Re: [PATCH] sunrpc: use better NUMA affinities

From: J. Bruce Fields
Date: Fri Jul 29 2011 - 19:49:18 EST


On Sat, Jul 30, 2011 at 09:30:25AM +1000, NeilBrown wrote:
> On Sat, 30 Jul 2011 06:34:44 +1000 Greg Banks <gnb@xxxxxxxxxxx> wrote:
>
> >
> >
> > Sent from my iPhone
> >
> > On 30/07/2011, at 2:53, "J. Bruce Fields" <bfields@xxxxxxxxxxxx> wrote:
> >
> > > On Fri, Jul 29, 2011 at 12:48:36PM -0400, bfields wrote:
> > >> On Fri, Jul 29, 2011 at 11:30:05PM +1000, Greg Banks wrote:
> > >>>
> > >>>
> > >>> Sent from my iPhone
> > >>>
> > >>> On 29/07/2011, at 22:11, Eric Dumazet <eric.dumazet@xxxxxxxxx>
> > >>> wrote:
> > >>>
> > >>>> Le vendredi 29 juillet 2011 Ã 21:58 +1000, Greg Banks a Ãcrit :
> > >>>>
> > >>>>>
> > >>>>> Sure, and a whole lot of the callsites are ("..._%d", cpu),
> > >>>>> hence the
> > >>>>> unfortune :(
> > >>>>
> > >>>> BTW, we could name nfsd threads differently :
> > >>>>
> > >>>> Currently, they all are named : "nfsd"
> > >>>>
> > >>>> If SVC_POOL_PERCPU is selected, we could name them :
> > >>>> nfsd_c0 -> nfsd_cN
> > >>>>
> > >>>> If SVC_POOL_PERNODE is selected, we could name them :
> > >>>> nfsd_n0 -> nfsd_nN
> > >>>>
> > >>>> That would help to check with "ps aux" which cpu/nodes are under
> > >>>> stress.
> > >>>>
> > >>>>
> > >>>
> > >>> I like it!
> > >>
> > >> Yup, patch welcomed.--b.
> > >
> > > (Annoying fact: some initscripts stop nfsd using a rough equivalent of
> > > "killall nfsd". So the name of the threads is arguably ABI. I think
> > > those initscripts are nuts and deserve what they get, but that may be
> > > because I'm forgetting the reason they do that.)
> > >
> >
> > We had this discussion in May-June 2008; it's because the nfsds were
> > once many many years ago userspace threads.
>
> Even when they became kernel threads, 'kill' was the only way to kill them -
> at first.
>
> >
> > The "killall nfsd" semantics in those scripts are awful and lead to
> > problems shutting down when there are lots of threads. It would
> > probably be an improvement to provide a better shutdown mechanism and
> > force distros to use it.
>
> rpc.nfsd 0
>
> will stop all nfsd threads. Follow with
>
> exportfs -f
>
> and you should be done. I'm not 100% sure about the nfsv4 thread though -
> would need to check.

Should be fine.

--b.
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