NFS: introduce mechanism for tracking NFS client metrics
Add a per-superblock performance counter facility to the NFS client. This
facility mimics the counters available for block devices and for
networking. Expose these new counters via the new /proc/self/mountstats
interface.
Thanks to Andrew Morton and Trond Myklebust for their review and comments.
Test plan:
fsx and iozone on UP and SMP systems, with and without pre-emption. Watch
for memory overwrite bugs, and performance loss (significantly more CPU
required per op).
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index a522ab9..d65e69a 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -4,6 +4,8 @@
#include <linux/list.h>
#include <linux/backing-dev.h>
+struct nfs_iostats;
+
/*
* NFS client parameters stored in the superblock.
*/
@@ -12,6 +14,7 @@
struct rpc_clnt * client_sys; /* 2nd handle for FSINFO */
struct rpc_clnt * client_acl; /* ACL RPC client handle */
struct nfs_rpc_ops * rpc_ops; /* NFS protocol vector */
+ struct nfs_iostats * io_stats; /* I/O statistics */
struct backing_dev_info backing_dev_info;
int flags; /* various flags */
unsigned int caps; /* server capabilities */