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 <sur...@google.com>
---
 include/linux/psi_types.h | 15 ++++++++-------
 kernel/sched/psi.c        | 26 ++++++++++++++------------
 2 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/include/linux/psi_types.h b/include/linux/psi_types.h
index 762c6bb16f3c..47757668bdcb 100644
--- a/include/linux/psi_types.h
+++ b/include/linux/psi_types.h
@@ -69,20 +69,21 @@ 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 update_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;
 
-       /* Total stall times and sampled pressure averages */
+       /* Total stall times observed */
        u64 total[NR_PSI_STATES - 1];
+
+       /* Running pressure averages */
+       u64 avg_total[NR_PSI_STATES - 1];
+       u64 avg_last_update;
+       u64 avg_next_update;
        unsigned long avg[NR_PSI_STATES - 1][3];
 };
 
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index 2262d920295f..c366503ba135 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -172,9 +172,9 @@ 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;
+       group->avg_next_update = sched_clock() + psi_period;
        INIT_DELAYED_WORK(&group->clock_work, psi_update_work);
-       mutex_init(&group->stat_lock);
+       mutex_init(&group->update_lock);
 }
 
 void __init psi_init(void)
@@ -277,7 +277,7 @@ static bool update_stats(struct psi_group *group)
        int cpu;
        int s;
 
-       mutex_lock(&group->stat_lock);
+       mutex_lock(&group->update_lock);
 
        /*
         * Collect the per-cpu time buckets and average them into a
@@ -318,7 +318,7 @@ 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)
@@ -331,14 +331,14 @@ 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,
@@ -358,11 +358,11 @@ 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->update_lock);
        return nonidle_total;
 }
 
@@ -390,8 +390,10 @@ 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);
        }
 }
-- 
2.20.1.321.g9e740568ce-goog

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