1/*
2 *  linux/fs/nfs/iostat.h
3 *
4 *  Declarations for NFS client per-mount statistics
5 *
6 *  Copyright (C) 2005, 2006 Chuck Lever <cel@netapp.com>
7 *
8 *  NFS client per-mount statistics provide information about the health of
9 *  the NFS client and the health of each NFS mount point.  Generally these
10 *  are not for detailed problem diagnosis, but simply to indicate that there
11 *  is a problem.
12 *
13 *  These counters are not meant to be human-readable, but are meant to be
14 *  integrated into system monitoring tools such as "sar" and "iostat".  As
15 *  such, the counters are sampled by the tools over time, and are never
16 *  zeroed after a file system is mounted.  Moving averages can be computed
17 *  by the tools by taking the difference between two instantaneous samples
18 *  and dividing that by the time between the samples.
19 */
20
21#ifndef _NFS_IOSTAT
22#define _NFS_IOSTAT
23
24#define NFS_IOSTAT_VERS		"1.0"
25
26/*
27 * NFS byte counters
28 *
29 * 1.  SERVER - the number of payload bytes read from or written to the
30 *     server by the NFS client via an NFS READ or WRITE request.
31 *
32 * 2.  NORMAL - the number of bytes read or written by applications via
33 *     the read(2) and write(2) system call interfaces.
34 *
35 * 3.  DIRECT - the number of bytes read or written from files opened
36 *     with the O_DIRECT flag.
37 *
38 * These counters give a view of the data throughput into and out of the NFS
39 * client.  Comparing the number of bytes requested by an application with the
40 * number of bytes the client requests from the server can provide an
41 * indication of client efficiency (per-op, cache hits, etc).
42 *
43 * These counters can also help characterize which access methods are in
44 * use.  DIRECT by itself shows whether there is any O_DIRECT traffic.
45 * NORMAL + DIRECT shows how much data is going through the system call
46 * interface.  A large amount of SERVER traffic without much NORMAL or
47 * DIRECT traffic shows that applications are using mapped files.
48 *
49 * NFS page counters
50 *
51 * These count the number of pages read or written via nfs_readpage(),
52 * nfs_readpages(), or their write equivalents.
53 */
54enum nfs_stat_bytecounters {
55	NFSIOS_NORMALREADBYTES = 0,
56	NFSIOS_NORMALWRITTENBYTES,
57	NFSIOS_DIRECTREADBYTES,
58	NFSIOS_DIRECTWRITTENBYTES,
59	NFSIOS_SERVERREADBYTES,
60	NFSIOS_SERVERWRITTENBYTES,
61	NFSIOS_READPAGES,
62	NFSIOS_WRITEPAGES,
63	__NFSIOS_BYTESMAX,
64};
65
66/*
67 * NFS event counters
68 *
69 * These counters provide a low-overhead way of monitoring client activity
70 * without enabling NFS trace debugging.  The counters show the rate at
71 * which VFS requests are made, and how often the client invalidates its
72 * data and attribute caches.  This allows system administrators to monitor
73 * such things as how close-to-open is working, and answer questions such
74 * as "why are there so many GETATTR requests on the wire?"
75 *
76 * They also count anamolous events such as short reads and writes, silly
77 * renames due to close-after-delete, and operations that change the size
78 * of a file (such operations can often be the source of data corruption
79 * if applications aren't using file locking properly).
80 */
81enum nfs_stat_eventcounters {
82	NFSIOS_INODEREVALIDATE = 0,
83	NFSIOS_DENTRYREVALIDATE,
84	NFSIOS_DATAINVALIDATE,
85	NFSIOS_ATTRINVALIDATE,
86	NFSIOS_VFSOPEN,
87	NFSIOS_VFSLOOKUP,
88	NFSIOS_VFSACCESS,
89	NFSIOS_VFSUPDATEPAGE,
90	NFSIOS_VFSREADPAGE,
91	NFSIOS_VFSREADPAGES,
92	NFSIOS_VFSWRITEPAGE,
93	NFSIOS_VFSWRITEPAGES,
94	NFSIOS_VFSGETDENTS,
95	NFSIOS_VFSSETATTR,
96	NFSIOS_VFSFLUSH,
97	NFSIOS_VFSFSYNC,
98	NFSIOS_VFSLOCK,
99	NFSIOS_VFSRELEASE,
100	NFSIOS_CONGESTIONWAIT,
101	NFSIOS_SETATTRTRUNC,
102	NFSIOS_EXTENDWRITE,
103	NFSIOS_SILLYRENAME,
104	NFSIOS_SHORTREAD,
105	NFSIOS_SHORTWRITE,
106	NFSIOS_DELAY,
107	__NFSIOS_COUNTSMAX,
108};
109
110#ifdef __KERNEL__
111
112#include <linux/percpu.h>
113#include <linux/cache.h>
114
115struct nfs_iostats {
116	unsigned long long	bytes[__NFSIOS_BYTESMAX];
117	unsigned long		events[__NFSIOS_COUNTSMAX];
118} ____cacheline_aligned;
119
120static inline void nfs_inc_server_stats(struct nfs_server *server, enum nfs_stat_eventcounters stat)
121{
122	struct nfs_iostats *iostats;
123	int cpu;
124
125	cpu = get_cpu();
126	iostats = per_cpu_ptr(server->io_stats, cpu);
127	iostats->events[stat] ++;
128	put_cpu_no_resched();
129}
130
131static inline void nfs_inc_stats(struct inode *inode, enum nfs_stat_eventcounters stat)
132{
133	nfs_inc_server_stats(NFS_SERVER(inode), stat);
134}
135
136static inline void nfs_add_server_stats(struct nfs_server *server, enum nfs_stat_bytecounters stat, unsigned long addend)
137{
138	struct nfs_iostats *iostats;
139	int cpu;
140
141	cpu = get_cpu();
142	iostats = per_cpu_ptr(server->io_stats, cpu);
143	iostats->bytes[stat] += addend;
144	put_cpu_no_resched();
145}
146
147static inline void nfs_add_stats(struct inode *inode, enum nfs_stat_bytecounters stat, unsigned long addend)
148{
149	nfs_add_server_stats(NFS_SERVER(inode), stat, addend);
150}
151
152static inline struct nfs_iostats *nfs_alloc_iostats(void)
153{
154	return alloc_percpu(struct nfs_iostats);
155}
156
157static inline void nfs_free_iostats(struct nfs_iostats *stats)
158{
159	if (stats != NULL)
160		free_percpu(stats);
161}
162
163#endif
164#endif
165