projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 9ae326a6 DH |
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 | ||
| 9ae326a6 DH |
87 | /* |
| 88 | * initialise the /proc/fs/cachefiles/ directory | |
| 89 | */ | |
| 90 | int __init cachefiles_proc_init(void) | |
| 91 | { | |
| 92 | _enter(""); | |
| 93 | ||
| 94 | if (!proc_mkdir("fs/cachefiles", NULL)) | |
| 95 | goto error_dir; | |
| 96 | ||
| fddda2b7 CH |
97 | if (!proc_create_seq("fs/cachefiles/histogram", S_IFREG | 0444, NULL, |
| 98 | &cachefiles_histogram_ops)) | |
| 9ae326a6 DH |
99 | goto error_histogram; |
| 100 | ||
| 101 | _leave(" = 0"); | |
| 102 | return 0; | |
| 103 | ||
| 104 | error_histogram: | |
| 105 | remove_proc_entry("fs/cachefiles", NULL); | |
| 106 | error_dir: | |
| 107 | _leave(" = -ENOMEM"); | |
| 108 | return -ENOMEM; | |
| 109 | } | |
| 110 | ||
| 111 | /* | |
| 112 | * clean up the /proc/fs/cachefiles/ directory | |
| 113 | */ | |
| 114 | void cachefiles_proc_cleanup(void) | |
| 115 | { | |
| 116 | remove_proc_entry("fs/cachefiles/histogram", NULL); | |
| 117 | remove_proc_entry("fs/cachefiles", NULL); | |
| 118 | } |