sched/fair: Make the entity load aging on attaching tunable

In case there are problems with the aging on attach, provide a debug
knob to turn it off.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: yuyang.du@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 5143ea0cb55bcbc3b4ace40acc6c39e5d028a7b5..5cd7054aac85fc465861c6b7242e082f1397fd63 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2712,6 +2712,9 @@ static inline void update_load_avg(struct sched_entity *se, int update_tg)
 
 static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
+       if (!sched_feat(ATTACH_AGE_LOAD))
+               goto skip_aging;
+
        /*
         * If we got migrated (either between CPUs or between cgroups) we'll
         * have aged the average right before clearing @last_update_time.
@@ -2726,6 +2729,7 @@ static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
                 */
        }
 
+skip_aging:
        se->avg.last_update_time = cfs_rq->avg.last_update_time;
        cfs_rq->avg.load_avg += se->avg.load_avg;
        cfs_rq->avg.load_sum += se->avg.load_sum;

diff --git a/kernel/sched/features.h b/kernel/sched/features.h
index 83a50e7ca53315695f779e2c5ac7177c423b646d..e6fd23b7459b3379fabcac549608e5c839d4a1a4 100644 (file)
--- a/kernel/sched/features.h
+++ b/kernel/sched/features.h
@@ -73,6 +73,8 @@ SCHED_FEAT(FORCE_SD_OVERLAP, false)
 SCHED_FEAT(RT_RUNTIME_SHARE, true)
 SCHED_FEAT(LB_MIN, false)
 
+SCHED_FEAT(ATTACH_AGE_LOAD, true)
+
 /*
  * Apply the automatic NUMA scheduling policy. Enabled automatically
  * at runtime if running on a NUMA machine. Can be controlled via