SUNRPC: provide a mechanism for collecting stats in the RPC client

Add a simple mechanism for collecting stats in the RPC client.  Stats are
tabulated during xprt_release.  Note that per_cpu shenanigans are not
required here because the RPC client already serializes on the transport
write lock.

Test plan:
Compile kernel with CONFIG_NFS enabled.  Basic performance regression
testing with high-speed networking and high performance server.

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

1 files changed, 6 insertions, 3 deletions

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 84eb5b4565fc..0bb23e8e9d0c 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -28,12 +28,11 @@
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/utsname.h>
+#include <linux/workqueue.h>
 
 #include <linux/sunrpc/clnt.h>
-#include <linux/workqueue.h>
 #include <linux/sunrpc/rpc_pipe_fs.h>
-
-#include <linux/nfs.h>
+#include <linux/sunrpc/metrics.h>
 
 
 #define RPC_SLACK_SPACE         (1024)  /* total overkill */
@@ -147,6 +146,7 @@ rpc_new_client(struct rpc_xprt *xprt, char *servname,
         clnt->cl_vers     = version->number;
         clnt->cl_prot     = xprt->prot;
         clnt->cl_stats    = program->stats;
+        clnt->cl_metrics  = rpc_alloc_iostats(clnt);
         rpc_init_wait_queue(&clnt->cl_pmap_default.pm_bindwait, "bindwait");
 
         if (!clnt->cl_port)
@@ -245,6 +245,7 @@ rpc_clone_client(struct rpc_clnt *clnt)
         if (new->cl_auth)
                 atomic_inc(&new->cl_auth->au_count);
         new->cl_pmap            = &new->cl_pmap_default;
+        new->cl_metrics         = rpc_alloc_iostats(clnt);
         rpc_init_wait_queue(&new->cl_pmap_default.pm_bindwait, "bindwait");
         return new;
 out_no_clnt:
@@ -315,6 +316,8 @@ rpc_destroy_client(struct rpc_clnt *clnt)
         if (clnt->cl_server != clnt->cl_inline_name)
                 kfree(clnt->cl_server);
 out_free:
+        rpc_free_iostats(clnt->cl_metrics);
+        clnt->cl_metrics = NULL;
         if (clnt->cl_dentry)
                 dput(clnt->cl_dentry);
         kfree(clnt);