1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
|
/* General filesystem local caching manager
*
* Copyright (C) 2004-2007 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 License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#define FSCACHE_DEBUG_LEVEL CACHE
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/completion.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include "internal.h"
MODULE_DESCRIPTION("FS Cache Manager");
MODULE_AUTHOR("Red Hat, Inc.");
MODULE_LICENSE("GPL");
unsigned fscache_defer_lookup = 1;
module_param_named(defer_lookup, fscache_defer_lookup, uint,
S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(fscache_defer_lookup,
"Defer cookie lookup to background thread");
unsigned fscache_defer_create = 1;
module_param_named(defer_create, fscache_defer_create, uint,
S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(fscache_defer_create,
"Defer cookie creation to background thread");
unsigned fscache_debug;
module_param_named(debug, fscache_debug, uint,
S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(fscache_debug,
"FS-Cache debugging mask");
struct kobject *fscache_root;
struct workqueue_struct *fscache_object_wq;
struct workqueue_struct *fscache_op_wq;
DEFINE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);
/* these values serve as lower bounds, will be adjusted in fscache_init() */
static unsigned fscache_object_max_active = 4;
static unsigned fscache_op_max_active = 2;
#ifdef CONFIG_SYSCTL
static struct ctl_table_header *fscache_sysctl_header;
static int fscache_max_active_sysctl(struct ctl_table *table, int write,
void __user *buffer,
size_t *lenp, loff_t *ppos)
{
struct workqueue_struct **wqp = table->extra1;
unsigned int *datap = table->data;
int ret;
ret = proc_dointvec(table, write, buffer, lenp, ppos);
if (ret == 0)
workqueue_set_max_active(*wqp, *datap);
return ret;
}
struct ctl_table fscache_sysctls[] = {
{
.procname = "object_max_active",
.data = &fscache_object_max_active,
.maxlen = sizeof(unsigned),
.mode = 0644,
.proc_handler = fscache_max_active_sysctl,
.extra1 = &fscache_object_wq,
},
{
.procname = "operation_max_active",
.data = &fscache_op_max_active,
.maxlen = sizeof(unsigned),
.mode = 0644,
.proc_handler = fscache_max_active_sysctl,
.extra1 = &fscache_op_wq,
},
{}
};
struct ctl_table fscache_sysctls_root[] = {
{
.procname = "fscache",
.mode = 0555,
.child = fscache_sysctls,
},
{}
};
#endif
/*
* initialise the fs caching module
*/
static int __init fscache_init(void)
{
unsigned int nr_cpus = num_possible_cpus();
unsigned int cpu;
int ret;
fscache_object_max_active =
clamp_val(nr_cpus,
fscache_object_max_active, WQ_UNBOUND_MAX_ACTIVE);
ret = -ENOMEM;
fscache_object_wq = alloc_workqueue("fscache_object", WQ_UNBOUND,
fscache_object_max_active);
if (!fscache_object_wq)
goto error_object_wq;
fscache_op_max_active =
clamp_val(fscache_object_max_active / 2,
fscache_op_max_active, WQ_UNBOUND_MAX_ACTIVE);
ret = -ENOMEM;
fscache_op_wq = alloc_workqueue("fscache_operation", WQ_UNBOUND,
fscache_op_max_active);
if (!fscache_op_wq)
goto error_op_wq;
for_each_possible_cpu(cpu)
init_waitqueue_head(&per_cpu(fscache_object_cong_wait, cpu));
ret = fscache_proc_init();
if (ret < 0)
goto error_proc;
#ifdef CONFIG_SYSCTL
ret = -ENOMEM;
fscache_sysctl_header = register_sysctl_table(fscache_sysctls_root);
if (!fscache_sysctl_header)
goto error_sysctl;
#endif
fscache_cookie_jar = kmem_cache_create("fscache_cookie_jar",
sizeof(struct fscache_cookie),
0,
0,
fscache_cookie_init_once);
if (!fscache_cookie_jar) {
pr_notice("Failed to allocate a cookie jar\n");
ret = -ENOMEM;
goto error_cookie_jar;
}
fscache_root = kobject_create_and_add("fscache", kernel_kobj);
if (!fscache_root)
goto error_kobj;
pr_notice("Loaded\n");
return 0;
error_kobj:
kmem_cache_destroy(fscache_cookie_jar);
error_cookie_jar:
#ifdef CONFIG_SYSCTL
unregister_sysctl_table(fscache_sysctl_header);
error_sysctl:
#endif
fscache_proc_cleanup();
error_proc:
destroy_workqueue(fscache_op_wq);
error_op_wq:
destroy_workqueue(fscache_object_wq);
error_object_wq:
return ret;
}
fs_initcall(fscache_init);
/*
* clean up on module removal
*/
static void __exit fscache_exit(void)
{
_enter("");
kobject_put(fscache_root);
kmem_cache_destroy(fscache_cookie_jar);
#ifdef CONFIG_SYSCTL
unregister_sysctl_table(fscache_sysctl_header);
#endif
fscache_proc_cleanup();
destroy_workqueue(fscache_op_wq);
destroy_workqueue(fscache_object_wq);
pr_notice("Unloaded\n");
}
module_exit(fscache_exit);
/*
* wait_on_atomic_t() sleep function for uninterruptible waiting
*/
int fscache_wait_atomic_t(atomic_t *p)
{
schedule();
return 0;
}
|
