osfmk/kern/locks.c

66 #include <kern/thread.h>
498 	thread_t		thread = current_thread();
509 		 * during the time that this thread is asleep, so that when it
513 		thread->rwlock_count++;
532 		if ((thread->rwlock_count-- == 1 /* field now 0 */) && (thread->sched_flags & TH_SFLAG_RW_PROMOTED)) {
534 			lck_rw_clear_promotion(thread);
556 	thread_t		thread = current_thread();
568 		thread->rwlock_count++;
587 		if ((thread->rwlock_count-- == 1 /* field now 0 */) && (thread->sched_flags & TH_SFLAG_RW_PROMOTED)) {
589 			lck_rw_clear_promotion(thread);
702 	thread_t		thread = current_thread();
710 	if (thread->pending_promoter[thread->pending_promoter_index] == mutex) {
711 		thread->pending_promoter[thread->pending_promoter_index] = NULL;
712 		if (thread->pending_promoter_index > 0)
713 			thread->pending_promoter_index--;
721 		thread_lock(thread);
722 		thread->promotions++;
723 		thread->sched_flags |= TH_SFLAG_PROMOTED;
724 		if (thread->sched_pri < priority) {
727 						thread->sched_pri, priority, 0, lck, 0);
730 			set_sched_pri(thread, priority);
732 		thread_unlock(thread);
762 	thread_t		thread = current_thread();
770 	if (thread != holder)
778 	if (thread->promotions > 0) {
781 		thread_lock(thread);
782 		if (	--thread->promotions == 0				&&
783 				(thread->sched_flags & TH_SFLAG_PROMOTED)		) {
784 			thread->sched_flags &= ~TH_SFLAG_PROMOTED;
786 			if (thread->sched_flags & TH_SFLAG_RW_PROMOTED) {
788 			} else if (thread->sched_flags & TH_SFLAG_DEPRESSED_MASK) {
791 						  thread->sched_pri, DEPRESSPRI, 0, lck, 0);
793 				set_sched_pri(thread, DEPRESSPRI);
796 				if (thread->priority < thread->sched_pri) {
800 							thread->sched_pri, thread->priority,
804 				SCHED(compute_priority)(thread, FALSE);
807 		thread_unlock(thread);
910 	thread_t		thread = current_thread();
918 		 * is that this thread remains as an observer, since it may hold
920 		 * this situation, make sure that the thread is boosted to the
924 		thread->rwlock_count++;
945 		if ((thread->rwlock_count-- == 1 /* field now 0 */) && (thread->sched_flags & TH_SFLAG_RW_PROMOTED)) {
951 			lck_rw_clear_promotion(thread);
972 	thread_t		thread = current_thread();
978 		thread->rwlock_count++;
999 		if ((thread->rwlock_count-- == 1 /* field now 0 */) && (thread->sched_flags & TH_SFLAG_RW_PROMOTED)) {
1005 			lck_rw_clear_promotion(thread);
1033  * a per-thread counter. Only if that thread stops
1037  * When the thread becomes runnable again (or in
1048  * to the thread and independent of any particular
1054  * per-thread counter should err on the side of
1065  * lock is released by a thread (if a promotion was active)
1067 void lck_rw_clear_promotion(thread_t thread)
1069 	assert(thread->rwlock_count == 0);
1071 	/* Cancel any promotions if the thread had actually blocked while holding a RW lock */
1074 	thread_lock(thread);
1076 	if (thread->sched_flags & TH_SFLAG_RW_PROMOTED) {
1077 		thread->sched_flags &= ~TH_SFLAG_RW_PROMOTED;
1079 		if (thread->sched_flags & TH_SFLAG_PROMOTED) {
1081 		} else if (thread->sched_flags & TH_SFLAG_DEPRESSED_MASK) {
1083 							      thread->sched_pri, DEPRESSPRI, 0, 0, 0);
1085 			set_sched_pri(thread, DEPRESSPRI);
1088 								  thread->sched_pri, thread->priority, 0, 0, 0);
1090 			SCHED(compute_priority)(thread, FALSE);
1094 	thread_unlock(thread);