Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 1 | /* |
| 2 | * async.c: Asynchronous function calls for boot performance |
| 3 | * |
| 4 | * (C) Copyright 2009 Intel Corporation |
| 5 | * Author: Arjan van de Ven <arjan@linux.intel.com> |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU General Public License |
| 9 | * as published by the Free Software Foundation; version 2 |
| 10 | * of the License. |
| 11 | */ |
| 12 | |
| 13 | |
| 14 | /* |
| 15 | |
| 16 | Goals and Theory of Operation |
| 17 | |
| 18 | The primary goal of this feature is to reduce the kernel boot time, |
| 19 | by doing various independent hardware delays and discovery operations |
| 20 | decoupled and not strictly serialized. |
| 21 | |
| 22 | More specifically, the asynchronous function call concept allows |
| 23 | certain operations (primarily during system boot) to happen |
| 24 | asynchronously, out of order, while these operations still |
| 25 | have their externally visible parts happen sequentially and in-order. |
| 26 | (not unlike how out-of-order CPUs retire their instructions in order) |
| 27 | |
| 28 | Key to the asynchronous function call implementation is the concept of |
| 29 | a "sequence cookie" (which, although it has an abstracted type, can be |
| 30 | thought of as a monotonically incrementing number). |
| 31 | |
| 32 | The async core will assign each scheduled event such a sequence cookie and |
| 33 | pass this to the called functions. |
| 34 | |
| 35 | The asynchronously called function should before doing a globally visible |
| 36 | operation, such as registering device numbers, call the |
| 37 | async_synchronize_cookie() function and pass in its own cookie. The |
| 38 | async_synchronize_cookie() function will make sure that all asynchronous |
| 39 | operations that were scheduled prior to the operation corresponding with the |
| 40 | cookie have completed. |
| 41 | |
| 42 | Subsystem/driver initialization code that scheduled asynchronous probe |
| 43 | functions, but which shares global resources with other drivers/subsystems |
| 44 | that do not use the asynchronous call feature, need to do a full |
| 45 | synchronization with the async_synchronize_full() function, before returning |
| 46 | from their init function. This is to maintain strict ordering between the |
| 47 | asynchronous and synchronous parts of the kernel. |
| 48 | |
| 49 | */ |
| 50 | |
| 51 | #include <linux/async.h> |
Arjan van de Ven | 9710794 | 2009-03-15 11:11:44 -0700 | [diff] [blame] | 52 | #include <linux/bug.h> |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 53 | #include <linux/module.h> |
| 54 | #include <linux/wait.h> |
| 55 | #include <linux/sched.h> |
| 56 | #include <linux/init.h> |
| 57 | #include <linux/kthread.h> |
Cornelia Huck | 86532d8 | 2009-01-19 13:45:31 +0100 | [diff] [blame] | 58 | #include <linux/delay.h> |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 59 | #include <asm/atomic.h> |
| 60 | |
| 61 | static async_cookie_t next_cookie = 1; |
| 62 | |
| 63 | #define MAX_THREADS 256 |
| 64 | #define MAX_WORK 32768 |
| 65 | |
| 66 | static LIST_HEAD(async_pending); |
| 67 | static LIST_HEAD(async_running); |
| 68 | static DEFINE_SPINLOCK(async_lock); |
| 69 | |
Arjan van de Ven | cdb80f6 | 2009-01-09 13:23:45 -0800 | [diff] [blame] | 70 | static int async_enabled = 0; |
| 71 | |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 72 | struct async_entry { |
| 73 | struct list_head list; |
| 74 | async_cookie_t cookie; |
| 75 | async_func_ptr *func; |
| 76 | void *data; |
| 77 | struct list_head *running; |
| 78 | }; |
| 79 | |
| 80 | static DECLARE_WAIT_QUEUE_HEAD(async_done); |
| 81 | static DECLARE_WAIT_QUEUE_HEAD(async_new); |
| 82 | |
| 83 | static atomic_t entry_count; |
| 84 | static atomic_t thread_count; |
| 85 | |
| 86 | extern int initcall_debug; |
| 87 | |
| 88 | |
| 89 | /* |
| 90 | * MUST be called with the lock held! |
| 91 | */ |
| 92 | static async_cookie_t __lowest_in_progress(struct list_head *running) |
| 93 | { |
| 94 | struct async_entry *entry; |
James Bottomley | d5a877e | 2009-05-24 13:03:43 -0700 | [diff] [blame] | 95 | |
Arjan van de Ven | 37a76bd | 2009-01-11 15:35:01 +0000 | [diff] [blame] | 96 | if (!list_empty(running)) { |
| 97 | entry = list_first_entry(running, |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 98 | struct async_entry, list); |
Linus Torvalds | 3af968e | 2009-06-08 12:31:53 -0700 | [diff] [blame] | 99 | return entry->cookie; |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 100 | } |
| 101 | |
Linus Torvalds | 3af968e | 2009-06-08 12:31:53 -0700 | [diff] [blame] | 102 | list_for_each_entry(entry, &async_pending, list) |
| 103 | if (entry->running == running) |
| 104 | return entry->cookie; |
James Bottomley | d5a877e | 2009-05-24 13:03:43 -0700 | [diff] [blame] | 105 | |
Linus Torvalds | 3af968e | 2009-06-08 12:31:53 -0700 | [diff] [blame] | 106 | return next_cookie; /* "infinity" value */ |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 107 | } |
Arjan van de Ven | 37a76bd | 2009-01-11 15:35:01 +0000 | [diff] [blame] | 108 | |
| 109 | static async_cookie_t lowest_in_progress(struct list_head *running) |
| 110 | { |
| 111 | unsigned long flags; |
| 112 | async_cookie_t ret; |
| 113 | |
| 114 | spin_lock_irqsave(&async_lock, flags); |
| 115 | ret = __lowest_in_progress(running); |
| 116 | spin_unlock_irqrestore(&async_lock, flags); |
| 117 | return ret; |
| 118 | } |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 119 | /* |
| 120 | * pick the first pending entry and run it |
| 121 | */ |
| 122 | static void run_one_entry(void) |
| 123 | { |
| 124 | unsigned long flags; |
| 125 | struct async_entry *entry; |
| 126 | ktime_t calltime, delta, rettime; |
| 127 | |
| 128 | /* 1) pick one task from the pending queue */ |
| 129 | |
| 130 | spin_lock_irqsave(&async_lock, flags); |
| 131 | if (list_empty(&async_pending)) |
| 132 | goto out; |
| 133 | entry = list_first_entry(&async_pending, struct async_entry, list); |
| 134 | |
| 135 | /* 2) move it to the running queue */ |
Stefan Richter | f7de7621f | 2009-02-02 13:24:34 +0100 | [diff] [blame] | 136 | list_move_tail(&entry->list, entry->running); |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 137 | spin_unlock_irqrestore(&async_lock, flags); |
| 138 | |
| 139 | /* 3) run it (and print duration)*/ |
Arjan van de Ven | ad160d2 | 2009-01-07 09:28:53 -0800 | [diff] [blame] | 140 | if (initcall_debug && system_state == SYSTEM_BOOTING) { |
Andrew Morton | 58763a2 | 2009-02-04 15:11:58 -0800 | [diff] [blame] | 141 | printk("calling %lli_%pF @ %i\n", (long long)entry->cookie, |
| 142 | entry->func, task_pid_nr(current)); |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 143 | calltime = ktime_get(); |
| 144 | } |
| 145 | entry->func(entry->data, entry->cookie); |
Arjan van de Ven | ad160d2 | 2009-01-07 09:28:53 -0800 | [diff] [blame] | 146 | if (initcall_debug && system_state == SYSTEM_BOOTING) { |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 147 | rettime = ktime_get(); |
| 148 | delta = ktime_sub(rettime, calltime); |
Andrew Morton | 58763a2 | 2009-02-04 15:11:58 -0800 | [diff] [blame] | 149 | printk("initcall %lli_%pF returned 0 after %lld usecs\n", |
| 150 | (long long)entry->cookie, |
| 151 | entry->func, |
| 152 | (long long)ktime_to_ns(delta) >> 10); |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 153 | } |
| 154 | |
| 155 | /* 4) remove it from the running queue */ |
| 156 | spin_lock_irqsave(&async_lock, flags); |
| 157 | list_del(&entry->list); |
| 158 | |
| 159 | /* 5) free the entry */ |
| 160 | kfree(entry); |
| 161 | atomic_dec(&entry_count); |
| 162 | |
| 163 | spin_unlock_irqrestore(&async_lock, flags); |
| 164 | |
| 165 | /* 6) wake up any waiters. */ |
| 166 | wake_up(&async_done); |
| 167 | return; |
| 168 | |
| 169 | out: |
| 170 | spin_unlock_irqrestore(&async_lock, flags); |
| 171 | } |
| 172 | |
| 173 | |
| 174 | static async_cookie_t __async_schedule(async_func_ptr *ptr, void *data, struct list_head *running) |
| 175 | { |
| 176 | struct async_entry *entry; |
| 177 | unsigned long flags; |
| 178 | async_cookie_t newcookie; |
| 179 | |
| 180 | |
| 181 | /* allow irq-off callers */ |
| 182 | entry = kzalloc(sizeof(struct async_entry), GFP_ATOMIC); |
| 183 | |
| 184 | /* |
| 185 | * If we're out of memory or if there's too much work |
| 186 | * pending already, we execute synchronously. |
| 187 | */ |
Arjan van de Ven | cdb80f6 | 2009-01-09 13:23:45 -0800 | [diff] [blame] | 188 | if (!async_enabled || !entry || atomic_read(&entry_count) > MAX_WORK) { |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 189 | kfree(entry); |
| 190 | spin_lock_irqsave(&async_lock, flags); |
| 191 | newcookie = next_cookie++; |
| 192 | spin_unlock_irqrestore(&async_lock, flags); |
| 193 | |
| 194 | /* low on memory.. run synchronously */ |
| 195 | ptr(data, newcookie); |
| 196 | return newcookie; |
| 197 | } |
| 198 | entry->func = ptr; |
| 199 | entry->data = data; |
| 200 | entry->running = running; |
| 201 | |
| 202 | spin_lock_irqsave(&async_lock, flags); |
| 203 | newcookie = entry->cookie = next_cookie++; |
| 204 | list_add_tail(&entry->list, &async_pending); |
| 205 | atomic_inc(&entry_count); |
| 206 | spin_unlock_irqrestore(&async_lock, flags); |
| 207 | wake_up(&async_new); |
| 208 | return newcookie; |
| 209 | } |
| 210 | |
Cornelia Huck | f30d5b3 | 2009-01-19 13:45:33 +0100 | [diff] [blame] | 211 | /** |
| 212 | * async_schedule - schedule a function for asynchronous execution |
| 213 | * @ptr: function to execute asynchronously |
| 214 | * @data: data pointer to pass to the function |
| 215 | * |
| 216 | * Returns an async_cookie_t that may be used for checkpointing later. |
| 217 | * Note: This function may be called from atomic or non-atomic contexts. |
| 218 | */ |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 219 | async_cookie_t async_schedule(async_func_ptr *ptr, void *data) |
| 220 | { |
Cornelia Huck | 7a89bbc | 2009-01-19 13:45:28 +0100 | [diff] [blame] | 221 | return __async_schedule(ptr, data, &async_running); |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 222 | } |
| 223 | EXPORT_SYMBOL_GPL(async_schedule); |
| 224 | |
Cornelia Huck | f30d5b3 | 2009-01-19 13:45:33 +0100 | [diff] [blame] | 225 | /** |
Cornelia Huck | 766ccb9 | 2009-01-20 15:31:31 +0100 | [diff] [blame] | 226 | * async_schedule_domain - schedule a function for asynchronous execution within a certain domain |
Cornelia Huck | f30d5b3 | 2009-01-19 13:45:33 +0100 | [diff] [blame] | 227 | * @ptr: function to execute asynchronously |
| 228 | * @data: data pointer to pass to the function |
Cornelia Huck | 766ccb9 | 2009-01-20 15:31:31 +0100 | [diff] [blame] | 229 | * @running: running list for the domain |
Cornelia Huck | f30d5b3 | 2009-01-19 13:45:33 +0100 | [diff] [blame] | 230 | * |
| 231 | * Returns an async_cookie_t that may be used for checkpointing later. |
Cornelia Huck | 766ccb9 | 2009-01-20 15:31:31 +0100 | [diff] [blame] | 232 | * @running may be used in the async_synchronize_*_domain() functions |
| 233 | * to wait within a certain synchronization domain rather than globally. |
| 234 | * A synchronization domain is specified via the running queue @running to use. |
Cornelia Huck | f30d5b3 | 2009-01-19 13:45:33 +0100 | [diff] [blame] | 235 | * Note: This function may be called from atomic or non-atomic contexts. |
| 236 | */ |
Cornelia Huck | 766ccb9 | 2009-01-20 15:31:31 +0100 | [diff] [blame] | 237 | async_cookie_t async_schedule_domain(async_func_ptr *ptr, void *data, |
| 238 | struct list_head *running) |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 239 | { |
| 240 | return __async_schedule(ptr, data, running); |
| 241 | } |
Cornelia Huck | 766ccb9 | 2009-01-20 15:31:31 +0100 | [diff] [blame] | 242 | EXPORT_SYMBOL_GPL(async_schedule_domain); |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 243 | |
Cornelia Huck | f30d5b3 | 2009-01-19 13:45:33 +0100 | [diff] [blame] | 244 | /** |
| 245 | * async_synchronize_full - synchronize all asynchronous function calls |
| 246 | * |
| 247 | * This function waits until all asynchronous function calls have been done. |
| 248 | */ |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 249 | void async_synchronize_full(void) |
| 250 | { |
Arjan van de Ven | 33b04b9 | 2009-01-08 12:35:11 -0800 | [diff] [blame] | 251 | do { |
| 252 | async_synchronize_cookie(next_cookie); |
| 253 | } while (!list_empty(&async_running) || !list_empty(&async_pending)); |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 254 | } |
| 255 | EXPORT_SYMBOL_GPL(async_synchronize_full); |
| 256 | |
Cornelia Huck | f30d5b3 | 2009-01-19 13:45:33 +0100 | [diff] [blame] | 257 | /** |
Cornelia Huck | 766ccb9 | 2009-01-20 15:31:31 +0100 | [diff] [blame] | 258 | * async_synchronize_full_domain - synchronize all asynchronous function within a certain domain |
Cornelia Huck | f30d5b3 | 2009-01-19 13:45:33 +0100 | [diff] [blame] | 259 | * @list: running list to synchronize on |
| 260 | * |
Cornelia Huck | 766ccb9 | 2009-01-20 15:31:31 +0100 | [diff] [blame] | 261 | * This function waits until all asynchronous function calls for the |
| 262 | * synchronization domain specified by the running list @list have been done. |
Cornelia Huck | f30d5b3 | 2009-01-19 13:45:33 +0100 | [diff] [blame] | 263 | */ |
Cornelia Huck | 766ccb9 | 2009-01-20 15:31:31 +0100 | [diff] [blame] | 264 | void async_synchronize_full_domain(struct list_head *list) |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 265 | { |
Cornelia Huck | 766ccb9 | 2009-01-20 15:31:31 +0100 | [diff] [blame] | 266 | async_synchronize_cookie_domain(next_cookie, list); |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 267 | } |
Cornelia Huck | 766ccb9 | 2009-01-20 15:31:31 +0100 | [diff] [blame] | 268 | EXPORT_SYMBOL_GPL(async_synchronize_full_domain); |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 269 | |
Cornelia Huck | f30d5b3 | 2009-01-19 13:45:33 +0100 | [diff] [blame] | 270 | /** |
Cornelia Huck | 766ccb9 | 2009-01-20 15:31:31 +0100 | [diff] [blame] | 271 | * async_synchronize_cookie_domain - synchronize asynchronous function calls within a certain domain with cookie checkpointing |
Cornelia Huck | f30d5b3 | 2009-01-19 13:45:33 +0100 | [diff] [blame] | 272 | * @cookie: async_cookie_t to use as checkpoint |
| 273 | * @running: running list to synchronize on |
| 274 | * |
Cornelia Huck | 766ccb9 | 2009-01-20 15:31:31 +0100 | [diff] [blame] | 275 | * This function waits until all asynchronous function calls for the |
| 276 | * synchronization domain specified by the running list @list submitted |
| 277 | * prior to @cookie have been done. |
Cornelia Huck | f30d5b3 | 2009-01-19 13:45:33 +0100 | [diff] [blame] | 278 | */ |
Cornelia Huck | 766ccb9 | 2009-01-20 15:31:31 +0100 | [diff] [blame] | 279 | void async_synchronize_cookie_domain(async_cookie_t cookie, |
| 280 | struct list_head *running) |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 281 | { |
| 282 | ktime_t starttime, delta, endtime; |
| 283 | |
Arjan van de Ven | ad160d2 | 2009-01-07 09:28:53 -0800 | [diff] [blame] | 284 | if (initcall_debug && system_state == SYSTEM_BOOTING) { |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 285 | printk("async_waiting @ %i\n", task_pid_nr(current)); |
| 286 | starttime = ktime_get(); |
| 287 | } |
| 288 | |
Arjan van de Ven | 37a76bd | 2009-01-11 15:35:01 +0000 | [diff] [blame] | 289 | wait_event(async_done, lowest_in_progress(running) >= cookie); |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 290 | |
Arjan van de Ven | ad160d2 | 2009-01-07 09:28:53 -0800 | [diff] [blame] | 291 | if (initcall_debug && system_state == SYSTEM_BOOTING) { |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 292 | endtime = ktime_get(); |
| 293 | delta = ktime_sub(endtime, starttime); |
| 294 | |
| 295 | printk("async_continuing @ %i after %lli usec\n", |
Andrew Morton | 58763a2 | 2009-02-04 15:11:58 -0800 | [diff] [blame] | 296 | task_pid_nr(current), |
| 297 | (long long)ktime_to_ns(delta) >> 10); |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 298 | } |
| 299 | } |
Cornelia Huck | 766ccb9 | 2009-01-20 15:31:31 +0100 | [diff] [blame] | 300 | EXPORT_SYMBOL_GPL(async_synchronize_cookie_domain); |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 301 | |
Cornelia Huck | f30d5b3 | 2009-01-19 13:45:33 +0100 | [diff] [blame] | 302 | /** |
| 303 | * async_synchronize_cookie - synchronize asynchronous function calls with cookie checkpointing |
| 304 | * @cookie: async_cookie_t to use as checkpoint |
| 305 | * |
| 306 | * This function waits until all asynchronous function calls prior to @cookie |
| 307 | * have been done. |
| 308 | */ |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 309 | void async_synchronize_cookie(async_cookie_t cookie) |
| 310 | { |
Cornelia Huck | 766ccb9 | 2009-01-20 15:31:31 +0100 | [diff] [blame] | 311 | async_synchronize_cookie_domain(cookie, &async_running); |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 312 | } |
| 313 | EXPORT_SYMBOL_GPL(async_synchronize_cookie); |
| 314 | |
| 315 | |
| 316 | static int async_thread(void *unused) |
| 317 | { |
| 318 | DECLARE_WAITQUEUE(wq, current); |
| 319 | add_wait_queue(&async_new, &wq); |
| 320 | |
| 321 | while (!kthread_should_stop()) { |
| 322 | int ret = HZ; |
| 323 | set_current_state(TASK_INTERRUPTIBLE); |
| 324 | /* |
| 325 | * check the list head without lock.. false positives |
| 326 | * are dealt with inside run_one_entry() while holding |
| 327 | * the lock. |
| 328 | */ |
| 329 | rmb(); |
| 330 | if (!list_empty(&async_pending)) |
| 331 | run_one_entry(); |
| 332 | else |
| 333 | ret = schedule_timeout(HZ); |
| 334 | |
| 335 | if (ret == 0) { |
| 336 | /* |
| 337 | * we timed out, this means we as thread are redundant. |
| 338 | * we sign off and die, but we to avoid any races there |
| 339 | * is a last-straw check to see if work snuck in. |
| 340 | */ |
| 341 | atomic_dec(&thread_count); |
| 342 | wmb(); /* manager must see our departure first */ |
| 343 | if (list_empty(&async_pending)) |
| 344 | break; |
| 345 | /* |
| 346 | * woops work came in between us timing out and us |
| 347 | * signing off; we need to stay alive and keep working. |
| 348 | */ |
| 349 | atomic_inc(&thread_count); |
| 350 | } |
| 351 | } |
| 352 | remove_wait_queue(&async_new, &wq); |
| 353 | |
| 354 | return 0; |
| 355 | } |
| 356 | |
| 357 | static int async_manager_thread(void *unused) |
| 358 | { |
| 359 | DECLARE_WAITQUEUE(wq, current); |
| 360 | add_wait_queue(&async_new, &wq); |
| 361 | |
| 362 | while (!kthread_should_stop()) { |
| 363 | int tc, ec; |
| 364 | |
| 365 | set_current_state(TASK_INTERRUPTIBLE); |
| 366 | |
| 367 | tc = atomic_read(&thread_count); |
| 368 | rmb(); |
| 369 | ec = atomic_read(&entry_count); |
| 370 | |
| 371 | while (tc < ec && tc < MAX_THREADS) { |
Cornelia Huck | 86532d8 | 2009-01-19 13:45:31 +0100 | [diff] [blame] | 372 | if (IS_ERR(kthread_run(async_thread, NULL, "async/%i", |
| 373 | tc))) { |
| 374 | msleep(100); |
| 375 | continue; |
| 376 | } |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 377 | atomic_inc(&thread_count); |
| 378 | tc++; |
| 379 | } |
| 380 | |
| 381 | schedule(); |
| 382 | } |
| 383 | remove_wait_queue(&async_new, &wq); |
| 384 | |
| 385 | return 0; |
| 386 | } |
| 387 | |
| 388 | static int __init async_init(void) |
| 389 | { |
Arjan van de Ven | 9710794 | 2009-03-15 11:11:44 -0700 | [diff] [blame] | 390 | async_enabled = |
| 391 | !IS_ERR(kthread_run(async_manager_thread, NULL, "async/mgr")); |
| 392 | |
| 393 | WARN_ON(!async_enabled); |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 394 | return 0; |
| 395 | } |
| 396 | |
Arjan van de Ven | 22a9d64 | 2009-01-07 08:45:46 -0800 | [diff] [blame] | 397 | core_initcall(async_init); |