PM: domains: Move genpd's time-accounting to ktime_get_mono_fast_ns()

To move towards a more consistent behaviour between genpd and the runtime
PM core, let's start by converting genpd's time-accounting from ktime_get()
into ktime_get_mono_fast_ns().

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 1ee878d126fdf5c789f052d9ebb57f666c4fdc5d..18cd7965e5d6e3626322dae0e5fd3e19be1d3243 100644 (file)
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -225,24 +225,23 @@ static void genpd_debug_remove(struct generic_pm_domain *genpd)
 
 static void genpd_update_accounting(struct generic_pm_domain *genpd)
 {
-       ktime_t delta, now;
+       u64 delta, now;
 
-       now = ktime_get();
-       delta = ktime_sub(now, genpd->accounting_time);
+       now = ktime_get_mono_fast_ns();
+       if (now <= genpd->accounting_time)
+               return;
+
+       delta = now - genpd->accounting_time;
 
        /*
         * If genpd->status is active, it means we are just
         * out of off and so update the idle time and vice
         * versa.
         */
-       if (genpd->status == GENPD_STATE_ON) {
-               int state_idx = genpd->state_idx;
-
-               genpd->states[state_idx].idle_time =
-                       ktime_add(genpd->states[state_idx].idle_time, delta);
-       } else {
-               genpd->on_time = ktime_add(genpd->on_time, delta);
-       }
+       if (genpd->status == GENPD_STATE_ON)
+               genpd->states[genpd->state_idx].idle_time += delta;
+       else
+               genpd->on_time += delta;
 
        genpd->accounting_time = now;
 }
@@ -1999,7 +1998,7 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
        genpd->max_off_time_changed = true;
        genpd->provider = NULL;
        genpd->has_provider = false;
-       genpd->accounting_time = ktime_get();
+       genpd->accounting_time = ktime_get_mono_fast_ns();
        genpd->domain.ops.runtime_suspend = genpd_runtime_suspend;
        genpd->domain.ops.runtime_resume = genpd_runtime_resume;
        genpd->domain.ops.prepare = genpd_prepare;
@@ -3163,6 +3162,7 @@ static int sub_domains_show(struct seq_file *s, void *data)
 static int idle_states_show(struct seq_file *s, void *data)
 {
        struct generic_pm_domain *genpd = s->private;
+       u64 now, delta, idle_time = 0;
        unsigned int i;
        int ret = 0;
 
@@ -3173,17 +3173,19 @@ static int idle_states_show(struct seq_file *s, void *data)
        seq_puts(s, "State          Time Spent(ms) Usage          Rejected\n");
 
        for (i = 0; i < genpd->state_count; i++) {
-               ktime_t delta = 0;
-               s64 msecs;
+               idle_time += genpd->states[i].idle_time;
 
-               if ((genpd->status == GENPD_STATE_OFF) &&
-                               (genpd->state_idx == i))
-                       delta = ktime_sub(ktime_get(), genpd->accounting_time);
+               if (genpd->status == GENPD_STATE_OFF && genpd->state_idx == i) {
+                       now = ktime_get_mono_fast_ns();
+                       if (now > genpd->accounting_time) {
+                               delta = now - genpd->accounting_time;
+                               idle_time += delta;
+                       }
+               }
 
-               msecs = ktime_to_ms(
-                       ktime_add(genpd->states[i].idle_time, delta));
-               seq_printf(s, "S%-13i %-14lld %-14llu %llu\n", i, msecs,
-                             genpd->states[i].usage, genpd->states[i].rejected);
+               do_div(idle_time, NSEC_PER_MSEC);
+               seq_printf(s, "S%-13i %-14llu %-14llu %llu\n", i, idle_time,
+                          genpd->states[i].usage, genpd->states[i].rejected);
        }
 
        genpd_unlock(genpd);
@@ -3193,18 +3195,22 @@ static int idle_states_show(struct seq_file *s, void *data)
 static int active_time_show(struct seq_file *s, void *data)
 {
        struct generic_pm_domain *genpd = s->private;
-       ktime_t delta = 0;
+       u64 now, on_time, delta = 0;
        int ret = 0;
 
        ret = genpd_lock_interruptible(genpd);
        if (ret)
                return -ERESTARTSYS;
 
-       if (genpd->status == GENPD_STATE_ON)
-               delta = ktime_sub(ktime_get(), genpd->accounting_time);
+       if (genpd->status == GENPD_STATE_ON) {
+               now = ktime_get_mono_fast_ns();
+               if (now > genpd->accounting_time)
+                       delta = now - genpd->accounting_time;
+       }
 
-       seq_printf(s, "%lld ms\n", ktime_to_ms(
-                               ktime_add(genpd->on_time, delta)));
+       on_time = genpd->on_time + delta;
+       do_div(on_time, NSEC_PER_MSEC);
+       seq_printf(s, "%llu ms\n", on_time);
 
        genpd_unlock(genpd);
        return ret;
@@ -3213,7 +3219,7 @@ static int active_time_show(struct seq_file *s, void *data)
 static int total_idle_time_show(struct seq_file *s, void *data)
 {
        struct generic_pm_domain *genpd = s->private;
-       ktime_t delta = 0, total = 0;
+       u64 now, delta, total = 0;
        unsigned int i;
        int ret = 0;
 
@@ -3222,16 +3228,19 @@ static int total_idle_time_show(struct seq_file *s, void *data)
                return -ERESTARTSYS;
 
        for (i = 0; i < genpd->state_count; i++) {
+               total += genpd->states[i].idle_time;
 
-               if ((genpd->status == GENPD_STATE_OFF) &&
-                               (genpd->state_idx == i))
-                       delta = ktime_sub(ktime_get(), genpd->accounting_time);
-
-               total = ktime_add(total, genpd->states[i].idle_time);
+               if (genpd->status == GENPD_STATE_OFF && genpd->state_idx == i) {
+                       now = ktime_get_mono_fast_ns();
+                       if (now > genpd->accounting_time) {
+                               delta = now - genpd->accounting_time;
+                               total += delta;
+                       }
+               }
        }
-       total = ktime_add(total, delta);
 
-       seq_printf(s, "%lld ms\n", ktime_to_ms(total));
+       do_div(total, NSEC_PER_MSEC);
+       seq_printf(s, "%llu ms\n", total);
 
        genpd_unlock(genpd);
        return ret;

diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 67017c9390c878cc9e09f20e4bdaa5499e3d2646..043d48e4420aca84617c6b774ee1d621e8469905 100644 (file)
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -98,7 +98,7 @@ struct genpd_power_state {
        u64 usage;
        u64 rejected;
        struct fwnode_handle *fwnode;
-       ktime_t idle_time;
+       u64 idle_time;
        void *data;
 };
 
@@ -149,8 +149,8 @@ struct generic_pm_domain {
                            unsigned int state_count);
        unsigned int state_count; /* number of states */
        unsigned int state_idx; /* state that genpd will go to when off */
-       ktime_t on_time;
-       ktime_t accounting_time;
+       u64 on_time;
+       u64 accounting_time;
        const struct genpd_lock_ops *lock_ops;
        union {
                struct mutex mlock;