Revert "sched: Update_cfs_shares at period edge"
This reverts commit f269ae0469fc882332bdfb5db15d3c1315fe2a10.
It turns out it causes a very noticeable interactivity regression with
CONFIG_SCHED_AUTOGROUP (test-case: "make -j32" of the kernel in a
terminal window, while scrolling in a browser - the autogrouping means
that the two end up in separate cgroups, and the browser should be
smooth as silk despite the high load).
Says Paul Turner:
"It seems that the update-throttling on the wake-side is reducing the
interactive tasks' ability to preempt. While I suspect the right
longer term answer here is force these updates only in the
cross-cgroup case; this is less trivial. For this release I believe
the right answer is either going to be a revert or restore the updates
on the enqueue-side."
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Bisected-by: Mike Galbraith <efault@gmx.de>
Acked-by: Paul Turner <pjt@google.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 59e072b..756f9f9 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1265,7 +1265,6 @@
}
__update_cfs_rq_tg_load_contrib(cfs_rq, force_update);
- update_cfs_shares(cfs_rq);
}
static inline void update_rq_runnable_avg(struct rq *rq, int runnable)
@@ -1475,8 +1474,9 @@
* Update run-time statistics of the 'current'.
*/
update_curr(cfs_rq);
- account_entity_enqueue(cfs_rq, se);
enqueue_entity_load_avg(cfs_rq, se, flags & ENQUEUE_WAKEUP);
+ account_entity_enqueue(cfs_rq, se);
+ update_cfs_shares(cfs_rq);
if (flags & ENQUEUE_WAKEUP) {
place_entity(cfs_rq, se, 0);
@@ -1549,6 +1549,7 @@
* Update run-time statistics of the 'current'.
*/
update_curr(cfs_rq);
+ dequeue_entity_load_avg(cfs_rq, se, flags & DEQUEUE_SLEEP);
update_stats_dequeue(cfs_rq, se);
if (flags & DEQUEUE_SLEEP) {
@@ -1568,8 +1569,8 @@
if (se != cfs_rq->curr)
__dequeue_entity(cfs_rq, se);
+ se->on_rq = 0;
account_entity_dequeue(cfs_rq, se);
- dequeue_entity_load_avg(cfs_rq, se, flags & DEQUEUE_SLEEP);
/*
* Normalize the entity after updating the min_vruntime because the
@@ -1583,7 +1584,7 @@
return_cfs_rq_runtime(cfs_rq);
update_min_vruntime(cfs_rq);
- se->on_rq = 0;
+ update_cfs_shares(cfs_rq);
}
/*
@@ -2595,8 +2596,8 @@
if (cfs_rq_throttled(cfs_rq))
break;
+ update_cfs_shares(cfs_rq);
update_entity_load_avg(se, 1);
- update_cfs_rq_blocked_load(cfs_rq, 0);
}
if (!se) {
@@ -2656,8 +2657,8 @@
if (cfs_rq_throttled(cfs_rq))
break;
+ update_cfs_shares(cfs_rq);
update_entity_load_avg(se, 1);
- update_cfs_rq_blocked_load(cfs_rq, 0);
}
if (!se) {
@@ -5837,11 +5838,8 @@
se = tg->se[i];
/* Propagate contribution to hierarchy */
raw_spin_lock_irqsave(&rq->lock, flags);
- for_each_sched_entity(se) {
+ for_each_sched_entity(se)
update_cfs_shares(group_cfs_rq(se));
- /* update contribution to parent */
- update_entity_load_avg(se, 1);
- }
raw_spin_unlock_irqrestore(&rq->lock, flags);
}