From: Gioh Kim gi-oh.kim@cloud.ionos.com
[ Upstream commit 3a98ea7041b7d18ac356da64823c2ba2f8391b3e ]
Max IB immediate data size is 2^28 (MAX_IMM_PAYL_BITS) and the minimum chunk size is 4096 (2^12). Therefore the maximum sess_queue_depth is 65536 (2^16).
Link: https://lore.kernel.org/r/20210528113018.52290-6-jinpu.wang@ionos.com Signed-off-by: Gioh Kim gi-oh.kim@ionos.com Signed-off-by: Jack Wang jinpu.wang@ionos.com Reported-by: kernel test robot lkp@intel.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/infiniband/ulp/rtrs/rtrs-pri.h | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/infiniband/ulp/rtrs/rtrs-pri.h b/drivers/infiniband/ulp/rtrs/rtrs-pri.h index 86e65cf30cab..d957bbf1ddd3 100644 --- a/drivers/infiniband/ulp/rtrs/rtrs-pri.h +++ b/drivers/infiniband/ulp/rtrs/rtrs-pri.h @@ -47,12 +47,15 @@ enum { MAX_PATHS_NUM = 128,
/* - * With the size of struct rtrs_permit allocated on the client, 4K - * is the maximum number of rtrs_permits we can allocate. This number is - * also used on the client to allocate the IU for the user connection - * to receive the RDMA addresses from the server. + * Max IB immediate data size is 2^28 (MAX_IMM_PAYL_BITS) + * and the minimum chunk size is 4096 (2^12). + * So the maximum sess_queue_depth is 65536 (2^16) in theory. + * But mempool_create, create_qp and ib_post_send fail with + * "cannot allocate memory" error if sess_queue_depth is too big. + * Therefore the pratical max value of sess_queue_depth is + * somewhere between 1 and 65536 and it depends on the system. */ - MAX_SESS_QUEUE_DEPTH = 4096, + MAX_SESS_QUEUE_DEPTH = 65536,
RTRS_HB_INTERVAL_MS = 5000, RTRS_HB_MISSED_MAX = 5,