From 15ec928a65e0528ef4999e2947b4802b772f0891 Mon Sep 17 00:00:00 2001 From: Sagi Grimberg Date: Thu, 18 Jun 2020 17:30:22 -0700 Subject: [PATCH] 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 Tested-by: Mark Wunderlich [hch: simplified a loop] Signed-off-by: Christoph Hellwig --- drivers/nvme/host/tcp.c | 34 ++++++++++++++++++++++++---------- 1 file changed, 24 insertions(+), 10 deletions(-) diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c index 7006aca..4788685 100644 --- a/drivers/nvme/host/tcp.c +++ b/drivers/nvme/host/tcp.c @@ -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; -- 2.7.4