> -----Original Message-----
> From: Eric Dumazet [mailto:eric.duma...@gmail.com]
> Sent: Thursday, April 30, 2015 9:37 PM
> To: KY Srinivasan
> Cc: da...@davemloft.net; net...@vger.kernel.org; linux-
> ker...@vger.kernel.org; de...@linuxdriverproject.org; o...@aepfle.de;
> a...@canonical.com; jasow...@redhat.com
> Subject: Re: [PATCH V2 net-next 1/1] hv_netvsc: Use the xmit_more skb flag
> to optimize signaling the host
> 
> On Thu, 2015-04-30 at 16:29 -0700, K. Y. Srinivasan wrote:
> > Based on the information given to this driver (via the xmit_more skb flag),
> > we can defer signaling the host if more packets are on the way. This will
> help
> > make the host more efficient since it can potentially process a larger batch
> of
> > packets. Implement this optimization.
> >
> > Signed-off-by: K. Y. Srinivasan <k...@microsoft.com>
> > ---
> >     v2: Fixed up indentation based on feedback from David Miller.
> >
> >  drivers/net/hyperv/netvsc.c |   20 ++++++++++++--------
> >  1 files changed, 12 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
> > index 2e8ad06..5fdc5e1 100644
> > --- a/drivers/net/hyperv/netvsc.c
> > +++ b/drivers/net/hyperv/netvsc.c
> > @@ -743,6 +743,7 @@ static inline int netvsc_send_pkt(
> >     u64 req_id;
> >     int ret;
> >     struct hv_page_buffer *pgbuf;
> > +   u32 vmbus_flags =
> VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
> >
> >     nvmsg.hdr.msg_type = NVSP_MSG1_TYPE_SEND_RNDIS_PKT;
> >     if (packet->is_data_pkt) {
> > @@ -772,19 +773,22 @@ static inline int netvsc_send_pkt(
> >     if (packet->page_buf_cnt) {
> >             pgbuf = packet->cp_partial ? packet->page_buf +
> >                     packet->rmsg_pgcnt : packet->page_buf;
> > -           ret = vmbus_sendpacket_pagebuffer(out_channel,
> > -                                             pgbuf,
> > -                                             packet->page_buf_cnt,
> > -                                             &nvmsg,
> > -                                             sizeof(struct
> nvsp_message),
> > -                                             req_id);
> > +           ret = vmbus_sendpacket_pagebuffer_ctl(out_channel,
> > +                                                 pgbuf,
> > +                                                 packet->page_buf_cnt,
> > +                                                 &nvmsg,
> > +                                                 sizeof(struct
> > +                                                        nvsp_message),
> > +                                                 req_id,
> > +                                                 vmbus_flags,
> > +                                                 !packet->xmit_more);
> >     } else {
> > -           ret = vmbus_sendpacket(
> > +           ret = vmbus_sendpacket_ctl(
> >                             out_channel, &nvmsg,
> >                             sizeof(struct nvsp_message),
> >                             req_id,
> >                             VM_PKT_DATA_INBAND,
> > -
>       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
> > +                           vmbus_flags, !packet->xmit_more);
> >     }
> >
> >     if (ret == 0) {
> 
> This might be problematic, if queue is stopped ( netif_tx_stop_queue())
> 
> You need to force a kick if we are about to stop the queue :
> 
> Random example : commit ddd0ca5d60b350bbfbfb60b25885a9779ce6d6c7

Thanks Eric; I will fix and resend.

Regards,

K. Y
> 
> 

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