workqueue: Provide queue_work_node to queue work near a given NUMA node

Provide a new function, queue_work_node, which is meant to schedule work on
a "random" CPU of the requested NUMA node. The main motivation for this is
to help assist asynchronous init to better improve boot times for devices
that are local to a specific node.

For now we just default to the first CPU that is in the intersection of the
cpumask of the node and the online cpumask. The only exception is if the
CPU is local to the node we will just use the current CPU. This should work
for our purposes as we are currently only using this for unbound work so
the CPU will be translated to a node anyway instead of being directly used.

As we are only using the first CPU to represent the NUMA node for now I am
limiting the scope of the function so that it can only be used with unbound
workqueues.

Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 60d673e15632..1f50c1e586e7 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -463,6 +463,8 @@ int workqueue_set_unbound_cpumask(cpumask_var_t cpumask);
 
 extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
 			struct work_struct *work);
+extern bool queue_work_node(int node, struct workqueue_struct *wq,
+			    struct work_struct *work);
 extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 			struct delayed_work *work, unsigned long delay);
 extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,