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psi: split update_stats into parts

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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.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Johannes 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Suren Baghdasaryan 2019-05-14 15:41:06 -07:00 committed by Linus Torvalds
parent bcc78db641
commit 7fc70a3999
1 changed files with 34 additions and 23 deletions
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57
kernel/sched/psi.c
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@ -269,17 +269,13 @@ static void calc_avgs(unsigned long avg[3], int missed_periods,
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, };
unsigned long missed_periods = 0;
unsigned long nonidle_total = 0;
u64 now, expires, period;
int cpu;
int s;
mutex_lock(&group->avgs_lock);
/*
* Collect the per-cpu time buckets and average them into a
* single time sample that is normalized to wallclock time.
@ -317,11 +313,18 @@ static bool update_stats(struct psi_group *group)
for (s = 0; s < NR_PSI_STATES - 1; s++)
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= */
now = sched_clock();
expires = group->avg_next_update;
if (now < expires)
goto out;
if (now - expires >= psi_period)
missed_periods = div_u64(now - expires, psi_period);
@ -332,7 +335,7 @@ static bool update_stats(struct psi_group *group)
* But the deltas we sample out of the per-cpu buckets above
* 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));
group->avg_last_update = now;
@ -362,9 +365,8 @@ static bool update_stats(struct psi_group *group)
group->avg_total[s] += sample;
calc_avgs(group->avg[s], missed_periods, sample, period);
}
out:
mutex_unlock(&group->avgs_lock);
return nonidle_total;
return avg_next_update;
}
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 psi_group *group;
bool nonidle;
u64 now;
dwork = to_delayed_work(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
* times and feed samples into the running averages. If things
@ -383,19 +391,15 @@ static void psi_avgs_work(struct work_struct *work)
* Once restarted, we'll catch up the running averages in one
* go - see calc_avgs() and missed_periods.
*/
nonidle = update_stats(group);
if (now >= group->avg_next_update)
group->avg_next_update = update_averages(group, now);
if (nonidle) {
unsigned long delay = 0;
u64 now;
now = sched_clock();
if (group->avg_next_update > now)
delay = nsecs_to_jiffies(
group->avg_next_update - now) + 1;
schedule_delayed_work(dwork, delay);
schedule_delayed_work(dwork, nsecs_to_jiffies(
group->avg_next_update - now) + 1);
}
mutex_unlock(&group->avgs_lock);
}
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)
int psi_show(struct seq_file *m, struct psi_group *group, enum psi_res res)
{
int full;
u64 now;
if (static_branch_likely(&psi_disabled))
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++) {
unsigned long avg[3];