From: "tip-bot2 for Vincent Guittot" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Vincent Guittot <vincent.guittot@linaro.org>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Valentin Schneider <valentin.schneider@arm.com>,
Mel Gorman <mgorman@suse.de>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: sched/core] sched/fair: Don't set LBF_ALL_PINNED unnecessarily
Date: Thu, 14 Jan 2021 11:29:05 -0000 [thread overview]
Message-ID: <161062374587.414.798453801576383250.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20210107103325.30851-3-vincent.guittot@linaro.org>
The following commit has been merged into the sched/core branch of tip:
Commit-ID: 8a41dfcda7a32ed4435c00d98a9dc7156b08b671
Gitweb: https://git.kernel.org/tip/8a41dfcda7a32ed4435c00d98a9dc7156b08b671
Author: Vincent Guittot <vincent.guittot@linaro.org>
AuthorDate: Thu, 07 Jan 2021 11:33:24 +01:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Thu, 14 Jan 2021 11:20:11 +01:00
sched/fair: Don't set LBF_ALL_PINNED unnecessarily
Setting LBF_ALL_PINNED during active load balance is only valid when there
is only 1 running task on the rq otherwise this ends up increasing the
balance interval whereas other tasks could migrate after the next interval
once they become cache-cold as an example.
LBF_ALL_PINNED flag is now always set it by default. It is then cleared
when we find one task that can be pulled when calling detach_tasks() or
during active migration.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Link: https://lkml.kernel.org/r/20210107103325.30851-3-vincent.guittot@linaro.org
---
kernel/sched/fair.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 13de7ae..48f99c8 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -9639,6 +9639,8 @@ redo:
env.src_rq = busiest;
ld_moved = 0;
+ /* Clear this flag as soon as we find a pullable task */
+ env.flags |= LBF_ALL_PINNED;
if (busiest->nr_running > 1) {
/*
* Attempt to move tasks. If find_busiest_group has found
@@ -9646,7 +9648,6 @@ redo:
* still unbalanced. ld_moved simply stays zero, so it is
* correctly treated as an imbalance.
*/
- env.flags |= LBF_ALL_PINNED;
env.loop_max = min(sysctl_sched_nr_migrate, busiest->nr_running);
more_balance:
@@ -9772,10 +9773,12 @@ more_balance:
if (!cpumask_test_cpu(this_cpu, busiest->curr->cpus_ptr)) {
raw_spin_unlock_irqrestore(&busiest->lock,
flags);
- env.flags |= LBF_ALL_PINNED;
goto out_one_pinned;
}
+ /* Record that we found at least one task that could run on this_cpu */
+ env.flags &= ~LBF_ALL_PINNED;
+
/*
* ->active_balance synchronizes accesses to
* ->active_balance_work. Once set, it's cleared
next prev parent reply other threads:[~2021-01-14 11:30 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-07 10:33 [PATCH 0/3 v2] Reduce number of active LB Vincent Guittot
2021-01-07 10:33 ` [PATCH 1/3 v2] sched/fair: skip idle cfs_rq Vincent Guittot
2021-01-11 14:46 ` Mel Gorman
2021-01-14 11:29 ` [tip: sched/core] sched/fair: Skip " tip-bot2 for Vincent Guittot
2021-01-07 10:33 ` [PATCH 2/3 v2] sched/fair: don't set LBF_ALL_PINNED unnecessarily Vincent Guittot
2021-01-07 11:26 ` Valentin Schneider
[not found] ` <BN8PR12MB2978EC9CFBAF529C527D05919AAF0@BN8PR12MB2978.namprd12.prod.outlook.com>
2021-01-07 16:00 ` Vincent Guittot
2021-01-11 15:42 ` Mel Gorman
2021-01-14 11:29 ` tip-bot2 for Vincent Guittot [this message]
2021-01-07 10:33 ` [PATCH 3/3 v2] sched/fair: reduce cases for active balance Vincent Guittot
2021-01-07 11:26 ` Valentin Schneider
2021-01-07 12:20 ` Vincent Guittot
2021-01-07 17:40 ` Valentin Schneider
2021-01-08 8:11 ` Vincent Guittot
2021-01-08 14:36 ` Valentin Schneider
2021-01-12 9:16 ` Mel Gorman
2021-01-14 11:29 ` [tip: sched/core] sched/fair: Reduce " tip-bot2 for Vincent Guittot
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