diff options
| author | Marta Rybczynska <mrybczyn@kalray.eu> | 2017-04-10 18:12:34 +0300 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2017-05-22 21:49:49 +0300 |
| commit | 0544f5494a03b8846db74e02be5685d1f32b06c9 (patch) | |
| tree | 00c2f3c58c70d5d995ac4e8f32d7d201a8e45698 /drivers/nvme | |
| parent | 08332893e37af6ae779367e78e444f8f9571511d (diff) | |
| download | linux-0544f5494a03b8846db74e02be5685d1f32b06c9.tar.xz | |
nvme-rdma: support devices with queue size < 32
In the case of small NVMe-oF queue size (<32) we may enter a deadlock
caused by the fact that the IB completions aren't sent waiting for 32
and the send queue will fill up.
The error is seen as (using mlx5):
[ 2048.693355] mlx5_0:mlx5_ib_post_send:3765:(pid 7273):
[ 2048.693360] nvme nvme1: nvme_rdma_post_send failed with error code -12
This patch changes the way the signaling is done so that it depends on
the queue depth now. The magic define has been removed completely.
Cc: stable@vger.kernel.org
Signed-off-by: Marta Rybczynska <marta.rybczynska@kalray.eu>
Signed-off-by: Samuel Jones <sjones@kalray.eu>
Acked-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'drivers/nvme')
| -rw-r--r-- | drivers/nvme/host/rdma.c | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c index dd1c6deef82f..e2c18f3d9dcf 100644 --- a/drivers/nvme/host/rdma.c +++ b/drivers/nvme/host/rdma.c @@ -1038,6 +1038,19 @@ static void nvme_rdma_send_done(struct ib_cq *cq, struct ib_wc *wc) nvme_rdma_wr_error(cq, wc, "SEND"); } +static inline int nvme_rdma_queue_sig_limit(struct nvme_rdma_queue *queue) +{ + int sig_limit; + + /* + * We signal completion every queue depth/2 and also handle the + * degenerated case of a device with queue_depth=1, where we + * would need to signal every message. + */ + sig_limit = max(queue->queue_size / 2, 1); + return (++queue->sig_count % sig_limit) == 0; +} + static int nvme_rdma_post_send(struct nvme_rdma_queue *queue, struct nvme_rdma_qe *qe, struct ib_sge *sge, u32 num_sge, struct ib_send_wr *first, bool flush) @@ -1065,9 +1078,6 @@ static int nvme_rdma_post_send(struct nvme_rdma_queue *queue, * Would have been way to obvious to handle this in hardware or * at least the RDMA stack.. * - * This messy and racy code sniplet is copy and pasted from the iSER - * initiator, and the magic '32' comes from there as well. - * * Always signal the flushes. The magic request used for the flush * sequencer is not allocated in our driver's tagset and it's * triggered to be freed by blk_cleanup_queue(). So we need to @@ -1075,7 +1085,7 @@ static int nvme_rdma_post_send(struct nvme_rdma_queue *queue, * embedded in request's payload, is not freed when __ib_process_cq() * calls wr_cqe->done(). */ - if ((++queue->sig_count % 32) == 0 || flush) + if (nvme_rdma_queue_sig_limit(queue) || flush) wr.send_flags |= IB_SEND_SIGNALED; if (first) |