diff options
| author | Srikar Dronamraju <srikar@linux.vnet.ibm.com> | 2016-03-23 17:54:44 +0530 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-03-31 10:49:44 +0200 |
| commit | d02c071183e1c01a76811c878c8a52322201f81f (patch) | |
| tree | 98fb73f6d3e52cc148d7ac792add8588f46553f6 /kernel/sched/fair.c | |
| parent | d740037fac7052e49450f6fa1454f1144a103b55 (diff) | |
sched/fair: Reset nr_balance_failed after active balancing
To force a task migration during active balancing, nr_balance_failed is set
to cache_nice_tries + 1. However nr_balance_failed is not reset. As a side
effect, the next regular load balance under the same sd, a cache hot task
might be migrated, just because nr_balance_failed count is high.
Resetting nr_balance_failed after a successful active balance ensures
that a hot task is not unreasonably migrated. This can be verified by
looking at othe number of hot task migrations reported by /proc/schedstat.
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1458735884-30105-1-git-send-email-srikar@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/fair.c')
| -rw-r--r-- | kernel/sched/fair.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 0fe30e66aff1..cbb075e46b2c 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7399,10 +7399,7 @@ more_balance: &busiest->active_balance_work); } - /* - * We've kicked active balancing, reset the failure - * counter. - */ + /* We've kicked active balancing, force task migration. */ sd->nr_balance_failed = sd->cache_nice_tries+1; } } else @@ -7637,10 +7634,13 @@ static int active_load_balance_cpu_stop(void *data) schedstat_inc(sd, alb_count); p = detach_one_task(&env); - if (p) + if (p) { schedstat_inc(sd, alb_pushed); - else + /* Active balancing done, reset the failure counter. */ + sd->nr_balance_failed = 0; + } else { schedstat_inc(sd, alb_failed); + } } rcu_read_unlock(); out_unlock: |