fs/nfs/iostat.h

   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  */
  54 enum 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  */
  81 enum 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
 115 struct nfs_iostats {
 116         unsigned long long      bytes[__NFSIOS_BYTESMAX];
 117         unsigned long           events[__NFSIOS_COUNTSMAX];
 118 } ____cacheline_aligned;
 119
 120 static 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
 131 static 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
 136 static 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
 147 static 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
 152 static inline struct nfs_iostats *nfs_alloc_iostats(void)
 153 {
 154         return alloc_percpu(struct nfs_iostats);
 155 }
 156
 157 static inline void nfs_free_iostats(struct nfs_iostats *stats)
 158 {
 159         if (stats != NULL)
 160                 free_percpu(stats);
 161 }
 162
 163 #endif
 164 #endif