diff options
| author | Sagi Grimberg <sagi@grimberg.me> | 2020-05-01 23:25:44 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-05-10 00:18:36 +0200 |
| commit | 72e5d757c62029664c0287d14519ec4451901b5e (patch) | |
| tree | 7ed9be40a5b02309c28f84868a158d028e7c6b4e | |
| parent | nvme-tcp: use bh_lock in data_ready (diff) | |
| download | linux-72e5d757c62029664c0287d14519ec4451901b5e.tar.xz linux-72e5d757c62029664c0287d14519ec4451901b5e.zip | |
nvme-tcp: avoid scheduling io_work if we are already polling
When the user runs polled I/O, we shouldn't have to trigger
the workqueue to generate the receive work upon the .data_ready
upcall. This prevents a redundant context switch when the
application is already polling for completions.
Proposed-by: Mark Wunderlich <mark.wunderlich@intel.com>
Signed-off-by: Mark Wunderlich <mark.wunderlich@intel.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | drivers/nvme/host/tcp.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c index 4862fa962011..b28f91d0f083 100644 --- a/drivers/nvme/host/tcp.c +++ b/drivers/nvme/host/tcp.c @@ -60,6 +60,7 @@ struct nvme_tcp_request { enum nvme_tcp_queue_flags { NVME_TCP_Q_ALLOCATED = 0, NVME_TCP_Q_LIVE = 1, + NVME_TCP_Q_POLLING = 2, }; enum nvme_tcp_recv_state { @@ -796,7 +797,8 @@ static void nvme_tcp_data_ready(struct sock *sk) read_lock_bh(&sk->sk_callback_lock); queue = sk->sk_user_data; - if (likely(queue && queue->rd_enabled)) + if (likely(queue && queue->rd_enabled) && + !test_bit(NVME_TCP_Q_POLLING, &queue->flags)) queue_work_on(queue->io_cpu, nvme_tcp_wq, &queue->io_work); read_unlock_bh(&sk->sk_callback_lock); } @@ -2302,9 +2304,11 @@ static int nvme_tcp_poll(struct blk_mq_hw_ctx *hctx) if (!test_bit(NVME_TCP_Q_LIVE, &queue->flags)) return 0; + set_bit(NVME_TCP_Q_POLLING, &queue->flags); if (sk_can_busy_loop(sk) && skb_queue_empty_lockless(&sk->sk_receive_queue)) sk_busy_loop(sk, true); nvme_tcp_try_recv(queue); + clear_bit(NVME_TCP_Q_POLLING, &queue->flags); return queue->nr_cqe; } |