Eric Lee / smarc-fsl-linux-kernel

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fs/cachefiles/proc.c 2.51 KB
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b4d0d230c   Thomas Gleixner   treewide: Replace... 
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  // SPDX-License-Identifier: GPL-2.0-or-later
9ae326a69   David Howells   CacheFiles: A cac... 
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  /* CacheFiles statistics
   *
   * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   * Written by David Howells (dhowells@redhat.com)
9ae326a69   David Howells   CacheFiles: A cac... 
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   */
  
  #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
  ");
  		return 0;
  	case 2:
  		seq_puts(m, "===== ===== ========= ========= =========
  ");
  		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
  ", 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,
  };
  
  /*
9ae326a69   David Howells   CacheFiles: A cac... 
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   * initialise the /proc/fs/cachefiles/ directory
   */
  int __init cachefiles_proc_init(void)
  {
  	_enter("");
  
  	if (!proc_mkdir("fs/cachefiles", NULL))
  		goto error_dir;
fddda2b7b   Christoph Hellwig   proc: introduce p... 
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  	if (!proc_create_seq("fs/cachefiles/histogram", S_IFREG | 0444, NULL,
  			 &cachefiles_histogram_ops))
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  		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);
  }