Home
last modified time | relevance | path

Searched hist:db5ad6b7 (Results 1 – 1 of 1) sorted by relevance

/openbmc/linux/drivers/nvme/host/
H A Dtcp.cdb5ad6b7 Fri May 01 16:25:45 CDT 2020 Sagi Grimberg <sagi@grimberg.me> nvme-tcp: try to send request in queue_rq context

Today, nvme-tcp automatically schedules a send request
to a workqueue context, which is 1 more than we'd need
in case the socket buffer is wide open.

However, because we have async send activity (as a result
of r2t, or write_space callbacks), we need to synchronize
sends from possibly multiple contexts (ideally all running
on the same cpu though).

Thus, we only try to send directly from queue_rq in cases:
1. the send_list is empty
2. we can send it synchronously (i.e. not from the RX path)
3. we run on the same cpu as the queue->io_cpu to avoid
contention on the send operation.

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>
db5ad6b7 Fri May 01 16:25:45 CDT 2020 Sagi Grimberg <sagi@grimberg.me> nvme-tcp: try to send request in queue_rq context

Today, nvme-tcp automatically schedules a send request
to a workqueue context, which is 1 more than we'd need
in case the socket buffer is wide open.

However, because we have async send activity (as a result
of r2t, or write_space callbacks), we need to synchronize
sends from possibly multiple contexts (ideally all running
on the same cpu though).

Thus, we only try to send directly from queue_rq in cases:
1. the send_list is empty
2. we can send it synchronously (i.e. not from the RX path)
3. we run on the same cpu as the queue->io_cpu to avoid
contention on the send operation.

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>