xprtrdma: Raise maximum payload size to one megabyte

[ Queued for upstream v4.3 ]

The point of larger rsize and wsize is to reduce the per-byte cost
of memory registration and deregistration. Modern HCAs can typically
handle a megabyte or more with a single registration operation.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Devesh Sharma <devesh.sharma@avagotech.com>
Reviewed-By: Sagi Grimberg <sagig@mellanox.com>
Tested-by: Devesh Sharma <devesh.sharma@avagotech.com>

diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index e718d0959af34207082211b5a3b0c69bc5d779eb..aa38e42b240996f63e13728e5767035f2d3ba22d 100644 (file)
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -164,8 +164,7 @@ rdmab_to_msg(struct rpcrdma_regbuf *rb)
  * struct rpcrdma_buffer. N is the max number of outstanding requests.
  */
 
-/* temporary static scatter/gather max */
-#define RPCRDMA_MAX_DATA_SEGS  (64)    /* max scatter/gather */
+#define RPCRDMA_MAX_DATA_SEGS  ((1 * 1024 * 1024) / PAGE_SIZE)
 #define RPCRDMA_MAX_SEGS       (RPCRDMA_MAX_DATA_SEGS + 2) /* head+tail = 2 */
 
 struct rpcrdma_buffer;