X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/d26ffc64f583ab2d29df48f13518685602bc8832..d9a64523371fa019c4575bb400cbbc3a50ac9903:/osfmk/kern/priority.c?ds=sidebyside
diff --git a/osfmk/kern/priority.c b/osfmk/kern/priority.c
index 29ee2506f..40eb17242 100644
--- a/osfmk/kern/priority.c
+++ b/osfmk/kern/priority.c
@@ -117,12 +117,14 @@ thread_quantum_expire(
/*
* We bill CPU time to both the individual thread and its task.
*
- * Because this balance adjustment could potentially attempt to wake this very
- * thread, we must credit the ledger before taking the thread lock. The ledger
- * pointers are only manipulated by the thread itself at the ast boundary.
+ * Because this balance adjustment could potentially attempt to wake this
+ * very thread, we must credit the ledger before taking the thread lock.
+ * The ledger pointers are only manipulated by the thread itself at the ast
+ * boundary.
*
- * TODO: This fails to account for the time between when the timer was armed and when it fired.
- * It should be based on the system_timer and running a thread_timer_event operation here.
+ * TODO: This fails to account for the time between when the timer was
+ * armed and when it fired. It should be based on the system_timer and
+ * running a timer_update operation here.
*/
ledger_credit(thread->t_ledger, task_ledgers.cpu_time, thread->quantum_remaining);
ledger_credit(thread->t_threadledger, thread_ledgers.cpu_time, thread->quantum_remaining);
@@ -154,14 +156,15 @@ thread_quantum_expire(
/*
* Check for fail-safe trip.
*/
- if ((thread->sched_mode == TH_MODE_REALTIME || thread->sched_mode == TH_MODE_FIXED) &&
- !(thread->sched_flags & TH_SFLAG_PROMOTED_MASK) &&
- !(thread->options & TH_OPT_SYSTEM_CRITICAL)) {
- uint64_t new_computation;
-
- new_computation = ctime - thread->computation_epoch;
- new_computation += thread->computation_metered;
- if (new_computation > max_unsafe_computation) {
+ if ((thread->sched_mode == TH_MODE_REALTIME || thread->sched_mode == TH_MODE_FIXED) &&
+ !(thread->sched_flags & TH_SFLAG_PROMOTED) &&
+ !(thread->sched_flags & TH_SFLAG_PROMOTE_REASON_MASK) &&
+ !(thread->options & TH_OPT_SYSTEM_CRITICAL)) {
+ uint64_t new_computation;
+
+ new_computation = ctime - thread->computation_epoch;
+ new_computation += thread->computation_metered;
+ if (new_computation > max_unsafe_computation) {
KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_FAILSAFE)|DBG_FUNC_NONE,
(uintptr_t)thread->sched_pri, (uintptr_t)thread->sched_mode, 0, 0, 0);
@@ -199,12 +202,9 @@ thread_quantum_expire(
* during privilege transitions, synthesize an event now.
*/
if (!thread->precise_user_kernel_time) {
- timer_switch(PROCESSOR_DATA(processor, current_state),
- ctime,
- PROCESSOR_DATA(processor, current_state));
- timer_switch(PROCESSOR_DATA(processor, thread_timer),
- ctime,
- PROCESSOR_DATA(processor, thread_timer));
+ timer_update(PROCESSOR_DATA(processor, current_state), ctime);
+ timer_update(PROCESSOR_DATA(processor, thread_timer), ctime);
+ timer_update(&thread->runnable_timer, ctime);
}
@@ -301,7 +301,7 @@ sched_set_thread_base_priority(thread_t thread, int priority)
}
sched_update_thread_bucket(thread);
- thread_recompute_sched_pri(thread, FALSE);
+ thread_recompute_sched_pri(thread, SETPRI_DEFAULT);
}
/*
@@ -311,28 +311,54 @@ sched_set_thread_base_priority(thread_t thread, int priority)
* according to its base priority if the
* thread has not been promoted or depressed.
*
- * This is the standard way to push base_pri changes into sched_pri,
- * or to recalculate the appropriate sched_pri after clearing
+ * This is the only way to push base_pri changes into sched_pri,
+ * or to recalculate the appropriate sched_pri after changing
* a promotion or depression.
*
* Called at splsched with the thread locked.
+ *
+ * TODO: Add an 'update urgency' flag to avoid urgency callouts on every rwlock operation
*/
void
-thread_recompute_sched_pri(
- thread_t thread,
- boolean_t override_depress)
+thread_recompute_sched_pri(thread_t thread, set_sched_pri_options_t options)
{
- int priority;
+ uint32_t sched_flags = thread->sched_flags;
+ sched_mode_t sched_mode = thread->sched_mode;
- if (thread->sched_mode == TH_MODE_TIMESHARE)
+ int priority = thread->base_pri;
+
+ if (sched_mode == TH_MODE_TIMESHARE)
priority = SCHED(compute_timeshare_priority)(thread);
- else
- priority = thread->base_pri;
- if ((!(thread->sched_flags & TH_SFLAG_PROMOTED_MASK) || (priority > thread->sched_pri)) &&
- (!(thread->sched_flags & TH_SFLAG_DEPRESSED_MASK) || override_depress)) {
- set_sched_pri(thread, priority);
+ if (sched_flags & TH_SFLAG_DEPRESS) {
+ /* thread_yield_internal overrides kernel mutex promotion */
+ priority = DEPRESSPRI;
+ } else {
+ /* poll-depress is overridden by mutex promotion and promote-reasons */
+ if ((sched_flags & TH_SFLAG_POLLDEPRESS)) {
+ priority = DEPRESSPRI;
+ }
+
+ if (sched_flags & TH_SFLAG_PROMOTED) {
+ priority = MAX(priority, thread->promotion_priority);
+
+ if (sched_mode != TH_MODE_REALTIME)
+ priority = MIN(priority, MAXPRI_PROMOTE);
+ }
+
+ if (sched_flags & TH_SFLAG_PROMOTE_REASON_MASK) {
+ if (sched_flags & TH_SFLAG_RW_PROMOTED)
+ priority = MAX(priority, MINPRI_RWLOCK);
+
+ if (sched_flags & TH_SFLAG_WAITQ_PROMOTED)
+ priority = MAX(priority, MINPRI_WAITQ);
+
+ if (sched_flags & TH_SFLAG_EXEC_PROMOTED)
+ priority = MAX(priority, MINPRI_EXEC);
+ }
}
+
+ set_sched_pri(thread, priority, options);
}
void
@@ -380,23 +406,8 @@ lightweight_update_priority(thread_t thread)
priority = sched_compute_timeshare_priority(thread);
- /*
- * Adjust the scheduled priority like thread_recompute_sched_pri,
- * except with the benefit of knowing the thread is on this core.
- */
- if ((!(thread->sched_flags & TH_SFLAG_PROMOTED_MASK) || (priority > thread->sched_pri)) &&
- (!(thread->sched_flags & TH_SFLAG_DEPRESSED_MASK)) &&
- priority != thread->sched_pri) {
-
- thread->sched_pri = priority;
-
- KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_SCHED_CHANGE_PRIORITY),
- (uintptr_t)thread_tid(thread),
- thread->base_pri,
- thread->sched_pri,
- thread->sched_usage,
- 0);
- }
+ if (priority != thread->sched_pri)
+ thread_recompute_sched_pri(thread, SETPRI_LAZY);
}
}
@@ -512,8 +523,6 @@ update_priority(
thread->sched_stamp += ticks;
- thread->pri_shift = sched_pri_shifts[thread->th_sched_bucket];
-
/* If requested, accelerate aging of sched_usage */
if (sched_decay_usage_age_factor > 1)
ticks *= sched_decay_usage_age_factor;
@@ -524,9 +533,9 @@ update_priority(
thread_timer_delta(thread, delta);
if (ticks < SCHED_DECAY_TICKS) {
/*
- * Accumulate timesharing usage only
- * during contention for processor
- * resources.
+ * Accumulate timesharing usage only during contention for processor
+ * resources. Use the pri_shift from the previous tick window to
+ * determine if the system was in a contended state.
*/
if (thread->pri_shift < INT8_MAX)
thread->sched_usage += delta;
@@ -561,36 +570,17 @@ update_priority(
}
/*
- * Recompute scheduled priority if appropriate.
+ * Now that the thread's CPU usage has been accumulated and aged
+ * based on contention of the previous tick window, update the
+ * pri_shift of the thread to match the current global load/shift
+ * values. The updated pri_shift would be used to calculate the
+ * new priority of the thread.
*/
- if (thread->sched_mode == TH_MODE_TIMESHARE) {
- int priority = sched_compute_timeshare_priority(thread);
-
- /*
- * Adjust the scheduled priority like thread_recompute_sched_pri,
- * except without setting an AST.
- */
- if ((!(thread->sched_flags & TH_SFLAG_PROMOTED_MASK) || (priority > thread->sched_pri)) &&
- (!(thread->sched_flags & TH_SFLAG_DEPRESSED_MASK)) &&
- priority != thread->sched_pri) {
-
- boolean_t removed = thread_run_queue_remove(thread);
-
- thread->sched_pri = priority;
-
- KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_SCHED_CHANGE_PRIORITY),
- (uintptr_t)thread_tid(thread),
- thread->base_pri,
- thread->sched_pri,
- thread->sched_usage,
- 0);
-
- if (removed)
- thread_run_queue_reinsert(thread, SCHED_TAILQ);
- }
- }
+ thread->pri_shift = sched_pri_shifts[thread->th_sched_bucket];
- return;
+ /* Recompute scheduled priority if appropriate. */
+ if (thread->sched_mode == TH_MODE_TIMESHARE)
+ thread_recompute_sched_pri(thread, SETPRI_LAZY);
}
#endif /* CONFIG_SCHED_TIMESHARE_CORE */
@@ -662,8 +652,10 @@ sched_update_thread_bucket(thread_t thread)
break;
case TH_MODE_TIMESHARE:
- if (thread->base_pri > BASEPRI_UTILITY)
+ if (thread->base_pri > BASEPRI_DEFAULT)
new_bucket = TH_BUCKET_SHARE_FG;
+ else if (thread->base_pri > BASEPRI_UTILITY)
+ new_bucket = TH_BUCKET_SHARE_DF;
else if (thread->base_pri > MAXPRI_THROTTLE)
new_bucket = TH_BUCKET_SHARE_UT;
else
@@ -779,4 +771,168 @@ sched_thread_mode_undemote(thread_t thread, uint32_t reason)
thread_run_queue_reinsert(thread, SCHED_TAILQ);
}
+/*
+ * Promote thread to a specific priority
+ *
+ * Promotion must not last past syscall boundary
+ * Clients must always pair promote and unpromote 1:1
+ *
+ * Called at splsched with thread locked
+ */
+void
+sched_thread_promote_to_pri(thread_t thread,
+ int priority,
+ __kdebug_only uintptr_t trace_obj /* already unslid */)
+{
+ assert((thread->sched_flags & TH_SFLAG_PROMOTED) != TH_SFLAG_PROMOTED);
+ assert(thread->promotion_priority == 0);
+ assert(priority <= MAXPRI_PROMOTE);
+ assert(priority > 0);
+
+ KDBG(MACHDBG_CODE(DBG_MACH_SCHED, MACH_PROMOTED),
+ thread_tid(thread), trace_obj, priority);
+
+ thread->sched_flags |= TH_SFLAG_PROMOTED;
+ thread->promotion_priority = priority;
+
+ thread_recompute_sched_pri(thread, SETPRI_DEFAULT);
+}
+
+
+/*
+ * Update a pre-existing priority promotion to have a higher priority floor
+ * Priority can only go up from the previous value
+ * Update must occur while a promotion is active
+ *
+ * Called at splsched with thread locked
+ */
+void
+sched_thread_update_promotion_to_pri(thread_t thread,
+ int priority,
+ __kdebug_only uintptr_t trace_obj /* already unslid */)
+{
+ assert(thread->promotions > 0);
+ assert((thread->sched_flags & TH_SFLAG_PROMOTED) == TH_SFLAG_PROMOTED);
+ assert(thread->promotion_priority > 0);
+ assert(priority <= MAXPRI_PROMOTE);
+
+ if (thread->promotion_priority < priority) {
+ KDBG(MACHDBG_CODE(DBG_MACH_SCHED, MACH_PROMOTED_UPDATE),
+ thread_tid(thread), trace_obj, priority);
+
+ thread->promotion_priority = priority;
+ thread_recompute_sched_pri(thread, SETPRI_DEFAULT);
+ }
+}
+
+/*
+ * End a priority promotion
+ * Demotes a thread back to its expected priority without the promotion in place
+ *
+ * Called at splsched with thread locked
+ */
+void
+sched_thread_unpromote(thread_t thread,
+ __kdebug_only uintptr_t trace_obj /* already unslid */)
+{
+ assert((thread->sched_flags & TH_SFLAG_PROMOTED) == TH_SFLAG_PROMOTED);
+ assert(thread->promotion_priority > 0);
+
+ KDBG(MACHDBG_CODE(DBG_MACH_SCHED, MACH_UNPROMOTED),
+ thread_tid(thread), trace_obj, 0);
+
+ thread->sched_flags &= ~TH_SFLAG_PROMOTED;
+ thread->promotion_priority = 0;
+
+ thread_recompute_sched_pri(thread, SETPRI_DEFAULT);
+}
+
+/* called with thread locked */
+void
+assert_promotions_invariant(thread_t thread)
+{
+ if (thread->promotions > 0)
+ assert((thread->sched_flags & TH_SFLAG_PROMOTED) == TH_SFLAG_PROMOTED);
+
+ if (thread->promotions == 0)
+ assert((thread->sched_flags & TH_SFLAG_PROMOTED) != TH_SFLAG_PROMOTED);
+}
+
+/*
+ * Promote thread to have a sched pri floor for a specific reason
+ *
+ * Promotion must not last past syscall boundary
+ * Clients must always pair promote and demote 1:1,
+ * Handling nesting of the same promote reason is the client's responsibility
+ *
+ * Called at splsched with thread locked
+ */
+void
+sched_thread_promote_reason(thread_t thread,
+ uint32_t reason,
+ __kdebug_only uintptr_t trace_obj /* already unslid */)
+{
+ assert(reason & TH_SFLAG_PROMOTE_REASON_MASK);
+ assert((thread->sched_flags & reason) != reason);
+
+ switch (reason) {
+ case TH_SFLAG_RW_PROMOTED:
+ KDBG(MACHDBG_CODE(DBG_MACH_SCHED, MACH_RW_PROMOTE),
+ thread_tid(thread), thread->sched_pri,
+ thread->base_pri, trace_obj);
+ break;
+ case TH_SFLAG_WAITQ_PROMOTED:
+ KDBG(MACHDBG_CODE(DBG_MACH_SCHED, MACH_WAITQ_PROMOTE),
+ thread_tid(thread), thread->sched_pri,
+ thread->base_pri, trace_obj);
+ break;
+ case TH_SFLAG_EXEC_PROMOTED:
+ KDBG(MACHDBG_CODE(DBG_MACH_SCHED, MACH_EXEC_PROMOTE),
+ thread_tid(thread), thread->sched_pri,
+ thread->base_pri, trace_obj);
+ break;
+ }
+
+ thread->sched_flags |= reason;
+
+ thread_recompute_sched_pri(thread, SETPRI_DEFAULT);
+}
+
+/*
+ * End a specific promotion reason
+ * Demotes a thread back to its expected priority without the promotion in place
+ *
+ * Called at splsched with thread locked
+ */
+void
+sched_thread_unpromote_reason(thread_t thread,
+ uint32_t reason,
+ __kdebug_only uintptr_t trace_obj /* already unslid */)
+{
+ assert(reason & TH_SFLAG_PROMOTE_REASON_MASK);
+ assert((thread->sched_flags & reason) == reason);
+
+ switch (reason) {
+ case TH_SFLAG_RW_PROMOTED:
+ KDBG(MACHDBG_CODE(DBG_MACH_SCHED, MACH_RW_DEMOTE),
+ thread_tid(thread), thread->sched_pri,
+ thread->base_pri, trace_obj);
+ break;
+ case TH_SFLAG_WAITQ_PROMOTED:
+ KDBG(MACHDBG_CODE(DBG_MACH_SCHED, MACH_WAITQ_DEMOTE),
+ thread_tid(thread), thread->sched_pri,
+ thread->base_pri, trace_obj);
+ break;
+ case TH_SFLAG_EXEC_PROMOTED:
+ KDBG(MACHDBG_CODE(DBG_MACH_SCHED, MACH_EXEC_DEMOTE),
+ thread_tid(thread), thread->sched_pri,
+ thread->base_pri, trace_obj);
+ break;
+ }
+
+ thread->sched_flags &= ~reason;
+
+ thread_recompute_sched_pri(thread, SETPRI_DEFAULT);
+}
+