// SPDX-License-Identifier: GPL-2.0-or-later
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/* CacheFiles statistics
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#include <linux/module.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include "internal.h"
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atomic_t cachefiles_lookup_histogram[HZ];
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atomic_t cachefiles_mkdir_histogram[HZ];
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atomic_t cachefiles_create_histogram[HZ];
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/*
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* display the latency histogram
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*/
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static int cachefiles_histogram_show(struct seq_file *m, void *v)
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{
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unsigned long index;
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unsigned x, y, z, t;
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switch ((unsigned long) v) {
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case 1:
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seq_puts(m, "JIFS SECS LOOKUPS MKDIRS CREATES\n");
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return 0;
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case 2:
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seq_puts(m, "===== ===== ========= ========= =========\n");
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return 0;
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default:
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index = (unsigned long) v - 3;
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x = atomic_read(&cachefiles_lookup_histogram[index]);
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y = atomic_read(&cachefiles_mkdir_histogram[index]);
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z = atomic_read(&cachefiles_create_histogram[index]);
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if (x == 0 && y == 0 && z == 0)
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return 0;
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t = (index * 1000) / HZ;
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seq_printf(m, "%4lu 0.%03u %9u %9u %9u\n", index, t, x, y, z);
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return 0;
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}
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}
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/*
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* set up the iterator to start reading from the first line
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*/
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static void *cachefiles_histogram_start(struct seq_file *m, loff_t *_pos)
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{
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if ((unsigned long long)*_pos >= HZ + 2)
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return NULL;
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if (*_pos == 0)
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*_pos = 1;
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return (void *)(unsigned long) *_pos;
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}
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/*
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* move to the next line
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*/
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static void *cachefiles_histogram_next(struct seq_file *m, void *v, loff_t *pos)
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{
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(*pos)++;
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return (unsigned long long)*pos > HZ + 2 ?
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NULL : (void *)(unsigned long) *pos;
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}
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/*
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* clean up after reading
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*/
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static void cachefiles_histogram_stop(struct seq_file *m, void *v)
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{
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}
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static const struct seq_operations cachefiles_histogram_ops = {
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.start = cachefiles_histogram_start,
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.stop = cachefiles_histogram_stop,
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.next = cachefiles_histogram_next,
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.show = cachefiles_histogram_show,
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};
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/*
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* initialise the /proc/fs/cachefiles/ directory
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*/
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int __init cachefiles_proc_init(void)
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{
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_enter("");
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if (!proc_mkdir("fs/cachefiles", NULL))
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goto error_dir;
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if (!proc_create_seq("fs/cachefiles/histogram", S_IFREG | 0444, NULL,
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&cachefiles_histogram_ops))
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goto error_histogram;
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_leave(" = 0");
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return 0;
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error_histogram:
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remove_proc_entry("fs/cachefiles", NULL);
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error_dir:
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_leave(" = -ENOMEM");
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return -ENOMEM;
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}
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/*
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* clean up the /proc/fs/cachefiles/ directory
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*/
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void cachefiles_proc_cleanup(void)
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{
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remove_proc_entry("fs/cachefiles/histogram", NULL);
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remove_proc_entry("fs/cachefiles", NULL);
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}
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