| /* CacheFiles statistics |
| * |
| * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. |
| * Written by David Howells (dhowells@redhat.com) |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public Licence |
| * as published by the Free Software Foundation; either version |
| * 2 of the Licence, or (at your option) any later version. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/proc_fs.h> |
| #include <linux/seq_file.h> |
| #include "internal.h" |
| |
| atomic_t cachefiles_lookup_histogram[HZ]; |
| atomic_t cachefiles_mkdir_histogram[HZ]; |
| atomic_t cachefiles_create_histogram[HZ]; |
| |
| /* |
| * display the latency histogram |
| */ |
| static int cachefiles_histogram_show(struct seq_file *m, void *v) |
| { |
| unsigned long index; |
| unsigned x, y, z, t; |
| |
| switch ((unsigned long) v) { |
| case 1: |
| seq_puts(m, "JIFS SECS LOOKUPS MKDIRS CREATES\n"); |
| return 0; |
| case 2: |
| seq_puts(m, "===== ===== ========= ========= =========\n"); |
| return 0; |
| default: |
| index = (unsigned long) v - 3; |
| x = atomic_read(&cachefiles_lookup_histogram[index]); |
| y = atomic_read(&cachefiles_mkdir_histogram[index]); |
| z = atomic_read(&cachefiles_create_histogram[index]); |
| if (x == 0 && y == 0 && z == 0) |
| return 0; |
| |
| t = (index * 1000) / HZ; |
| |
| seq_printf(m, "%4lu 0.%03u %9u %9u %9u\n", index, t, x, y, z); |
| return 0; |
| } |
| } |
| |
| /* |
| * set up the iterator to start reading from the first line |
| */ |
| static void *cachefiles_histogram_start(struct seq_file *m, loff_t *_pos) |
| { |
| if ((unsigned long long)*_pos >= HZ + 2) |
| return NULL; |
| if (*_pos == 0) |
| *_pos = 1; |
| return (void *)(unsigned long) *_pos; |
| } |
| |
| /* |
| * move to the next line |
| */ |
| static void *cachefiles_histogram_next(struct seq_file *m, void *v, loff_t *pos) |
| { |
| (*pos)++; |
| return (unsigned long long)*pos > HZ + 2 ? |
| NULL : (void *)(unsigned long) *pos; |
| } |
| |
| /* |
| * clean up after reading |
| */ |
| static void cachefiles_histogram_stop(struct seq_file *m, void *v) |
| { |
| } |
| |
| static const struct seq_operations cachefiles_histogram_ops = { |
| .start = cachefiles_histogram_start, |
| .stop = cachefiles_histogram_stop, |
| .next = cachefiles_histogram_next, |
| .show = cachefiles_histogram_show, |
| }; |
| |
| /* |
| * initialise the /proc/fs/cachefiles/ directory |
| */ |
| int __init cachefiles_proc_init(void) |
| { |
| _enter(""); |
| |
| if (!proc_mkdir("fs/cachefiles", NULL)) |
| goto error_dir; |
| |
| if (!proc_create_seq("fs/cachefiles/histogram", S_IFREG | 0444, NULL, |
| &cachefiles_histogram_ops)) |
| goto error_histogram; |
| |
| _leave(" = 0"); |
| return 0; |
| |
| error_histogram: |
| remove_proc_entry("fs/cachefiles", NULL); |
| error_dir: |
| _leave(" = -ENOMEM"); |
| return -ENOMEM; |
| } |
| |
| /* |
| * clean up the /proc/fs/cachefiles/ directory |
| */ |
| void cachefiles_proc_cleanup(void) |
| { |
| remove_proc_entry("fs/cachefiles/histogram", NULL); |
| remove_proc_entry("fs/cachefiles", NULL); |
| } |