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