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hv_netvsc: Implement batching in send buffer
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With this patch, we can send out multiple RNDIS data packets in one send buffer
slot and one VMBus message. It reduces the overhead associated with VMBus messages.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Haiyang Zhang authored and David S. Miller committed Mar 29, 2015
1 parent 4ef295e commit 7c3877f
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Showing 4 changed files with 162 additions and 47 deletions.
16 changes: 15 additions & 1 deletion drivers/net/hyperv/hyperv_net.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -131,6 +131,7 @@ struct hv_netvsc_packet {

struct hv_device *device;
bool is_data_pkt;
bool xmit_more; /* from skb */
u16 vlan_tci;

u16 q_idx;
Expand Down Expand Up @@ -596,7 +597,16 @@ struct nvsp_message {

#define VRSS_SEND_TAB_SIZE 16

/* Per netvsc channel-specific */
#define RNDIS_MAX_PKT_DEFAULT 8
#define RNDIS_PKT_ALIGN_DEFAULT 8

struct multi_send_data {
spinlock_t lock; /* protect struct multi_send_data */
struct hv_netvsc_packet *pkt; /* netvsc pkt pending */
u32 count; /* counter of batched packets */
};

/* Per netvsc device */
struct netvsc_device {
struct hv_device *dev;

Expand Down Expand Up @@ -647,6 +657,10 @@ struct netvsc_device {
unsigned char *cb_buffer;
/* The sub channel callback buffer */
unsigned char *sub_cb_buf;

struct multi_send_data msd[NR_CPUS];
u32 max_pkt; /* max number of pkt in one send, e.g. 8 */
u32 pkt_align; /* alignment bytes, e.g. 8 */
};

/* NdisInitialize message */
Expand Down
187 changes: 141 additions & 46 deletions drivers/net/hyperv/netvsc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,7 @@ static struct netvsc_device *alloc_net_device(struct hv_device *device)
{
struct netvsc_device *net_device;
struct net_device *ndev = hv_get_drvdata(device);
int i;

net_device = kzalloc(sizeof(struct netvsc_device), GFP_KERNEL);
if (!net_device)
Expand All @@ -53,6 +54,11 @@ static struct netvsc_device *alloc_net_device(struct hv_device *device)
net_device->destroy = false;
net_device->dev = device;
net_device->ndev = ndev;
net_device->max_pkt = RNDIS_MAX_PKT_DEFAULT;
net_device->pkt_align = RNDIS_PKT_ALIGN_DEFAULT;

for (i = 0; i < num_online_cpus(); i++)
spin_lock_init(&net_device->msd[i].lock);

hv_set_drvdata(device, net_device);
return net_device;
Expand Down Expand Up @@ -687,12 +693,23 @@ static u32 netvsc_get_next_send_section(struct netvsc_device *net_device)

static u32 netvsc_copy_to_send_buf(struct netvsc_device *net_device,
unsigned int section_index,
u32 pend_size,
struct hv_netvsc_packet *packet)
{
char *start = net_device->send_buf;
char *dest = (start + (section_index * net_device->send_section_size));
char *dest = start + (section_index * net_device->send_section_size)
+ pend_size;
int i;
u32 msg_size = 0;
u32 padding = 0;
u32 remain = packet->total_data_buflen % net_device->pkt_align;

/* Add padding */
if (packet->is_data_pkt && packet->xmit_more && remain) {
padding = net_device->pkt_align - remain;
packet->rndis_msg->msg_len += padding;
packet->total_data_buflen += padding;
}

for (i = 0; i < packet->page_buf_cnt; i++) {
char *src = phys_to_virt(packet->page_buf[i].pfn << PAGE_SHIFT);
Expand All @@ -703,79 +720,61 @@ static u32 netvsc_copy_to_send_buf(struct netvsc_device *net_device,
msg_size += len;
dest += len;
}

if (padding) {
memset(dest, 0, padding);
msg_size += padding;
}

return msg_size;
}

int netvsc_send(struct hv_device *device,
struct hv_netvsc_packet *packet)
static inline int netvsc_send_pkt(
struct hv_netvsc_packet *packet,
struct netvsc_device *net_device)
{
struct netvsc_device *net_device;
int ret = 0;
struct nvsp_message sendMessage;
struct net_device *ndev;
struct vmbus_channel *out_channel = NULL;
u64 req_id;
unsigned int section_index = NETVSC_INVALID_INDEX;
u32 msg_size = 0;
struct sk_buff *skb = NULL;
struct nvsp_message nvmsg;
struct vmbus_channel *out_channel = packet->channel;
u16 q_idx = packet->q_idx;
struct net_device *ndev = net_device->ndev;
u64 req_id;
int ret;


net_device = get_outbound_net_device(device);
if (!net_device)
return -ENODEV;
ndev = net_device->ndev;

sendMessage.hdr.msg_type = NVSP_MSG1_TYPE_SEND_RNDIS_PKT;
nvmsg.hdr.msg_type = NVSP_MSG1_TYPE_SEND_RNDIS_PKT;
if (packet->is_data_pkt) {
/* 0 is RMC_DATA; */
sendMessage.msg.v1_msg.send_rndis_pkt.channel_type = 0;
nvmsg.msg.v1_msg.send_rndis_pkt.channel_type = 0;
} else {
/* 1 is RMC_CONTROL; */
sendMessage.msg.v1_msg.send_rndis_pkt.channel_type = 1;
nvmsg.msg.v1_msg.send_rndis_pkt.channel_type = 1;
}

/* Attempt to send via sendbuf */
if (packet->total_data_buflen < net_device->send_section_size) {
section_index = netvsc_get_next_send_section(net_device);
if (section_index != NETVSC_INVALID_INDEX) {
msg_size = netvsc_copy_to_send_buf(net_device,
section_index,
packet);
skb = (struct sk_buff *)
(unsigned long)packet->send_completion_tid;
packet->page_buf_cnt = 0;
}
}
packet->send_buf_index = section_index;


sendMessage.msg.v1_msg.send_rndis_pkt.send_buf_section_index =
section_index;
sendMessage.msg.v1_msg.send_rndis_pkt.send_buf_section_size = msg_size;
nvmsg.msg.v1_msg.send_rndis_pkt.send_buf_section_index =
packet->send_buf_index;
if (packet->send_buf_index == NETVSC_INVALID_INDEX)
nvmsg.msg.v1_msg.send_rndis_pkt.send_buf_section_size = 0;
else
nvmsg.msg.v1_msg.send_rndis_pkt.send_buf_section_size =
packet->total_data_buflen;

if (packet->send_completion)
req_id = (ulong)packet;
else
req_id = 0;

out_channel = net_device->chn_table[packet->q_idx];
if (out_channel == NULL)
out_channel = device->channel;
packet->channel = out_channel;

if (out_channel->rescind)
return -ENODEV;

if (packet->page_buf_cnt) {
ret = vmbus_sendpacket_pagebuffer(out_channel,
packet->page_buf,
packet->page_buf_cnt,
&sendMessage,
&nvmsg,
sizeof(struct nvsp_message),
req_id);
} else {
ret = vmbus_sendpacket(out_channel, &sendMessage,
ret = vmbus_sendpacket(
out_channel, &nvmsg,
sizeof(struct nvsp_message),
req_id,
VM_PKT_DATA_INBAND,
Expand Down Expand Up @@ -809,6 +808,102 @@ int netvsc_send(struct hv_device *device,
packet, ret);
}

return ret;
}

int netvsc_send(struct hv_device *device,
struct hv_netvsc_packet *packet)
{
struct netvsc_device *net_device;
int ret = 0, m_ret = 0;
struct vmbus_channel *out_channel;
u16 q_idx = packet->q_idx;
u32 pktlen = packet->total_data_buflen, msd_len = 0;
unsigned int section_index = NETVSC_INVALID_INDEX;
struct sk_buff *skb = NULL;
unsigned long flag;
struct multi_send_data *msdp;
struct hv_netvsc_packet *msd_send = NULL, *cur_send = NULL;

net_device = get_outbound_net_device(device);
if (!net_device)
return -ENODEV;

out_channel = net_device->chn_table[q_idx];
if (!out_channel) {
out_channel = device->channel;
q_idx = 0;
packet->q_idx = 0;
}
packet->channel = out_channel;
packet->send_buf_index = NETVSC_INVALID_INDEX;

msdp = &net_device->msd[q_idx];

/* batch packets in send buffer if possible */
spin_lock_irqsave(&msdp->lock, flag);
if (msdp->pkt)
msd_len = msdp->pkt->total_data_buflen;

if (packet->is_data_pkt && msd_len > 0 &&
msdp->count < net_device->max_pkt &&
msd_len + pktlen + net_device->pkt_align <
net_device->send_section_size) {
section_index = msdp->pkt->send_buf_index;

} else if (packet->is_data_pkt && pktlen + net_device->pkt_align <
net_device->send_section_size) {
section_index = netvsc_get_next_send_section(net_device);
if (section_index != NETVSC_INVALID_INDEX) {
msd_send = msdp->pkt;
msdp->pkt = NULL;
msdp->count = 0;
msd_len = 0;
}
}

if (section_index != NETVSC_INVALID_INDEX) {
netvsc_copy_to_send_buf(net_device,
section_index, msd_len,
packet);
skb = (struct sk_buff *)
(unsigned long)packet->send_completion_tid;

packet->page_buf_cnt = 0;
packet->send_buf_index = section_index;
packet->total_data_buflen += msd_len;

kfree(msdp->pkt);
if (packet->xmit_more) {
msdp->pkt = packet;
msdp->count++;
} else {
cur_send = packet;
msdp->pkt = NULL;
msdp->count = 0;
}
} else {
msd_send = msdp->pkt;
msdp->pkt = NULL;
msdp->count = 0;
cur_send = packet;
}

spin_unlock_irqrestore(&msdp->lock, flag);

if (msd_send) {
m_ret = netvsc_send_pkt(msd_send, net_device);

if (m_ret != 0) {
netvsc_free_send_slot(net_device,
msd_send->send_buf_index);
kfree(msd_send);
}
}

if (cur_send)
ret = netvsc_send_pkt(cur_send, net_device);

if (ret != 0) {
if (section_index != NETVSC_INVALID_INDEX)
netvsc_free_send_slot(net_device, section_index);
Expand Down
2 changes: 2 additions & 0 deletions drivers/net/hyperv/netvsc_drv.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -413,6 +413,8 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
return NETDEV_TX_OK;
}

packet->xmit_more = skb->xmit_more;

packet->vlan_tci = skb->vlan_tci;

packet->q_idx = skb_get_queue_mapping(skb);
Expand Down
4 changes: 4 additions & 0 deletions drivers/net/hyperv/rndis_filter.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -237,6 +237,7 @@ static int rndis_filter_send_request(struct rndis_device *dev,
}

packet->send_completion = NULL;
packet->xmit_more = false;

ret = netvsc_send(dev->net_dev->dev, packet);
return ret;
Expand Down Expand Up @@ -855,6 +856,7 @@ static int rndis_filter_init_device(struct rndis_device *dev)
u32 status;
int ret;
unsigned long t;
struct netvsc_device *nvdev = dev->net_dev;

request = get_rndis_request(dev, RNDIS_MSG_INIT,
RNDIS_MESSAGE_SIZE(struct rndis_initialize_request));
Expand Down Expand Up @@ -889,6 +891,8 @@ static int rndis_filter_init_device(struct rndis_device *dev)
status = init_complete->status;
if (status == RNDIS_STATUS_SUCCESS) {
dev->state = RNDIS_DEV_INITIALIZED;
nvdev->max_pkt = init_complete->max_pkt_per_msg;
nvdev->pkt_align = 1 << init_complete->pkt_alignment_factor;
ret = 0;
} else {
dev->state = RNDIS_DEV_UNINITIALIZED;
Expand Down

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