Commit 7fc70a39 authored by Suren Baghdasaryan's avatar Suren Baghdasaryan Committed by Linus Torvalds

psi: split update_stats into parts

Split update_stats into collect_percpu_times and update_averages for
collect_percpu_times to be reused later inside psi monitor.

Link: http://lkml.kernel.org/r/20190319235619.260832-5-surenb@google.comSigned-off-by: default avatarSuren Baghdasaryan <surenb@google.com>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent bcc78db6
...@@ -269,17 +269,13 @@ static void calc_avgs(unsigned long avg[3], int missed_periods, ...@@ -269,17 +269,13 @@ static void calc_avgs(unsigned long avg[3], int missed_periods,
avg[2] = calc_load(avg[2], EXP_300s, pct); avg[2] = calc_load(avg[2], EXP_300s, pct);
} }
static bool update_stats(struct psi_group *group) static bool collect_percpu_times(struct psi_group *group)
{ {
u64 deltas[NR_PSI_STATES - 1] = { 0, }; u64 deltas[NR_PSI_STATES - 1] = { 0, };
unsigned long missed_periods = 0;
unsigned long nonidle_total = 0; unsigned long nonidle_total = 0;
u64 now, expires, period;
int cpu; int cpu;
int s; int s;
mutex_lock(&group->avgs_lock);
/* /*
* Collect the per-cpu time buckets and average them into a * Collect the per-cpu time buckets and average them into a
* single time sample that is normalized to wallclock time. * single time sample that is normalized to wallclock time.
...@@ -317,11 +313,18 @@ static bool update_stats(struct psi_group *group) ...@@ -317,11 +313,18 @@ static bool update_stats(struct psi_group *group)
for (s = 0; s < NR_PSI_STATES - 1; s++) for (s = 0; s < NR_PSI_STATES - 1; s++)
group->total[s] += div_u64(deltas[s], max(nonidle_total, 1UL)); group->total[s] += div_u64(deltas[s], max(nonidle_total, 1UL));
return nonidle_total;
}
static u64 update_averages(struct psi_group *group, u64 now)
{
unsigned long missed_periods = 0;
u64 expires, period;
u64 avg_next_update;
int s;
/* avgX= */ /* avgX= */
now = sched_clock();
expires = group->avg_next_update; expires = group->avg_next_update;
if (now < expires)
goto out;
if (now - expires >= psi_period) if (now - expires >= psi_period)
missed_periods = div_u64(now - expires, psi_period); missed_periods = div_u64(now - expires, psi_period);
...@@ -332,7 +335,7 @@ static bool update_stats(struct psi_group *group) ...@@ -332,7 +335,7 @@ static bool update_stats(struct psi_group *group)
* But the deltas we sample out of the per-cpu buckets above * But the deltas we sample out of the per-cpu buckets above
* are based on the actual time elapsing between clock ticks. * are based on the actual time elapsing between clock ticks.
*/ */
group->avg_next_update = expires + ((1 + missed_periods) * psi_period); avg_next_update = expires + ((1 + missed_periods) * psi_period);
period = now - (group->avg_last_update + (missed_periods * psi_period)); period = now - (group->avg_last_update + (missed_periods * psi_period));
group->avg_last_update = now; group->avg_last_update = now;
...@@ -362,9 +365,8 @@ static bool update_stats(struct psi_group *group) ...@@ -362,9 +365,8 @@ static bool update_stats(struct psi_group *group)
group->avg_total[s] += sample; group->avg_total[s] += sample;
calc_avgs(group->avg[s], missed_periods, sample, period); calc_avgs(group->avg[s], missed_periods, sample, period);
} }
out:
mutex_unlock(&group->avgs_lock); return avg_next_update;
return nonidle_total;
} }
static void psi_avgs_work(struct work_struct *work) static void psi_avgs_work(struct work_struct *work)
...@@ -372,10 +374,16 @@ static void psi_avgs_work(struct work_struct *work) ...@@ -372,10 +374,16 @@ static void psi_avgs_work(struct work_struct *work)
struct delayed_work *dwork; struct delayed_work *dwork;
struct psi_group *group; struct psi_group *group;
bool nonidle; bool nonidle;
u64 now;
dwork = to_delayed_work(work); dwork = to_delayed_work(work);
group = container_of(dwork, struct psi_group, avgs_work); group = container_of(dwork, struct psi_group, avgs_work);
mutex_lock(&group->avgs_lock);
now = sched_clock();
nonidle = collect_percpu_times(group);
/* /*
* If there is task activity, periodically fold the per-cpu * If there is task activity, periodically fold the per-cpu
* times and feed samples into the running averages. If things * times and feed samples into the running averages. If things
...@@ -383,19 +391,15 @@ static void psi_avgs_work(struct work_struct *work) ...@@ -383,19 +391,15 @@ static void psi_avgs_work(struct work_struct *work)
* Once restarted, we'll catch up the running averages in one * Once restarted, we'll catch up the running averages in one
* go - see calc_avgs() and missed_periods. * go - see calc_avgs() and missed_periods.
*/ */
if (now >= group->avg_next_update)
nonidle = update_stats(group); group->avg_next_update = update_averages(group, now);
if (nonidle) { if (nonidle) {
unsigned long delay = 0; schedule_delayed_work(dwork, nsecs_to_jiffies(
u64 now; group->avg_next_update - now) + 1);
now = sched_clock();
if (group->avg_next_update > now)
delay = nsecs_to_jiffies(
group->avg_next_update - now) + 1;
schedule_delayed_work(dwork, delay);
} }
mutex_unlock(&group->avgs_lock);
} }
static void record_times(struct psi_group_cpu *groupc, int cpu, static void record_times(struct psi_group_cpu *groupc, int cpu,
...@@ -707,11 +711,18 @@ void cgroup_move_task(struct task_struct *task, struct css_set *to) ...@@ -707,11 +711,18 @@ void cgroup_move_task(struct task_struct *task, struct css_set *to)
int psi_show(struct seq_file *m, struct psi_group *group, enum psi_res res) int psi_show(struct seq_file *m, struct psi_group *group, enum psi_res res)
{ {
int full; int full;
u64 now;
if (static_branch_likely(&psi_disabled)) if (static_branch_likely(&psi_disabled))
return -EOPNOTSUPP; return -EOPNOTSUPP;
update_stats(group); /* Update averages before reporting them */
mutex_lock(&group->avgs_lock);
now = sched_clock();
collect_percpu_times(group);
if (now >= group->avg_next_update)
group->avg_next_update = update_averages(group, now);
mutex_unlock(&group->avgs_lock);
for (full = 0; full < 2 - (res == PSI_CPU); full++) { for (full = 0; full < 2 - (res == PSI_CPU); full++) {
unsigned long avg[3]; unsigned long avg[3];
......
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