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 | |
Gautham R Shenoy | 88f18ba | 2007-05-23 13:57:29 -0700 | [diff] [blame] | 34 | /* |
| 35 | * freezing is complete, mark current process as frozen |
| 36 | */ |
| 37 | static inline void frozen_process(void) |
| 38 | { |
| 39 | if (!unlikely(current->flags & PF_NOFREEZE)) { |
| 40 | current->flags |= PF_FROZEN; |
| 41 | wmb(); |
| 42 | } |
Rafael J. Wysocki | 0c1eecf | 2007-07-19 01:47:33 -0700 | [diff] [blame] | 43 | clear_freeze_flag(current); |
Gautham R Shenoy | 88f18ba | 2007-05-23 13:57:29 -0700 | [diff] [blame] | 44 | } |
| 45 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 46 | /* Refrigerator is place where frozen processes are stored :-). */ |
Christoph Lameter | 3e1d1d2 | 2005-06-24 23:13:50 -0700 | [diff] [blame] | 47 | void refrigerator(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | { |
| 49 | /* Hmm, should we be allowed to suspend when there are realtime |
| 50 | processes around? */ |
| 51 | long save; |
Rafael J. Wysocki | 33e1c28 | 2007-05-23 13:57:24 -0700 | [diff] [blame] | 52 | |
| 53 | task_lock(current); |
| 54 | if (freezing(current)) { |
Gautham R Shenoy | 88f18ba | 2007-05-23 13:57:29 -0700 | [diff] [blame] | 55 | frozen_process(); |
Rafael J. Wysocki | 33e1c28 | 2007-05-23 13:57:24 -0700 | [diff] [blame] | 56 | task_unlock(current); |
| 57 | } else { |
| 58 | task_unlock(current); |
| 59 | return; |
| 60 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 61 | save = current->state; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 62 | pr_debug("%s entered refrigerator\n", current->comm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | |
| 64 | spin_lock_irq(¤t->sighand->siglock); |
| 65 | recalc_sigpending(); /* We sent fake signal, clean it up */ |
| 66 | spin_unlock_irq(¤t->sighand->siglock); |
| 67 | |
Oleg Nesterov | 433ecb4 | 2007-05-06 14:50:40 -0700 | [diff] [blame] | 68 | for (;;) { |
| 69 | set_current_state(TASK_UNINTERRUPTIBLE); |
| 70 | if (!frozen(current)) |
| 71 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 72 | schedule(); |
Pavel Machek | 2a23b5d | 2005-09-03 15:56:53 -0700 | [diff] [blame] | 73 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | pr_debug("%s left refrigerator\n", current->comm); |
Rafael J. Wysocki | f4a3a7d | 2007-07-19 01:47:33 -0700 | [diff] [blame^] | 75 | __set_current_state(save); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 76 | } |
| 77 | |
Rafael J. Wysocki | 0c1eecf | 2007-07-19 01:47:33 -0700 | [diff] [blame] | 78 | static void freeze_task(struct task_struct *p) |
Rafael J. Wysocki | 02aaeb9 | 2006-03-23 03:00:04 -0800 | [diff] [blame] | 79 | { |
| 80 | unsigned long flags; |
| 81 | |
| 82 | if (!freezing(p)) { |
Rafael J. Wysocki | 8a102ee | 2006-12-13 00:34:30 -0800 | [diff] [blame] | 83 | rmb(); |
| 84 | if (!frozen(p)) { |
Rafael J. Wysocki | 0c1eecf | 2007-07-19 01:47:33 -0700 | [diff] [blame] | 85 | set_freeze_flag(p); |
Rafael J. Wysocki | 8a102ee | 2006-12-13 00:34:30 -0800 | [diff] [blame] | 86 | if (p->state == TASK_STOPPED) |
| 87 | force_sig_specific(SIGSTOP, p); |
Rafael J. Wysocki | 8a102ee | 2006-12-13 00:34:30 -0800 | [diff] [blame] | 88 | spin_lock_irqsave(&p->sighand->siglock, flags); |
| 89 | signal_wake_up(p, p->state == TASK_STOPPED); |
| 90 | spin_unlock_irqrestore(&p->sighand->siglock, flags); |
| 91 | } |
Rafael J. Wysocki | 02aaeb9 | 2006-03-23 03:00:04 -0800 | [diff] [blame] | 92 | } |
| 93 | } |
| 94 | |
Rafael J. Wysocki | a7ef787 | 2006-08-05 12:13:42 -0700 | [diff] [blame] | 95 | static void cancel_freezing(struct task_struct *p) |
| 96 | { |
| 97 | unsigned long flags; |
| 98 | |
| 99 | if (freezing(p)) { |
| 100 | pr_debug(" clean up: %s\n", p->comm); |
Rafael J. Wysocki | 0c1eecf | 2007-07-19 01:47:33 -0700 | [diff] [blame] | 101 | clear_freeze_flag(p); |
Rafael J. Wysocki | a7ef787 | 2006-08-05 12:13:42 -0700 | [diff] [blame] | 102 | spin_lock_irqsave(&p->sighand->siglock, flags); |
Roland McGrath | 7bb44ad | 2007-05-23 13:57:44 -0700 | [diff] [blame] | 103 | recalc_sigpending_and_wake(p); |
Rafael J. Wysocki | a7ef787 | 2006-08-05 12:13:42 -0700 | [diff] [blame] | 104 | spin_unlock_irqrestore(&p->sighand->siglock, flags); |
| 105 | } |
| 106 | } |
| 107 | |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 108 | static unsigned int try_to_freeze_tasks(int freeze_user_space) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 109 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 110 | struct task_struct *g, *p; |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 111 | unsigned long end_time; |
| 112 | unsigned int todo; |
Christoph Lameter | 3e1d1d2 | 2005-06-24 23:13:50 -0700 | [diff] [blame] | 113 | |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 114 | end_time = jiffies + TIMEOUT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 115 | do { |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 116 | todo = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | read_lock(&tasklist_lock); |
| 118 | do_each_thread(g, p) { |
Rafael J. Wysocki | 0c1eecf | 2007-07-19 01:47:33 -0700 | [diff] [blame] | 119 | if (frozen(p) || !freezeable(p)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | continue; |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 121 | |
Rafael J. Wysocki | 0c1eecf | 2007-07-19 01:47:33 -0700 | [diff] [blame] | 122 | if (freeze_user_space) { |
| 123 | if (p->state == TASK_TRACED && |
| 124 | frozen(p->parent)) { |
| 125 | cancel_freezing(p); |
| 126 | continue; |
| 127 | } |
| 128 | /* |
| 129 | * Kernel threads should not have TIF_FREEZE set |
| 130 | * at this point, so we must ensure that either |
| 131 | * p->mm is not NULL *and* PF_BORROWED_MM is |
| 132 | * unset, or TIF_FRREZE is left unset. |
| 133 | * The task_lock() is necessary to prevent races |
| 134 | * with exit_mm() or use_mm()/unuse_mm() from |
| 135 | * occuring. |
| 136 | */ |
| 137 | task_lock(p); |
| 138 | if (!p->mm || (p->flags & PF_BORROWED_MM)) { |
| 139 | task_unlock(p); |
| 140 | continue; |
| 141 | } |
| 142 | freeze_task(p); |
| 143 | task_unlock(p); |
| 144 | } else { |
| 145 | freeze_task(p); |
Rafael J. Wysocki | a7ef787 | 2006-08-05 12:13:42 -0700 | [diff] [blame] | 146 | } |
Rafael J. Wysocki | ba96a0c | 2007-05-23 13:57:25 -0700 | [diff] [blame] | 147 | if (!freezer_should_skip(p)) |
| 148 | todo++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 149 | } while_each_thread(g, p); |
| 150 | read_unlock(&tasklist_lock); |
Rafael J. Wysocki | 02aaeb9 | 2006-03-23 03:00:04 -0800 | [diff] [blame] | 151 | yield(); /* Yield is okay here */ |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 152 | if (todo && time_after(jiffies, end_time)) |
Rafael J. Wysocki | 02aaeb9 | 2006-03-23 03:00:04 -0800 | [diff] [blame] | 153 | break; |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 154 | } while (todo); |
Christoph Lameter | 3e1d1d2 | 2005-06-24 23:13:50 -0700 | [diff] [blame] | 155 | |
Pavel Machek | 6161b2c | 2005-09-03 15:57:05 -0700 | [diff] [blame] | 156 | if (todo) { |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 157 | /* This does not unfreeze processes that are already frozen |
| 158 | * (we have slightly ugly calling convention in that respect, |
| 159 | * and caller must call thaw_processes() if something fails), |
| 160 | * but it cleans up leftover PF_FREEZE requests. |
| 161 | */ |
Nigel Cunningham | 14b5b7c | 2006-12-06 20:34:26 -0800 | [diff] [blame] | 162 | printk("\n"); |
Rafael J. Wysocki | 0c1eecf | 2007-07-19 01:47:33 -0700 | [diff] [blame] | 163 | printk(KERN_ERR "Freezing of %s timed out after %d seconds " |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 164 | "(%d tasks refusing to freeze):\n", |
Rafael J. Wysocki | 0c1eecf | 2007-07-19 01:47:33 -0700 | [diff] [blame] | 165 | freeze_user_space ? "user space " : "tasks ", |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 166 | TIMEOUT / HZ, todo); |
Andrew Morton | 328616e | 2007-07-19 01:47:26 -0700 | [diff] [blame] | 167 | show_state(); |
Pavel Machek | 6161b2c | 2005-09-03 15:57:05 -0700 | [diff] [blame] | 168 | read_lock(&tasklist_lock); |
Rafael J. Wysocki | 02aaeb9 | 2006-03-23 03:00:04 -0800 | [diff] [blame] | 169 | do_each_thread(g, p) { |
Rafael J. Wysocki | 33e1c28 | 2007-05-23 13:57:24 -0700 | [diff] [blame] | 170 | task_lock(p); |
Rafael J. Wysocki | 0c1eecf | 2007-07-19 01:47:33 -0700 | [diff] [blame] | 171 | if (freezing(p) && !freezer_should_skip(p)) |
Nigel Cunningham | 14b5b7c | 2006-12-06 20:34:26 -0800 | [diff] [blame] | 172 | printk(KERN_ERR " %s\n", p->comm); |
Rafael J. Wysocki | a7ef787 | 2006-08-05 12:13:42 -0700 | [diff] [blame] | 173 | cancel_freezing(p); |
Rafael J. Wysocki | 33e1c28 | 2007-05-23 13:57:24 -0700 | [diff] [blame] | 174 | task_unlock(p); |
Rafael J. Wysocki | 02aaeb9 | 2006-03-23 03:00:04 -0800 | [diff] [blame] | 175 | } while_each_thread(g, p); |
Pavel Machek | 6161b2c | 2005-09-03 15:57:05 -0700 | [diff] [blame] | 176 | read_unlock(&tasklist_lock); |
Pavel Machek | 6161b2c | 2005-09-03 15:57:05 -0700 | [diff] [blame] | 177 | } |
| 178 | |
Rafael J. Wysocki | 11b2ce2 | 2006-12-06 20:34:40 -0800 | [diff] [blame] | 179 | return todo; |
| 180 | } |
| 181 | |
| 182 | /** |
| 183 | * freeze_processes - tell processes to enter the refrigerator |
| 184 | * |
| 185 | * Returns 0 on success, or the number of processes that didn't freeze, |
| 186 | * although they were told to. |
| 187 | */ |
| 188 | int freeze_processes(void) |
| 189 | { |
| 190 | unsigned int nr_unfrozen; |
| 191 | |
| 192 | printk("Stopping tasks ... "); |
| 193 | nr_unfrozen = try_to_freeze_tasks(FREEZER_USER_SPACE); |
| 194 | if (nr_unfrozen) |
| 195 | return nr_unfrozen; |
| 196 | |
| 197 | sys_sync(); |
| 198 | nr_unfrozen = try_to_freeze_tasks(FREEZER_KERNEL_THREADS); |
| 199 | if (nr_unfrozen) |
| 200 | return nr_unfrozen; |
| 201 | |
Nigel Cunningham | 14b5b7c | 2006-12-06 20:34:26 -0800 | [diff] [blame] | 202 | printk("done.\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 203 | BUG_ON(in_atomic()); |
| 204 | return 0; |
| 205 | } |
| 206 | |
Rafael J. Wysocki | a9b6f56 | 2006-12-06 20:34:37 -0800 | [diff] [blame] | 207 | static void thaw_tasks(int thaw_user_space) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 208 | { |
| 209 | struct task_struct *g, *p; |
| 210 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 211 | read_lock(&tasklist_lock); |
Rafael J. Wysocki | a9b6f56 | 2006-12-06 20:34:37 -0800 | [diff] [blame] | 212 | do_each_thread(g, p) { |
| 213 | if (!freezeable(p)) |
| 214 | continue; |
Nigel Cunningham | ff39593 | 2006-12-06 20:34:28 -0800 | [diff] [blame] | 215 | |
Rafael J. Wysocki | 0c1eecf | 2007-07-19 01:47:33 -0700 | [diff] [blame] | 216 | if (!p->mm == thaw_user_space) |
Rafael J. Wysocki | a9b6f56 | 2006-12-06 20:34:37 -0800 | [diff] [blame] | 217 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 218 | |
Rafael J. Wysocki | ba96a0c | 2007-05-23 13:57:25 -0700 | [diff] [blame] | 219 | thaw_process(p); |
Rafael J. Wysocki | a9b6f56 | 2006-12-06 20:34:37 -0800 | [diff] [blame] | 220 | } while_each_thread(g, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 221 | read_unlock(&tasklist_lock); |
Rafael J. Wysocki | a9b6f56 | 2006-12-06 20:34:37 -0800 | [diff] [blame] | 222 | } |
| 223 | |
| 224 | void thaw_processes(void) |
| 225 | { |
| 226 | printk("Restarting tasks ... "); |
| 227 | thaw_tasks(FREEZER_KERNEL_THREADS); |
| 228 | thaw_tasks(FREEZER_USER_SPACE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 229 | schedule(); |
Nigel Cunningham | 14b5b7c | 2006-12-06 20:34:26 -0800 | [diff] [blame] | 230 | printk("done.\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 231 | } |
| 232 | |
| 233 | EXPORT_SYMBOL(refrigerator); |