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-rw-r--r--kernel/sched/psi.c58
1 files changed, 25 insertions, 33 deletions
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index 1d0f634725..7b4aa5809c 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -434,14 +434,13 @@ static u64 window_update(struct psi_window *win, u64 now, u64 value)
return growth;
}
-static u64 update_triggers(struct psi_group *group, u64 now, bool *update_total,
+static void update_triggers(struct psi_group *group, u64 now,
enum psi_aggregators aggregator)
{
struct psi_trigger *t;
u64 *total = group->total[aggregator];
struct list_head *triggers;
u64 *aggregator_total;
- *update_total = false;
if (aggregator == PSI_AVGS) {
triggers = &group->avg_triggers;
@@ -471,14 +470,6 @@ static u64 update_triggers(struct psi_group *group, u64 now, bool *update_total,
* events without dropping any).
*/
if (new_stall) {
- /*
- * Multiple triggers might be looking at the same state,
- * remember to update group->polling_total[] once we've
- * been through all of them. Also remember to extend the
- * polling time if we see new stall activity.
- */
- *update_total = true;
-
/* Calculate growth since last update */
growth = window_update(&t->win, now, total[t->state]);
if (!t->pending_event) {
@@ -503,8 +494,6 @@ static u64 update_triggers(struct psi_group *group, u64 now, bool *update_total,
/* Reset threshold breach flag once event got generated */
t->pending_event = false;
}
-
- return now + group->rtpoll_min_period;
}
static u64 update_averages(struct psi_group *group, u64 now)
@@ -565,7 +554,6 @@ static void psi_avgs_work(struct work_struct *work)
struct delayed_work *dwork;
struct psi_group *group;
u32 changed_states;
- bool update_total;
u64 now;
dwork = to_delayed_work(work);
@@ -584,7 +572,7 @@ static void psi_avgs_work(struct work_struct *work)
* go - see calc_avgs() and missed_periods.
*/
if (now >= group->avg_next_update) {
- update_triggers(group, now, &update_total, PSI_AVGS);
+ update_triggers(group, now, PSI_AVGS);
group->avg_next_update = update_averages(group, now);
}
@@ -608,7 +596,7 @@ static void init_rtpoll_triggers(struct psi_group *group, u64 now)
group->rtpoll_next_update = now + group->rtpoll_min_period;
}
-/* Schedule polling if it's not already scheduled or forced. */
+/* Schedule rtpolling if it's not already scheduled or forced. */
static void psi_schedule_rtpoll_work(struct psi_group *group, unsigned long delay,
bool force)
{
@@ -640,7 +628,6 @@ static void psi_rtpoll_work(struct psi_group *group)
{
bool force_reschedule = false;
u32 changed_states;
- bool update_total;
u64 now;
mutex_lock(&group->rtpoll_trigger_lock);
@@ -649,37 +636,37 @@ static void psi_rtpoll_work(struct psi_group *group)
if (now > group->rtpoll_until) {
/*
- * We are either about to start or might stop polling if no
- * state change was recorded. Resetting poll_scheduled leaves
+ * We are either about to start or might stop rtpolling if no
+ * state change was recorded. Resetting rtpoll_scheduled leaves
* a small window for psi_group_change to sneak in and schedule
- * an immediate poll_work before we get to rescheduling. One
- * potential extra wakeup at the end of the polling window
- * should be negligible and polling_next_update still keeps
+ * an immediate rtpoll_work before we get to rescheduling. One
+ * potential extra wakeup at the end of the rtpolling window
+ * should be negligible and rtpoll_next_update still keeps
* updates correctly on schedule.
*/
atomic_set(&group->rtpoll_scheduled, 0);
/*
- * A task change can race with the poll worker that is supposed to
+ * A task change can race with the rtpoll worker that is supposed to
* report on it. To avoid missing events, ensure ordering between
- * poll_scheduled and the task state accesses, such that if the poll
- * worker misses the state update, the task change is guaranteed to
- * reschedule the poll worker:
+ * rtpoll_scheduled and the task state accesses, such that if the
+ * rtpoll worker misses the state update, the task change is
+ * guaranteed to reschedule the rtpoll worker:
*
- * poll worker:
- * atomic_set(poll_scheduled, 0)
+ * rtpoll worker:
+ * atomic_set(rtpoll_scheduled, 0)
* smp_mb()
* LOAD states
*
* task change:
* STORE states
- * if atomic_xchg(poll_scheduled, 1) == 0:
- * schedule poll worker
+ * if atomic_xchg(rtpoll_scheduled, 1) == 0:
+ * schedule rtpoll worker
*
* The atomic_xchg() implies a full barrier.
*/
smp_mb();
} else {
- /* Polling window is not over, keep rescheduling */
+ /* The rtpolling window is not over, keep rescheduling */
force_reschedule = true;
}
@@ -687,7 +674,7 @@ static void psi_rtpoll_work(struct psi_group *group)
collect_percpu_times(group, PSI_POLL, &changed_states);
if (changed_states & group->rtpoll_states) {
- /* Initialize trigger windows when entering polling mode */
+ /* Initialize trigger windows when entering rtpolling mode */
if (now > group->rtpoll_until)
init_rtpoll_triggers(group, now);
@@ -706,10 +693,12 @@ static void psi_rtpoll_work(struct psi_group *group)
}
if (now >= group->rtpoll_next_update) {
- group->rtpoll_next_update = update_triggers(group, now, &update_total, PSI_POLL);
- if (update_total)
+ if (changed_states & group->rtpoll_states) {
+ update_triggers(group, now, PSI_POLL);
memcpy(group->rtpoll_total, group->total[PSI_POLL],
sizeof(group->rtpoll_total));
+ }
+ group->rtpoll_next_update = now + group->rtpoll_min_period;
}
psi_schedule_rtpoll_work(group,
@@ -1009,6 +998,9 @@ void psi_account_irqtime(struct task_struct *task, u32 delta)
struct psi_group_cpu *groupc;
u64 now;
+ if (static_branch_likely(&psi_disabled))
+ return;
+
if (!task->pid)
return;