Re: [PATCH V3 net-next 0/3] RDS: optimized notification for zerocopy completion

[Willem de Bruijn]

On Sun, Feb 25, 2018 at 6:21 PM, Sowmini Varadhan
 wrote:
> RDS applications use predominantly request-response, transacation
> based IPC, so that ingress and egress traffic are well-balanced,
> and it is possible/desirable to reduce system-call overhead by
> piggybacking the notifications for zerocopy completion response
> with data.
>
> Moreover, it has been pointed out that socket functions block
> if sk_err is non-zero, thus if the RDS code does not plan/need
> to use sk_error_queue path for completion notification, it
> is preferable to remove the sk_errror_queue related paths in
> RDS.
>
> Both of these goals are implemented in this series.
>
> v2: removed sk_error_queue support
> v3: incorporated additional code review comments (details in each patch)
>
> Sowmini Varadhan (3):
>   selftests/net: revert the zerocopy Rx path for PF_RDS
>   rds: deliver zerocopy completion notification with data
>   selftests/net: reap zerocopy completions passed up as ancillary data.
>
>  include/uapi/linux/errqueue.h  |2 -
>  include/uapi/linux/rds.h   |7 ++
>  net/rds/af_rds.c   |7 +-
>  net/rds/message.c  |   38 -
>  net/rds/rds.h  |2 +
>  net/rds/recv.c |   31 +++-
>  tools/testing/selftests/net/msg_zerocopy.c |  120 
> 
>  7 files changed, 111 insertions(+), 96 deletions(-)

For the series:

Acked-by Willem de Bruijn 

Small item I missed in v2: the recvmsg in patch 3 should fail hard with
error() on an unexpected errno. Not worth sending a v4 just for that.

[PATCH V3 net-next 0/3] RDS: optimized notification for zerocopy completion

[Sowmini Varadhan]

RDS applications use predominantly request-response, transacation
based IPC, so that ingress and egress traffic are well-balanced,
and it is possible/desirable to reduce system-call overhead by
piggybacking the notifications for zerocopy completion response
with data.

Moreover, it has been pointed out that socket functions block
if sk_err is non-zero, thus if the RDS code does not plan/need
to use sk_error_queue path for completion notification, it
is preferable to remove the sk_errror_queue related paths in
RDS.

Both of these goals are implemented in this series.

v2: removed sk_error_queue support
v3: incorporated additional code review comments (details in each patch)

Sowmini Varadhan (3):
  selftests/net: revert the zerocopy Rx path for PF_RDS
  rds: deliver zerocopy completion notification with data
  selftests/net: reap zerocopy completions passed up as ancillary data.

 include/uapi/linux/errqueue.h  |2 -
 include/uapi/linux/rds.h   |7 ++
 net/rds/af_rds.c   |7 +-
 net/rds/message.c  |   38 -
 net/rds/rds.h  |2 +
 net/rds/recv.c |   31 +++-
 tools/testing/selftests/net/msg_zerocopy.c |  120 
 7 files changed, 111 insertions(+), 96 deletions(-)