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nvme-tcp: have queue prod/cons send list become a llist 

The queue processing will splice to a queue local list, this should
alleviate some contention on the send_list lock, but also prepares
us to the next patch where we look on these lists for network stack
flag optimization.

Remove queue lock as its not used anymore.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
[hch: simplified a loop]
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Sagi Grimberg 2020-06-18 17:30:22 -07:00 committed by Christoph Hellwig
parent ca8f4beebf
commit 15ec928a65
1 changed files with 24 additions and 10 deletions
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34
drivers/nvme/host/tcp.c
View File

@ -46,6 +46,7 @@ struct nvme_tcp_request {
u32 pdu_sent;
u16 ttag;
struct list_head entry;
struct llist_node lentry;
__le32 ddgst;
struct bio *curr_bio;
@ -75,8 +76,8 @@ struct nvme_tcp_queue {
struct work_struct io_work;
int io_cpu;
spinlock_t lock;
struct mutex send_mutex;
struct llist_head req_list;
struct list_head send_list;
/* recv state */
@ -266,10 +267,8 @@ static inline void nvme_tcp_queue_request(struct nvme_tcp_request *req,
struct nvme_tcp_queue *queue = req->queue;
bool empty;
spin_lock(&queue->lock);
empty = list_empty(&queue->send_list) && !queue->request;
list_add_tail(&req->entry, &queue->send_list);
spin_unlock(&queue->lock);
empty = llist_add(&req->lentry, &queue->req_list) &&
list_empty(&queue->send_list) && !queue->request;
/*
* if we're the first on the send_list and we can try to send
@ -285,18 +284,33 @@ static inline void nvme_tcp_queue_request(struct nvme_tcp_request *req,
}
}
static void nvme_tcp_process_req_list(struct nvme_tcp_queue *queue)
{
struct nvme_tcp_request *req;
struct llist_node *node;
for (node = llist_del_all(&queue->req_list); node; node = node->next) {
req = llist_entry(node, struct nvme_tcp_request, lentry);
list_add(&req->entry, &queue->send_list);
}
}
static inline struct nvme_tcp_request *
nvme_tcp_fetch_request(struct nvme_tcp_queue *queue)
{
struct nvme_tcp_request *req;
spin_lock(&queue->lock);
req = list_first_entry_or_null(&queue->send_list,
struct nvme_tcp_request, entry);
if (req)
list_del(&req->entry);
spin_unlock(&queue->lock);
if (!req) {
nvme_tcp_process_req_list(queue);
req = list_first_entry_or_null(&queue->send_list,
struct nvme_tcp_request, entry);
if (unlikely(!req))
return NULL;
}
list_del(&req->entry);
return req;
}
@ -1344,8 +1358,8 @@ static int nvme_tcp_alloc_queue(struct nvme_ctrl *nctrl,
int ret, rcv_pdu_size;
queue->ctrl = ctrl;
init_llist_head(&queue->req_list);
INIT_LIST_HEAD(&queue->send_list);
spin_lock_init(&queue->lock);
mutex_init(&queue->send_mutex);
INIT_WORK(&queue->io_work, nvme_tcp_io_work);
queue->queue_size = queue_size;