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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/mm/oom_kill.c | |
3 | * | |
4 | * Copyright (C) 1998,2000 Rik van Riel | |
5 | * Thanks go out to Claus Fischer for some serious inspiration and | |
6 | * for goading me into coding this file... | |
7 | * | |
8 | * The routines in this file are used to kill a process when | |
a49335cc PJ |
9 | * we're seriously out of memory. This gets called from __alloc_pages() |
10 | * in mm/page_alloc.c when we really run out of memory. | |
1da177e4 LT |
11 | * |
12 | * Since we won't call these routines often (on a well-configured | |
13 | * machine) this file will double as a 'coding guide' and a signpost | |
14 | * for newbie kernel hackers. It features several pointers to major | |
15 | * kernel subsystems and hints as to where to find out what things do. | |
16 | */ | |
17 | ||
8ac773b4 | 18 | #include <linux/oom.h> |
1da177e4 | 19 | #include <linux/mm.h> |
4e950f6f | 20 | #include <linux/err.h> |
1da177e4 LT |
21 | #include <linux/sched.h> |
22 | #include <linux/swap.h> | |
23 | #include <linux/timex.h> | |
24 | #include <linux/jiffies.h> | |
ef08e3b4 | 25 | #include <linux/cpuset.h> |
8bc719d3 MS |
26 | #include <linux/module.h> |
27 | #include <linux/notifier.h> | |
c7ba5c9e | 28 | #include <linux/memcontrol.h> |
5cd9c58f | 29 | #include <linux/security.h> |
1da177e4 | 30 | |
fadd8fbd | 31 | int sysctl_panic_on_oom; |
fe071d7e | 32 | int sysctl_oom_kill_allocating_task; |
fef1bdd6 | 33 | int sysctl_oom_dump_tasks; |
c7d4caeb | 34 | static DEFINE_SPINLOCK(zone_scan_lock); |
1da177e4 LT |
35 | /* #define DEBUG */ |
36 | ||
37 | /** | |
6937a25c | 38 | * badness - calculate a numeric value for how bad this task has been |
1da177e4 | 39 | * @p: task struct of which task we should calculate |
a49335cc | 40 | * @uptime: current uptime in seconds |
1da177e4 LT |
41 | * |
42 | * The formula used is relatively simple and documented inline in the | |
43 | * function. The main rationale is that we want to select a good task | |
44 | * to kill when we run out of memory. | |
45 | * | |
46 | * Good in this context means that: | |
47 | * 1) we lose the minimum amount of work done | |
48 | * 2) we recover a large amount of memory | |
49 | * 3) we don't kill anything innocent of eating tons of memory | |
50 | * 4) we want to kill the minimum amount of processes (one) | |
51 | * 5) we try to kill the process the user expects us to kill, this | |
52 | * algorithm has been meticulously tuned to meet the principle | |
53 | * of least surprise ... (be careful when you change it) | |
54 | */ | |
55 | ||
97d87c97 | 56 | unsigned long badness(struct task_struct *p, unsigned long uptime) |
1da177e4 | 57 | { |
a12888f7 | 58 | unsigned long points, cpu_time, run_time; |
97c2c9b8 AM |
59 | struct mm_struct *mm; |
60 | struct task_struct *child; | |
28b83c51 KM |
61 | int oom_adj = p->signal->oom_adj; |
62 | ||
63 | if (oom_adj == OOM_DISABLE) | |
64 | return 0; | |
1da177e4 | 65 | |
97c2c9b8 AM |
66 | task_lock(p); |
67 | mm = p->mm; | |
68 | if (!mm) { | |
69 | task_unlock(p); | |
1da177e4 | 70 | return 0; |
97c2c9b8 | 71 | } |
1da177e4 LT |
72 | |
73 | /* | |
74 | * The memory size of the process is the basis for the badness. | |
75 | */ | |
97c2c9b8 AM |
76 | points = mm->total_vm; |
77 | ||
78 | /* | |
79 | * After this unlock we can no longer dereference local variable `mm' | |
80 | */ | |
81 | task_unlock(p); | |
1da177e4 | 82 | |
7ba34859 HD |
83 | /* |
84 | * swapoff can easily use up all memory, so kill those first. | |
85 | */ | |
35451bee | 86 | if (p->flags & PF_OOM_ORIGIN) |
7ba34859 HD |
87 | return ULONG_MAX; |
88 | ||
1da177e4 LT |
89 | /* |
90 | * Processes which fork a lot of child processes are likely | |
9827b781 | 91 | * a good choice. We add half the vmsize of the children if they |
1da177e4 | 92 | * have an own mm. This prevents forking servers to flood the |
9827b781 KG |
93 | * machine with an endless amount of children. In case a single |
94 | * child is eating the vast majority of memory, adding only half | |
95 | * to the parents will make the child our kill candidate of choice. | |
1da177e4 | 96 | */ |
97c2c9b8 AM |
97 | list_for_each_entry(child, &p->children, sibling) { |
98 | task_lock(child); | |
99 | if (child->mm != mm && child->mm) | |
100 | points += child->mm->total_vm/2 + 1; | |
101 | task_unlock(child); | |
1da177e4 LT |
102 | } |
103 | ||
104 | /* | |
105 | * CPU time is in tens of seconds and run time is in thousands | |
106 | * of seconds. There is no particular reason for this other than | |
107 | * that it turned out to work very well in practice. | |
108 | */ | |
109 | cpu_time = (cputime_to_jiffies(p->utime) + cputime_to_jiffies(p->stime)) | |
110 | >> (SHIFT_HZ + 3); | |
111 | ||
112 | if (uptime >= p->start_time.tv_sec) | |
113 | run_time = (uptime - p->start_time.tv_sec) >> 10; | |
114 | else | |
115 | run_time = 0; | |
116 | ||
a12888f7 CG |
117 | if (cpu_time) |
118 | points /= int_sqrt(cpu_time); | |
119 | if (run_time) | |
120 | points /= int_sqrt(int_sqrt(run_time)); | |
1da177e4 LT |
121 | |
122 | /* | |
123 | * Niced processes are most likely less important, so double | |
124 | * their badness points. | |
125 | */ | |
126 | if (task_nice(p) > 0) | |
127 | points *= 2; | |
128 | ||
129 | /* | |
130 | * Superuser processes are usually more important, so we make it | |
131 | * less likely that we kill those. | |
132 | */ | |
a2f2945a EP |
133 | if (has_capability_noaudit(p, CAP_SYS_ADMIN) || |
134 | has_capability_noaudit(p, CAP_SYS_RESOURCE)) | |
1da177e4 LT |
135 | points /= 4; |
136 | ||
137 | /* | |
138 | * We don't want to kill a process with direct hardware access. | |
139 | * Not only could that mess up the hardware, but usually users | |
140 | * tend to only have this flag set on applications they think | |
141 | * of as important. | |
142 | */ | |
a2f2945a | 143 | if (has_capability_noaudit(p, CAP_SYS_RAWIO)) |
1da177e4 LT |
144 | points /= 4; |
145 | ||
7887a3da NP |
146 | /* |
147 | * If p's nodes don't overlap ours, it may still help to kill p | |
148 | * because p may have allocated or otherwise mapped memory on | |
149 | * this node before. However it will be less likely. | |
150 | */ | |
bbe373f2 | 151 | if (!cpuset_mems_allowed_intersects(current, p)) |
7887a3da NP |
152 | points /= 8; |
153 | ||
1da177e4 | 154 | /* |
28b83c51 | 155 | * Adjust the score by oom_adj. |
1da177e4 | 156 | */ |
28b83c51 KM |
157 | if (oom_adj) { |
158 | if (oom_adj > 0) { | |
9a82782f JP |
159 | if (!points) |
160 | points = 1; | |
28b83c51 | 161 | points <<= oom_adj; |
9a82782f | 162 | } else |
28b83c51 | 163 | points >>= -(oom_adj); |
1da177e4 LT |
164 | } |
165 | ||
166 | #ifdef DEBUG | |
a5e58a61 | 167 | printk(KERN_DEBUG "OOMkill: task %d (%s) got %lu points\n", |
1da177e4 LT |
168 | p->pid, p->comm, points); |
169 | #endif | |
170 | return points; | |
171 | } | |
172 | ||
9b0f8b04 CL |
173 | /* |
174 | * Determine the type of allocation constraint. | |
175 | */ | |
70e24bdf DR |
176 | static inline enum oom_constraint constrained_alloc(struct zonelist *zonelist, |
177 | gfp_t gfp_mask) | |
9b0f8b04 CL |
178 | { |
179 | #ifdef CONFIG_NUMA | |
54a6eb5c | 180 | struct zone *zone; |
dd1a239f | 181 | struct zoneref *z; |
54a6eb5c | 182 | enum zone_type high_zoneidx = gfp_zone(gfp_mask); |
ee31af5d | 183 | nodemask_t nodes = node_states[N_HIGH_MEMORY]; |
9b0f8b04 | 184 | |
54a6eb5c MG |
185 | for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) |
186 | if (cpuset_zone_allowed_softwall(zone, gfp_mask)) | |
187 | node_clear(zone_to_nid(zone), nodes); | |
9b0f8b04 CL |
188 | else |
189 | return CONSTRAINT_CPUSET; | |
190 | ||
191 | if (!nodes_empty(nodes)) | |
192 | return CONSTRAINT_MEMORY_POLICY; | |
193 | #endif | |
194 | ||
195 | return CONSTRAINT_NONE; | |
196 | } | |
197 | ||
1da177e4 LT |
198 | /* |
199 | * Simple selection loop. We chose the process with the highest | |
200 | * number of 'points'. We expect the caller will lock the tasklist. | |
201 | * | |
202 | * (not docbooked, we don't want this one cluttering up the manual) | |
203 | */ | |
c7ba5c9e PE |
204 | static struct task_struct *select_bad_process(unsigned long *ppoints, |
205 | struct mem_cgroup *mem) | |
1da177e4 | 206 | { |
1da177e4 LT |
207 | struct task_struct *g, *p; |
208 | struct task_struct *chosen = NULL; | |
209 | struct timespec uptime; | |
9827b781 | 210 | *ppoints = 0; |
1da177e4 LT |
211 | |
212 | do_posix_clock_monotonic_gettime(&uptime); | |
a49335cc PJ |
213 | do_each_thread(g, p) { |
214 | unsigned long points; | |
a49335cc | 215 | |
28324d1d ON |
216 | /* |
217 | * skip kernel threads and tasks which have already released | |
218 | * their mm. | |
219 | */ | |
5081dde3 NP |
220 | if (!p->mm) |
221 | continue; | |
28324d1d | 222 | /* skip the init task */ |
b460cbc5 | 223 | if (is_global_init(p)) |
a49335cc | 224 | continue; |
4c4a2214 DR |
225 | if (mem && !task_in_mem_cgroup(p, mem)) |
226 | continue; | |
ef08e3b4 | 227 | |
b78483a4 NP |
228 | /* |
229 | * This task already has access to memory reserves and is | |
230 | * being killed. Don't allow any other task access to the | |
231 | * memory reserve. | |
232 | * | |
233 | * Note: this may have a chance of deadlock if it gets | |
234 | * blocked waiting for another task which itself is waiting | |
235 | * for memory. Is there a better alternative? | |
236 | */ | |
237 | if (test_tsk_thread_flag(p, TIF_MEMDIE)) | |
238 | return ERR_PTR(-1UL); | |
239 | ||
a49335cc | 240 | /* |
6937a25c | 241 | * This is in the process of releasing memory so wait for it |
a49335cc | 242 | * to finish before killing some other task by mistake. |
50ec3bbf NP |
243 | * |
244 | * However, if p is the current task, we allow the 'kill' to | |
245 | * go ahead if it is exiting: this will simply set TIF_MEMDIE, | |
246 | * which will allow it to gain access to memory reserves in | |
247 | * the process of exiting and releasing its resources. | |
b78483a4 | 248 | * Otherwise we could get an easy OOM deadlock. |
a49335cc | 249 | */ |
b78483a4 NP |
250 | if (p->flags & PF_EXITING) { |
251 | if (p != current) | |
252 | return ERR_PTR(-1UL); | |
253 | ||
972c4ea5 ON |
254 | chosen = p; |
255 | *ppoints = ULONG_MAX; | |
50ec3bbf | 256 | } |
972c4ea5 | 257 | |
28b83c51 | 258 | if (p->signal->oom_adj == OOM_DISABLE) |
0753ba01 KM |
259 | continue; |
260 | ||
97d87c97 | 261 | points = badness(p, uptime.tv_sec); |
0753ba01 | 262 | if (points > *ppoints || !chosen) { |
a49335cc | 263 | chosen = p; |
9827b781 | 264 | *ppoints = points; |
1da177e4 | 265 | } |
a49335cc | 266 | } while_each_thread(g, p); |
972c4ea5 | 267 | |
1da177e4 LT |
268 | return chosen; |
269 | } | |
270 | ||
fef1bdd6 | 271 | /** |
1b578df0 RD |
272 | * dump_tasks - dump current memory state of all system tasks |
273 | * @mem: target memory controller | |
274 | * | |
fef1bdd6 DR |
275 | * Dumps the current memory state of all system tasks, excluding kernel threads. |
276 | * State information includes task's pid, uid, tgid, vm size, rss, cpu, oom_adj | |
277 | * score, and name. | |
278 | * | |
279 | * If the actual is non-NULL, only tasks that are a member of the mem_cgroup are | |
280 | * shown. | |
281 | * | |
282 | * Call with tasklist_lock read-locked. | |
283 | */ | |
284 | static void dump_tasks(const struct mem_cgroup *mem) | |
285 | { | |
286 | struct task_struct *g, *p; | |
287 | ||
288 | printk(KERN_INFO "[ pid ] uid tgid total_vm rss cpu oom_adj " | |
289 | "name\n"); | |
290 | do_each_thread(g, p) { | |
6d2661ed DR |
291 | struct mm_struct *mm; |
292 | ||
fef1bdd6 DR |
293 | if (mem && !task_in_mem_cgroup(p, mem)) |
294 | continue; | |
b4416d2b DR |
295 | if (!thread_group_leader(p)) |
296 | continue; | |
fef1bdd6 DR |
297 | |
298 | task_lock(p); | |
6d2661ed DR |
299 | mm = p->mm; |
300 | if (!mm) { | |
301 | /* | |
302 | * total_vm and rss sizes do not exist for tasks with no | |
303 | * mm so there's no need to report them; they can't be | |
304 | * oom killed anyway. | |
305 | */ | |
306 | task_unlock(p); | |
307 | continue; | |
308 | } | |
fef1bdd6 | 309 | printk(KERN_INFO "[%5d] %5d %5d %8lu %8lu %3d %3d %s\n", |
6d2661ed | 310 | p->pid, __task_cred(p)->uid, p->tgid, mm->total_vm, |
28b83c51 | 311 | get_mm_rss(mm), (int)task_cpu(p), p->signal->oom_adj, |
0753ba01 | 312 | p->comm); |
fef1bdd6 DR |
313 | task_unlock(p); |
314 | } while_each_thread(g, p); | |
315 | } | |
316 | ||
1b578df0 | 317 | /* |
5a291b98 RG |
318 | * Send SIGKILL to the selected process irrespective of CAP_SYS_RAW_IO |
319 | * flag though it's unlikely that we select a process with CAP_SYS_RAW_IO | |
320 | * set. | |
1da177e4 | 321 | */ |
f3af38d3 | 322 | static void __oom_kill_task(struct task_struct *p, int verbose) |
1da177e4 | 323 | { |
b460cbc5 | 324 | if (is_global_init(p)) { |
1da177e4 LT |
325 | WARN_ON(1); |
326 | printk(KERN_WARNING "tried to kill init!\n"); | |
327 | return; | |
328 | } | |
329 | ||
0753ba01 KM |
330 | if (!p->mm) { |
331 | WARN_ON(1); | |
332 | printk(KERN_WARNING "tried to kill an mm-less task!\n"); | |
1da177e4 | 333 | return; |
0753ba01 | 334 | } |
50ec3bbf | 335 | |
f3af38d3 | 336 | if (verbose) |
ba25f9dc PE |
337 | printk(KERN_ERR "Killed process %d (%s)\n", |
338 | task_pid_nr(p), p->comm); | |
1da177e4 LT |
339 | |
340 | /* | |
341 | * We give our sacrificial lamb high priority and access to | |
342 | * all the memory it needs. That way it should be able to | |
343 | * exit() and clear out its resources quickly... | |
344 | */ | |
fa717060 | 345 | p->rt.time_slice = HZ; |
1da177e4 LT |
346 | set_tsk_thread_flag(p, TIF_MEMDIE); |
347 | ||
348 | force_sig(SIGKILL, p); | |
349 | } | |
350 | ||
f3af38d3 | 351 | static int oom_kill_task(struct task_struct *p) |
1da177e4 | 352 | { |
01315922 | 353 | struct mm_struct *mm; |
36c8b586 | 354 | struct task_struct *g, *q; |
1da177e4 | 355 | |
01315922 | 356 | mm = p->mm; |
0753ba01 KM |
357 | |
358 | /* WARNING: mm may not be dereferenced since we did not obtain its | |
359 | * value from get_task_mm(p). This is OK since all we need to do is | |
360 | * compare mm to q->mm below. | |
361 | * | |
362 | * Furthermore, even if mm contains a non-NULL value, p->mm may | |
363 | * change to NULL at any time since we do not hold task_lock(p). | |
364 | * However, this is of no concern to us. | |
365 | */ | |
28b83c51 | 366 | if (!mm || p->signal->oom_adj == OOM_DISABLE) |
01315922 | 367 | return 1; |
0753ba01 | 368 | |
f3af38d3 | 369 | __oom_kill_task(p, 1); |
c33e0fca | 370 | |
1da177e4 LT |
371 | /* |
372 | * kill all processes that share the ->mm (i.e. all threads), | |
f2a2a710 NP |
373 | * but are in a different thread group. Don't let them have access |
374 | * to memory reserves though, otherwise we might deplete all memory. | |
1da177e4 | 375 | */ |
c33e0fca | 376 | do_each_thread(g, q) { |
bac0abd6 | 377 | if (q->mm == mm && !same_thread_group(q, p)) |
650a7c97 | 378 | force_sig(SIGKILL, q); |
c33e0fca | 379 | } while_each_thread(g, q); |
1da177e4 | 380 | |
01315922 | 381 | return 0; |
1da177e4 LT |
382 | } |
383 | ||
7213f506 | 384 | static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, |
fef1bdd6 DR |
385 | unsigned long points, struct mem_cgroup *mem, |
386 | const char *message) | |
1da177e4 | 387 | { |
1da177e4 | 388 | struct task_struct *c; |
1da177e4 | 389 | |
7213f506 | 390 | if (printk_ratelimit()) { |
2ff05b2b | 391 | printk(KERN_WARNING "%s invoked oom-killer: " |
28b83c51 KM |
392 | "gfp_mask=0x%x, order=%d, oom_adj=%d\n", |
393 | current->comm, gfp_mask, order, | |
394 | current->signal->oom_adj); | |
0753ba01 | 395 | task_lock(current); |
75aa1994 DR |
396 | cpuset_print_task_mems_allowed(current); |
397 | task_unlock(current); | |
7213f506 | 398 | dump_stack(); |
e222432b | 399 | mem_cgroup_print_oom_info(mem, current); |
7213f506 | 400 | show_mem(); |
fef1bdd6 DR |
401 | if (sysctl_oom_dump_tasks) |
402 | dump_tasks(mem); | |
7213f506 DR |
403 | } |
404 | ||
50ec3bbf NP |
405 | /* |
406 | * If the task is already exiting, don't alarm the sysadmin or kill | |
407 | * its children or threads, just set TIF_MEMDIE so it can die quickly | |
408 | */ | |
0753ba01 | 409 | if (p->flags & PF_EXITING) { |
f3af38d3 | 410 | __oom_kill_task(p, 0); |
50ec3bbf NP |
411 | return 0; |
412 | } | |
413 | ||
f3af38d3 | 414 | printk(KERN_ERR "%s: kill process %d (%s) score %li or a child\n", |
ba25f9dc | 415 | message, task_pid_nr(p), p->comm, points); |
f3af38d3 | 416 | |
1da177e4 | 417 | /* Try to kill a child first */ |
7b1915a9 | 418 | list_for_each_entry(c, &p->children, sibling) { |
1da177e4 LT |
419 | if (c->mm == p->mm) |
420 | continue; | |
f3af38d3 | 421 | if (!oom_kill_task(c)) |
01315922 | 422 | return 0; |
1da177e4 | 423 | } |
f3af38d3 | 424 | return oom_kill_task(p); |
1da177e4 LT |
425 | } |
426 | ||
00f0b825 | 427 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
c7ba5c9e PE |
428 | void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask) |
429 | { | |
430 | unsigned long points = 0; | |
431 | struct task_struct *p; | |
432 | ||
e115f2d8 | 433 | read_lock(&tasklist_lock); |
c7ba5c9e PE |
434 | retry: |
435 | p = select_bad_process(&points, mem); | |
436 | if (PTR_ERR(p) == -1UL) | |
437 | goto out; | |
438 | ||
439 | if (!p) | |
440 | p = current; | |
441 | ||
fef1bdd6 | 442 | if (oom_kill_process(p, gfp_mask, 0, points, mem, |
c7ba5c9e PE |
443 | "Memory cgroup out of memory")) |
444 | goto retry; | |
445 | out: | |
e115f2d8 | 446 | read_unlock(&tasklist_lock); |
c7ba5c9e PE |
447 | } |
448 | #endif | |
449 | ||
8bc719d3 MS |
450 | static BLOCKING_NOTIFIER_HEAD(oom_notify_list); |
451 | ||
452 | int register_oom_notifier(struct notifier_block *nb) | |
453 | { | |
454 | return blocking_notifier_chain_register(&oom_notify_list, nb); | |
455 | } | |
456 | EXPORT_SYMBOL_GPL(register_oom_notifier); | |
457 | ||
458 | int unregister_oom_notifier(struct notifier_block *nb) | |
459 | { | |
460 | return blocking_notifier_chain_unregister(&oom_notify_list, nb); | |
461 | } | |
462 | EXPORT_SYMBOL_GPL(unregister_oom_notifier); | |
463 | ||
098d7f12 DR |
464 | /* |
465 | * Try to acquire the OOM killer lock for the zones in zonelist. Returns zero | |
466 | * if a parallel OOM killing is already taking place that includes a zone in | |
467 | * the zonelist. Otherwise, locks all zones in the zonelist and returns 1. | |
468 | */ | |
dd1a239f | 469 | int try_set_zone_oom(struct zonelist *zonelist, gfp_t gfp_mask) |
098d7f12 | 470 | { |
dd1a239f MG |
471 | struct zoneref *z; |
472 | struct zone *zone; | |
098d7f12 DR |
473 | int ret = 1; |
474 | ||
c7d4caeb | 475 | spin_lock(&zone_scan_lock); |
dd1a239f MG |
476 | for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) { |
477 | if (zone_is_oom_locked(zone)) { | |
098d7f12 DR |
478 | ret = 0; |
479 | goto out; | |
480 | } | |
dd1a239f MG |
481 | } |
482 | ||
483 | for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) { | |
484 | /* | |
c7d4caeb | 485 | * Lock each zone in the zonelist under zone_scan_lock so a |
dd1a239f MG |
486 | * parallel invocation of try_set_zone_oom() doesn't succeed |
487 | * when it shouldn't. | |
488 | */ | |
489 | zone_set_flag(zone, ZONE_OOM_LOCKED); | |
490 | } | |
098d7f12 | 491 | |
098d7f12 | 492 | out: |
c7d4caeb | 493 | spin_unlock(&zone_scan_lock); |
098d7f12 DR |
494 | return ret; |
495 | } | |
496 | ||
497 | /* | |
498 | * Clears the ZONE_OOM_LOCKED flag for all zones in the zonelist so that failed | |
499 | * allocation attempts with zonelists containing them may now recall the OOM | |
500 | * killer, if necessary. | |
501 | */ | |
dd1a239f | 502 | void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask) |
098d7f12 | 503 | { |
dd1a239f MG |
504 | struct zoneref *z; |
505 | struct zone *zone; | |
098d7f12 | 506 | |
c7d4caeb | 507 | spin_lock(&zone_scan_lock); |
dd1a239f MG |
508 | for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) { |
509 | zone_clear_flag(zone, ZONE_OOM_LOCKED); | |
510 | } | |
c7d4caeb | 511 | spin_unlock(&zone_scan_lock); |
098d7f12 DR |
512 | } |
513 | ||
1c0fe6e3 NP |
514 | /* |
515 | * Must be called with tasklist_lock held for read. | |
516 | */ | |
517 | static void __out_of_memory(gfp_t gfp_mask, int order) | |
518 | { | |
184101bf DR |
519 | struct task_struct *p; |
520 | unsigned long points; | |
1c0fe6e3 | 521 | |
184101bf DR |
522 | if (sysctl_oom_kill_allocating_task) |
523 | if (!oom_kill_process(current, gfp_mask, order, 0, NULL, | |
524 | "Out of memory (oom_kill_allocating_task)")) | |
1c0fe6e3 | 525 | return; |
184101bf DR |
526 | retry: |
527 | /* | |
528 | * Rambo mode: Shoot down a process and hope it solves whatever | |
529 | * issues we may have. | |
530 | */ | |
531 | p = select_bad_process(&points, NULL); | |
1c0fe6e3 | 532 | |
184101bf DR |
533 | if (PTR_ERR(p) == -1UL) |
534 | return; | |
1c0fe6e3 | 535 | |
184101bf DR |
536 | /* Found nothing?!?! Either we hang forever, or we panic. */ |
537 | if (!p) { | |
538 | read_unlock(&tasklist_lock); | |
539 | panic("Out of memory and no killable processes...\n"); | |
1c0fe6e3 | 540 | } |
184101bf DR |
541 | |
542 | if (oom_kill_process(p, gfp_mask, order, points, NULL, | |
543 | "Out of memory")) | |
544 | goto retry; | |
1c0fe6e3 NP |
545 | } |
546 | ||
547 | /* | |
548 | * pagefault handler calls into here because it is out of memory but | |
549 | * doesn't know exactly how or why. | |
550 | */ | |
551 | void pagefault_out_of_memory(void) | |
552 | { | |
553 | unsigned long freed = 0; | |
554 | ||
555 | blocking_notifier_call_chain(&oom_notify_list, 0, &freed); | |
556 | if (freed > 0) | |
557 | /* Got some memory back in the last second. */ | |
558 | return; | |
559 | ||
a636b327 KH |
560 | /* |
561 | * If this is from memcg, oom-killer is already invoked. | |
562 | * and not worth to go system-wide-oom. | |
563 | */ | |
564 | if (mem_cgroup_oom_called(current)) | |
565 | goto rest_and_return; | |
566 | ||
1c0fe6e3 NP |
567 | if (sysctl_panic_on_oom) |
568 | panic("out of memory from page fault. panic_on_oom is selected.\n"); | |
569 | ||
570 | read_lock(&tasklist_lock); | |
571 | __out_of_memory(0, 0); /* unknown gfp_mask and order */ | |
572 | read_unlock(&tasklist_lock); | |
573 | ||
574 | /* | |
575 | * Give "p" a good chance of killing itself before we | |
576 | * retry to allocate memory. | |
577 | */ | |
a636b327 | 578 | rest_and_return: |
1c0fe6e3 NP |
579 | if (!test_thread_flag(TIF_MEMDIE)) |
580 | schedule_timeout_uninterruptible(1); | |
581 | } | |
582 | ||
1da177e4 | 583 | /** |
6937a25c | 584 | * out_of_memory - kill the "best" process when we run out of memory |
1b578df0 RD |
585 | * @zonelist: zonelist pointer |
586 | * @gfp_mask: memory allocation flags | |
587 | * @order: amount of memory being requested as a power of 2 | |
1da177e4 LT |
588 | * |
589 | * If we run out of memory, we have the choice between either | |
590 | * killing a random task (bad), letting the system crash (worse) | |
591 | * OR try to be smart about which process to kill. Note that we | |
592 | * don't have to be perfect here, we just have to be good. | |
593 | */ | |
9b0f8b04 | 594 | void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order) |
1da177e4 | 595 | { |
8bc719d3 | 596 | unsigned long freed = 0; |
70e24bdf | 597 | enum oom_constraint constraint; |
8bc719d3 MS |
598 | |
599 | blocking_notifier_call_chain(&oom_notify_list, 0, &freed); | |
600 | if (freed > 0) | |
601 | /* Got some memory back in the last second. */ | |
602 | return; | |
1da177e4 | 603 | |
2b744c01 YG |
604 | if (sysctl_panic_on_oom == 2) |
605 | panic("out of memory. Compulsory panic_on_oom is selected.\n"); | |
606 | ||
9b0f8b04 CL |
607 | /* |
608 | * Check if there were limitations on the allocation (only relevant for | |
609 | * NUMA) that may require different handling. | |
610 | */ | |
2b45ab33 | 611 | constraint = constrained_alloc(zonelist, gfp_mask); |
2b45ab33 DR |
612 | read_lock(&tasklist_lock); |
613 | ||
614 | switch (constraint) { | |
9b0f8b04 | 615 | case CONSTRAINT_MEMORY_POLICY: |
1c0fe6e3 | 616 | oom_kill_process(current, gfp_mask, order, 0, NULL, |
9b0f8b04 CL |
617 | "No available memory (MPOL_BIND)"); |
618 | break; | |
619 | ||
9b0f8b04 | 620 | case CONSTRAINT_NONE: |
fadd8fbd KH |
621 | if (sysctl_panic_on_oom) |
622 | panic("out of memory. panic_on_oom is selected\n"); | |
fe071d7e DR |
623 | /* Fall-through */ |
624 | case CONSTRAINT_CPUSET: | |
1c0fe6e3 | 625 | __out_of_memory(gfp_mask, order); |
9b0f8b04 CL |
626 | break; |
627 | } | |
1da177e4 | 628 | |
140ffcec | 629 | read_unlock(&tasklist_lock); |
1da177e4 LT |
630 | |
631 | /* | |
632 | * Give "p" a good chance of killing itself before we | |
2f659f46 | 633 | * retry to allocate memory unless "p" is current |
1da177e4 | 634 | */ |
2f659f46 | 635 | if (!test_thread_flag(TIF_MEMDIE)) |
140ffcec | 636 | schedule_timeout_uninterruptible(1); |
1da177e4 | 637 | } |