RE: [PATCH V3 2/2 net-next] hyperv: Support batched notification
From: KY Srinivasan
Date: Thu Mar 19 2015 - 12:54:10 EST
> -----Original Message-----
> From: Jason Wang [mailto:jasowang@xxxxxxxxxx]
> Sent: Tuesday, March 17, 2015 8:09 PM
> To: KY Srinivasan
> Cc: davem@xxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; devel@xxxxxxxxxxxxxxxxxxxxxx; olaf@xxxxxxxxx;
> apw@xxxxxxxxxxxxx; KY Srinivasan
> Subject: Re: [PATCH V3 2/2 net-next] hyperv: Support batched notification
>
>
>
> On Wed, Mar 18, 2015 at 12:02 AM, K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
> wrote:
> > Optimize notifying the host by deferring notification until there
> > are no more packets to be sent. This will help in batching the
> > requests
> > on the host.
> >
> > Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
> > ---
> > drivers/net/hyperv/hyperv_net.h | 2 +-
> > drivers/net/hyperv/netvsc.c | 14 +++++++++-----
> > drivers/net/hyperv/netvsc_drv.c | 2 +-
> > drivers/net/hyperv/rndis_filter.c | 2 +-
> > 4 files changed, 12 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/net/hyperv/hyperv_net.h
> > b/drivers/net/hyperv/hyperv_net.h
> > index 4815843..3fd9896 100644
> > --- a/drivers/net/hyperv/hyperv_net.h
> > +++ b/drivers/net/hyperv/hyperv_net.h
> > @@ -184,7 +184,7 @@ struct rndis_device {
> > int netvsc_device_add(struct hv_device *device, void
> > *additional_info);
> > int netvsc_device_remove(struct hv_device *device);
> > int netvsc_send(struct hv_device *device,
> > - struct hv_netvsc_packet *packet);
> > + struct hv_netvsc_packet *packet, bool kick_q);
> > void netvsc_linkstatus_callback(struct hv_device *device_obj,
> > struct rndis_message *resp);
> > int netvsc_recv_callback(struct hv_device *device_obj,
> > diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
> > index 208eb05..9003b94 100644
> > --- a/drivers/net/hyperv/netvsc.c
> > +++ b/drivers/net/hyperv/netvsc.c
> > @@ -707,7 +707,7 @@ static u32 netvsc_copy_to_send_buf(struct
> > netvsc_device *net_device,
> > }
> >
> > int netvsc_send(struct hv_device *device,
> > - struct hv_netvsc_packet *packet)
> > + struct hv_netvsc_packet *packet, bool kick_q)
> > {
> > struct netvsc_device *net_device;
> > int ret = 0;
> > @@ -719,6 +719,7 @@ int netvsc_send(struct hv_device *device,
> > u32 msg_size = 0;
> > struct sk_buff *skb = NULL;
> > u16 q_idx = packet->q_idx;
> > + u32 vmbus_flags =
> VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
> >
> >
> > net_device = get_outbound_net_device(device);
> > @@ -768,18 +769,21 @@ int netvsc_send(struct hv_device *device,
> > return -ENODEV;
> >
> > if (packet->page_buf_cnt) {
> > - ret = vmbus_sendpacket_pagebuffer(out_channel,
> > + ret = vmbus_sendpacket_pagebuffer_ctl(out_channel,
> > packet->page_buf,
> > packet->page_buf_cnt,
> > &sendMessage,
> > sizeof(struct
> nvsp_message),
> > - req_id);
> > + req_id,
> > + vmbus_flags,
> > + kick_q);
> > } else {
> > - ret = vmbus_sendpacket(out_channel, &sendMessage,
> > + ret = vmbus_sendpacket_ctl(out_channel, &sendMessage,
> > sizeof(struct nvsp_message),
> > req_id,
> > VM_PKT_DATA_INBAND,
> > -
> VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
> > + vmbus_flags,
> > + kick_q);
> > }
> >
> > if (ret == 0) {
> > diff --git a/drivers/net/hyperv/netvsc_drv.c
> > b/drivers/net/hyperv/netvsc_drv.c
> > index a06bd66..eae58db 100644
> > --- a/drivers/net/hyperv/netvsc_drv.c
> > +++ b/drivers/net/hyperv/netvsc_drv.c
> > @@ -556,7 +556,7 @@ do_send:
> > packet->page_buf_cnt = init_page_array(rndis_msg,
> rndis_msg_size,
> > skb, &packet->page_buf[0]);
> >
> > - ret = netvsc_send(net_device_ctx->device_ctx, packet);
> > + ret = netvsc_send(net_device_ctx->device_ctx, packet,
> > !skb->xmit_more);
> >
>
> Looks like the issue of V2 still there (E.g we need to kick when
> hv_ringbuffer_write() returns -EAGAIN?
Jason, this issue will be handled in the lower layer. I have already submitted a patch to the vmbus
Driver that correctly signals the host when EAGAIN is encountered.
Regards,
K. Y