153 lines
4.5 KiB
C
153 lines
4.5 KiB
C
/*
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* linux/fs/nfs/iostat.h
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*
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* Declarations for NFS client per-mount statistics
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*
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* Copyright (C) 2005, 2006 Chuck Lever <cel@netapp.com>
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*
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* NFS client per-mount statistics provide information about the health of
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* the NFS client and the health of each NFS mount point. Generally these
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* are not for detailed problem diagnosis, but simply to indicate that there
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* is a problem.
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*
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* These counters are not meant to be human-readable, but are meant to be
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* integrated into system monitoring tools such as "sar" and "iostat". As
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* such, the counters are sampled by the tools over time, and are never
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* zeroed after a file system is mounted. Moving averages can be computed
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* by the tools by taking the difference between two instantaneous samples
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* and dividing that by the time between the samples.
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*/
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#ifndef _NFS_IOSTAT
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#define _NFS_IOSTAT
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#define NFS_IOSTAT_VERS "1.0"
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/*
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* NFS byte counters
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*
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* 1. SERVER - the number of payload bytes read from or written to the
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* server by the NFS client via an NFS READ or WRITE request.
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*
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* 2. NORMAL - the number of bytes read or written by applications via
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* the read(2) and write(2) system call interfaces.
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*
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* 3. DIRECT - the number of bytes read or written from files opened
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* with the O_DIRECT flag.
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*
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* These counters give a view of the data throughput into and out of the NFS
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* client. Comparing the number of bytes requested by an application with the
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* number of bytes the client requests from the server can provide an
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* indication of client efficiency (per-op, cache hits, etc).
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*
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* These counters can also help characterize which access methods are in
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* use. DIRECT by itself shows whether there is any O_DIRECT traffic.
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* NORMAL + DIRECT shows how much data is going through the system call
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* interface. A large amount of SERVER traffic without much NORMAL or
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* DIRECT traffic shows that applications are using mapped files.
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*
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* NFS page counters
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*
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* These count the number of pages read or written via nfs_readpage(),
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* nfs_readpages(), or their write equivalents.
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*/
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enum nfs_stat_bytecounters {
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NFSIOS_NORMALREADBYTES = 0,
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NFSIOS_NORMALWRITTENBYTES,
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NFSIOS_DIRECTREADBYTES,
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NFSIOS_DIRECTWRITTENBYTES,
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NFSIOS_SERVERREADBYTES,
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NFSIOS_SERVERWRITTENBYTES,
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NFSIOS_READPAGES,
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NFSIOS_WRITEPAGES,
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__NFSIOS_BYTESMAX,
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};
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/*
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* NFS event counters
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*
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* These counters provide a low-overhead way of monitoring client activity
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* without enabling NFS trace debugging. The counters show the rate at
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* which VFS requests are made, and how often the client invalidates its
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* data and attribute caches. This allows system administrators to monitor
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* such things as how close-to-open is working, and answer questions such
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* as "why are there so many GETATTR requests on the wire?"
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*
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* They also count anamolous events such as short reads and writes, silly
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* renames due to close-after-delete, and operations that change the size
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* of a file (such operations can often be the source of data corruption
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* if applications aren't using file locking properly).
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*/
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enum nfs_stat_eventcounters {
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NFSIOS_INODEREVALIDATE = 0,
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NFSIOS_DENTRYREVALIDATE,
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NFSIOS_DATAINVALIDATE,
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NFSIOS_ATTRINVALIDATE,
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NFSIOS_VFSOPEN,
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NFSIOS_VFSLOOKUP,
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NFSIOS_VFSACCESS,
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NFSIOS_VFSUPDATEPAGE,
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NFSIOS_VFSREADPAGE,
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NFSIOS_VFSREADPAGES,
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NFSIOS_VFSWRITEPAGE,
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NFSIOS_VFSWRITEPAGES,
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NFSIOS_VFSGETDENTS,
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NFSIOS_VFSSETATTR,
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NFSIOS_VFSFLUSH,
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NFSIOS_VFSFSYNC,
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NFSIOS_VFSLOCK,
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NFSIOS_VFSRELEASE,
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NFSIOS_CONGESTIONWAIT,
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NFSIOS_SETATTRTRUNC,
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NFSIOS_EXTENDWRITE,
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NFSIOS_SILLYRENAME,
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NFSIOS_SHORTREAD,
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NFSIOS_SHORTWRITE,
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__NFSIOS_COUNTSMAX,
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};
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#ifdef __KERNEL__
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#include <linux/percpu.h>
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#include <linux/cache.h>
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struct nfs_iostats {
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unsigned long long bytes[__NFSIOS_BYTESMAX];
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unsigned long events[__NFSIOS_COUNTSMAX];
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} ____cacheline_aligned;
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static inline void nfs_inc_stats(struct inode *inode, enum nfs_stat_eventcounters stat)
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{
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struct nfs_iostats *iostats;
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int cpu;
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cpu = get_cpu();
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iostats = per_cpu_ptr(NFS_SERVER(inode)->io_stats, cpu);
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iostats->events[stat] ++;
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put_cpu_no_resched();
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}
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static inline void nfs_add_stats(struct inode *inode, enum nfs_stat_bytecounters stat, unsigned long addend)
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{
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struct nfs_iostats *iostats;
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int cpu;
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cpu = get_cpu();
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iostats = per_cpu_ptr(NFS_SERVER(inode)->io_stats, cpu);
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iostats->bytes[stat] += addend;
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put_cpu_no_resched();
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}
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static inline struct nfs_iostats *nfs_alloc_iostats(void)
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{
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return alloc_percpu(struct nfs_iostats);
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}
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static inline void nfs_free_iostats(struct nfs_iostats *stats)
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{
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free_percpu(stats);
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}
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#endif
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#endif
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