches, the rcu_read_lock() - * ensures the memory stays valid. - */ - barrier(); - - return owner->on_cpu; -} - -/* - * Look out! "owner" is an entirely speculative pointer - * access and not reliable. - */ -int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner) -{ - if (!sched_feat(OWNER_SPIN)) - return 0; - - rcu_read_lock(); - while (owner_running(lock, owner)) { - if (need_resched()) - break; - - arch_mutex_cpu_relax(); - } - rcu_read_unlock(); - - /* - * We break out the loop above on need_resched() and when the - * owner changed, which is a sign for heavy contention. Return - * success only when lock->owner is NULL. - */ - return lock->owner == NULL; -} -#endif - #ifdef CONFIG_PREEMPT /* * this is the entry point to schedule() from in-kernel preemption diff --git a/kernel/sched/features.h b/kernel/sched/features.h index 1ad1d2b5395f..99399f8e4799 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -46,13 +46,6 @@ SCHED_FEAT(DOUBLE_TICK, false) SCHED_FEAT(LB_BIAS, true) /* - * Spin-wait on mutex acquisition when the mutex owner is running on - * another cpu -- assumes that when the owner is running, it will soon - * release the lock. Decreases scheduling overhead. - */ -SCHED_FEAT(OWNER_SPIN, true) - -/* * Decrement CPU power based on time not spent running tasks */ SCHED_FEAT(NONTASK_POWER, true) |