Messages in this thread Patch in this message | | | From | Waiman Long <> | Subject | [PATCH-wq v3 3/4] kernel/workqueue: Let rescuers follow unbound wq cpumask changes | Date | Mon, 5 Feb 2024 14:46:01 -0500 |
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From: Juri Lelli <juri.lelli@redhat.com>
When workqueue cpumask changes are committed the associated rescuer (if one exists) affinity is not touched and this might be a problem down the line for isolated setups.
Make sure rescuers affinity is updated every time a workqueue cpumask changes, so that rescuers can't break isolation.
[longman: set_cpus_allowed_ptr() will block until the designated task is enqueued on an allowed CPU, no wake_up_process() needed. Also use the unbound_effective_cpumask() helper as suggested by Tejun.]
Signed-off-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Waiman Long <longman@redhat.com> Tested-by: Juri Lelli <juri.lelli@redhat.com> --- kernel/workqueue.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index f453f339f74a..bbd4269d2729 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -5049,6 +5049,11 @@ static void apply_wqattrs_commit(struct apply_wqattrs_ctx *ctx) /* update node_nr_active->max */ wq_update_node_max_active(ctx->wq, -1); + /* rescuer needs to respect wq cpumask changes */ + if (ctx->wq->rescuer) + set_cpus_allowed_ptr(ctx->wq->rescuer->task, + unbound_effective_cpumask(ctx->wq)); + mutex_unlock(&ctx->wq->mutex); } -- 2.39.3
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