From: Linus Torvalds Date: Wed, 4 Sep 2013 15:18:19 +0000 (-0700) Subject: Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel... X-Git-Tag: upstream/snapshot3+hdmi~4459 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=4689550bb278cb142979c313a0d608e802c6711b;hp=b854e4de0bf88d094476af82c0d5a80f6f2af916;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git Merge branch 'core-locking-for-linus' of git://git./linux/kernel/git/tip/tip Pull core/locking changes from Ingo Molnar: "Main changes: - another mutex optimization, from Davidlohr Bueso - improved lglock lockdep tracking, from Michel Lespinasse - [ assorted smaller updates, improvements, cleanups. ]" * 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: generic-ipi/locking: Fix misleading smp_call_function_any() description hung_task debugging: Print more info when reporting the problem mutex: Avoid label warning when !CONFIG_MUTEX_SPIN_ON_OWNER mutex: Do not unnecessarily deal with waiters mutex: Fix/document access-once assumption in mutex_can_spin_on_owner() lglock: Update lockdep annotations to report recursive local locks lockdep: Introduce lock_acquire_exclusive()/shared() helper macros --- diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index f1e877b..cfc2f11 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -365,7 +365,7 @@ extern void lockdep_trace_alloc(gfp_t mask); #define lockdep_recursing(tsk) ((tsk)->lockdep_recursion) -#else /* !LOCKDEP */ +#else /* !CONFIG_LOCKDEP */ static inline void lockdep_off(void) { @@ -479,82 +479,36 @@ static inline void print_irqtrace_events(struct task_struct *curr) * on the per lock-class debug mode: */ -#ifdef CONFIG_DEBUG_LOCK_ALLOC -# ifdef CONFIG_PROVE_LOCKING -# define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i) -# define spin_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 2, n, i) -# else -# define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i) -# define spin_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, NULL, i) -# endif -# define spin_release(l, n, i) lock_release(l, n, i) +#ifdef CONFIG_PROVE_LOCKING + #define lock_acquire_exclusive(l, s, t, n, i) lock_acquire(l, s, t, 0, 2, n, i) + #define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 2, n, i) + #define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 2, n, i) #else -# define spin_acquire(l, s, t, i) do { } while (0) -# define spin_release(l, n, i) do { } while (0) + #define lock_acquire_exclusive(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i) + #define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 1, n, i) + #define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 1, n, i) #endif -#ifdef CONFIG_DEBUG_LOCK_ALLOC -# ifdef CONFIG_PROVE_LOCKING -# define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i) -# define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 2, NULL, i) -# else -# define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i) -# define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 1, NULL, i) -# endif -# define rwlock_release(l, n, i) lock_release(l, n, i) -#else -# define rwlock_acquire(l, s, t, i) do { } while (0) -# define rwlock_acquire_read(l, s, t, i) do { } while (0) -# define rwlock_release(l, n, i) do { } while (0) -#endif +#define spin_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) +#define spin_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i) +#define spin_release(l, n, i) lock_release(l, n, i) -#ifdef CONFIG_DEBUG_LOCK_ALLOC -# ifdef CONFIG_PROVE_LOCKING -# define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i) -# define mutex_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 2, n, i) -# else -# define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i) -# define mutex_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i) -# endif -# define mutex_release(l, n, i) lock_release(l, n, i) -#else -# define mutex_acquire(l, s, t, i) do { } while (0) -# define mutex_acquire_nest(l, s, t, n, i) do { } while (0) -# define mutex_release(l, n, i) do { } while (0) -#endif +#define rwlock_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) +#define rwlock_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i) +#define rwlock_release(l, n, i) lock_release(l, n, i) -#ifdef CONFIG_DEBUG_LOCK_ALLOC -# ifdef CONFIG_PROVE_LOCKING -# define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i) -# define rwsem_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 2, n, i) -# define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 2, NULL, i) -# else -# define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i) -# define rwsem_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i) -# define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 1, NULL, i) -# endif +#define mutex_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) +#define mutex_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i) +#define mutex_release(l, n, i) lock_release(l, n, i) + +#define rwsem_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) +#define rwsem_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i) +#define rwsem_acquire_read(l, s, t, i) lock_acquire_shared(l, s, t, NULL, i) # define rwsem_release(l, n, i) lock_release(l, n, i) -#else -# define rwsem_acquire(l, s, t, i) do { } while (0) -# define rwsem_acquire_nest(l, s, t, n, i) do { } while (0) -# define rwsem_acquire_read(l, s, t, i) do { } while (0) -# define rwsem_release(l, n, i) do { } while (0) -#endif -#ifdef CONFIG_DEBUG_LOCK_ALLOC -# ifdef CONFIG_PROVE_LOCKING -# define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 2, NULL, _THIS_IP_) -# define lock_map_acquire_read(l) lock_acquire(l, 0, 0, 2, 2, NULL, _THIS_IP_) -# else -# define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 1, NULL, _THIS_IP_) -# define lock_map_acquire_read(l) lock_acquire(l, 0, 0, 2, 1, NULL, _THIS_IP_) -# endif +#define lock_map_acquire(l) lock_acquire_exclusive(l, 0, 0, NULL, _THIS_IP_) +#define lock_map_acquire_read(l) lock_acquire_shared_recursive(l, 0, 0, NULL, _THIS_IP_) # define lock_map_release(l) lock_release(l, 1, _THIS_IP_) -#else -# define lock_map_acquire(l) do { } while (0) -# define lock_map_acquire_read(l) do { } while (0) -# define lock_map_release(l) do { } while (0) -#endif #ifdef CONFIG_PROVE_LOCKING # define might_lock(lock) \ diff --git a/kernel/hung_task.c b/kernel/hung_task.c index 6df6149..3e97fb1 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -15,6 +15,7 @@ #include #include #include +#include /* * The number of tasks checked: @@ -99,10 +100,14 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) * Ok, the task did not get scheduled for more than 2 minutes, * complain: */ - printk(KERN_ERR "INFO: task %s:%d blocked for more than " - "%ld seconds.\n", t->comm, t->pid, timeout); - printk(KERN_ERR "\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\"" - " disables this message.\n"); + pr_err("INFO: task %s:%d blocked for more than %ld seconds.\n", + t->comm, t->pid, timeout); + pr_err(" %s %s %.*s\n", + print_tainted(), init_utsname()->release, + (int)strcspn(init_utsname()->version, " "), + init_utsname()->version); + pr_err("\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\"" + " disables this message.\n"); sched_show_task(t); debug_show_held_locks(t); diff --git a/kernel/lglock.c b/kernel/lglock.c index 6535a66..86ae2ae 100644 --- a/kernel/lglock.c +++ b/kernel/lglock.c @@ -21,7 +21,7 @@ void lg_local_lock(struct lglock *lg) arch_spinlock_t *lock; preempt_disable(); - rwlock_acquire_read(&lg->lock_dep_map, 0, 0, _RET_IP_); + lock_acquire_shared(&lg->lock_dep_map, 0, 0, NULL, _RET_IP_); lock = this_cpu_ptr(lg->lock); arch_spin_lock(lock); } @@ -31,7 +31,7 @@ void lg_local_unlock(struct lglock *lg) { arch_spinlock_t *lock; - rwlock_release(&lg->lock_dep_map, 1, _RET_IP_); + lock_release(&lg->lock_dep_map, 1, _RET_IP_); lock = this_cpu_ptr(lg->lock); arch_spin_unlock(lock); preempt_enable(); @@ -43,7 +43,7 @@ void lg_local_lock_cpu(struct lglock *lg, int cpu) arch_spinlock_t *lock; preempt_disable(); - rwlock_acquire_read(&lg->lock_dep_map, 0, 0, _RET_IP_); + lock_acquire_shared(&lg->lock_dep_map, 0, 0, NULL, _RET_IP_); lock = per_cpu_ptr(lg->lock, cpu); arch_spin_lock(lock); } @@ -53,7 +53,7 @@ void lg_local_unlock_cpu(struct lglock *lg, int cpu) { arch_spinlock_t *lock; - rwlock_release(&lg->lock_dep_map, 1, _RET_IP_); + lock_release(&lg->lock_dep_map, 1, _RET_IP_); lock = per_cpu_ptr(lg->lock, cpu); arch_spin_unlock(lock); preempt_enable(); @@ -65,7 +65,7 @@ void lg_global_lock(struct lglock *lg) int i; preempt_disable(); - rwlock_acquire(&lg->lock_dep_map, 0, 0, _RET_IP_); + lock_acquire_exclusive(&lg->lock_dep_map, 0, 0, NULL, _RET_IP_); for_each_possible_cpu(i) { arch_spinlock_t *lock; lock = per_cpu_ptr(lg->lock, i); @@ -78,7 +78,7 @@ void lg_global_unlock(struct lglock *lg) { int i; - rwlock_release(&lg->lock_dep_map, 1, _RET_IP_); + lock_release(&lg->lock_dep_map, 1, _RET_IP_); for_each_possible_cpu(i) { arch_spinlock_t *lock; lock = per_cpu_ptr(lg->lock, i); diff --git a/kernel/mutex.c b/kernel/mutex.c index a52ee7bb..6d647ae 100644 --- a/kernel/mutex.c +++ b/kernel/mutex.c @@ -209,11 +209,13 @@ int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner) */ static inline int mutex_can_spin_on_owner(struct mutex *lock) { + struct task_struct *owner; int retval = 1; rcu_read_lock(); - if (lock->owner) - retval = lock->owner->on_cpu; + owner = ACCESS_ONCE(lock->owner); + if (owner) + retval = owner->on_cpu; rcu_read_unlock(); /* * if lock->owner is not set, the mutex owner may have just acquired @@ -461,7 +463,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, * performed the optimistic spinning cannot be done. */ if (ACCESS_ONCE(ww->ctx)) - break; + goto slowpath; } /* @@ -472,7 +474,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, owner = ACCESS_ONCE(lock->owner); if (owner && !mutex_spin_on_owner(lock, owner)) { mspin_unlock(MLOCK(lock), &node); - break; + goto slowpath; } if ((atomic_read(&lock->count) == 1) && @@ -499,7 +501,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, * the owner complete. */ if (!owner && (need_resched() || rt_task(task))) - break; + goto slowpath; /* * The cpu_relax() call is a compiler barrier which forces @@ -513,6 +515,10 @@ slowpath: #endif spin_lock_mutex(&lock->wait_lock, flags); + /* once more, can we acquire the lock? */ + if (MUTEX_SHOW_NO_WAITER(lock) && (atomic_xchg(&lock->count, 0) == 1)) + goto skip_wait; + debug_mutex_lock_common(lock, &waiter); debug_mutex_add_waiter(lock, &waiter, task_thread_info(task)); @@ -520,9 +526,6 @@ slowpath: list_add_tail(&waiter.list, &lock->wait_list); waiter.task = task; - if (MUTEX_SHOW_NO_WAITER(lock) && (atomic_xchg(&lock->count, -1) == 1)) - goto done; - lock_contended(&lock->dep_map, ip); for (;;) { @@ -536,7 +539,7 @@ slowpath: * other waiters: */ if (MUTEX_SHOW_NO_WAITER(lock) && - (atomic_xchg(&lock->count, -1) == 1)) + (atomic_xchg(&lock->count, -1) == 1)) break; /* @@ -561,24 +564,25 @@ slowpath: schedule_preempt_disabled(); spin_lock_mutex(&lock->wait_lock, flags); } + 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))) + atomic_set(&lock->count, 0); + debug_mutex_free_waiter(&waiter); -done: +skip_wait: + /* got the lock - cleanup and rejoice! */ lock_acquired(&lock->dep_map, ip); - /* got the lock - rejoice! */ - mutex_remove_waiter(lock, &waiter, current_thread_info()); mutex_set_owner(lock); if (!__builtin_constant_p(ww_ctx == NULL)) { - struct ww_mutex *ww = container_of(lock, - struct ww_mutex, - base); + 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; @@ -592,15 +596,8 @@ done: } } - /* set it to 0 if there are no waiters left: */ - if (likely(list_empty(&lock->wait_list))) - atomic_set(&lock->count, 0); - spin_unlock_mutex(&lock->wait_lock, flags); - - debug_mutex_free_waiter(&waiter); preempt_enable(); - return 0; err: diff --git a/kernel/smp.c b/kernel/smp.c index fe9f773..b1c9034 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -278,8 +278,6 @@ EXPORT_SYMBOL(smp_call_function_single); * @wait: If true, wait until function has completed. * * Returns 0 on success, else a negative status code (if no cpus were online). - * Note that @wait will be implicitly turned on in case of allocation failures, - * since we fall back to on-stack allocation. * * Selection preference: * 1) current cpu if in @mask