1  /* SPDX-License-Identifier: GPL-2.0 */
2  /*
3   *  User-space visible declarations for NFS client per-mount
4   *  point statistics
5   *
6   *  Copyright (C) 2005, 2006 Chuck Lever <cel@netapp.com>
7   *
8   *  NFS client per-mount statistics provide information about the
9   *  health of the NFS client and the health of each NFS mount point.
10   *  Generally these are not for detailed problem diagnosis, but
11   *  simply to indicate that there is a problem.
12   *
13   *  These counters are not meant to be human-readable, but are meant
14   *  to be integrated into system monitoring tools such as "sar" and
15   *  "iostat".  As such, the counters are sampled by the tools over
16   *  time, and are never zeroed after a file system is mounted.
17   *  Moving averages can be computed by the tools by taking the
18   *  difference between two instantaneous samples  and dividing that
19   *  by the time between the samples.
20   */
21  
22  #ifndef _LINUX_NFS_IOSTAT
23  #define _LINUX_NFS_IOSTAT
24  
25  #define NFS_IOSTAT_VERS		"1.1"
26  
27  /*
28   * NFS byte counters
29   *
30   * 1.  SERVER - the number of payload bytes read from or written
31   *     to the server by the NFS client via an NFS READ or WRITE
32   *     request.
33   *
34   * 2.  NORMAL - the number of bytes read or written by applications
35   *     via the read(2) and write(2) system call interfaces.
36   *
37   * 3.  DIRECT - the number of bytes read or written from files
38   *     opened with the O_DIRECT flag.
39   *
40   * These counters give a view of the data throughput into and out
41   * of the NFS client.  Comparing the number of bytes requested by
42   * an application with the number of bytes the client requests from
43   * the server can provide an indication of client efficiency
44   * (per-op, cache hits, etc).
45   *
46   * These counters can also help characterize which access methods
47   * are in use.  DIRECT by itself shows whether there is any O_DIRECT
48   * traffic.  NORMAL + DIRECT shows how much data is going through
49   * the system call interface.  A large amount of SERVER traffic
50   * without much NORMAL or DIRECT traffic shows that applications
51   * are using mapped files.
52   *
53   * NFS page counters
54   *
55   * These count the number of pages read or written via nfs_readpage(),
56   * nfs_readpages(), or their write equivalents.
57   *
58   * NB: When adding new byte counters, please include the measured
59   * units in the name of each byte counter to help users of this
60   * interface determine what exactly is being counted.
61   */
62  enum nfs_stat_bytecounters {
63  	NFSIOS_NORMALREADBYTES = 0,
64  	NFSIOS_NORMALWRITTENBYTES,
65  	NFSIOS_DIRECTREADBYTES,
66  	NFSIOS_DIRECTWRITTENBYTES,
67  	NFSIOS_SERVERREADBYTES,
68  	NFSIOS_SERVERWRITTENBYTES,
69  	NFSIOS_READPAGES,
70  	NFSIOS_WRITEPAGES,
71  	__NFSIOS_BYTESMAX,
72  };
73  
74  /*
75   * NFS event counters
76   *
77   * These counters provide a low-overhead way of monitoring client
78   * activity without enabling NFS trace debugging.  The counters
79   * show the rate at which VFS requests are made, and how often the
80   * client invalidates its data and attribute caches.  This allows
81   * system administrators to monitor such things as how close-to-open
82   * is working, and answer questions such as "why are there so many
83   * GETATTR requests on the wire?"
84   *
85   * They also count anamolous events such as short reads and writes,
86   * silly renames due to close-after-delete, and operations that
87   * change the size of a file (such operations can often be the
88   * source of data corruption if applications aren't using file
89   * locking properly).
90   */
91  enum nfs_stat_eventcounters {
92  	NFSIOS_INODEREVALIDATE = 0,
93  	NFSIOS_DENTRYREVALIDATE,
94  	NFSIOS_DATAINVALIDATE,
95  	NFSIOS_ATTRINVALIDATE,
96  	NFSIOS_VFSOPEN,
97  	NFSIOS_VFSLOOKUP,
98  	NFSIOS_VFSACCESS,
99  	NFSIOS_VFSUPDATEPAGE,
100  	NFSIOS_VFSREADPAGE,
101  	NFSIOS_VFSREADPAGES,
102  	NFSIOS_VFSWRITEPAGE,
103  	NFSIOS_VFSWRITEPAGES,
104  	NFSIOS_VFSGETDENTS,
105  	NFSIOS_VFSSETATTR,
106  	NFSIOS_VFSFLUSH,
107  	NFSIOS_VFSFSYNC,
108  	NFSIOS_VFSLOCK,
109  	NFSIOS_VFSRELEASE,
110  	NFSIOS_CONGESTIONWAIT,
111  	NFSIOS_SETATTRTRUNC,
112  	NFSIOS_EXTENDWRITE,
113  	NFSIOS_SILLYRENAME,
114  	NFSIOS_SHORTREAD,
115  	NFSIOS_SHORTWRITE,
116  	NFSIOS_DELAY,
117  	NFSIOS_PNFS_READ,
118  	NFSIOS_PNFS_WRITE,
119  	__NFSIOS_COUNTSMAX,
120  };
121  
122  #endif	/* _LINUX_NFS_IOSTAT */
123