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nvme-tcp: optimize network stack with setting msg flags according to batch size 

If we have a long list of request to send, signal the network stack
that more is coming (MSG_MORE). If we have nothing else, signal MSG_EOR.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Sagi Grimberg 2020-06-18 17:30:24 -07:00 committed by Christoph Hellwig
parent 86f0348ace
commit 122e5b9f3d
1 changed files with 17 additions and 3 deletions
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20
drivers/nvme/host/tcp.c
View File

@ -79,6 +79,7 @@ struct nvme_tcp_queue {
struct mutex send_mutex;
struct llist_head req_list;
struct list_head send_list;
bool more_requests;
/* recv state */
void *pdu;
@ -277,7 +278,9 @@ static inline void nvme_tcp_queue_request(struct nvme_tcp_request *req,
*/
if (queue->io_cpu == smp_processor_id() &&
sync && empty && mutex_trylock(&queue->send_mutex)) {
queue->more_requests = !last;
nvme_tcp_try_send(queue);
queue->more_requests = false;
mutex_unlock(&queue->send_mutex);
} else if (last) {
queue_work_on(queue->io_cpu, nvme_tcp_wq, &queue->io_work);
@ -877,6 +880,12 @@ static void nvme_tcp_state_change(struct sock *sk)
read_unlock(&sk->sk_callback_lock);
}
static inline bool nvme_tcp_queue_more(struct nvme_tcp_queue *queue)
{
return !list_empty(&queue->send_list) ||
!llist_empty(&queue->req_list) || queue->more_requests;
}
static inline void nvme_tcp_done_send_req(struct nvme_tcp_queue *queue)
{
queue->request = NULL;
@ -898,7 +907,7 @@ static int nvme_tcp_try_send_data(struct nvme_tcp_request *req)
bool last = nvme_tcp_pdu_last_send(req, len);
int ret, flags = MSG_DONTWAIT;
if (last && !queue->data_digest)
if (last && !queue->data_digest && !nvme_tcp_queue_more(queue))
flags |= MSG_EOR;
else
flags |= MSG_MORE | MSG_SENDPAGE_NOTLAST;
@ -945,7 +954,7 @@ static int nvme_tcp_try_send_cmd_pdu(struct nvme_tcp_request *req)
int flags = MSG_DONTWAIT;
int ret;
if (inline_data)
if (inline_data || nvme_tcp_queue_more(queue))
flags |= MSG_MORE | MSG_SENDPAGE_NOTLAST;
else
flags |= MSG_EOR;
@ -1010,12 +1019,17 @@ static int nvme_tcp_try_send_ddgst(struct nvme_tcp_request *req)
{
struct nvme_tcp_queue *queue = req->queue;
int ret;
struct msghdr msg = { .msg_flags = MSG_DONTWAIT | MSG_EOR };
struct msghdr msg = { .msg_flags = MSG_DONTWAIT };
struct kvec iov = {
.iov_base = &req->ddgst + req->offset,
.iov_len = NVME_TCP_DIGEST_LENGTH - req->offset
};
if (nvme_tcp_queue_more(queue))
msg.msg_flags |= MSG_MORE;
else
msg.msg_flags |= MSG_EOR;
ret = kernel_sendmsg(queue->sock, &msg, &iov, 1, iov.iov_len);
if (unlikely(ret <= 0))
return ret;