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