| David Howells | 9ae326a | 2009-04-03 16:42:41 +0100 | [diff] [blame] | 1 | /* CacheFiles statistics |
| 2 | * |
| 3 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. |
| 4 | * Written by David Howells (dhowells@redhat.com) |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public Licence |
| 8 | * as published by the Free Software Foundation; either version |
| 9 | * 2 of the Licence, or (at your option) any later version. |
| 10 | */ |
| 11 | |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/proc_fs.h> |
| 14 | #include <linux/seq_file.h> |
| 15 | #include "internal.h" |
| 16 | |
| 17 | atomic_t cachefiles_lookup_histogram[HZ]; |
| 18 | atomic_t cachefiles_mkdir_histogram[HZ]; |
| 19 | atomic_t cachefiles_create_histogram[HZ]; |
| 20 | |
| 21 | /* |
| 22 | * display the latency histogram |
| 23 | */ |
| 24 | static int cachefiles_histogram_show(struct seq_file *m, void *v) |
| 25 | { |
| 26 | unsigned long index; |
| 27 | unsigned x, y, z, t; |
| 28 | |
| 29 | switch ((unsigned long) v) { |
| 30 | case 1: |
| 31 | seq_puts(m, "JIFS SECS LOOKUPS MKDIRS CREATES\n"); |
| 32 | return 0; |
| 33 | case 2: |
| 34 | seq_puts(m, "===== ===== ========= ========= =========\n"); |
| 35 | return 0; |
| 36 | default: |
| 37 | index = (unsigned long) v - 3; |
| 38 | x = atomic_read(&cachefiles_lookup_histogram[index]); |
| 39 | y = atomic_read(&cachefiles_mkdir_histogram[index]); |
| 40 | z = atomic_read(&cachefiles_create_histogram[index]); |
| 41 | if (x == 0 && y == 0 && z == 0) |
| 42 | return 0; |
| 43 | |
| 44 | t = (index * 1000) / HZ; |
| 45 | |
| 46 | seq_printf(m, "%4lu 0.%03u %9u %9u %9u\n", index, t, x, y, z); |
| 47 | return 0; |
| 48 | } |
| 49 | } |
| 50 | |
| 51 | /* |
| 52 | * set up the iterator to start reading from the first line |
| 53 | */ |
| 54 | static void *cachefiles_histogram_start(struct seq_file *m, loff_t *_pos) |
| 55 | { |
| 56 | if ((unsigned long long)*_pos >= HZ + 2) |
| 57 | return NULL; |
| 58 | if (*_pos == 0) |
| 59 | *_pos = 1; |
| 60 | return (void *)(unsigned long) *_pos; |
| 61 | } |
| 62 | |
| 63 | /* |
| 64 | * move to the next line |
| 65 | */ |
| 66 | static void *cachefiles_histogram_next(struct seq_file *m, void *v, loff_t *pos) |
| 67 | { |
| 68 | (*pos)++; |
| 69 | return (unsigned long long)*pos > HZ + 2 ? |
| 70 | NULL : (void *)(unsigned long) *pos; |
| 71 | } |
| 72 | |
| 73 | /* |
| 74 | * clean up after reading |
| 75 | */ |
| 76 | static void cachefiles_histogram_stop(struct seq_file *m, void *v) |
| 77 | { |
| 78 | } |
| 79 | |
| 80 | static const struct seq_operations cachefiles_histogram_ops = { |
| 81 | .start = cachefiles_histogram_start, |
| 82 | .stop = cachefiles_histogram_stop, |
| 83 | .next = cachefiles_histogram_next, |
| 84 | .show = cachefiles_histogram_show, |
| 85 | }; |
| 86 | |
| 87 | /* |
| 88 | * open "/proc/fs/cachefiles/XXX" which provide statistics summaries |
| 89 | */ |
| 90 | static int cachefiles_histogram_open(struct inode *inode, struct file *file) |
| 91 | { |
| 92 | return seq_open(file, &cachefiles_histogram_ops); |
| 93 | } |
| 94 | |
| 95 | static const struct file_operations cachefiles_histogram_fops = { |
| 96 | .owner = THIS_MODULE, |
| 97 | .open = cachefiles_histogram_open, |
| 98 | .read = seq_read, |
| 99 | .llseek = seq_lseek, |
| 100 | .release = seq_release, |
| 101 | }; |
| 102 | |
| 103 | /* |
| 104 | * initialise the /proc/fs/cachefiles/ directory |
| 105 | */ |
| 106 | int __init cachefiles_proc_init(void) |
| 107 | { |
| 108 | _enter(""); |
| 109 | |
| 110 | if (!proc_mkdir("fs/cachefiles", NULL)) |
| 111 | goto error_dir; |
| 112 | |
| 113 | if (!proc_create("fs/cachefiles/histogram", S_IFREG | 0444, NULL, |
| 114 | &cachefiles_histogram_fops)) |
| 115 | goto error_histogram; |
| 116 | |
| 117 | _leave(" = 0"); |
| 118 | return 0; |
| 119 | |
| 120 | error_histogram: |
| 121 | remove_proc_entry("fs/cachefiles", NULL); |
| 122 | error_dir: |
| 123 | _leave(" = -ENOMEM"); |
| 124 | return -ENOMEM; |
| 125 | } |
| 126 | |
| 127 | /* |
| 128 | * clean up the /proc/fs/cachefiles/ directory |
| 129 | */ |
| 130 | void cachefiles_proc_cleanup(void) |
| 131 | { |
| 132 | remove_proc_entry("fs/cachefiles/histogram", NULL); |
| 133 | remove_proc_entry("fs/cachefiles", NULL); |
| 134 | } |