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  • Committer: Package Import Robot
  • Author(s): Alessio Igor Bogani
  • Date: 2011-10-26 11:13:05 UTC
  • Revision ID: package-import@ubuntu.com-20111026111305-tz023xykf0i6eosh
Tags: upstream-3.2.0
Import upstream version 3.2.0

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fs/fscache/main.c
 
1
/* General filesystem local caching manager
 
2
 *
 
3
 * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
 
4
 * Written by David Howells (dhowells@redhat.com)
 
5
 *
 
6
 * This program is free software; you can redistribute it and/or
 
7
 * modify it under the terms of the GNU General Public License
 
8
 * as published by the Free Software Foundation; either version
 
9
 * 2 of the License, or (at your option) any later version.
 
10
 */
 
11
 
 
12
#define FSCACHE_DEBUG_LEVEL CACHE
 
13
#include <linux/module.h>
 
14
#include <linux/init.h>
 
15
#include <linux/sched.h>
 
16
#include <linux/completion.h>
 
17
#include <linux/slab.h>
 
18
#include <linux/seq_file.h>
 
19
#include "internal.h"
 
20
 
 
21
MODULE_DESCRIPTION("FS Cache Manager");
 
22
MODULE_AUTHOR("Red Hat, Inc.");
 
23
MODULE_LICENSE("GPL");
 
24
 
 
25
unsigned fscache_defer_lookup = 1;
 
26
module_param_named(defer_lookup, fscache_defer_lookup, uint,
 
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                   S_IWUSR | S_IRUGO);
 
28
MODULE_PARM_DESC(fscache_defer_lookup,
 
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                 "Defer cookie lookup to background thread");
 
30
 
 
31
unsigned fscache_defer_create = 1;
 
32
module_param_named(defer_create, fscache_defer_create, uint,
 
33
                   S_IWUSR | S_IRUGO);
 
34
MODULE_PARM_DESC(fscache_defer_create,
 
35
                 "Defer cookie creation to background thread");
 
36
 
 
37
unsigned fscache_debug;
 
38
module_param_named(debug, fscache_debug, uint,
 
39
                   S_IWUSR | S_IRUGO);
 
40
MODULE_PARM_DESC(fscache_debug,
 
41
                 "FS-Cache debugging mask");
 
42
 
 
43
struct kobject *fscache_root;
 
44
struct workqueue_struct *fscache_object_wq;
 
45
struct workqueue_struct *fscache_op_wq;
 
46
 
 
47
DEFINE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);
 
48
 
 
49
/* these values serve as lower bounds, will be adjusted in fscache_init() */
 
50
static unsigned fscache_object_max_active = 4;
 
51
static unsigned fscache_op_max_active = 2;
 
52
 
 
53
#ifdef CONFIG_SYSCTL
 
54
static struct ctl_table_header *fscache_sysctl_header;
 
55
 
 
56
static int fscache_max_active_sysctl(struct ctl_table *table, int write,
 
57
                                     void __user *buffer,
 
58
                                     size_t *lenp, loff_t *ppos)
 
59
{
 
60
        struct workqueue_struct **wqp = table->extra1;
 
61
        unsigned int *datap = table->data;
 
62
        int ret;
 
63
 
 
64
        ret = proc_dointvec(table, write, buffer, lenp, ppos);
 
65
        if (ret == 0)
 
66
                workqueue_set_max_active(*wqp, *datap);
 
67
        return ret;
 
68
}
 
69
 
 
70
ctl_table fscache_sysctls[] = {
 
71
        {
 
72
                .procname       = "object_max_active",
 
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                .data           = &fscache_object_max_active,
 
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                .maxlen         = sizeof(unsigned),
 
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                .mode           = 0644,
 
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                .proc_handler   = fscache_max_active_sysctl,
 
77
                .extra1         = &fscache_object_wq,
 
78
        },
 
79
        {
 
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                .procname       = "operation_max_active",
 
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                .data           = &fscache_op_max_active,
 
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                .maxlen         = sizeof(unsigned),
 
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                .mode           = 0644,
 
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                .proc_handler   = fscache_max_active_sysctl,
 
85
                .extra1         = &fscache_op_wq,
 
86
        },
 
87
        {}
 
88
};
 
89
 
 
90
ctl_table fscache_sysctls_root[] = {
 
91
        {
 
92
                .procname       = "fscache",
 
93
                .mode           = 0555,
 
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                .child          = fscache_sysctls,
 
95
        },
 
96
        {}
 
97
};
 
98
#endif
 
99
 
 
100
/*
 
101
 * initialise the fs caching module
 
102
 */
 
103
static int __init fscache_init(void)
 
104
{
 
105
        unsigned int nr_cpus = num_possible_cpus();
 
106
        unsigned int cpu;
 
107
        int ret;
 
108
 
 
109
        fscache_object_max_active =
 
110
                clamp_val(nr_cpus,
 
111
                          fscache_object_max_active, WQ_UNBOUND_MAX_ACTIVE);
 
112
 
 
113
        ret = -ENOMEM;
 
114
        fscache_object_wq = alloc_workqueue("fscache_object", WQ_UNBOUND,
 
115
                                            fscache_object_max_active);
 
116
        if (!fscache_object_wq)
 
117
                goto error_object_wq;
 
118
 
 
119
        fscache_op_max_active =
 
120
                clamp_val(fscache_object_max_active / 2,
 
121
                          fscache_op_max_active, WQ_UNBOUND_MAX_ACTIVE);
 
122
 
 
123
        ret = -ENOMEM;
 
124
        fscache_op_wq = alloc_workqueue("fscache_operation", WQ_UNBOUND,
 
125
                                        fscache_op_max_active);
 
126
        if (!fscache_op_wq)
 
127
                goto error_op_wq;
 
128
 
 
129
        for_each_possible_cpu(cpu)
 
130
                init_waitqueue_head(&per_cpu(fscache_object_cong_wait, cpu));
 
131
 
 
132
        ret = fscache_proc_init();
 
133
        if (ret < 0)
 
134
                goto error_proc;
 
135
 
 
136
#ifdef CONFIG_SYSCTL
 
137
        ret = -ENOMEM;
 
138
        fscache_sysctl_header = register_sysctl_table(fscache_sysctls_root);
 
139
        if (!fscache_sysctl_header)
 
140
                goto error_sysctl;
 
141
#endif
 
142
 
 
143
        fscache_cookie_jar = kmem_cache_create("fscache_cookie_jar",
 
144
                                               sizeof(struct fscache_cookie),
 
145
                                               0,
 
146
                                               0,
 
147
                                               fscache_cookie_init_once);
 
148
        if (!fscache_cookie_jar) {
 
149
                printk(KERN_NOTICE
 
150
                       "FS-Cache: Failed to allocate a cookie jar\n");
 
151
                ret = -ENOMEM;
 
152
                goto error_cookie_jar;
 
153
        }
 
154
 
 
155
        fscache_root = kobject_create_and_add("fscache", kernel_kobj);
 
156
        if (!fscache_root)
 
157
                goto error_kobj;
 
158
 
 
159
        printk(KERN_NOTICE "FS-Cache: Loaded\n");
 
160
        return 0;
 
161
 
 
162
error_kobj:
 
163
        kmem_cache_destroy(fscache_cookie_jar);
 
164
error_cookie_jar:
 
165
#ifdef CONFIG_SYSCTL
 
166
        unregister_sysctl_table(fscache_sysctl_header);
 
167
error_sysctl:
 
168
#endif
 
169
        fscache_proc_cleanup();
 
170
error_proc:
 
171
        destroy_workqueue(fscache_op_wq);
 
172
error_op_wq:
 
173
        destroy_workqueue(fscache_object_wq);
 
174
error_object_wq:
 
175
        return ret;
 
176
}
 
177
 
 
178
fs_initcall(fscache_init);
 
179
 
 
180
/*
 
181
 * clean up on module removal
 
182
 */
 
183
static void __exit fscache_exit(void)
 
184
{
 
185
        _enter("");
 
186
 
 
187
        kobject_put(fscache_root);
 
188
        kmem_cache_destroy(fscache_cookie_jar);
 
189
#ifdef CONFIG_SYSCTL
 
190
        unregister_sysctl_table(fscache_sysctl_header);
 
191
#endif
 
192
        fscache_proc_cleanup();
 
193
        destroy_workqueue(fscache_op_wq);
 
194
        destroy_workqueue(fscache_object_wq);
 
195
        printk(KERN_NOTICE "FS-Cache: Unloaded\n");
 
196
}
 
197
 
 
198
module_exit(fscache_exit);
 
199
 
 
200
/*
 
201
 * wait_on_bit() sleep function for uninterruptible waiting
 
202
 */
 
203
int fscache_wait_bit(void *flags)
 
204
{
 
205
        schedule();
 
206
        return 0;
 
207
}
 
208
EXPORT_SYMBOL(fscache_wait_bit);
 
209
 
 
210
/*
 
211
 * wait_on_bit() sleep function for interruptible waiting
 
212
 */
 
213
int fscache_wait_bit_interruptible(void *flags)
 
214
{
 
215
        schedule();
 
216
        return signal_pending(current);
 
217
}
 
218
EXPORT_SYMBOL(fscache_wait_bit_interruptible);