[PATCH v6 3/7] psi: rename psi fields in preparation for psi trigger addition

From: Suren Baghdasaryan
Date: Tue Mar 19 2019 - 19:56:44 EST


Renaming psi_group structure member fields used for calculating psi totals
and averages for clear distinction between them and trigger-related fields
that will be added next.

Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
---
include/linux/psi_types.h | 14 ++++++-------
kernel/sched/psi.c | 41 ++++++++++++++++++++-------------------
2 files changed, 28 insertions(+), 27 deletions(-)

diff --git a/include/linux/psi_types.h b/include/linux/psi_types.h
index 762c6bb16f3c..4d1c1f67be18 100644
--- a/include/linux/psi_types.h
+++ b/include/linux/psi_types.h
@@ -69,17 +69,17 @@ struct psi_group_cpu {
};

struct psi_group {
- /* Protects data updated during an aggregation */
- struct mutex stat_lock;
+ /* Protects data used by the aggregator */
+ struct mutex avgs_lock;

/* Per-cpu task state & time tracking */
struct psi_group_cpu __percpu *pcpu;

- /* Periodic aggregation state */
- u64 total_prev[NR_PSI_STATES - 1];
- u64 last_update;
- u64 next_update;
- struct delayed_work clock_work;
+ /* Running pressure averages */
+ u64 avg_total[NR_PSI_STATES - 1];
+ u64 avg_last_update;
+ u64 avg_next_update;
+ struct delayed_work avgs_work;

/* Total stall times and sampled pressure averages */
u64 total[NR_PSI_STATES - 1];
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index 281702de9772..4fb4d9913bc8 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -165,7 +165,7 @@ static struct psi_group psi_system = {
.pcpu = &system_group_pcpu,
};

-static void psi_update_work(struct work_struct *work);
+static void psi_avgs_work(struct work_struct *work);

static void group_init(struct psi_group *group)
{
@@ -173,9 +173,9 @@ static void group_init(struct psi_group *group)

for_each_possible_cpu(cpu)
seqcount_init(&per_cpu_ptr(group->pcpu, cpu)->seq);
- group->next_update = sched_clock() + psi_period;
- INIT_DELAYED_WORK(&group->clock_work, psi_update_work);
- mutex_init(&group->stat_lock);
+ group->avg_next_update = sched_clock() + psi_period;
+ INIT_DELAYED_WORK(&group->avgs_work, psi_avgs_work);
+ mutex_init(&group->avgs_lock);
}

void __init psi_init(void)
@@ -278,7 +278,7 @@ static bool update_stats(struct psi_group *group)
int cpu;
int s;

- mutex_lock(&group->stat_lock);
+ mutex_lock(&group->avgs_lock);

/*
* Collect the per-cpu time buckets and average them into a
@@ -319,7 +319,7 @@ static bool update_stats(struct psi_group *group)

/* avgX= */
now = sched_clock();
- expires = group->next_update;
+ expires = group->avg_next_update;
if (now < expires)
goto out;
if (now - expires >= psi_period)
@@ -332,14 +332,14 @@ 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->next_update = expires + ((1 + missed_periods) * psi_period);
- period = now - (group->last_update + (missed_periods * psi_period));
- group->last_update = now;
+ group->avg_next_update = expires + ((1 + missed_periods) * psi_period);
+ period = now - (group->avg_last_update + (missed_periods * psi_period));
+ group->avg_last_update = now;

for (s = 0; s < NR_PSI_STATES - 1; s++) {
u32 sample;

- sample = group->total[s] - group->total_prev[s];
+ sample = group->total[s] - group->avg_total[s];
/*
* Due to the lockless sampling of the time buckets,
* recorded time deltas can slip into the next period,
@@ -359,22 +359,22 @@ static bool update_stats(struct psi_group *group)
*/
if (sample > period)
sample = period;
- group->total_prev[s] += sample;
+ group->avg_total[s] += sample;
calc_avgs(group->avg[s], missed_periods, sample, period);
}
out:
- mutex_unlock(&group->stat_lock);
+ mutex_unlock(&group->avgs_lock);
return nonidle_total;
}

-static void psi_update_work(struct work_struct *work)
+static void psi_avgs_work(struct work_struct *work)
{
struct delayed_work *dwork;
struct psi_group *group;
bool nonidle;

dwork = to_delayed_work(work);
- group = container_of(dwork, struct psi_group, clock_work);
+ group = container_of(dwork, struct psi_group, avgs_work);

/*
* If there is task activity, periodically fold the per-cpu
@@ -391,8 +391,9 @@ static void psi_update_work(struct work_struct *work)
u64 now;

now = sched_clock();
- if (group->next_update > now)
- delay = nsecs_to_jiffies(group->next_update - now) + 1;
+ if (group->avg_next_update > now)
+ delay = nsecs_to_jiffies(
+ group->avg_next_update - now) + 1;
schedule_delayed_work(dwork, delay);
}
}
@@ -546,13 +547,13 @@ void psi_task_change(struct task_struct *task, int clear, int set)
*/
if (unlikely((clear & TSK_RUNNING) &&
(task->flags & PF_WQ_WORKER) &&
- wq_worker_last_func(task) == psi_update_work))
+ wq_worker_last_func(task) == psi_avgs_work))
wake_clock = false;

while ((group = iterate_groups(task, &iter))) {
psi_group_change(group, cpu, clear, set);
- if (wake_clock && !delayed_work_pending(&group->clock_work))
- schedule_delayed_work(&group->clock_work, PSI_FREQ);
+ if (wake_clock && !delayed_work_pending(&group->avgs_work))
+ schedule_delayed_work(&group->avgs_work, PSI_FREQ);
}
}

@@ -649,7 +650,7 @@ void psi_cgroup_free(struct cgroup *cgroup)
if (static_branch_likely(&psi_disabled))
return;

- cancel_delayed_work_sync(&cgroup->psi.clock_work);
+ cancel_delayed_work_sync(&cgroup->psi.avgs_work);
free_percpu(cgroup->psi.pcpu);
}

--
2.21.0.225.g810b269d1ac-goog