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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... | |
a63d83f4 DR |
7 | * Copyright (C) 2010 Google, Inc. |
8 | * Rewritten by David Rientjes | |
1da177e4 LT |
9 | * |
10 | * The routines in this file are used to kill a process when | |
a49335cc PJ |
11 | * we're seriously out of memory. This gets called from __alloc_pages() |
12 | * in mm/page_alloc.c when we really run out of memory. | |
1da177e4 LT |
13 | * |
14 | * Since we won't call these routines often (on a well-configured | |
15 | * machine) this file will double as a 'coding guide' and a signpost | |
16 | * for newbie kernel hackers. It features several pointers to major | |
17 | * kernel subsystems and hints as to where to find out what things do. | |
18 | */ | |
19 | ||
8ac773b4 | 20 | #include <linux/oom.h> |
1da177e4 | 21 | #include <linux/mm.h> |
4e950f6f | 22 | #include <linux/err.h> |
5a0e3ad6 | 23 | #include <linux/gfp.h> |
1da177e4 LT |
24 | #include <linux/sched.h> |
25 | #include <linux/swap.h> | |
26 | #include <linux/timex.h> | |
27 | #include <linux/jiffies.h> | |
ef08e3b4 | 28 | #include <linux/cpuset.h> |
b95f1b31 | 29 | #include <linux/export.h> |
8bc719d3 | 30 | #include <linux/notifier.h> |
c7ba5c9e | 31 | #include <linux/memcontrol.h> |
6f48d0eb | 32 | #include <linux/mempolicy.h> |
5cd9c58f | 33 | #include <linux/security.h> |
edd45544 | 34 | #include <linux/ptrace.h> |
f660daac | 35 | #include <linux/freezer.h> |
43d2b113 KH |
36 | #include <linux/ftrace.h> |
37 | ||
38 | #define CREATE_TRACE_POINTS | |
39 | #include <trace/events/oom.h> | |
1da177e4 | 40 | |
fadd8fbd | 41 | int sysctl_panic_on_oom; |
fe071d7e | 42 | int sysctl_oom_kill_allocating_task; |
ad915c43 | 43 | int sysctl_oom_dump_tasks = 1; |
c7d4caeb | 44 | static DEFINE_SPINLOCK(zone_scan_lock); |
1da177e4 | 45 | |
43362a49 DR |
46 | /* |
47 | * compare_swap_oom_score_adj() - compare and swap current's oom_score_adj | |
48 | * @old_val: old oom_score_adj for compare | |
49 | * @new_val: new oom_score_adj for swap | |
50 | * | |
51 | * Sets the oom_score_adj value for current to @new_val iff its present value is | |
52 | * @old_val. Usually used to reinstate a previous value to prevent racing with | |
53 | * userspacing tuning the value in the interim. | |
54 | */ | |
55 | void compare_swap_oom_score_adj(int old_val, int new_val) | |
56 | { | |
57 | struct sighand_struct *sighand = current->sighand; | |
58 | ||
59 | spin_lock_irq(&sighand->siglock); | |
60 | if (current->signal->oom_score_adj == old_val) | |
61 | current->signal->oom_score_adj = new_val; | |
43d2b113 | 62 | trace_oom_score_adj_update(current); |
43362a49 DR |
63 | spin_unlock_irq(&sighand->siglock); |
64 | } | |
65 | ||
72788c38 DR |
66 | /** |
67 | * test_set_oom_score_adj() - set current's oom_score_adj and return old value | |
68 | * @new_val: new oom_score_adj value | |
69 | * | |
70 | * Sets the oom_score_adj value for current to @new_val with proper | |
71 | * synchronization and returns the old value. Usually used to temporarily | |
72 | * set a value, save the old value in the caller, and then reinstate it later. | |
73 | */ | |
74 | int test_set_oom_score_adj(int new_val) | |
75 | { | |
76 | struct sighand_struct *sighand = current->sighand; | |
77 | int old_val; | |
78 | ||
79 | spin_lock_irq(&sighand->siglock); | |
80 | old_val = current->signal->oom_score_adj; | |
c9f01245 | 81 | current->signal->oom_score_adj = new_val; |
43d2b113 | 82 | trace_oom_score_adj_update(current); |
72788c38 DR |
83 | spin_unlock_irq(&sighand->siglock); |
84 | ||
85 | return old_val; | |
86 | } | |
87 | ||
6f48d0eb DR |
88 | #ifdef CONFIG_NUMA |
89 | /** | |
90 | * has_intersects_mems_allowed() - check task eligiblity for kill | |
91 | * @tsk: task struct of which task to consider | |
92 | * @mask: nodemask passed to page allocator for mempolicy ooms | |
93 | * | |
94 | * Task eligibility is determined by whether or not a candidate task, @tsk, | |
95 | * shares the same mempolicy nodes as current if it is bound by such a policy | |
96 | * and whether or not it has the same set of allowed cpuset nodes. | |
495789a5 | 97 | */ |
6f48d0eb DR |
98 | static bool has_intersects_mems_allowed(struct task_struct *tsk, |
99 | const nodemask_t *mask) | |
495789a5 | 100 | { |
6f48d0eb | 101 | struct task_struct *start = tsk; |
495789a5 | 102 | |
495789a5 | 103 | do { |
6f48d0eb DR |
104 | if (mask) { |
105 | /* | |
106 | * If this is a mempolicy constrained oom, tsk's | |
107 | * cpuset is irrelevant. Only return true if its | |
108 | * mempolicy intersects current, otherwise it may be | |
109 | * needlessly killed. | |
110 | */ | |
111 | if (mempolicy_nodemask_intersects(tsk, mask)) | |
112 | return true; | |
113 | } else { | |
114 | /* | |
115 | * This is not a mempolicy constrained oom, so only | |
116 | * check the mems of tsk's cpuset. | |
117 | */ | |
118 | if (cpuset_mems_allowed_intersects(current, tsk)) | |
119 | return true; | |
120 | } | |
df1090a8 KM |
121 | } while_each_thread(start, tsk); |
122 | ||
6f48d0eb DR |
123 | return false; |
124 | } | |
125 | #else | |
126 | static bool has_intersects_mems_allowed(struct task_struct *tsk, | |
127 | const nodemask_t *mask) | |
128 | { | |
129 | return true; | |
495789a5 | 130 | } |
6f48d0eb | 131 | #endif /* CONFIG_NUMA */ |
495789a5 | 132 | |
6f48d0eb DR |
133 | /* |
134 | * The process p may have detached its own ->mm while exiting or through | |
135 | * use_mm(), but one or more of its subthreads may still have a valid | |
136 | * pointer. Return p, or any of its subthreads with a valid ->mm, with | |
137 | * task_lock() held. | |
138 | */ | |
158e0a2d | 139 | struct task_struct *find_lock_task_mm(struct task_struct *p) |
dd8e8f40 ON |
140 | { |
141 | struct task_struct *t = p; | |
142 | ||
143 | do { | |
144 | task_lock(t); | |
145 | if (likely(t->mm)) | |
146 | return t; | |
147 | task_unlock(t); | |
148 | } while_each_thread(p, t); | |
149 | ||
150 | return NULL; | |
151 | } | |
152 | ||
ab290adb | 153 | /* return true if the task is not adequate as candidate victim task. */ |
e85bfd3a | 154 | static bool oom_unkillable_task(struct task_struct *p, |
72835c86 | 155 | const struct mem_cgroup *memcg, const nodemask_t *nodemask) |
ab290adb KM |
156 | { |
157 | if (is_global_init(p)) | |
158 | return true; | |
159 | if (p->flags & PF_KTHREAD) | |
160 | return true; | |
161 | ||
162 | /* When mem_cgroup_out_of_memory() and p is not member of the group */ | |
72835c86 | 163 | if (memcg && !task_in_mem_cgroup(p, memcg)) |
ab290adb KM |
164 | return true; |
165 | ||
166 | /* p may not have freeable memory in nodemask */ | |
167 | if (!has_intersects_mems_allowed(p, nodemask)) | |
168 | return true; | |
169 | ||
170 | return false; | |
171 | } | |
172 | ||
1da177e4 | 173 | /** |
a63d83f4 | 174 | * oom_badness - heuristic function to determine which candidate task to kill |
1da177e4 | 175 | * @p: task struct of which task we should calculate |
a63d83f4 | 176 | * @totalpages: total present RAM allowed for page allocation |
1da177e4 | 177 | * |
a63d83f4 DR |
178 | * The heuristic for determining which task to kill is made to be as simple and |
179 | * predictable as possible. The goal is to return the highest value for the | |
180 | * task consuming the most memory to avoid subsequent oom failures. | |
1da177e4 | 181 | */ |
72835c86 | 182 | unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *memcg, |
a63d83f4 | 183 | const nodemask_t *nodemask, unsigned long totalpages) |
1da177e4 | 184 | { |
ff05b6f7 | 185 | long points; |
28b83c51 | 186 | |
72835c86 | 187 | if (oom_unkillable_task(p, memcg, nodemask)) |
26ebc984 | 188 | return 0; |
1da177e4 | 189 | |
dd8e8f40 ON |
190 | p = find_lock_task_mm(p); |
191 | if (!p) | |
1da177e4 LT |
192 | return 0; |
193 | ||
5aecc85a MH |
194 | if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) { |
195 | task_unlock(p); | |
196 | return 0; | |
197 | } | |
198 | ||
1da177e4 | 199 | /* |
a63d83f4 DR |
200 | * The memory controller may have a limit of 0 bytes, so avoid a divide |
201 | * by zero, if necessary. | |
1da177e4 | 202 | */ |
a63d83f4 DR |
203 | if (!totalpages) |
204 | totalpages = 1; | |
1da177e4 LT |
205 | |
206 | /* | |
a63d83f4 | 207 | * The baseline for the badness score is the proportion of RAM that each |
f755a042 | 208 | * task's rss, pagetable and swap space use. |
1da177e4 | 209 | */ |
f755a042 KM |
210 | points = get_mm_rss(p->mm) + p->mm->nr_ptes; |
211 | points += get_mm_counter(p->mm, MM_SWAPENTS); | |
212 | ||
213 | points *= 1000; | |
214 | points /= totalpages; | |
a63d83f4 | 215 | task_unlock(p); |
1da177e4 LT |
216 | |
217 | /* | |
a63d83f4 DR |
218 | * Root processes get 3% bonus, just like the __vm_enough_memory() |
219 | * implementation used by LSMs. | |
1da177e4 | 220 | */ |
a63d83f4 DR |
221 | if (has_capability_noaudit(p, CAP_SYS_ADMIN)) |
222 | points -= 30; | |
1da177e4 LT |
223 | |
224 | /* | |
a63d83f4 DR |
225 | * /proc/pid/oom_score_adj ranges from -1000 to +1000 such that it may |
226 | * either completely disable oom killing or always prefer a certain | |
227 | * task. | |
1da177e4 | 228 | */ |
a63d83f4 | 229 | points += p->signal->oom_score_adj; |
1da177e4 | 230 | |
f19e8aa1 DR |
231 | /* |
232 | * Never return 0 for an eligible task that may be killed since it's | |
233 | * possible that no single user task uses more than 0.1% of memory and | |
234 | * no single admin tasks uses more than 3.0%. | |
235 | */ | |
236 | if (points <= 0) | |
237 | return 1; | |
a63d83f4 | 238 | return (points < 1000) ? points : 1000; |
1da177e4 LT |
239 | } |
240 | ||
9b0f8b04 CL |
241 | /* |
242 | * Determine the type of allocation constraint. | |
243 | */ | |
9b0f8b04 | 244 | #ifdef CONFIG_NUMA |
4365a567 | 245 | static enum oom_constraint constrained_alloc(struct zonelist *zonelist, |
a63d83f4 DR |
246 | gfp_t gfp_mask, nodemask_t *nodemask, |
247 | unsigned long *totalpages) | |
4365a567 | 248 | { |
54a6eb5c | 249 | struct zone *zone; |
dd1a239f | 250 | struct zoneref *z; |
54a6eb5c | 251 | enum zone_type high_zoneidx = gfp_zone(gfp_mask); |
a63d83f4 DR |
252 | bool cpuset_limited = false; |
253 | int nid; | |
9b0f8b04 | 254 | |
a63d83f4 DR |
255 | /* Default to all available memory */ |
256 | *totalpages = totalram_pages + total_swap_pages; | |
257 | ||
258 | if (!zonelist) | |
259 | return CONSTRAINT_NONE; | |
4365a567 KH |
260 | /* |
261 | * Reach here only when __GFP_NOFAIL is used. So, we should avoid | |
262 | * to kill current.We have to random task kill in this case. | |
263 | * Hopefully, CONSTRAINT_THISNODE...but no way to handle it, now. | |
264 | */ | |
265 | if (gfp_mask & __GFP_THISNODE) | |
266 | return CONSTRAINT_NONE; | |
9b0f8b04 | 267 | |
4365a567 | 268 | /* |
a63d83f4 DR |
269 | * This is not a __GFP_THISNODE allocation, so a truncated nodemask in |
270 | * the page allocator means a mempolicy is in effect. Cpuset policy | |
271 | * is enforced in get_page_from_freelist(). | |
4365a567 | 272 | */ |
a63d83f4 DR |
273 | if (nodemask && !nodes_subset(node_states[N_HIGH_MEMORY], *nodemask)) { |
274 | *totalpages = total_swap_pages; | |
275 | for_each_node_mask(nid, *nodemask) | |
276 | *totalpages += node_spanned_pages(nid); | |
9b0f8b04 | 277 | return CONSTRAINT_MEMORY_POLICY; |
a63d83f4 | 278 | } |
4365a567 KH |
279 | |
280 | /* Check this allocation failure is caused by cpuset's wall function */ | |
281 | for_each_zone_zonelist_nodemask(zone, z, zonelist, | |
282 | high_zoneidx, nodemask) | |
283 | if (!cpuset_zone_allowed_softwall(zone, gfp_mask)) | |
a63d83f4 | 284 | cpuset_limited = true; |
9b0f8b04 | 285 | |
a63d83f4 DR |
286 | if (cpuset_limited) { |
287 | *totalpages = total_swap_pages; | |
288 | for_each_node_mask(nid, cpuset_current_mems_allowed) | |
289 | *totalpages += node_spanned_pages(nid); | |
290 | return CONSTRAINT_CPUSET; | |
291 | } | |
9b0f8b04 CL |
292 | return CONSTRAINT_NONE; |
293 | } | |
4365a567 KH |
294 | #else |
295 | static enum oom_constraint constrained_alloc(struct zonelist *zonelist, | |
a63d83f4 DR |
296 | gfp_t gfp_mask, nodemask_t *nodemask, |
297 | unsigned long *totalpages) | |
4365a567 | 298 | { |
a63d83f4 | 299 | *totalpages = totalram_pages + total_swap_pages; |
4365a567 KH |
300 | return CONSTRAINT_NONE; |
301 | } | |
302 | #endif | |
9b0f8b04 | 303 | |
1da177e4 LT |
304 | /* |
305 | * Simple selection loop. We chose the process with the highest | |
306 | * number of 'points'. We expect the caller will lock the tasklist. | |
307 | * | |
308 | * (not docbooked, we don't want this one cluttering up the manual) | |
309 | */ | |
a63d83f4 | 310 | static struct task_struct *select_bad_process(unsigned int *ppoints, |
72835c86 | 311 | unsigned long totalpages, struct mem_cgroup *memcg, |
a63d83f4 | 312 | const nodemask_t *nodemask) |
1da177e4 | 313 | { |
3a5dda7a | 314 | struct task_struct *g, *p; |
1da177e4 | 315 | struct task_struct *chosen = NULL; |
9827b781 | 316 | *ppoints = 0; |
1da177e4 | 317 | |
3a5dda7a | 318 | do_each_thread(g, p) { |
a63d83f4 | 319 | unsigned int points; |
a49335cc | 320 | |
c027a474 | 321 | if (p->exit_state) |
30e2b41f | 322 | continue; |
72835c86 | 323 | if (oom_unkillable_task(p, memcg, nodemask)) |
6cf86ac6 | 324 | continue; |
ef08e3b4 | 325 | |
b78483a4 NP |
326 | /* |
327 | * This task already has access to memory reserves and is | |
328 | * being killed. Don't allow any other task access to the | |
329 | * memory reserve. | |
330 | * | |
331 | * Note: this may have a chance of deadlock if it gets | |
332 | * blocked waiting for another task which itself is waiting | |
333 | * for memory. Is there a better alternative? | |
334 | */ | |
f660daac DR |
335 | if (test_tsk_thread_flag(p, TIF_MEMDIE)) { |
336 | if (unlikely(frozen(p))) | |
a5be2d0d | 337 | __thaw_task(p); |
b78483a4 | 338 | return ERR_PTR(-1UL); |
f660daac | 339 | } |
c027a474 ON |
340 | if (!p->mm) |
341 | continue; | |
b78483a4 | 342 | |
30e2b41f | 343 | if (p->flags & PF_EXITING) { |
edd45544 DR |
344 | /* |
345 | * If p is the current task and is in the process of | |
346 | * releasing memory, we allow the "kill" to set | |
347 | * TIF_MEMDIE, which will allow it to gain access to | |
348 | * memory reserves. Otherwise, it may stall forever. | |
349 | * | |
350 | * The loop isn't broken here, however, in case other | |
351 | * threads are found to have already been oom killed. | |
352 | */ | |
353 | if (p == current) { | |
354 | chosen = p; | |
355 | *ppoints = 1000; | |
356 | } else { | |
357 | /* | |
358 | * If this task is not being ptraced on exit, | |
359 | * then wait for it to finish before killing | |
360 | * some other task unnecessarily. | |
361 | */ | |
d21142ec | 362 | if (!(p->group_leader->ptrace & PT_TRACE_EXIT)) |
edd45544 DR |
363 | return ERR_PTR(-1UL); |
364 | } | |
50ec3bbf | 365 | } |
972c4ea5 | 366 | |
72835c86 | 367 | points = oom_badness(p, memcg, nodemask, totalpages); |
a63d83f4 | 368 | if (points > *ppoints) { |
a49335cc | 369 | chosen = p; |
9827b781 | 370 | *ppoints = points; |
1da177e4 | 371 | } |
3a5dda7a | 372 | } while_each_thread(g, p); |
972c4ea5 | 373 | |
1da177e4 LT |
374 | return chosen; |
375 | } | |
376 | ||
fef1bdd6 | 377 | /** |
1b578df0 | 378 | * dump_tasks - dump current memory state of all system tasks |
74ab7f1d | 379 | * @mem: current's memory controller, if constrained |
e85bfd3a | 380 | * @nodemask: nodemask passed to page allocator for mempolicy ooms |
1b578df0 | 381 | * |
e85bfd3a DR |
382 | * Dumps the current memory state of all eligible tasks. Tasks not in the same |
383 | * memcg, not in the same cpuset, or bound to a disjoint set of mempolicy nodes | |
384 | * are not shown. | |
fef1bdd6 | 385 | * State information includes task's pid, uid, tgid, vm size, rss, cpu, oom_adj |
a63d83f4 | 386 | * value, oom_score_adj value, and name. |
fef1bdd6 | 387 | * |
fef1bdd6 DR |
388 | * Call with tasklist_lock read-locked. |
389 | */ | |
72835c86 | 390 | static void dump_tasks(const struct mem_cgroup *memcg, const nodemask_t *nodemask) |
fef1bdd6 | 391 | { |
c55db957 KM |
392 | struct task_struct *p; |
393 | struct task_struct *task; | |
fef1bdd6 | 394 | |
a63d83f4 | 395 | pr_info("[ pid ] uid tgid total_vm rss cpu oom_adj oom_score_adj name\n"); |
c55db957 | 396 | for_each_process(p) { |
72835c86 | 397 | if (oom_unkillable_task(p, memcg, nodemask)) |
b4416d2b | 398 | continue; |
fef1bdd6 | 399 | |
c55db957 KM |
400 | task = find_lock_task_mm(p); |
401 | if (!task) { | |
6d2661ed | 402 | /* |
74ab7f1d DR |
403 | * This is a kthread or all of p's threads have already |
404 | * detached their mm's. There's no need to report | |
c55db957 | 405 | * them; they can't be oom killed anyway. |
6d2661ed | 406 | */ |
6d2661ed DR |
407 | continue; |
408 | } | |
c55db957 | 409 | |
a63d83f4 | 410 | pr_info("[%5d] %5d %5d %8lu %8lu %3u %3d %5d %s\n", |
8d6c83f0 | 411 | task->pid, task_uid(task), task->tgid, |
a63d83f4 DR |
412 | task->mm->total_vm, get_mm_rss(task->mm), |
413 | task_cpu(task), task->signal->oom_adj, | |
414 | task->signal->oom_score_adj, task->comm); | |
c55db957 KM |
415 | task_unlock(task); |
416 | } | |
fef1bdd6 DR |
417 | } |
418 | ||
d31f56db | 419 | static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order, |
72835c86 | 420 | struct mem_cgroup *memcg, const nodemask_t *nodemask) |
1b604d75 | 421 | { |
5e9d834a | 422 | task_lock(current); |
1b604d75 | 423 | pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, " |
a63d83f4 DR |
424 | "oom_adj=%d, oom_score_adj=%d\n", |
425 | current->comm, gfp_mask, order, current->signal->oom_adj, | |
426 | current->signal->oom_score_adj); | |
1b604d75 DR |
427 | cpuset_print_task_mems_allowed(current); |
428 | task_unlock(current); | |
429 | dump_stack(); | |
72835c86 | 430 | mem_cgroup_print_oom_info(memcg, p); |
b2b755b5 | 431 | show_mem(SHOW_MEM_FILTER_NODES); |
1b604d75 | 432 | if (sysctl_oom_dump_tasks) |
72835c86 | 433 | dump_tasks(memcg, nodemask); |
1b604d75 DR |
434 | } |
435 | ||
3b4798cb | 436 | #define K(x) ((x) << (PAGE_SHIFT-10)) |
2a1c9b1f | 437 | static void oom_kill_task(struct task_struct *p) |
1da177e4 | 438 | { |
1e99bad0 DR |
439 | struct task_struct *q; |
440 | struct mm_struct *mm; | |
441 | ||
dd8e8f40 | 442 | p = find_lock_task_mm(p); |
be71cf22 | 443 | if (!p) |
2a1c9b1f | 444 | return; |
be71cf22 | 445 | |
1e99bad0 DR |
446 | /* mm cannot be safely dereferenced after task_unlock(p) */ |
447 | mm = p->mm; | |
448 | ||
b940fd70 DR |
449 | pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB\n", |
450 | task_pid_nr(p), p->comm, K(p->mm->total_vm), | |
451 | K(get_mm_counter(p->mm, MM_ANONPAGES)), | |
452 | K(get_mm_counter(p->mm, MM_FILEPAGES))); | |
3b4798cb | 453 | task_unlock(p); |
1da177e4 | 454 | |
1e99bad0 | 455 | /* |
7b0d44fa | 456 | * Kill all user processes sharing p->mm in other thread groups, if any. |
1e99bad0 DR |
457 | * They don't get access to memory reserves or a higher scheduler |
458 | * priority, though, to avoid depletion of all memory or task | |
459 | * starvation. This prevents mm->mmap_sem livelock when an oom killed | |
460 | * task cannot exit because it requires the semaphore and its contended | |
461 | * by another thread trying to allocate memory itself. That thread will | |
462 | * now get access to memory reserves since it has a pending fatal | |
463 | * signal. | |
464 | */ | |
465 | for_each_process(q) | |
7b0d44fa DR |
466 | if (q->mm == mm && !same_thread_group(q, p) && |
467 | !(q->flags & PF_KTHREAD)) { | |
c9f01245 DR |
468 | if (q->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) |
469 | continue; | |
470 | ||
1e99bad0 DR |
471 | task_lock(q); /* Protect ->comm from prctl() */ |
472 | pr_err("Kill process %d (%s) sharing same memory\n", | |
473 | task_pid_nr(q), q->comm); | |
474 | task_unlock(q); | |
475 | force_sig(SIGKILL, q); | |
476 | } | |
93b43fa5 | 477 | |
1da177e4 | 478 | set_tsk_thread_flag(p, TIF_MEMDIE); |
1da177e4 | 479 | force_sig(SIGKILL, p); |
1da177e4 | 480 | } |
b940fd70 | 481 | #undef K |
1da177e4 | 482 | |
2a1c9b1f DR |
483 | static void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, |
484 | unsigned int points, unsigned long totalpages, | |
485 | struct mem_cgroup *memcg, nodemask_t *nodemask, | |
486 | const char *message) | |
1da177e4 | 487 | { |
52d3c036 | 488 | struct task_struct *victim = p; |
5e9d834a | 489 | struct task_struct *child; |
52d3c036 LT |
490 | struct task_struct *t = p; |
491 | unsigned int victim_points = 0; | |
1da177e4 | 492 | |
1b604d75 | 493 | if (printk_ratelimit()) |
72835c86 | 494 | dump_header(p, gfp_mask, order, memcg, nodemask); |
7213f506 | 495 | |
50ec3bbf NP |
496 | /* |
497 | * If the task is already exiting, don't alarm the sysadmin or kill | |
498 | * its children or threads, just set TIF_MEMDIE so it can die quickly | |
499 | */ | |
0753ba01 | 500 | if (p->flags & PF_EXITING) { |
4358997a | 501 | set_tsk_thread_flag(p, TIF_MEMDIE); |
2a1c9b1f | 502 | return; |
50ec3bbf NP |
503 | } |
504 | ||
5e9d834a | 505 | task_lock(p); |
a63d83f4 | 506 | pr_err("%s: Kill process %d (%s) score %d or sacrifice child\n", |
5e9d834a DR |
507 | message, task_pid_nr(p), p->comm, points); |
508 | task_unlock(p); | |
f3af38d3 | 509 | |
5e9d834a DR |
510 | /* |
511 | * If any of p's children has a different mm and is eligible for kill, | |
11239836 | 512 | * the one with the highest oom_badness() score is sacrificed for its |
5e9d834a DR |
513 | * parent. This attempts to lose the minimal amount of work done while |
514 | * still freeing memory. | |
515 | */ | |
dd8e8f40 | 516 | do { |
5e9d834a | 517 | list_for_each_entry(child, &t->children, sibling) { |
a63d83f4 | 518 | unsigned int child_points; |
5e9d834a | 519 | |
edd45544 DR |
520 | if (child->mm == p->mm) |
521 | continue; | |
a63d83f4 DR |
522 | /* |
523 | * oom_badness() returns 0 if the thread is unkillable | |
524 | */ | |
72835c86 | 525 | child_points = oom_badness(child, memcg, nodemask, |
a63d83f4 | 526 | totalpages); |
5e9d834a DR |
527 | if (child_points > victim_points) { |
528 | victim = child; | |
529 | victim_points = child_points; | |
530 | } | |
dd8e8f40 ON |
531 | } |
532 | } while_each_thread(p, t); | |
533 | ||
2a1c9b1f | 534 | oom_kill_task(victim); |
1da177e4 LT |
535 | } |
536 | ||
309ed882 DR |
537 | /* |
538 | * Determines whether the kernel must panic because of the panic_on_oom sysctl. | |
539 | */ | |
540 | static void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask, | |
e85bfd3a | 541 | int order, const nodemask_t *nodemask) |
309ed882 DR |
542 | { |
543 | if (likely(!sysctl_panic_on_oom)) | |
544 | return; | |
545 | if (sysctl_panic_on_oom != 2) { | |
546 | /* | |
547 | * panic_on_oom == 1 only affects CONSTRAINT_NONE, the kernel | |
548 | * does not panic for cpuset, mempolicy, or memcg allocation | |
549 | * failures. | |
550 | */ | |
551 | if (constraint != CONSTRAINT_NONE) | |
552 | return; | |
553 | } | |
554 | read_lock(&tasklist_lock); | |
e85bfd3a | 555 | dump_header(NULL, gfp_mask, order, NULL, nodemask); |
309ed882 DR |
556 | read_unlock(&tasklist_lock); |
557 | panic("Out of memory: %s panic_on_oom is enabled\n", | |
558 | sysctl_panic_on_oom == 2 ? "compulsory" : "system-wide"); | |
559 | } | |
560 | ||
00f0b825 | 561 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
72835c86 | 562 | void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask) |
c7ba5c9e | 563 | { |
a63d83f4 DR |
564 | unsigned long limit; |
565 | unsigned int points = 0; | |
c7ba5c9e PE |
566 | struct task_struct *p; |
567 | ||
f9434ad1 DR |
568 | /* |
569 | * If current has a pending SIGKILL, then automatically select it. The | |
570 | * goal is to allow it to allocate so that it may quickly exit and free | |
571 | * its memory. | |
572 | */ | |
573 | if (fatal_signal_pending(current)) { | |
574 | set_thread_flag(TIF_MEMDIE); | |
f9434ad1 DR |
575 | return; |
576 | } | |
577 | ||
e85bfd3a | 578 | check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, 0, NULL); |
72835c86 | 579 | limit = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT; |
e115f2d8 | 580 | read_lock(&tasklist_lock); |
72835c86 | 581 | p = select_bad_process(&points, limit, memcg, NULL); |
2a1c9b1f DR |
582 | if (p && PTR_ERR(p) != -1UL) |
583 | oom_kill_process(p, gfp_mask, 0, points, limit, memcg, NULL, | |
584 | "Memory cgroup out of memory"); | |
e115f2d8 | 585 | read_unlock(&tasklist_lock); |
c7ba5c9e PE |
586 | } |
587 | #endif | |
588 | ||
8bc719d3 MS |
589 | static BLOCKING_NOTIFIER_HEAD(oom_notify_list); |
590 | ||
591 | int register_oom_notifier(struct notifier_block *nb) | |
592 | { | |
593 | return blocking_notifier_chain_register(&oom_notify_list, nb); | |
594 | } | |
595 | EXPORT_SYMBOL_GPL(register_oom_notifier); | |
596 | ||
597 | int unregister_oom_notifier(struct notifier_block *nb) | |
598 | { | |
599 | return blocking_notifier_chain_unregister(&oom_notify_list, nb); | |
600 | } | |
601 | EXPORT_SYMBOL_GPL(unregister_oom_notifier); | |
602 | ||
098d7f12 DR |
603 | /* |
604 | * Try to acquire the OOM killer lock for the zones in zonelist. Returns zero | |
605 | * if a parallel OOM killing is already taking place that includes a zone in | |
606 | * the zonelist. Otherwise, locks all zones in the zonelist and returns 1. | |
607 | */ | |
ff321fea | 608 | int try_set_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask) |
098d7f12 | 609 | { |
dd1a239f MG |
610 | struct zoneref *z; |
611 | struct zone *zone; | |
098d7f12 DR |
612 | int ret = 1; |
613 | ||
c7d4caeb | 614 | spin_lock(&zone_scan_lock); |
dd1a239f MG |
615 | for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) { |
616 | if (zone_is_oom_locked(zone)) { | |
098d7f12 DR |
617 | ret = 0; |
618 | goto out; | |
619 | } | |
dd1a239f MG |
620 | } |
621 | ||
622 | for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) { | |
623 | /* | |
c7d4caeb | 624 | * Lock each zone in the zonelist under zone_scan_lock so a |
ff321fea | 625 | * parallel invocation of try_set_zonelist_oom() doesn't succeed |
dd1a239f MG |
626 | * when it shouldn't. |
627 | */ | |
628 | zone_set_flag(zone, ZONE_OOM_LOCKED); | |
629 | } | |
098d7f12 | 630 | |
098d7f12 | 631 | out: |
c7d4caeb | 632 | spin_unlock(&zone_scan_lock); |
098d7f12 DR |
633 | return ret; |
634 | } | |
635 | ||
636 | /* | |
637 | * Clears the ZONE_OOM_LOCKED flag for all zones in the zonelist so that failed | |
638 | * allocation attempts with zonelists containing them may now recall the OOM | |
639 | * killer, if necessary. | |
640 | */ | |
dd1a239f | 641 | void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask) |
098d7f12 | 642 | { |
dd1a239f MG |
643 | struct zoneref *z; |
644 | struct zone *zone; | |
098d7f12 | 645 | |
c7d4caeb | 646 | spin_lock(&zone_scan_lock); |
dd1a239f MG |
647 | for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) { |
648 | zone_clear_flag(zone, ZONE_OOM_LOCKED); | |
649 | } | |
c7d4caeb | 650 | spin_unlock(&zone_scan_lock); |
098d7f12 DR |
651 | } |
652 | ||
e3658932 DR |
653 | /* |
654 | * Try to acquire the oom killer lock for all system zones. Returns zero if a | |
655 | * parallel oom killing is taking place, otherwise locks all zones and returns | |
656 | * non-zero. | |
657 | */ | |
658 | static int try_set_system_oom(void) | |
659 | { | |
660 | struct zone *zone; | |
661 | int ret = 1; | |
662 | ||
663 | spin_lock(&zone_scan_lock); | |
664 | for_each_populated_zone(zone) | |
665 | if (zone_is_oom_locked(zone)) { | |
666 | ret = 0; | |
667 | goto out; | |
668 | } | |
669 | for_each_populated_zone(zone) | |
670 | zone_set_flag(zone, ZONE_OOM_LOCKED); | |
671 | out: | |
672 | spin_unlock(&zone_scan_lock); | |
673 | return ret; | |
674 | } | |
675 | ||
676 | /* | |
677 | * Clears ZONE_OOM_LOCKED for all system zones so that failed allocation | |
678 | * attempts or page faults may now recall the oom killer, if necessary. | |
679 | */ | |
680 | static void clear_system_oom(void) | |
681 | { | |
682 | struct zone *zone; | |
683 | ||
684 | spin_lock(&zone_scan_lock); | |
685 | for_each_populated_zone(zone) | |
686 | zone_clear_flag(zone, ZONE_OOM_LOCKED); | |
687 | spin_unlock(&zone_scan_lock); | |
688 | } | |
689 | ||
1da177e4 | 690 | /** |
6937a25c | 691 | * out_of_memory - kill the "best" process when we run out of memory |
1b578df0 RD |
692 | * @zonelist: zonelist pointer |
693 | * @gfp_mask: memory allocation flags | |
694 | * @order: amount of memory being requested as a power of 2 | |
6f48d0eb | 695 | * @nodemask: nodemask passed to page allocator |
1da177e4 LT |
696 | * |
697 | * If we run out of memory, we have the choice between either | |
698 | * killing a random task (bad), letting the system crash (worse) | |
699 | * OR try to be smart about which process to kill. Note that we | |
700 | * don't have to be perfect here, we just have to be good. | |
701 | */ | |
4365a567 KH |
702 | void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, |
703 | int order, nodemask_t *nodemask) | |
1da177e4 | 704 | { |
e85bfd3a | 705 | const nodemask_t *mpol_mask; |
0aad4b31 | 706 | struct task_struct *p; |
a63d83f4 | 707 | unsigned long totalpages; |
8bc719d3 | 708 | unsigned long freed = 0; |
a63d83f4 | 709 | unsigned int points; |
e3658932 | 710 | enum oom_constraint constraint = CONSTRAINT_NONE; |
b52723c5 | 711 | int killed = 0; |
8bc719d3 MS |
712 | |
713 | blocking_notifier_call_chain(&oom_notify_list, 0, &freed); | |
714 | if (freed > 0) | |
715 | /* Got some memory back in the last second. */ | |
716 | return; | |
1da177e4 | 717 | |
7b98c2e4 DR |
718 | /* |
719 | * If current has a pending SIGKILL, then automatically select it. The | |
720 | * goal is to allow it to allocate so that it may quickly exit and free | |
721 | * its memory. | |
722 | */ | |
723 | if (fatal_signal_pending(current)) { | |
724 | set_thread_flag(TIF_MEMDIE); | |
725 | return; | |
726 | } | |
727 | ||
9b0f8b04 CL |
728 | /* |
729 | * Check if there were limitations on the allocation (only relevant for | |
730 | * NUMA) that may require different handling. | |
731 | */ | |
a63d83f4 DR |
732 | constraint = constrained_alloc(zonelist, gfp_mask, nodemask, |
733 | &totalpages); | |
e85bfd3a DR |
734 | mpol_mask = (constraint == CONSTRAINT_MEMORY_POLICY) ? nodemask : NULL; |
735 | check_panic_on_oom(constraint, gfp_mask, order, mpol_mask); | |
0aad4b31 | 736 | |
2b45ab33 | 737 | read_lock(&tasklist_lock); |
f88ccad5 | 738 | if (sysctl_oom_kill_allocating_task && |
a96cfd6e | 739 | !oom_unkillable_task(current, NULL, nodemask) && |
c9f01245 | 740 | current->mm) { |
2a1c9b1f DR |
741 | oom_kill_process(current, gfp_mask, order, 0, totalpages, NULL, |
742 | nodemask, | |
743 | "Out of memory (oom_kill_allocating_task)"); | |
744 | goto out; | |
0aad4b31 DR |
745 | } |
746 | ||
e85bfd3a | 747 | p = select_bad_process(&points, totalpages, NULL, mpol_mask); |
0aad4b31 DR |
748 | /* Found nothing?!?! Either we hang forever, or we panic. */ |
749 | if (!p) { | |
e85bfd3a | 750 | dump_header(NULL, gfp_mask, order, NULL, mpol_mask); |
0aad4b31 DR |
751 | read_unlock(&tasklist_lock); |
752 | panic("Out of memory and no killable processes...\n"); | |
753 | } | |
2a1c9b1f DR |
754 | if (PTR_ERR(p) != -1UL) { |
755 | oom_kill_process(p, gfp_mask, order, points, totalpages, NULL, | |
756 | nodemask, "Out of memory"); | |
757 | killed = 1; | |
758 | } | |
b52723c5 | 759 | out: |
140ffcec | 760 | read_unlock(&tasklist_lock); |
1da177e4 LT |
761 | |
762 | /* | |
763 | * Give "p" a good chance of killing itself before we | |
2f659f46 | 764 | * retry to allocate memory unless "p" is current |
1da177e4 | 765 | */ |
b52723c5 | 766 | if (killed && !test_thread_flag(TIF_MEMDIE)) |
140ffcec | 767 | schedule_timeout_uninterruptible(1); |
1da177e4 | 768 | } |
e3658932 DR |
769 | |
770 | /* | |
771 | * The pagefault handler calls here because it is out of memory, so kill a | |
772 | * memory-hogging task. If a populated zone has ZONE_OOM_LOCKED set, a parallel | |
773 | * oom killing is already in progress so do nothing. If a task is found with | |
774 | * TIF_MEMDIE set, it has been killed so do nothing and allow it to exit. | |
775 | */ | |
776 | void pagefault_out_of_memory(void) | |
777 | { | |
778 | if (try_set_system_oom()) { | |
779 | out_of_memory(NULL, 0, 0, NULL); | |
780 | clear_system_oom(); | |
781 | } | |
782 | if (!test_thread_flag(TIF_MEMDIE)) | |
783 | schedule_timeout_uninterruptible(1); | |
784 | } |