sched/fair: Propagate an effective runnable_load_avg

The load balancer uses runnable_load_avg as load indicator. For
!cgroup this is:

  runnable_load_avg = \Sum se->avg.load_avg ; where se->on_rq

That is, a direct sum of all runnable tasks on that runqueue. As
opposed to load_avg, which is a sum of all tasks on the runqueue,
which includes a blocked component.

However, in the cgroup case, this comes apart since the group entities
are always runnable, even if most of their constituent entities are
blocked.

Therefore introduce a runnable_weight which for task entities is the
same as the regular weight, but for group entities is a fraction of
the entity weight and represents the runnable part of the group
runqueue.

Then propagate this load through the PELT hierarchy to arrive at an
effective runnable load avgerage -- which we should not confuse with
the canonical runnable load average.

Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 2e039a81864c..1ca0130ed4f9 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -441,9 +441,11 @@ static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group
                 P_SCHEDSTAT(se->statistics.wait_count);
         }
         P(se->load.weight);
+        P(se->runnable_weight);
 #ifdef CONFIG_SMP
         P(se->avg.load_avg);
         P(se->avg.util_avg);
+        P(se->avg.runnable_load_avg);
 #endif
 
 #undef PN_SCHEDSTAT
@@ -558,10 +560,11 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
         SEQ_printf(m, "  .%-30s: %d\n", "nr_running", cfs_rq->nr_running);
         SEQ_printf(m, "  .%-30s: %ld\n", "load", cfs_rq->load.weight);
 #ifdef CONFIG_SMP
+        SEQ_printf(m, "  .%-30s: %ld\n", "runnable_weight", cfs_rq->runnable_weight);
         SEQ_printf(m, "  .%-30s: %lu\n", "load_avg",
                         cfs_rq->avg.load_avg);
         SEQ_printf(m, "  .%-30s: %lu\n", "runnable_load_avg",
-                        cfs_rq->runnable_load_avg);
+                        cfs_rq->avg.runnable_load_avg);
         SEQ_printf(m, "  .%-30s: %lu\n", "util_avg",
                         cfs_rq->avg.util_avg);
         SEQ_printf(m, "  .%-30s: %ld\n", "removed.load_avg",
@@ -1006,10 +1009,13 @@ void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
                    "nr_involuntary_switches", (long long)p->nivcsw);
 
         P(se.load.weight);
+        P(se.runnable_weight);
 #ifdef CONFIG_SMP
         P(se.avg.load_sum);
+        P(se.avg.runnable_load_sum);
         P(se.avg.util_sum);
         P(se.avg.load_avg);
+        P(se.avg.runnable_load_avg);
         P(se.avg.util_avg);
         P(se.avg.last_update_time);
 #endif