[PATCHv3 for-next 05/20] RDMA/rtrs: Change MAX_SESS_QUEUE_DEPTH
From: Jack Wang <jinpu.wang@ionos.com>
Date: 2021-05-28 11:30:36
Subsystem:
infiniband subsystem, rtrs transport drivers, the rest · Maintainers:
Jason Gunthorpe, Leon Romanovsky, Md. Haris Iqbal, Jack Wang, Linus Torvalds
From: Gioh Kim <redacted> 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). Signed-off-by: Gioh Kim <redacted> Signed-off-by: Jack Wang <jinpu.wang@ionos.com> --- 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,
--
2.25.1