[PATCH v4 14/14] SUNRPC: Bump the maximum payload size for the server

cel
2025-04-28T19:37:20Z

From: Chuck Lever <chuck.lever@oracle.com>

Increase the maximum server-side RPC payload to 4MB. The default
remains at 1MB.

To adjust the operational maximum, shut down the NFS server. Then
echo a new value into:

/proc/fs/nfsd/max_block_size

And restart the NFS server.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
include/linux/sunrpc/svc.h | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index e27bc051ec67..b449eb02e00a 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -119,14 +119,14 @@ void svc_destroy(struct svc_serv **svcp);
* Linux limit; someone who cares more about NFS/UDP performance
* can test a larger number.
*
- * For TCP transports we have more freedom. A size of 1MB is
- * chosen to match the client limit. Other OSes are known to
- * have larger limits, but those numbers are probably beyond
- * the point of diminishing returns.
+ * For non-UDP transports we have more freedom. A size of 4MB is
+ * chosen to accommodate clients that support larger I/O sizes.
*/
-#define RPCSVC_MAXPAYLOAD (1*1024*1024u)
-#define RPCSVC_MAXPAYLOAD_TCP RPCSVC_MAXPAYLOAD
-#define RPCSVC_MAXPAYLOAD_UDP (32*1024u)
+enum {
+ RPCSVC_MAXPAYLOAD = 4 * 1024 * 1024,
+ RPCSVC_MAXPAYLOAD_TCP = RPCSVC_MAXPAYLOAD,
+ RPCSVC_MAXPAYLOAD_UDP = 32 * 1024,
+};

extern u32 svc_max_payload(const struct svc_rqst *rqstp);

--
2.49.0