Messages in this thread Patch in this message | | | From | Jason Low <> | Subject | [PATCH 1/2] sched: Fix updating rq->max_idle_balance_cost and rq->next_balance in idle_balance() | Date | Mon, 28 Apr 2014 15:45:54 -0700 |
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Commit e5fc6611 can potentially cause rq->max_idle_balance_cost to not be updated, even when load_balance(NEWLY_IDLE) is attempted and the per-sd max cost value is updated.
Preeti noticed a similar issue with updating rq->next_balance.
In this patch, we fix this by making sure we still check/update those values even if a task gets enqueued while browsing the domains.
Cc: daniel.lezcano@linaro.org Cc: alex.shi@linaro.org Cc: efault@gmx.de Cc: vincent.guittot@linaro.org Cc: morten.rasmussen@arm.com Cc: aswin@hp.com Cc: mingo@kernel.org Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Signed-off-by: Jason Low <jason.low2@hp.com> --- kernel/sched/fair.c | 16 ++++++++-------- 1 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index af47873..e0f3019 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6658,6 +6658,7 @@ static int idle_balance(struct rq *this_rq) int this_cpu = this_rq->cpu; idle_enter_fair(this_rq); + /* * We must set idle_stamp _before_ calling idle_balance(), such that we * measure the duration of idle_balance() as idle time. @@ -6714,14 +6715,16 @@ static int idle_balance(struct rq *this_rq) raw_spin_lock(&this_rq->lock); + if (curr_cost > this_rq->max_idle_balance_cost) + this_rq->max_idle_balance_cost = curr_cost; + /* - * While browsing the domains, we released the rq lock. - * A task could have be enqueued in the meantime + * While browsing the domains, we released the rq lock, a task could + * have been enqueued in the meantime. Since we're not going idle, + * pretend we pulled a task. */ - if (this_rq->cfs.h_nr_running && !pulled_task) { + if (this_rq->cfs.h_nr_running && !pulled_task) pulled_task = 1; - goto out; - } if (pulled_task || time_after(jiffies, this_rq->next_balance)) { /* @@ -6731,9 +6734,6 @@ static int idle_balance(struct rq *this_rq) this_rq->next_balance = next_balance; } - if (curr_cost > this_rq->max_idle_balance_cost) - this_rq->max_idle_balance_cost = curr_cost; - out: /* Is there a task of a high priority class? */ if (this_rq->nr_running != this_rq->cfs.h_nr_running) -- 1.7.1
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