diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/Kconfig.locks | 4 | ||||
| -rw-r--r-- | kernel/futex.c | 6 | ||||
| -rw-r--r-- | kernel/locking/Makefile | 3 | ||||
| -rw-r--r-- | kernel/locking/mcs_spinlock.h | 16 | ||||
| -rw-r--r-- | kernel/locking/mutex.c | 60 | ||||
| -rw-r--r-- | kernel/locking/osq_lock.c (renamed from kernel/locking/mcs_spinlock.c) | 9 | ||||
| -rw-r--r-- | kernel/locking/rtmutex.c | 7 | ||||
| -rw-r--r-- | kernel/locking/rwsem-spinlock.c | 2 | ||||
| -rw-r--r-- | kernel/locking/rwsem-xadd.c | 3 | ||||
| -rw-r--r-- | kernel/sched/completion.c | 18 | ||||
| -rw-r--r-- | kernel/softirq.c | 6 |
11 files changed, 63 insertions, 71 deletions
diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks index 76768ee812b2..08561f1acd13 100644 --- a/kernel/Kconfig.locks +++ b/kernel/Kconfig.locks @@ -231,6 +231,10 @@ config RWSEM_SPIN_ON_OWNER def_bool y depends on SMP && RWSEM_XCHGADD_ALGORITHM && ARCH_SUPPORTS_ATOMIC_RMW +config LOCK_SPIN_ON_OWNER + def_bool y + depends on MUTEX_SPIN_ON_OWNER || RWSEM_SPIN_ON_OWNER + config ARCH_USE_QUEUE_RWLOCK bool diff --git a/kernel/futex.c b/kernel/futex.c index 63678b573d61..4eeb63de7e54 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -2258,7 +2258,7 @@ static long futex_wait_restart(struct restart_block *restart) * if there are waiters then it will block, it does PI, etc. (Due to * races the kernel might see a 0 value of the futex too.) */ -static int futex_lock_pi(u32 __user *uaddr, unsigned int flags, int detect, +static int futex_lock_pi(u32 __user *uaddr, unsigned int flags, ktime_t *time, int trylock) { struct hrtimer_sleeper timeout, *to = NULL; @@ -2953,11 +2953,11 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout, case FUTEX_WAKE_OP: return futex_wake_op(uaddr, flags, uaddr2, val, val2, val3); case FUTEX_LOCK_PI: - return futex_lock_pi(uaddr, flags, val, timeout, 0); + return futex_lock_pi(uaddr, flags, timeout, 0); case FUTEX_UNLOCK_PI: return futex_unlock_pi(uaddr, flags); case FUTEX_TRYLOCK_PI: - return futex_lock_pi(uaddr, flags, 0, timeout, 1); + return futex_lock_pi(uaddr, flags, NULL, 1); case FUTEX_WAIT_REQUEUE_PI: val3 = FUTEX_BITSET_MATCH_ANY; return futex_wait_requeue_pi(uaddr, flags, val, timeout, val3, diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile index 8541bfdfd232..4ca8eb151975 100644 --- a/kernel/locking/Makefile +++ b/kernel/locking/Makefile @@ -1,5 +1,5 @@ -obj-y += mutex.o semaphore.o rwsem.o mcs_spinlock.o +obj-y += mutex.o semaphore.o rwsem.o ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_lockdep.o = -pg @@ -14,6 +14,7 @@ ifeq ($(CONFIG_PROC_FS),y) obj-$(CONFIG_LOCKDEP) += lockdep_proc.o endif obj-$(CONFIG_SMP) += spinlock.o +obj-$(CONFIG_LOCK_SPIN_ON_OWNER) += osq_lock.o obj-$(CONFIG_SMP) += lglock.o obj-$(CONFIG_PROVE_LOCKING) += spinlock.o obj-$(CONFIG_RT_MUTEXES) += rtmutex.o diff --git a/kernel/locking/mcs_spinlock.h b/kernel/locking/mcs_spinlock.h index 4d60986fcbee..d1fe2ba5bac9 100644 --- a/kernel/locking/mcs_spinlock.h +++ b/kernel/locking/mcs_spinlock.h @@ -108,20 +108,4 @@ void mcs_spin_unlock(struct mcs_spinlock **lock, struct mcs_spinlock *node) arch_mcs_spin_unlock_contended(&next->locked); } -/* - * Cancellable version of the MCS lock above. - * - * Intended for adaptive spinning of sleeping locks: - * mutex_lock()/rwsem_down_{read,write}() etc. - */ - -struct optimistic_spin_node { - struct optimistic_spin_node *next, *prev; - int locked; /* 1 if lock acquired */ - int cpu; /* encoded CPU # value */ -}; - -extern bool osq_lock(struct optimistic_spin_queue *lock); -extern void osq_unlock(struct optimistic_spin_queue *lock); - #endif /* __LINUX_MCS_SPINLOCK_H */ diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index 454195194d4a..57407062e209 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -147,7 +147,7 @@ static __always_inline void ww_mutex_lock_acquired(struct ww_mutex *ww, } /* - * after acquiring lock with fastpath or when we lost out in contested + * After acquiring lock with fastpath or when we lost out in contested * slowpath, set ctx and wake up any waiters so they can recheck. * * This function is never called when CONFIG_DEBUG_LOCK_ALLOC is set, @@ -191,19 +191,32 @@ ww_mutex_set_context_fastpath(struct ww_mutex *lock, spin_unlock_mutex(&lock->base.wait_lock, flags); } - -#ifdef CONFIG_MUTEX_SPIN_ON_OWNER /* - * In order to avoid a stampede of mutex spinners from acquiring the mutex - * more or less simultaneously, the spinners need to acquire a MCS lock - * first before spinning on the owner field. + * After acquiring lock in the slowpath set ctx and wake up any + * waiters so they can recheck. * + * Callers must hold the mutex wait_lock. */ +static __always_inline void +ww_mutex_set_context_slowpath(struct ww_mutex *lock, + struct ww_acquire_ctx *ctx) +{ + struct mutex_waiter *cur; -/* - * Mutex spinning code migrated from kernel/sched/core.c - */ + ww_mutex_lock_acquired(lock, ctx); + lock->ctx = ctx; + + /* + * Give any possible sleeping processes the chance to wake up, + * so they can recheck if they have to back off. + */ + list_for_each_entry(cur, &lock->base.wait_list, list) { + debug_mutex_wake_waiter(&lock->base, cur); + wake_up_process(cur->task); + } +} +#ifdef CONFIG_MUTEX_SPIN_ON_OWNER static inline bool owner_running(struct mutex *lock, struct task_struct *owner) { if (lock->owner != owner) @@ -307,6 +320,11 @@ static bool mutex_optimistic_spin(struct mutex *lock, if (!mutex_can_spin_on_owner(lock)) goto done; + /* + * In order to avoid a stampede of mutex spinners trying to + * acquire the mutex all at once, the spinners need to take a + * MCS (queued) lock first before spinning on the owner field. + */ if (!osq_lock(&lock->osq)) goto done; @@ -469,7 +487,7 @@ void __sched ww_mutex_unlock(struct ww_mutex *lock) EXPORT_SYMBOL(ww_mutex_unlock); static inline int __sched -__mutex_lock_check_stamp(struct mutex *lock, struct ww_acquire_ctx *ctx) +__ww_mutex_lock_check_stamp(struct mutex *lock, struct ww_acquire_ctx *ctx) { struct ww_mutex *ww = container_of(lock, struct ww_mutex, base); struct ww_acquire_ctx *hold_ctx = ACCESS_ONCE(ww->ctx); @@ -557,7 +575,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, } if (use_ww_ctx && ww_ctx->acquired > 0) { - ret = __mutex_lock_check_stamp(lock, ww_ctx); + ret = __ww_mutex_lock_check_stamp(lock, ww_ctx); if (ret) goto err; } @@ -569,6 +587,8 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, schedule_preempt_disabled(); spin_lock_mutex(&lock->wait_lock, flags); } + __set_task_state(task, TASK_RUNNING); + mutex_remove_waiter(lock, &waiter, current_thread_info()); /* set it to 0 if there are no waiters left: */ if (likely(list_empty(&lock->wait_list))) @@ -582,23 +602,7 @@ skip_wait: if (use_ww_ctx) { struct ww_mutex *ww = container_of(lock, struct ww_mutex, base); - struct mutex_waiter *cur; - - /* - * This branch gets optimized out for the common case, - * and is only important for ww_mutex_lock. - */ - ww_mutex_lock_acquired(ww, ww_ctx); - ww->ctx = ww_ctx; - - /* - * Give any possible sleeping processes the chance to wake up, - * so they can recheck if they have to back off. - */ - list_for_each_entry(cur, &lock->wait_list, list) { - debug_mutex_wake_waiter(lock, cur); - wake_up_process(cur->task); - } + ww_mutex_set_context_slowpath(ww, ww_ctx); } spin_unlock_mutex(&lock->wait_lock, flags); diff --git a/kernel/locking/mcs_spinlock.c b/kernel/locking/osq_lock.c index 9887a905a762..c112d00341b0 100644 --- a/kernel/locking/mcs_spinlock.c +++ b/kernel/locking/osq_lock.c @@ -1,8 +1,6 @@ #include <linux/percpu.h> #include <linux/sched.h> -#include "mcs_spinlock.h" - -#ifdef CONFIG_SMP +#include <linux/osq_lock.h> /* * An MCS like lock especially tailored for optimistic spinning for sleeping @@ -111,7 +109,7 @@ bool osq_lock(struct optimistic_spin_queue *lock) * cmpxchg in an attempt to undo our queueing. */ - while (!smp_load_acquire(&node->locked)) { + while (!ACCESS_ONCE(node->locked)) { /* * If we need to reschedule bail... so we can block. */ @@ -203,6 +201,3 @@ void osq_unlock(struct optimistic_spin_queue *lock) if (next) ACCESS_ONCE(next->locked) = 1; } - -#endif - diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 7c98873a3077..3059bc2f022d 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -1130,6 +1130,7 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state, set_current_state(state); } + __set_current_state(TASK_RUNNING); return ret; } @@ -1188,10 +1189,9 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state, ret = task_blocks_on_rt_mutex(lock, &waiter, current, chwalk); if (likely(!ret)) + /* sleep on the mutex */ ret = __rt_mutex_slowlock(lock, state, timeout, &waiter); - set_current_state(TASK_RUNNING); - if (unlikely(ret)) { remove_waiter(lock, &waiter); rt_mutex_handle_deadlock(ret, chwalk, &waiter); @@ -1626,10 +1626,9 @@ int rt_mutex_finish_proxy_lock(struct rt_mutex *lock, set_current_state(TASK_INTERRUPTIBLE); + /* sleep on the mutex */ ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter); - set_current_state(TASK_RUNNING); - if (unlikely(ret)) remove_waiter(lock, waiter); diff --git a/kernel/locking/rwsem-spinlock.c b/kernel/locking/rwsem-spinlock.c index 2c93571162cb..2555ae15ec14 100644 --- a/kernel/locking/rwsem-spinlock.c +++ b/kernel/locking/rwsem-spinlock.c @@ -154,7 +154,7 @@ void __sched __down_read(struct rw_semaphore *sem) set_task_state(tsk, TASK_UNINTERRUPTIBLE); } - tsk->state = TASK_RUNNING; + __set_task_state(tsk, TASK_RUNNING); out: ; } diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c index 7628c3fc37ca..2f7cc4076f50 100644 --- a/kernel/locking/rwsem-xadd.c +++ b/kernel/locking/rwsem-xadd.c @@ -242,8 +242,7 @@ struct rw_semaphore __sched *rwsem_down_read_failed(struct rw_semaphore *sem) schedule(); } - tsk->state = TASK_RUNNING; - + __set_task_state(tsk, TASK_RUNNING); return sem; } EXPORT_SYMBOL(rwsem_down_read_failed); diff --git a/kernel/sched/completion.c b/kernel/sched/completion.c index 607f852b4d04..7052d3fd4e7b 100644 --- a/kernel/sched/completion.c +++ b/kernel/sched/completion.c @@ -268,6 +268,15 @@ bool try_wait_for_completion(struct completion *x) unsigned long flags; int ret = 1; + /* + * Since x->done will need to be locked only + * in the non-blocking case, we check x->done + * first without taking the lock so we can + * return early in the blocking case. + */ + if (!ACCESS_ONCE(x->done)) + return 0; + spin_lock_irqsave(&x->wait.lock, flags); if (!x->done) ret = 0; @@ -288,13 +297,6 @@ EXPORT_SYMBOL(try_wait_for_completion); */ bool completion_done(struct completion *x) { - unsigned long flags; - int ret = 1; - - spin_lock_irqsave(&x->wait.lock, flags); - if (!x->done) - ret = 0; - spin_unlock_irqrestore(&x->wait.lock, flags); - return ret; + return !!ACCESS_ONCE(x->done); } EXPORT_SYMBOL(completion_done); diff --git a/kernel/softirq.c b/kernel/softirq.c index 8cdb98847c7b..479e4436f787 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -114,8 +114,12 @@ void __local_bh_disable_ip(unsigned long ip, unsigned int cnt) trace_softirqs_off(ip); raw_local_irq_restore(flags); - if (preempt_count() == cnt) + if (preempt_count() == cnt) { +#ifdef CONFIG_DEBUG_PREEMPT + current->preempt_disable_ip = get_parent_ip(CALLER_ADDR1); +#endif trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); + } } EXPORT_SYMBOL(__local_bh_disable_ip); #endif /* CONFIG_TRACE_IRQFLAGS */ |