Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * drivers/power/process.c - Functions for starting/stopping processes on |
| 3 | * suspend transitions. |
| 4 | * |
| 5 | * Originally from swsusp. |
| 6 | */ |
| 7 | |
| 8 | |
| 9 | #undef DEBUG |
| 10 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 11 | #include <linux/interrupt.h> |
| 12 | #include <linux/suspend.h> |
| 13 | #include <linux/module.h> |
Rafael J. Wysocki | 02aaeb9 | 2006-03-23 03:00:04 -0800 | [diff] [blame] | 14 | #include <linux/syscalls.h> |
Nigel Cunningham | 7dfb710 | 2006-12-06 20:34:23 -0800 | [diff] [blame] | 15 | #include <linux/freezer.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | |
| 17 | /* |
| 18 | * Timeout for stopping processes |
| 19 | */ |
Rafael J. Wysocki | 02aaeb9 | 2006-03-23 03:00:04 -0800 | [diff] [blame] | 20 | #define TIMEOUT (20 * HZ) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | |
Rafael J. Wysocki | a9b6f56 | 2006-12-06 20:34:37 -0800 | [diff] [blame] | 22 | #define FREEZER_KERNEL_THREADS 0 |
| 23 | #define FREEZER_USER_SPACE 1 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | |
| 25 | static inline int freezeable(struct task_struct * p) |
| 26 | { |
Oleg Nesterov | 1065d13 | 2007-05-08 00:24:01 -0700 | [diff] [blame] | 27 | if ((p == current) || |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | (p->flags & PF_NOFREEZE) || |
Oleg Nesterov | 1065d13 | 2007-05-08 00:24:01 -0700 | [diff] [blame] | 29 | (p->exit_state != 0)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | return 0; |
| 31 | return 1; |
| 32 | } |
| 33 | |
| 34 | /* Refrigerator is place where frozen processes are stored :-). */ |
Christoph Lameter | 3e1d1d2 | 2005-06-24 23:13:50 -0700 | [diff] [blame] | 35 | void refrigerator(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | { |
| 37 | /* Hmm, should we be allowed to suspend when there are realtime |
| 38 | processes around? */ |
| 39 | long save; |
Rafael J. Wysocki | 33e1c28 | 2007-05-23 13:57:24 -0700 | [diff] [blame^] | 40 | |
| 41 | task_lock(current); |
| 42 | if (freezing(current)) { |
| 43 | frozen_process(current); |
| 44 | task_unlock(current); |
| 45 | } else { |
| 46 | task_unlock(current); |
| 47 | return; |
| 48 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 49 | save = current->state; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | pr_debug("%s entered refrigerator\n", current->comm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 51 | |
| 52 | spin_lock_irq(¤t->sighand->siglock); |
| 53 | recalc_sigpending(); /* We sent fake signal, clean it up */ |
| 54 | spin_unlock_irq(¤t->sighand->siglock); |
| 55 | |
Oleg Nesterov | 433ecb4 | 2007-05-06 14:50:40 -0700 | [diff] [blame] | 56 | for (;;) { |
| 57 | set_current_state(TASK_UNINTERRUPTIBLE); |
| 58 | if (!frozen(current)) |
| 59 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 60 | schedule(); |
Pavel Machek | 2a23b5d | 2005-09-03 15:56:53 -0700 | [diff] [blame] | 61 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 62 | pr_debug("%s left refrigerator\n", current->comm); |
| 63 | current->state = save; |
| 64 | } |
| 65 | |
Rafael J. Wysocki | 02aaeb9 | 2006-03-23 03:00:04 -0800 | [diff] [blame] | 66 | static inline void freeze_process(struct task_struct *p) |
| 67 | { |
| 68 | unsigned long flags; |
| 69 | |
| 70 | if (!freezing(p)) { |
Rafael J. Wysocki | 8a102ee | 2006-12-13 00:34:30 -0800 | [diff] [blame] | 71 | rmb(); |
| 72 | if (!frozen(p)) { |
| 73 | if (p->state == TASK_STOPPED) |
| 74 | force_sig_specific(SIGSTOP, p); |
Rafael J. Wysocki | 3df494a | 2006-12-13 00:34:28 -0800 | [diff] [blame] | 75 | |
Rafael J. Wysocki | 8a102ee | 2006-12-13 00:34:30 -0800 | [diff] [blame] | 76 | freeze(p); |
| 77 | spin_lock_irqsave(&p->sighand->siglock, flags); |
| 78 | signal_wake_up(p, p->state == TASK_STOPPED); |
| 79 | spin_unlock_irqrestore(&p->sighand->siglock, flags); |
| 80 | } |
Rafael J. Wysocki | 02aaeb9 | 2006-03-23 03:00:04 -0800 | [diff] [blame] | 81 | } |
| 82 | } |
| 83 | |
Rafael J. Wysocki | a7ef787 | 2006-08-05 12:13:42 -0700 | [diff] [blame] | 84 | static void cancel_freezing(struct task_struct *p) |
| 85 | { |
| 86 | unsigned long flags; |
| 87 | |
| 88 | if (freezing(p)) { |
| 89 | pr_debug(" clean up: %s\n", p->comm); |
| 90 | do_not_freeze(p); |
| 91 | spin_lock_irqsave(&p->sighand->siglock, flags); |
| 92 | recalc_sigpending_tsk(p); |
| 93 | spin_unlock_irqrestore(&p->sighand->siglock, flags); |
| 94 | } |
| 95 | } |
| 96 | |
Rafael J. Wysocki | a9b6f56 | 2006-12-06 20:34:37 -0800 | [diff] [blame] | 97 | static inline int is_user_space(struct task_struct *p) |
| 98 | { |
| 99 | return p->mm && !(p->flags & PF_BORROWED_MM); |
| 100 | } |
| 101 | |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 102 | static unsigned int try_to_freeze_tasks(int freeze_user_space) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | struct task_struct *g, *p; |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 105 | unsigned long end_time; |
| 106 | unsigned int todo; |
Christoph Lameter | 3e1d1d2 | 2005-06-24 23:13:50 -0700 | [diff] [blame] | 107 | |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 108 | end_time = jiffies + TIMEOUT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 109 | do { |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 110 | todo = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 111 | read_lock(&tasklist_lock); |
| 112 | do_each_thread(g, p) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 113 | if (!freezeable(p)) |
| 114 | continue; |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 115 | |
Pavel Machek | 1322ad41 | 2005-07-07 17:56:45 -0700 | [diff] [blame] | 116 | if (frozen(p)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | continue; |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 118 | |
Rafael J. Wysocki | 3df494a | 2006-12-13 00:34:28 -0800 | [diff] [blame] | 119 | if (p->state == TASK_TRACED && frozen(p->parent)) { |
Rafael J. Wysocki | a7ef787 | 2006-08-05 12:13:42 -0700 | [diff] [blame] | 120 | cancel_freezing(p); |
| 121 | continue; |
| 122 | } |
Rafael J. Wysocki | a9b6f56 | 2006-12-06 20:34:37 -0800 | [diff] [blame] | 123 | if (is_user_space(p)) { |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 124 | if (!freeze_user_space) |
| 125 | continue; |
| 126 | |
Rafael J. Wysocki | a9b6f56 | 2006-12-06 20:34:37 -0800 | [diff] [blame] | 127 | /* Freeze the task unless there is a vfork |
| 128 | * completion pending |
Rafael J. Wysocki | 02aaeb9 | 2006-03-23 03:00:04 -0800 | [diff] [blame] | 129 | */ |
| 130 | if (!p->vfork_done) |
| 131 | freeze_process(p); |
Rafael J. Wysocki | 02aaeb9 | 2006-03-23 03:00:04 -0800 | [diff] [blame] | 132 | } else { |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 133 | if (freeze_user_space) |
| 134 | continue; |
| 135 | |
| 136 | freeze_process(p); |
Rafael J. Wysocki | 02aaeb9 | 2006-03-23 03:00:04 -0800 | [diff] [blame] | 137 | } |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 138 | todo++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 139 | } while_each_thread(g, p); |
| 140 | read_unlock(&tasklist_lock); |
Rafael J. Wysocki | 02aaeb9 | 2006-03-23 03:00:04 -0800 | [diff] [blame] | 141 | yield(); /* Yield is okay here */ |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 142 | if (todo && time_after(jiffies, end_time)) |
Rafael J. Wysocki | 02aaeb9 | 2006-03-23 03:00:04 -0800 | [diff] [blame] | 143 | break; |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 144 | } while (todo); |
Christoph Lameter | 3e1d1d2 | 2005-06-24 23:13:50 -0700 | [diff] [blame] | 145 | |
Pavel Machek | 6161b2c | 2005-09-03 15:57:05 -0700 | [diff] [blame] | 146 | if (todo) { |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 147 | /* This does not unfreeze processes that are already frozen |
| 148 | * (we have slightly ugly calling convention in that respect, |
| 149 | * and caller must call thaw_processes() if something fails), |
| 150 | * but it cleans up leftover PF_FREEZE requests. |
| 151 | */ |
Nigel Cunningham | 14b5b7c | 2006-12-06 20:34:26 -0800 | [diff] [blame] | 152 | printk("\n"); |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 153 | printk(KERN_ERR "Stopping %s timed out after %d seconds " |
| 154 | "(%d tasks refusing to freeze):\n", |
| 155 | freeze_user_space ? "user space processes" : |
| 156 | "kernel threads", |
| 157 | TIMEOUT / HZ, todo); |
Pavel Machek | 6161b2c | 2005-09-03 15:57:05 -0700 | [diff] [blame] | 158 | read_lock(&tasklist_lock); |
Rafael J. Wysocki | 02aaeb9 | 2006-03-23 03:00:04 -0800 | [diff] [blame] | 159 | do_each_thread(g, p) { |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 160 | if (is_user_space(p) == !freeze_user_space) |
| 161 | continue; |
| 162 | |
Rafael J. Wysocki | 33e1c28 | 2007-05-23 13:57:24 -0700 | [diff] [blame^] | 163 | task_lock(p); |
Rafael J. Wysocki | 02aaeb9 | 2006-03-23 03:00:04 -0800 | [diff] [blame] | 164 | if (freezeable(p) && !frozen(p)) |
Nigel Cunningham | 14b5b7c | 2006-12-06 20:34:26 -0800 | [diff] [blame] | 165 | printk(KERN_ERR " %s\n", p->comm); |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 166 | |
Rafael J. Wysocki | a7ef787 | 2006-08-05 12:13:42 -0700 | [diff] [blame] | 167 | cancel_freezing(p); |
Rafael J. Wysocki | 33e1c28 | 2007-05-23 13:57:24 -0700 | [diff] [blame^] | 168 | task_unlock(p); |
Rafael J. Wysocki | 02aaeb9 | 2006-03-23 03:00:04 -0800 | [diff] [blame] | 169 | } while_each_thread(g, p); |
Pavel Machek | 6161b2c | 2005-09-03 15:57:05 -0700 | [diff] [blame] | 170 | read_unlock(&tasklist_lock); |
Pavel Machek | 6161b2c | 2005-09-03 15:57:05 -0700 | [diff] [blame] | 171 | } |
| 172 | |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 173 | return todo; |
| 174 | } |
| 175 | |
| 176 | /** |
| 177 | * freeze_processes - tell processes to enter the refrigerator |
| 178 | * |
| 179 | * Returns 0 on success, or the number of processes that didn't freeze, |
| 180 | * although they were told to. |
| 181 | */ |
| 182 | int freeze_processes(void) |
| 183 | { |
| 184 | unsigned int nr_unfrozen; |
| 185 | |
| 186 | printk("Stopping tasks ... "); |
| 187 | nr_unfrozen = try_to_freeze_tasks(FREEZER_USER_SPACE); |
| 188 | if (nr_unfrozen) |
| 189 | return nr_unfrozen; |
| 190 | |
| 191 | sys_sync(); |
| 192 | nr_unfrozen = try_to_freeze_tasks(FREEZER_KERNEL_THREADS); |
| 193 | if (nr_unfrozen) |
| 194 | return nr_unfrozen; |
| 195 | |
Nigel Cunningham | 14b5b7c | 2006-12-06 20:34:26 -0800 | [diff] [blame] | 196 | printk("done.\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 197 | BUG_ON(in_atomic()); |
| 198 | return 0; |
| 199 | } |
| 200 | |
Rafael J. Wysocki | a9b6f56 | 2006-12-06 20:34:37 -0800 | [diff] [blame] | 201 | static void thaw_tasks(int thaw_user_space) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | { |
| 203 | struct task_struct *g, *p; |
| 204 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 205 | read_lock(&tasklist_lock); |
Rafael J. Wysocki | a9b6f56 | 2006-12-06 20:34:37 -0800 | [diff] [blame] | 206 | do_each_thread(g, p) { |
| 207 | if (!freezeable(p)) |
| 208 | continue; |
Nigel Cunningham | ff39593 | 2006-12-06 20:34:28 -0800 | [diff] [blame] | 209 | |
Rafael J. Wysocki | a9b6f56 | 2006-12-06 20:34:37 -0800 | [diff] [blame] | 210 | if (is_user_space(p) == !thaw_user_space) |
| 211 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 212 | |
Rafael J. Wysocki | a9b6f56 | 2006-12-06 20:34:37 -0800 | [diff] [blame] | 213 | if (!thaw_process(p)) |
| 214 | printk(KERN_WARNING " Strange, %s not stopped\n", |
| 215 | p->comm ); |
| 216 | } while_each_thread(g, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 217 | read_unlock(&tasklist_lock); |
Rafael J. Wysocki | a9b6f56 | 2006-12-06 20:34:37 -0800 | [diff] [blame] | 218 | } |
| 219 | |
| 220 | void thaw_processes(void) |
| 221 | { |
| 222 | printk("Restarting tasks ... "); |
| 223 | thaw_tasks(FREEZER_KERNEL_THREADS); |
| 224 | thaw_tasks(FREEZER_USER_SPACE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 225 | schedule(); |
Nigel Cunningham | 14b5b7c | 2006-12-06 20:34:26 -0800 | [diff] [blame] | 226 | printk("done.\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 227 | } |
| 228 | |
| 229 | EXPORT_SYMBOL(refrigerator); |