Commit-ID: 53d3bc773eaa7ab1cf63585e76af7ee869d5e709
Gitweb: http://git.kernel.org/tip/53d3bc773eaa7ab1cf63585e76af7ee869d5e709
Author: Ingo Molnar <mingo@xxxxxxxxxx>
AuthorDate: Wed, 11 May 2016 08:25:53 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 11 May 2016 08:25:53 +0200
Revert "sched/fair: Fix fairness issue on migration"
Mike reported that this recent commit:
3a47d5124a95 ("sched/fair: Fix fairness issue on migration")
... broke interactivity and the signal starvation test.
We have a proper fix series in the works but ran out of time for
v4.6, so revert the commit.
Reported-by: Mike Galbraith <efault@xxxxxx>
Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/fair.c | 20 ++++++--------------
1 file changed, 6 insertions(+), 14 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 40748dc..e7dd0ec 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3188,25 +3188,17 @@ static inline void check_schedstat_required(void)
static void
enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
{
- bool renorm = !(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_WAKING);
- bool curr = cfs_rq->curr == se;
-
/*
- * If we're the current task, we must renormalise before calling
- * update_curr().
+ * Update the normalized vruntime before updating min_vruntime
+ * through calling update_curr().
*/
- if (renorm && curr)
+ if (!(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_WAKING))
se->vruntime += cfs_rq->min_vruntime;
- update_curr(cfs_rq);
-
/*
- * Otherwise, renormalise after, such that we're placed at the current
- * moment in time, instead of some random moment in the past.
+ * Update run-time statistics of the 'current'.
*/
- if (renorm && !curr)
- se->vruntime += cfs_rq->min_vruntime;
-
+ update_curr(cfs_rq);
enqueue_entity_load_avg(cfs_rq, se);
account_entity_enqueue(cfs_rq, se);
update_cfs_shares(cfs_rq);
@@ -3222,7 +3214,7 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
update_stats_enqueue(cfs_rq, se);
check_spread(cfs_rq, se);
}
- if (!curr)
+ if (se != cfs_rq->curr)
__enqueue_entity(cfs_rq, se);
se->on_rq = 1;
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|