The patch titled
Subject: psi: split update_stats into parts
has been added to the -mm tree. Its filename is
psi-split-update_stats-into-parts.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/psi-split-update_stats-into-parts.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/psi-split-update_stats-into-parts.patch
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------------------------------------------------------
From: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx
Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Dennis Zhou <dennis@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Li Zefan <lizefan@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/kernel/sched/psi.c~psi-split-update_stats-into-parts
+++ a/kernel/sched/psi.c
@@ -269,17 +269,13 @@ static void calc_avgs(unsigned long avg[
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_grou
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_grou
* 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_grou
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_st
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_st
* 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
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];
_
Patches currently in -mm which might be from surenb@xxxxxxxxxx are
psi-introduce-state_mask-to-represent-stalled-psi-states.patch
psi-make-psi_enable-static.patch
psi-rename-psi-fields-in-preparation-for-psi-trigger-addition.patch
psi-rename-psi-fields-in-preparation-for-psi-trigger-addition-v6.patch
psi-split-update_stats-into-parts.patch
psi-track-changed-states.patch
refactor-header-includes-to-allow-kthreadh-inclusion-in-psi_typesh.patch
psi-introduce-psi-monitor.patch
