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| author |   Hillf Danton <hdanton@sina.com> | 2020-01-24 20:14:45 -0500 |
|---|---|---|
| committer |   Tejun Heo <tj@kernel.org> | 2020-03-10 10:30:51 -0400 |
| commit | aa202f1f56960c60e7befaa0f49c72b8fa11b0a8 (patch) | |
| tree | 4666dc8751cd9751ac29f07b96e083ae9bb29f48 /kernel/workqueue.c | |
| parent | workqueue: Document (some) memory-ordering properties of {queue,schedule}_work() (diff) | |
| download | linux-dev-aa202f1f56960c60e7befaa0f49c72b8fa11b0a8.tar.xz linux-dev-aa202f1f56960c60e7befaa0f49c72b8fa11b0a8.zip | |
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/workqueue.c')
| -rw-r--r-- | kernel/workqueue.c | 14 |
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 |