Re: [PATCH net-next 3/6] sunrpc: Use sendmsg(MSG_SPLICE_PAGES) rather then sendpage

[Jeff Layton <jlayton@kernel.org>]

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On Fri, 2023-08-11 at 18:50 -0400, Jeff Layton wrote:
> On Fri, 2023-06-09 at 11:02 +0100, David Howells wrote:
> > When transmitting data, call down into TCP using sendmsg with
> > MSG_SPLICE_PAGES to indicate that content should be spliced rather than
> > performing sendpage calls to transmit header, data pages and trailer.
> > 
> > Signed-off-by: David Howells <dhowells@redhat.com>
> > Acked-by: Chuck Lever <chuck.lever@oracle.com>
> > cc: Trond Myklebust <trond.myklebust@hammerspace.com>
> > cc: Anna Schumaker <anna@kernel.org>
> > cc: Jeff Layton <jlayton@kernel.org>
> > cc: "David S. Miller" <davem@davemloft.net>
> > cc: Eric Dumazet <edumazet@google.com>
> > cc: Jakub Kicinski <kuba@kernel.org>
> > cc: Paolo Abeni <pabeni@redhat.com>
> > cc: Jens Axboe <axboe@kernel.dk>
> > cc: Matthew Wilcox <willy@infradead.org>
> > cc: linux-nfs@vger.kernel.org
> > cc: netdev@vger.kernel.org
> > ---
> >  include/linux/sunrpc/svc.h | 11 +++++------
> >  net/sunrpc/svcsock.c       | 38 ++++++++++++--------------------------
> >  2 files changed, 17 insertions(+), 32 deletions(-)
> > 
> 
> I'm seeing a regression in pynfs runs with v6.5-rc5. 3 tests are failing
> in a similar fashion. WRT1b is one of them
> 
> [vagrant@jlayton-kdo-nfsd nfs4.0]$  ./testserver.py --rundeps --maketree --uid=0 --gid=0 localhost:/export/pynfs/4.0/ WRT1b                                                     
> **************************************************                                                                                                                              
> WRT1b    st_write.testSimpleWrite2                                : FAILURE                                                                                                     
>            READ returned                                                                                                                                                        
>            b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00',                                                                                                     
>            expected b'\x00\x00\x00\x00\x00write data'                                                                                                                           
> INIT     st_setclientid.testValid                                 : PASS                                                                                                        
> MKFILE   st_open.testOpen                                         : PASS                                                                                                        
> **************************************************                                                                                                                              
> Command line asked for 3 of 679 tests                                                                                                                                           
> Of those: 0 Skipped, 1 Failed, 0 Warned, 2 Passed                                                   

FWIW, here's a capture that shows the problem. See frames 109-112 in
particular. If no one has thoughts on this one, I'll plan to have a look
early next week.

Thanks,
-- 
Jeff Layton <jlayton@kernel.org>

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