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>

2 files changed, 6 insertions, 7 deletions

diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index 94b0afa4ab05..8b25629accd8 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -52,8 +52,6 @@ struct rpc_task {
          * RPC call state
          */
         struct rpc_message      tk_msg;         /* RPC call info */
-        __u32 *                 tk_buffer;      /* XDR buffer */
-        size_t                  tk_bufsize;
         __u8                    tk_garb_retry;
         __u8                    tk_cred_retry;
 
@@ -268,6 +266,7 @@ struct rpc_task *rpc_wake_up_next(struct rpc_wait_queue *);
 void            rpc_wake_up_status(struct rpc_wait_queue *, int);
 void            rpc_delay(struct rpc_task *, unsigned long);
 void *          rpc_malloc(struct rpc_task *, size_t);
+void            rpc_free(struct rpc_task *);
 int             rpciod_up(void);
 void            rpciod_down(void);
 void            rpciod_wake_up(void);
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);