Commit | Line | Data |
---|---|---|
1da177e4 LT |
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 | ||
1da177e4 | 11 | #include <linux/interrupt.h> |
1a8670a2 | 12 | #include <linux/oom.h> |
1da177e4 LT |
13 | #include <linux/suspend.h> |
14 | #include <linux/module.h> | |
02aaeb9b | 15 | #include <linux/syscalls.h> |
7dfb7103 | 16 | #include <linux/freezer.h> |
be404f02 | 17 | #include <linux/delay.h> |
a0a1a5fd | 18 | #include <linux/workqueue.h> |
1e73203c | 19 | #include <linux/kmod.h> |
1da177e4 LT |
20 | |
21 | /* | |
22 | * Timeout for stopping processes | |
23 | */ | |
957d1282 | 24 | unsigned int __read_mostly freeze_timeout_msecs = 20 * MSEC_PER_SEC; |
1da177e4 | 25 | |
839e3407 | 26 | static int try_to_freeze_tasks(bool user_only) |
1da177e4 | 27 | { |
1da177e4 | 28 | struct task_struct *g, *p; |
11b2ce2b RW |
29 | unsigned long end_time; |
30 | unsigned int todo; | |
a0a1a5fd | 31 | bool wq_busy = false; |
438e2ce6 | 32 | struct timeval start, end; |
18ad0c62 CC |
33 | u64 elapsed_msecs64; |
34 | unsigned int elapsed_msecs; | |
dbeeec5f | 35 | bool wakeup = false; |
18ad0c62 | 36 | int sleep_usecs = USEC_PER_MSEC; |
438e2ce6 RW |
37 | |
38 | do_gettimeofday(&start); | |
3e1d1d28 | 39 | |
957d1282 | 40 | end_time = jiffies + msecs_to_jiffies(freeze_timeout_msecs); |
a0a1a5fd | 41 | |
839e3407 | 42 | if (!user_only) |
a0a1a5fd TH |
43 | freeze_workqueues_begin(); |
44 | ||
be404f02 | 45 | while (true) { |
11b2ce2b | 46 | todo = 0; |
1da177e4 LT |
47 | read_lock(&tasklist_lock); |
48 | do_each_thread(g, p) { | |
839e3407 | 49 | if (p == current || !freeze_task(p)) |
d5d8c597 RW |
50 | continue; |
51 | ||
5d8f72b5 | 52 | if (!freezer_should_skip(p)) |
ba96a0c8 | 53 | todo++; |
1da177e4 LT |
54 | } while_each_thread(g, p); |
55 | read_unlock(&tasklist_lock); | |
a0a1a5fd | 56 | |
839e3407 | 57 | if (!user_only) { |
a0a1a5fd TH |
58 | wq_busy = freeze_workqueues_busy(); |
59 | todo += wq_busy; | |
60 | } | |
61 | ||
be404f02 | 62 | if (!todo || time_after(jiffies, end_time)) |
6161b2ce | 63 | break; |
be404f02 | 64 | |
a2867e08 | 65 | if (pm_wakeup_pending()) { |
dbeeec5f RW |
66 | wakeup = true; |
67 | break; | |
68 | } | |
69 | ||
be404f02 TH |
70 | /* |
71 | * We need to retry, but first give the freezing tasks some | |
18ad0c62 CC |
72 | * time to enter the refrigerator. Start with an initial |
73 | * 1 ms sleep followed by exponential backoff until 8 ms. | |
be404f02 | 74 | */ |
18ad0c62 CC |
75 | usleep_range(sleep_usecs / 2, sleep_usecs); |
76 | if (sleep_usecs < 8 * USEC_PER_MSEC) | |
77 | sleep_usecs *= 2; | |
be404f02 | 78 | } |
3e1d1d28 | 79 | |
438e2ce6 | 80 | do_gettimeofday(&end); |
18ad0c62 CC |
81 | elapsed_msecs64 = timeval_to_ns(&end) - timeval_to_ns(&start); |
82 | do_div(elapsed_msecs64, NSEC_PER_MSEC); | |
83 | elapsed_msecs = elapsed_msecs64; | |
438e2ce6 | 84 | |
6161b2ce | 85 | if (todo) { |
14b5b7cf | 86 | printk("\n"); |
18ad0c62 | 87 | printk(KERN_ERR "Freezing of tasks %s after %d.%03d seconds " |
a0a1a5fd | 88 | "(%d tasks refusing to freeze, wq_busy=%d):\n", |
dbeeec5f | 89 | wakeup ? "aborted" : "failed", |
18ad0c62 | 90 | elapsed_msecs / 1000, elapsed_msecs % 1000, |
a0a1a5fd TH |
91 | todo - wq_busy, wq_busy); |
92 | ||
6c83b481 RW |
93 | if (!wakeup) { |
94 | read_lock(&tasklist_lock); | |
95 | do_each_thread(g, p) { | |
96 | if (p != current && !freezer_should_skip(p) | |
97 | && freezing(p) && !frozen(p)) | |
98 | sched_show_task(p); | |
99 | } while_each_thread(g, p); | |
100 | read_unlock(&tasklist_lock); | |
101 | } | |
438e2ce6 | 102 | } else { |
18ad0c62 CC |
103 | printk("(elapsed %d.%03d seconds) ", elapsed_msecs / 1000, |
104 | elapsed_msecs % 1000); | |
6161b2ce PM |
105 | } |
106 | ||
e7cd8a72 | 107 | return todo ? -EBUSY : 0; |
11b2ce2b RW |
108 | } |
109 | ||
110 | /** | |
2aede851 | 111 | * freeze_processes - Signal user space processes to enter the refrigerator. |
2b44c4db CC |
112 | * The current thread will not be frozen. The same process that calls |
113 | * freeze_processes must later call thaw_processes. | |
03afed8b TH |
114 | * |
115 | * On success, returns 0. On failure, -errno and system is fully thawed. | |
11b2ce2b RW |
116 | */ |
117 | int freeze_processes(void) | |
118 | { | |
e7cd8a72 | 119 | int error; |
11b2ce2b | 120 | |
247bc037 | 121 | error = __usermodehelper_disable(UMH_FREEZING); |
1e73203c RW |
122 | if (error) |
123 | return error; | |
124 | ||
2b44c4db CC |
125 | /* Make sure this task doesn't get frozen */ |
126 | current->flags |= PF_SUSPEND_TASK; | |
127 | ||
a3201227 TH |
128 | if (!pm_freezing) |
129 | atomic_inc(&system_freezing_cnt); | |
130 | ||
b842ee57 | 131 | printk("Freezing user space processes ... "); |
a3201227 | 132 | pm_freezing = true; |
ebb12db5 | 133 | error = try_to_freeze_tasks(true); |
2aede851 RW |
134 | if (!error) { |
135 | printk("done."); | |
247bc037 | 136 | __usermodehelper_set_disable_depth(UMH_DISABLED); |
2aede851 RW |
137 | oom_killer_disable(); |
138 | } | |
139 | printk("\n"); | |
140 | BUG_ON(in_atomic()); | |
141 | ||
03afed8b TH |
142 | if (error) |
143 | thaw_processes(); | |
2aede851 RW |
144 | return error; |
145 | } | |
146 | ||
147 | /** | |
148 | * freeze_kernel_threads - Make freezable kernel threads go to the refrigerator. | |
03afed8b | 149 | * |
379e0be8 SB |
150 | * On success, returns 0. On failure, -errno and only the kernel threads are |
151 | * thawed, so as to give a chance to the caller to do additional cleanups | |
152 | * (if any) before thawing the userspace tasks. So, it is the responsibility | |
153 | * of the caller to thaw the userspace tasks, when the time is right. | |
2aede851 RW |
154 | */ |
155 | int freeze_kernel_threads(void) | |
156 | { | |
157 | int error; | |
11b2ce2b | 158 | |
b842ee57 | 159 | printk("Freezing remaining freezable tasks ... "); |
a3201227 | 160 | pm_nosig_freezing = true; |
ebb12db5 | 161 | error = try_to_freeze_tasks(false); |
2aede851 RW |
162 | if (!error) |
163 | printk("done."); | |
7f33d49a | 164 | |
b842ee57 | 165 | printk("\n"); |
2aede851 | 166 | BUG_ON(in_atomic()); |
7f33d49a | 167 | |
03afed8b | 168 | if (error) |
379e0be8 | 169 | thaw_kernel_threads(); |
b842ee57 | 170 | return error; |
1da177e4 LT |
171 | } |
172 | ||
6cd8dedc | 173 | void thaw_processes(void) |
1da177e4 LT |
174 | { |
175 | struct task_struct *g, *p; | |
2b44c4db | 176 | struct task_struct *curr = current; |
1da177e4 | 177 | |
a3201227 TH |
178 | if (pm_freezing) |
179 | atomic_dec(&system_freezing_cnt); | |
180 | pm_freezing = false; | |
181 | pm_nosig_freezing = false; | |
182 | ||
6cd8dedc TH |
183 | oom_killer_enable(); |
184 | ||
185 | printk("Restarting tasks ... "); | |
186 | ||
187 | thaw_workqueues(); | |
188 | ||
1da177e4 | 189 | read_lock(&tasklist_lock); |
a9b6f562 | 190 | do_each_thread(g, p) { |
2b44c4db CC |
191 | /* No other threads should have PF_SUSPEND_TASK set */ |
192 | WARN_ON((p != curr) && (p->flags & PF_SUSPEND_TASK)); | |
a5be2d0d | 193 | __thaw_task(p); |
a9b6f562 | 194 | } while_each_thread(g, p); |
1da177e4 | 195 | read_unlock(&tasklist_lock); |
7f33d49a | 196 | |
2b44c4db CC |
197 | WARN_ON(!(curr->flags & PF_SUSPEND_TASK)); |
198 | curr->flags &= ~PF_SUSPEND_TASK; | |
199 | ||
1e73203c RW |
200 | usermodehelper_enable(); |
201 | ||
1da177e4 | 202 | schedule(); |
14b5b7cf | 203 | printk("done.\n"); |
1da177e4 LT |
204 | } |
205 | ||
181e9bde RW |
206 | void thaw_kernel_threads(void) |
207 | { | |
208 | struct task_struct *g, *p; | |
209 | ||
210 | pm_nosig_freezing = false; | |
211 | printk("Restarting kernel threads ... "); | |
212 | ||
213 | thaw_workqueues(); | |
214 | ||
215 | read_lock(&tasklist_lock); | |
216 | do_each_thread(g, p) { | |
217 | if (p->flags & (PF_KTHREAD | PF_WQ_WORKER)) | |
218 | __thaw_task(p); | |
219 | } while_each_thread(g, p); | |
220 | read_unlock(&tasklist_lock); | |
221 | ||
222 | schedule(); | |
223 | printk("done.\n"); | |
224 | } |