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authorHillf Danton <hdanton@sina.com>2020-01-24 20:14:45 -0500
committerTejun Heo <tj@kernel.org>2020-03-10 10:30:51 -0400
commitaa202f1f56960c60e7befaa0f49c72b8fa11b0a8 (patch)
tree4666dc8751cd9751ac29f07b96e083ae9bb29f48 /kernel
parentdbb92f88648d6206bf22fcb764fb9fe2939d401a (diff)
workqueue: don't use wq_select_unbound_cpu() for bound works
wq_select_unbound_cpu() is designed for unbound workqueues only, but it's wrongly called when using a bound workqueue too. Fixing this ensures work queued to a bound workqueue with cpu=WORK_CPU_UNBOUND always runs on the local CPU. Before, that would happen only if wq_unbound_cpumask happened to include it (likely almost always the case), or was empty, or we got lucky with forced round-robin placement. So restricting /sys/devices/virtual/workqueue/cpumask to a small subset of a machine's CPUs would cause some bound work items to run unexpectedly there. Fixes: ef557180447f ("workqueue: schedule WORK_CPU_UNBOUND work on wq_unbound_cpumask CPUs") Cc: stable@vger.kernel.org # v4.5+ Signed-off-by: Hillf Danton <hdanton@sina.com> [dj: massage changelog] Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Tejun Heo <tj@kernel.org> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/workqueue.c14
1 files changed, 8 insertions, 6 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 301db4406bc3..4e01c448b4b4 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1411,14 +1411,16 @@ static void __queue_work(int cpu, struct workqueue_struct *wq,
return;
rcu_read_lock();
retry:
- if (req_cpu == WORK_CPU_UNBOUND)
- cpu = wq_select_unbound_cpu(raw_smp_processor_id());
-
/* pwq which will be used unless @work is executing elsewhere */
- if (!(wq->flags & WQ_UNBOUND))
- pwq = per_cpu_ptr(wq->cpu_pwqs, cpu);
- else
+ if (wq->flags & WQ_UNBOUND) {
+ if (req_cpu == WORK_CPU_UNBOUND)
+ cpu = wq_select_unbound_cpu(raw_smp_processor_id());
pwq = unbound_pwq_by_node(wq, cpu_to_node(cpu));
+ } else {
+ if (req_cpu == WORK_CPU_UNBOUND)
+ cpu = raw_smp_processor_id();
+ pwq = per_cpu_ptr(wq->cpu_pwqs, cpu);
+ }
/*
* If @work was previously on a different pool, it might still be