Re: [PATCH 1/2] SUNRPC: Make rpciod and xprtiod visible in sysfs

[Mike Snitzer <snitzer@kernel.org>]

On Fri, Nov 13, 2026 at 09:18:36AM -0500, Chuck Lever wrote:
> 
> 
> On Thu, Nov 12, 2026, at 7:16 PM, Mike Snitzer wrote:
> > rpciod and xprtiod are unbound workqueues.  An async task's work is
> > queued to the affinity pod of the CPU that queues it, but an unbound
> > workqueue's affinity is not strict by default, so the scheduler is free
> > to run the worker on any CPU the workqueue allows.  On a two-node NFS
> > client whose writers are pinned to the node local to their NIC, with
> > the workqueues' affinity scope set to numa, 1.5% to 2.4% of the skbs
> > sent on each port were still handed to the driver from the other
> > node's CPUs: 97% of them from rpciod running rpc_async_schedule(), the
> > rest from xprtiod.
> >
> > Neither workqueue can be made strict today, because neither is created
> > with WQ_SYSFS and so neither has affinity_scope, affinity_strict or
> > cpumask under /sys/devices/virtual/workqueue/.  Add WQ_SYSFS to both.
> > Nothing changes until an administrator writes those attributes.
> >
> > With affinity_strict set to 1 on both, the same client sent nothing
> > from the other node and spent about 1.7 fewer CPUs at the same
> > throughput.
> >
> > Signed-off-by: Mike Snitzer <snitzer@kernel.org>
> > ---
> >  net/sunrpc/sched.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
> > index 016f16ca57799..83e2974a44d9f 100644
> > --- a/net/sunrpc/sched.c
> > +++ b/net/sunrpc/sched.c
> > @@ -1278,11 +1278,11 @@ static int rpciod_start(void)
> >  	/*
> >  	 * Create the rpciod thread and wait for it to start.
> >  	 */
> > -	wq = alloc_workqueue("rpciod", WQ_MEM_RECLAIM | WQ_UNBOUND, 0);
> > +	wq = alloc_workqueue("rpciod", WQ_MEM_RECLAIM | WQ_UNBOUND | WQ_SYSFS, 0);
> >  	if (!wq)
> >  		goto out_failed;
> >  	rpciod_workqueue = wq;
> > -	wq = alloc_workqueue("xprtiod", WQ_UNBOUND | WQ_MEM_RECLAIM, 0);
> > +	wq = alloc_workqueue("xprtiod", WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS, 0);
> >  	if (!wq)
> >  		goto free_rpciod;
> >  	xprtiod_workqueue = wq;
> > -- 
> > 2.52.0
> 
> I already posted a patch for this back in September:
> 
> https://lore.kernel.org/linux-nfs/20260915-performance-v3-3-ae26d460bfd3@kernel.org/

Nice

> Did it get rejected?

Maybe it was overlooked, Anna?