psi: rename psi fields in preparation for psi trigger addition

Rename psi_group structure member fields used for calculating psi totals
and averages for clear distinction between them and for trigger-related
fields that will be added by "psi: introduce psi monitor".

[surenb@google.com: v6]
Link: http://lkml.kernel.org/r/20190319235619.260832-4-surenb@google.com
Link: http://lkml.kernel.org/r/20190124211518.244221-5-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>

diff --git a/include/linux/psi_types.h b/include/linux/psi_types.h
index 762c6bb..4d1c1f6 100644 (file)
--- 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 281702d..4fb4d99 100644 (file)
--- 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);
 }