Re: [RFC PATCH 5/5] SUNRPC: Reduce the priority of the xprtiod queue

[Trond Myklebust <trondmy@hammerspace.com>]

On Wed, 2019-05-29 at 14:38 -0400, Olga Kornievskaia wrote:
> On Tue, May 28, 2019 at 4:10 PM Olga Kornievskaia <aglo@umich.edu>
> wrote:
> > On Fri, May 3, 2019 at 7:24 AM Trond Myklebust <trondmy@gmail.com>
> > wrote:
> > > Allow more time for softirqd
> > > 
> > > Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
> > > ---
> > >  net/sunrpc/sched.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
> > > index c7e81336620c..6b37c9a4b48f 100644
> > > --- a/net/sunrpc/sched.c
> > > +++ b/net/sunrpc/sched.c
> > > @@ -1253,7 +1253,7 @@ static int rpciod_start(void)
> > >                 goto out_failed;
> > >         rpciod_workqueue = wq;
> > >         /* Note: highpri because network receive is latency
> > > sensitive */
> > > -       wq = alloc_workqueue("xprtiod",
> > > WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_HIGHPRI, 0);
> > 
> > I thought we needed UNBOUND otherwise there was performance
> > degradation for read IO.
> 
> I remove my objection as this is for the xprtiod queue and not the
> rpciod queue. The latter is the one when removing WQ_UNBOUND would
> only use a single rpciod thread for doing all the crypto and thus
> impact performance.
> 
> > > +       wq = alloc_workqueue("xprtiod", WQ_MEM_RECLAIM |
> > > WQ_UNBOUND, 0);
> > >         if (!wq)
> > >                 goto free_rpciod;
> > >         xprtiod_workqueue = wq;
> > > --
> > > 2.21.0
> > > 

It was only removing the WQ_HIGHPRI flag, not the WQ_UNBOUND. However
the point it moot, as I'm dropping the patch.

Cheers
 Trond

-- 
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@hammerspace.com