From: Peter Zijlstra <peterz@infradead.org>
To: mingo@kernel.org, tglx@linutronix.de
Cc: linux-kernel@vger.kernel.org, jiangshanlai@gmail.com,
valentin.schneider@arm.com, cai@redhat.com,
vincent.donnefort@arm.com, decui@microsoft.com,
paulmck@kernel.org, vincent.guittot@linaro.org,
rostedt@goodmis.org, tj@kernel.org, peterz@infradead.org
Subject: [PATCH 2/8] workqueue: Use cpu_possible_mask instead of cpu_active_mask to break affinity
Date: Sat, 16 Jan 2021 12:30:35 +0100 [thread overview]
Message-ID: <20210116113919.674601326@infradead.org> (raw)
In-Reply-To: 20210116113033.608340773@infradead.org
From: Lai Jiangshan <laijs@linux.alibaba.com>
The scheduler won't break affinity for us any more, and we should
"emulate" the same behavior when the scheduler breaks affinity for
us. The behavior is "changing the cpumask to cpu_possible_mask".
And there might be some other CPUs online later while the worker is
still running with the pending work items. The worker should be allowed
to use the later online CPUs as before and process the work items ASAP.
If we use cpu_active_mask here, we can't achieve this goal but
using cpu_possible_mask can.
Fixes: 06249738a41a ("workqueue: Manually break affinity on hotplug")
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Tejun Heo <tj@kernel.org>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lkml.kernel.org/r/20210111152638.2417-4-jiangshanlai@gmail.com
---
kernel/workqueue.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -4920,7 +4920,7 @@ static void unbind_workers(int cpu)
raw_spin_unlock_irq(&pool->lock);
for_each_pool_worker(worker, pool)
- WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, cpu_active_mask) < 0);
+ WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, cpu_possible_mask) < 0);
mutex_unlock(&wq_pool_attach_mutex);
next prev parent reply other threads:[~2021-01-16 11:44 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-16 11:30 [PATCH 0/8] sched: Fix hot-unplug regressions Peter Zijlstra
2021-01-16 11:30 ` [PATCH 1/8] sched/core: Print out straggler tasks in sched_cpu_dying() Peter Zijlstra
2021-01-16 11:30 ` Peter Zijlstra [this message]
2021-01-16 11:30 ` [PATCH 3/8] sched: Dont run cpu-online with balance_push() enabled Peter Zijlstra
2021-01-16 15:27 ` Peter Zijlstra
2021-01-16 11:30 ` [PATCH 4/8] kthread: Extract KTHREAD_IS_PER_CPU Peter Zijlstra
2021-01-16 11:30 ` [PATCH 5/8] workqueue: Tag bound workers with KTHREAD_IS_PER_CPU Peter Zijlstra
2021-01-16 11:30 ` [PATCH 6/8] workqueue: Restrict affinity change to rescuer Peter Zijlstra
2021-01-16 11:30 ` [PATCH 7/8] sched: Fix CPU hotplug / tighten is_per_cpu_kthread() Peter Zijlstra
2021-01-17 16:57 ` Valentin Schneider
2021-01-18 9:30 ` Peter Zijlstra
2021-01-16 11:30 ` [PATCH 8/8] sched: Relax the set_cpus_allowed_ptr() semantics Peter Zijlstra
2021-01-16 14:39 ` Lai Jiangshan
2021-01-16 15:19 ` Peter Zijlstra
2021-01-16 15:25 ` [PATCH 0/8] sched: Fix hot-unplug regressions Peter Zijlstra
2021-01-16 15:45 ` Paul E. McKenney
2021-01-16 18:51 ` Peter Zijlstra
2021-01-16 15:48 ` Paul E. McKenney
2021-01-18 5:28 ` Paul E. McKenney
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