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, 3 insertions, 0 deletions

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 6dda3860351f..069a6cbd49ea 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -838,6 +838,8 @@ static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
         req->rq_timeout = xprt->timeout.to_initval;
         req->rq_task    = task;
         req->rq_xprt    = xprt;
+        req->rq_buffer  = NULL;
+        req->rq_bufsize = 0;
         req->rq_xid     = xprt_alloc_xid(xprt);
         req->rq_release_snd_buf = NULL;
         dprintk("RPC: %4d reserved req %p xid %08x\n", task->tk_pid,
@@ -867,6 +869,7 @@ void xprt_release(struct rpc_task *task)
                 mod_timer(&xprt->timer,
                                 xprt->last_used + xprt->idle_timeout);
         spin_unlock_bh(&xprt->transport_lock);
+        xprt->ops->buf_free(task);
         task->tk_rqstp = NULL;
         if (req->rq_release_snd_buf)
                 req->rq_release_snd_buf(req);