linux/fs/cachefiles/proc.c
Thomas Gleixner b4d0d230cc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 114 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 17:27:11 +02:00

115 lines
2.5 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/* CacheFiles statistics
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#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);
}