SUNRPC: switchable buffer allocation

 Add RPC client transport switch support for replacing buffer management
 on a per-transport basis.

 In the current IPv4 socket transport implementation, RPC buffers are
 allocated as needed for each RPC message that is sent.  Some transport
 implementations may choose to use pre-allocated buffers for encoding,
 sending, receiving, and unmarshalling RPC messages, however.  For
 transports capable of direct data placement, the buffers can be carved
 out of a pre-registered area of memory rather than from a slab cache.

 Test-plan:
 Millions of fsx operations.  Performance characterization with "sio" and
 "iozone".  Use oprofile and other tools to look for significant regression
 in CPU utilization.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 5 insertions, 5 deletions

diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index 3b8b6e823c70..7885b9621ce3 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -79,21 +79,19 @@ struct rpc_rqst {
         void (*rq_release_snd_buf)(struct rpc_rqst *); /* release rq_enc_pages */
         struct list_head        rq_list;
 
+        __u32 *                 rq_buffer;      /* XDR encode buffer */
+        size_t                  rq_bufsize;
+
         struct xdr_buf          rq_private_buf;         /* The receive buffer
                                                          * used in the softirq.
                                                          */
         unsigned long           rq_majortimeo;  /* major timeout alarm */
         unsigned long           rq_timeout;     /* Current timeout value */
         unsigned int            rq_retries;     /* # of retries */
-        /*
-         * For authentication (e.g. auth_des)
-         */
-        u32                     rq_creddata[2];
         
         /*
          * Partial send handling
          */
-        
         u32                     rq_bytes_sent;  /* Bytes we have sent */
 
         unsigned long           rq_xtime;       /* when transmitted */
@@ -107,6 +105,8 @@ struct rpc_xprt_ops {
         int             (*reserve_xprt)(struct rpc_task *task);
         void            (*release_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);
         void            (*connect)(struct rpc_task *task);
+        void *          (*buf_alloc)(struct rpc_task *task, size_t size);
+        void            (*buf_free)(struct rpc_task *task);
         int             (*send_request)(struct rpc_task *task);
         void            (*set_retrans_timeout)(struct rpc_task *task);
         void            (*timer)(struct rpc_task *task);