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-rw-r--r--kernel/sched.c53
1 files changed, 26 insertions, 27 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 063d7a496f47..03dff14b44e5 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3392,13 +3392,10 @@ calc_load_n(unsigned long load, unsigned long exp,
* Once we've updated the global active value, we need to apply the exponential
* weights adjusted to the number of cycles missed.
*/
-static void calc_global_nohz(unsigned long ticks)
+static void calc_global_nohz(void)
{
long delta, active, n;
- if (time_before(jiffies, calc_load_update))
- return;
-
/*
* If we crossed a calc_load_update boundary, make sure to fold
* any pending idle changes, the respective CPUs might have
@@ -3410,31 +3407,25 @@ static void calc_global_nohz(unsigned long ticks)
atomic_long_add(delta, &calc_load_tasks);
/*
- * If we were idle for multiple load cycles, apply them.
+ * It could be the one fold was all it took, we done!
*/
- if (ticks >= LOAD_FREQ) {
- n = ticks / LOAD_FREQ;
+ if (time_before(jiffies, calc_load_update + 10))
+ return;
- active = atomic_long_read(&calc_load_tasks);
- active = active > 0 ? active * FIXED_1 : 0;
+ /*
+ * Catch-up, fold however many we are behind still
+ */
+ delta = jiffies - calc_load_update - 10;
+ n = 1 + (delta / LOAD_FREQ);
- avenrun[0] = calc_load_n(avenrun[0], EXP_1, active, n);
- avenrun[1] = calc_load_n(avenrun[1], EXP_5, active, n);
- avenrun[2] = calc_load_n(avenrun[2], EXP_15, active, n);
+ active = atomic_long_read(&calc_load_tasks);
+ active = active > 0 ? active * FIXED_1 : 0;
- calc_load_update += n * LOAD_FREQ;
- }
+ avenrun[0] = calc_load_n(avenrun[0], EXP_1, active, n);
+ avenrun[1] = calc_load_n(avenrun[1], EXP_5, active, n);
+ avenrun[2] = calc_load_n(avenrun[2], EXP_15, active, n);
- /*
- * Its possible the remainder of the above division also crosses
- * a LOAD_FREQ period, the regular check in calc_global_load()
- * which comes after this will take care of that.
- *
- * Consider us being 11 ticks before a cycle completion, and us
- * sleeping for 4*LOAD_FREQ + 22 ticks, then the above code will
- * age us 4 cycles, and the test in calc_global_load() will
- * pick up the final one.
- */
+ calc_load_update += n * LOAD_FREQ;
}
#else
static void calc_load_account_idle(struct rq *this_rq)
@@ -3446,7 +3437,7 @@ static inline long calc_load_fold_idle(void)
return 0;
}
-static void calc_global_nohz(unsigned long ticks)
+static void calc_global_nohz(void)
{
}
#endif
@@ -3474,8 +3465,6 @@ void calc_global_load(unsigned long ticks)
{
long active;
- calc_global_nohz(ticks);
-
if (time_before(jiffies, calc_load_update + 10))
return;
@@ -3487,6 +3476,16 @@ void calc_global_load(unsigned long ticks)
avenrun[2] = calc_load(avenrun[2], EXP_15, active);
calc_load_update += LOAD_FREQ;
+
+ /*
+ * Account one period with whatever state we found before
+ * folding in the nohz state and ageing the entire idle period.
+ *
+ * This avoids loosing a sample when we go idle between
+ * calc_load_account_active() (10 ticks ago) and now and thus
+ * under-accounting.
+ */
+ calc_global_nohz();
}
/*