+
+#define LCK_MTX_LCK_WAIT_CODE 0x20
+#define LCK_MTX_LCK_WAKEUP_CODE 0x21
+#define LCK_MTX_LCK_SPIN_CODE 0x22
+#define LCK_MTX_LCK_ACQUIRE_CODE 0x23
+#define LCK_MTX_LCK_DEMOTE_CODE 0x24
+
+
+/*
+ * Routine: lck_mtx_unlock_wakeup_x86
+ *
+ * Invoked on unlock when there is
+ * contention (i.e. the assembly routine sees that
+ * that mutex->lck_mtx_waiters != 0 or
+ * that mutex->lck_mtx_promoted != 0...
+ *
+ * neither the mutex or interlock is held
+ */
+void
+lck_mtx_unlock_wakeup_x86 (
+ lck_mtx_t *mutex,
+ int prior_lock_state)
+{
+ lck_mtx_t fake_lck;
+
+ /*
+ * prior_lock state is a snapshot of the 2nd word of the
+ * lock in question... we'll fake up a lock with the bits
+ * copied into place and carefully not access anything
+ * beyond whats defined in the second word of a lck_mtx_t
+ */
+ fake_lck.lck_mtx_state = prior_lock_state;
+
+ KERNEL_DEBUG(MACHDBG_CODE(DBG_MACH_LOCKS, LCK_MTX_LCK_WAKEUP_CODE) | DBG_FUNC_START,
+ mutex, fake_lck.lck_mtx_promoted, fake_lck.lck_mtx_waiters, fake_lck.lck_mtx_pri, 0);
+
+ if (__probable(fake_lck.lck_mtx_waiters)) {
+ if (fake_lck.lck_mtx_waiters > 1)
+ thread_wakeup_one_with_pri((event_t)(((unsigned int*)mutex)+(sizeof(lck_mtx_t)-1)/sizeof(unsigned int)), fake_lck.lck_mtx_pri);
+ else
+ thread_wakeup_one((event_t)(((unsigned int*)mutex)+(sizeof(lck_mtx_t)-1)/sizeof(unsigned int)));
+ }
+
+ if (__improbable(fake_lck.lck_mtx_promoted)) {
+ thread_t thread = current_thread();
+
+
+ KERNEL_DEBUG(MACHDBG_CODE(DBG_MACH_LOCKS, LCK_MTX_LCK_DEMOTE_CODE) | DBG_FUNC_NONE,
+ thread_tid(thread), thread->promotions, thread->sched_flags & TH_SFLAG_PROMOTED, 0, 0);
+
+ if (thread->promotions > 0) {
+ spl_t s = splsched();
+
+ thread_lock(thread);
+
+ if (--thread->promotions == 0 && (thread->sched_flags & TH_SFLAG_PROMOTED)) {
+
+ thread->sched_flags &= ~TH_SFLAG_PROMOTED;
+
+ if (thread->sched_flags & TH_SFLAG_RW_PROMOTED) {
+ /* Thread still has a RW lock promotion */
+ } else if (thread->sched_flags & TH_SFLAG_DEPRESSED_MASK) {
+ KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_DEMOTE) | DBG_FUNC_NONE,
+ thread->sched_pri, DEPRESSPRI, 0, mutex, 0);
+
+ set_sched_pri(thread, DEPRESSPRI);
+ }
+ else {
+ if (thread->priority < thread->sched_pri) {
+ KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_DEMOTE) | DBG_FUNC_NONE,
+ thread->sched_pri, thread->priority, 0, mutex, 0);
+
+ SCHED(compute_priority)(thread, FALSE);
+ }
+ }
+ }
+ thread_unlock(thread);
+ splx(s);
+ }
+ }
+ KERNEL_DEBUG(MACHDBG_CODE(DBG_MACH_LOCKS, LCK_MTX_LCK_WAKEUP_CODE) | DBG_FUNC_END,
+ mutex, 0, mutex->lck_mtx_waiters, 0, 0);
+}
+
+
+/*
+ * Routine: lck_mtx_lock_acquire_x86
+ *
+ * Invoked on acquiring the mutex when there is
+ * contention (i.e. the assembly routine sees that
+ * that mutex->lck_mtx_waiters != 0 or
+ * thread->was_promoted_on_wakeup != 0)...
+ *
+ * mutex is owned... interlock is held... preemption is disabled
+ */
+void
+lck_mtx_lock_acquire_x86(
+ lck_mtx_t *mutex)
+{
+ thread_t thread;
+ integer_t priority;
+ spl_t s;
+
+ KERNEL_DEBUG(MACHDBG_CODE(DBG_MACH_LOCKS, LCK_MTX_LCK_ACQUIRE_CODE) | DBG_FUNC_START,
+ mutex, thread->was_promoted_on_wakeup, mutex->lck_mtx_waiters, mutex->lck_mtx_pri, 0);
+
+ if (mutex->lck_mtx_waiters)
+ priority = mutex->lck_mtx_pri;
+ else
+ priority = 0;
+
+ thread = (thread_t)mutex->lck_mtx_owner; /* faster then current_thread() */
+
+ if (thread->sched_pri < priority || thread->was_promoted_on_wakeup) {
+
+ KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_PROMOTE) | DBG_FUNC_NONE,
+ thread->sched_pri, priority, thread->was_promoted_on_wakeup, mutex, 0);
+
+ s = splsched();
+ thread_lock(thread);
+
+ if (thread->sched_pri < priority) {
+ /* Do not promote past promotion ceiling */
+ assert(priority <= MAXPRI_PROMOTE);
+ set_sched_pri(thread, priority);
+ }
+ if (mutex->lck_mtx_promoted == 0) {
+ mutex->lck_mtx_promoted = 1;
+
+ thread->promotions++;
+ thread->sched_flags |= TH_SFLAG_PROMOTED;
+ }
+ thread->was_promoted_on_wakeup = 0;
+
+ thread_unlock(thread);
+ splx(s);
+ }
+ KERNEL_DEBUG(MACHDBG_CODE(DBG_MACH_LOCKS, LCK_MTX_LCK_ACQUIRE_CODE) | DBG_FUNC_END,
+ mutex, 0, mutex->lck_mtx_waiters, 0, 0);
+}
+
+
+
projects / apple / xnu.git / blobdiff