/*
* lck_rw_clear_promotion: Undo priority promotions when the last RW
* lock is released by a thread (if a promotion was active)
*/
void lck_rw_clear_promotion(thread_t thread)
{
assert(thread->rwlock_count == 0);
/* Cancel any promotions if the thread had actually blocked while holding a RW lock */
spl_t s = splsched();
thread_lock(thread);
if (thread->sched_flags & TH_SFLAG_RW_PROMOTED) {
thread->sched_flags &= ~TH_SFLAG_RW_PROMOTED;
if (thread->sched_flags & TH_SFLAG_PROMOTED) {
/* Thread still has a mutex promotion */
} else if (thread->sched_flags & TH_SFLAG_DEPRESSED_MASK) {
KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_RW_DEMOTE) | DBG_FUNC_NONE,
thread->sched_pri, DEPRESSPRI, 0, 0, 0);
set_sched_pri(thread, DEPRESSPRI);
} else {
KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_RW_DEMOTE) | DBG_FUNC_NONE,
thread->sched_pri, thread->base_pri, 0, 0, 0);
thread_recompute_sched_pri(thread, FALSE);
}
}
thread_unlock(thread);
splx(s);
}
/*
* install_special_handler_locked:
*
* Do the work of installing the special_handler.
*
* Called with the thread mutex and scheduling lock held.
*/
void
install_special_handler_locked(
thread_t thread)
{
/*
* Temporarily undepress, so target has
* a chance to do locking required to
* block itself in special_handler().
*/
if (thread->sched_flags & TH_SFLAG_DEPRESSED_MASK)
thread_recompute_sched_pri(thread, TRUE);
thread_ast_set(thread, AST_APC);
if (thread == current_thread())
ast_propagate(thread->ast);
else {
processor_t processor = thread->last_processor;
if ( processor != PROCESSOR_NULL &&
processor->state == PROCESSOR_RUNNING &&
processor->active_thread == thread )
cause_ast_check(processor);
}
}
/*
* thread_set_apc_ast_locked:
*
* Do the work of registering for the AST_APC callback.
*
* Called with the thread mutex and scheduling lock held.
*/
static void
thread_set_apc_ast_locked(thread_t thread)
{
/*
* Temporarily undepress, so target has
* a chance to do locking required to
* block itself in thread_suspended.
*
* Leaves the depress flag set so we can reinstate when it's blocked.
*/
if (thread->sched_flags & TH_SFLAG_DEPRESSED_MASK)
thread_recompute_sched_pri(thread, TRUE);
thread_ast_set(thread, AST_APC);
if (thread == current_thread()) {
ast_propagate(thread);
} else {
processor_t processor = thread->last_processor;
if (processor != PROCESSOR_NULL &&
processor->state == PROCESSOR_RUNNING &&
processor->active_thread == thread) {
cause_ast_check(processor);
}
}
}
/*
* Priority depression expiration.
*/
void
thread_depress_expire(
void *p0,
__unused void *p1)
{
thread_t thread = p0;
spl_t s;
s = splsched();
thread_lock(thread);
if (--thread->depress_timer_active == 0) {
thread->sched_flags &= ~TH_SFLAG_DEPRESSED_MASK;
thread_recompute_sched_pri(thread, FALSE);
}
thread_unlock(thread);
splx(s);
}
/*
* Routine: lck_mtx_clear_promoted
*
* Handle clearing of TH_SFLAG_PROMOTED,
* adjusting thread priority as needed.
*
* Called with thread lock held
*/
static void
lck_mtx_clear_promoted (
thread_t thread,
__kdebug_only uintptr_t trace_lck)
{
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, trace_lck, 0);
set_sched_pri(thread, DEPRESSPRI);
} else {
if (thread->base_pri < thread->sched_pri) {
KERNEL_DEBUG_CONSTANT(
MACHDBG_CODE(DBG_MACH_SCHED,MACH_DEMOTE) | DBG_FUNC_NONE,
thread->sched_pri, thread->base_pri, 0, trace_lck, 0);
}
thread_recompute_sched_pri(thread, FALSE);
}
}
/*
* Prematurely abort priority depression if there is one.
*/
kern_return_t
thread_depress_abort_internal(
thread_t thread)
{
kern_return_t result = KERN_NOT_DEPRESSED;
spl_t s;
s = splsched();
thread_lock(thread);
if (!(thread->sched_flags & TH_SFLAG_POLLDEPRESS)) {
if (thread->sched_flags & TH_SFLAG_DEPRESSED_MASK) {
thread->sched_flags &= ~TH_SFLAG_DEPRESSED_MASK;
thread_recompute_sched_pri(thread, FALSE);
result = KERN_SUCCESS;
}
if (timer_call_cancel(&thread->depress_timer))
thread->depress_timer_active--;
}
thread_unlock(thread);
splx(s);
return (result);
}
