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authorSuren Baghdasaryan <surenb@google.com>2019-05-14 15:41:06 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-14 19:52:47 -0700
commit7fc70a3999366560ad1d4f2389a78360300c2c6a (patch)
tree10117e129c7d1201a505786f4fa33ec7562b781f /kernel
parentbcc78db64168eb6dede056fed2999f75f7ace309 (diff)
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.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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched/psi.c57
1 files changed, 34 insertions, 23 deletions
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index 4fb4d9913bc8..ace5ed97b186 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -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];