/* 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, }; /* * open "/proc/fs/cachefiles/XXX" which provide statistics summaries */ static int cachefiles_histogram_open(struct inode *inode, struct file *file) { return seq_open(file, &cachefiles_histogram_ops); } static const struct file_operations cachefiles_histogram_fops = { .open = cachefiles_histogram_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release, }; /* * 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("fs/cachefiles/histogram", S_IFREG | 0444, NULL, &cachefiles_histogram_fops)) 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); }