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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
21MODULE_DESCRIPTION("FS Cache Manager");
22MODULE_AUTHOR("Red Hat, Inc.");
23MODULE_LICENSE("GPL");
24
25unsigned fscache_defer_lookup = 1;
26module_param_named(defer_lookup, fscache_defer_lookup, uint,
27 S_IWUSR | S_IRUGO);
28MODULE_PARM_DESC(fscache_defer_lookup,
29 "Defer cookie lookup to background thread");
30
31unsigned fscache_defer_create = 1;
32module_param_named(defer_create, fscache_defer_create, uint,
33 S_IWUSR | S_IRUGO);
34MODULE_PARM_DESC(fscache_defer_create,
35 "Defer cookie creation to background thread");
36
37unsigned fscache_debug;
38module_param_named(debug, fscache_debug, uint,
39 S_IWUSR | S_IRUGO);
40MODULE_PARM_DESC(fscache_debug,
41 "FS-Cache debugging mask");
42
43struct kobject *fscache_root;
44struct workqueue_struct *fscache_object_wq;
45struct workqueue_struct *fscache_op_wq;
46
47DEFINE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);
48
49/* these values serve as lower bounds, will be adjusted in fscache_init() */
50static unsigned fscache_object_max_active = 4;
51static unsigned fscache_op_max_active = 2;
52
53#ifdef CONFIG_SYSCTL
54static struct ctl_table_header *fscache_sysctl_header;
55
56static 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
70ctl_table fscache_sysctls[] = {
71 {
72 .procname = "object_max_active",
73 .data = &fscache_object_max_active,
74 .maxlen = sizeof(unsigned),
75 .mode = 0644,
76 .proc_handler = fscache_max_active_sysctl,
77 .extra1 = &fscache_object_wq,
78 },
79 {
80 .procname = "operation_max_active",
81 .data = &fscache_op_max_active,
82 .maxlen = sizeof(unsigned),
83 .mode = 0644,
84 .proc_handler = fscache_max_active_sysctl,
85 .extra1 = &fscache_op_wq,
86 },
87 {}
88};
89
90ctl_table fscache_sysctls_root[] = {
91 {
92 .procname = "fscache",
93 .mode = 0555,
94 .child = fscache_sysctls,
95 },
96 {}
97};
98#endif
99
100/*
101 * initialise the fs caching module
102 */
103static 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
162error_kobj:
163 kmem_cache_destroy(fscache_cookie_jar);
164error_cookie_jar:
165#ifdef CONFIG_SYSCTL
166 unregister_sysctl_table(fscache_sysctl_header);
167error_sysctl:
168#endif
169 fscache_proc_cleanup();
170error_proc:
171 destroy_workqueue(fscache_op_wq);
172error_op_wq:
173 destroy_workqueue(fscache_object_wq);
174error_object_wq:
175 return ret;
176}
177
178fs_initcall(fscache_init);
179
180/*
181 * clean up on module removal
182 */
183static 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
198module_exit(fscache_exit);
199
200/*
201 * wait_on_bit() sleep function for uninterruptible waiting
202 */
203int fscache_wait_bit(void *flags)
204{
205 schedule();
206 return 0;
207}
208
209/*
210 * wait_on_bit() sleep function for interruptible waiting
211 */
212int fscache_wait_bit_interruptible(void *flags)
213{
214 schedule();
215 return signal_pending(current);
216}
217
218/*
219 * wait_on_atomic_t() sleep function for uninterruptible waiting
220 */
221int fscache_wait_atomic_t(atomic_t *p)
222{
223 schedule();
224 return 0;
225}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* General filesystem local caching manager
3 *
4 * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#define FSCACHE_DEBUG_LEVEL CACHE
9#include <linux/module.h>
10#include <linux/init.h>
11#include <linux/sched.h>
12#include <linux/completion.h>
13#include <linux/slab.h>
14#include <linux/seq_file.h>
15#define CREATE_TRACE_POINTS
16#include "internal.h"
17
18MODULE_DESCRIPTION("FS Cache Manager");
19MODULE_AUTHOR("Red Hat, Inc.");
20MODULE_LICENSE("GPL");
21
22unsigned fscache_defer_lookup = 1;
23module_param_named(defer_lookup, fscache_defer_lookup, uint,
24 S_IWUSR | S_IRUGO);
25MODULE_PARM_DESC(fscache_defer_lookup,
26 "Defer cookie lookup to background thread");
27
28unsigned fscache_defer_create = 1;
29module_param_named(defer_create, fscache_defer_create, uint,
30 S_IWUSR | S_IRUGO);
31MODULE_PARM_DESC(fscache_defer_create,
32 "Defer cookie creation to background thread");
33
34unsigned fscache_debug;
35module_param_named(debug, fscache_debug, uint,
36 S_IWUSR | S_IRUGO);
37MODULE_PARM_DESC(fscache_debug,
38 "FS-Cache debugging mask");
39
40struct kobject *fscache_root;
41struct workqueue_struct *fscache_object_wq;
42struct workqueue_struct *fscache_op_wq;
43
44DEFINE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);
45
46/* these values serve as lower bounds, will be adjusted in fscache_init() */
47static unsigned fscache_object_max_active = 4;
48static unsigned fscache_op_max_active = 2;
49
50#ifdef CONFIG_SYSCTL
51static struct ctl_table_header *fscache_sysctl_header;
52
53static int fscache_max_active_sysctl(struct ctl_table *table, int write,
54 void *buffer, size_t *lenp, loff_t *ppos)
55{
56 struct workqueue_struct **wqp = table->extra1;
57 unsigned int *datap = table->data;
58 int ret;
59
60 ret = proc_dointvec(table, write, buffer, lenp, ppos);
61 if (ret == 0)
62 workqueue_set_max_active(*wqp, *datap);
63 return ret;
64}
65
66static struct ctl_table fscache_sysctls[] = {
67 {
68 .procname = "object_max_active",
69 .data = &fscache_object_max_active,
70 .maxlen = sizeof(unsigned),
71 .mode = 0644,
72 .proc_handler = fscache_max_active_sysctl,
73 .extra1 = &fscache_object_wq,
74 },
75 {
76 .procname = "operation_max_active",
77 .data = &fscache_op_max_active,
78 .maxlen = sizeof(unsigned),
79 .mode = 0644,
80 .proc_handler = fscache_max_active_sysctl,
81 .extra1 = &fscache_op_wq,
82 },
83 {}
84};
85
86static struct ctl_table fscache_sysctls_root[] = {
87 {
88 .procname = "fscache",
89 .mode = 0555,
90 .child = fscache_sysctls,
91 },
92 {}
93};
94#endif
95
96/*
97 * Mixing scores (in bits) for (7,20):
98 * Input delta: 1-bit 2-bit
99 * 1 round: 330.3 9201.6
100 * 2 rounds: 1246.4 25475.4
101 * 3 rounds: 1907.1 31295.1
102 * 4 rounds: 2042.3 31718.6
103 * Perfect: 2048 31744
104 * (32*64) (32*31/2 * 64)
105 */
106#define HASH_MIX(x, y, a) \
107 ( x ^= (a), \
108 y ^= x, x = rol32(x, 7),\
109 x += y, y = rol32(y,20),\
110 y *= 9 )
111
112static inline unsigned int fold_hash(unsigned long x, unsigned long y)
113{
114 /* Use arch-optimized multiply if one exists */
115 return __hash_32(y ^ __hash_32(x));
116}
117
118/*
119 * Generate a hash. This is derived from full_name_hash(), but we want to be
120 * sure it is arch independent and that it doesn't change as bits of the
121 * computed hash value might appear on disk. The caller also guarantees that
122 * the hashed data will be a series of aligned 32-bit words.
123 */
124unsigned int fscache_hash(unsigned int salt, unsigned int *data, unsigned int n)
125{
126 unsigned int a, x = 0, y = salt;
127
128 for (; n; n--) {
129 a = *data++;
130 HASH_MIX(x, y, a);
131 }
132 return fold_hash(x, y);
133}
134
135/*
136 * initialise the fs caching module
137 */
138static int __init fscache_init(void)
139{
140 unsigned int nr_cpus = num_possible_cpus();
141 unsigned int cpu;
142 int ret;
143
144 fscache_object_max_active =
145 clamp_val(nr_cpus,
146 fscache_object_max_active, WQ_UNBOUND_MAX_ACTIVE);
147
148 ret = -ENOMEM;
149 fscache_object_wq = alloc_workqueue("fscache_object", WQ_UNBOUND,
150 fscache_object_max_active);
151 if (!fscache_object_wq)
152 goto error_object_wq;
153
154 fscache_op_max_active =
155 clamp_val(fscache_object_max_active / 2,
156 fscache_op_max_active, WQ_UNBOUND_MAX_ACTIVE);
157
158 ret = -ENOMEM;
159 fscache_op_wq = alloc_workqueue("fscache_operation", WQ_UNBOUND,
160 fscache_op_max_active);
161 if (!fscache_op_wq)
162 goto error_op_wq;
163
164 for_each_possible_cpu(cpu)
165 init_waitqueue_head(&per_cpu(fscache_object_cong_wait, cpu));
166
167 ret = fscache_proc_init();
168 if (ret < 0)
169 goto error_proc;
170
171#ifdef CONFIG_SYSCTL
172 ret = -ENOMEM;
173 fscache_sysctl_header = register_sysctl_table(fscache_sysctls_root);
174 if (!fscache_sysctl_header)
175 goto error_sysctl;
176#endif
177
178 fscache_cookie_jar = kmem_cache_create("fscache_cookie_jar",
179 sizeof(struct fscache_cookie),
180 0, 0, NULL);
181 if (!fscache_cookie_jar) {
182 pr_notice("Failed to allocate a cookie jar\n");
183 ret = -ENOMEM;
184 goto error_cookie_jar;
185 }
186
187 fscache_root = kobject_create_and_add("fscache", kernel_kobj);
188 if (!fscache_root)
189 goto error_kobj;
190
191 pr_notice("Loaded\n");
192 return 0;
193
194error_kobj:
195 kmem_cache_destroy(fscache_cookie_jar);
196error_cookie_jar:
197#ifdef CONFIG_SYSCTL
198 unregister_sysctl_table(fscache_sysctl_header);
199error_sysctl:
200#endif
201 fscache_proc_cleanup();
202error_proc:
203 destroy_workqueue(fscache_op_wq);
204error_op_wq:
205 destroy_workqueue(fscache_object_wq);
206error_object_wq:
207 return ret;
208}
209
210fs_initcall(fscache_init);
211
212/*
213 * clean up on module removal
214 */
215static void __exit fscache_exit(void)
216{
217 _enter("");
218
219 kobject_put(fscache_root);
220 kmem_cache_destroy(fscache_cookie_jar);
221#ifdef CONFIG_SYSCTL
222 unregister_sysctl_table(fscache_sysctl_header);
223#endif
224 fscache_proc_cleanup();
225 destroy_workqueue(fscache_op_wq);
226 destroy_workqueue(fscache_object_wq);
227 pr_notice("Unloaded\n");
228}
229
230module_exit(fscache_exit);