Commit | Line | Data |
---|---|---|
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> |
8bc719d3 MS |
29 | #include <linux/module.h> |
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> |
1da177e4 | 36 | |
fadd8fbd | 37 | int sysctl_panic_on_oom; |
fe071d7e | 38 | int sysctl_oom_kill_allocating_task; |
ad915c43 | 39 | int sysctl_oom_dump_tasks = 1; |
c7d4caeb | 40 | static DEFINE_SPINLOCK(zone_scan_lock); |
1da177e4 | 41 | |
72788c38 DR |
42 | /** |
43 | * test_set_oom_score_adj() - set current's oom_score_adj and return old value | |
44 | * @new_val: new oom_score_adj value | |
45 | * | |
46 | * Sets the oom_score_adj value for current to @new_val with proper | |
47 | * synchronization and returns the old value. Usually used to temporarily | |
48 | * set a value, save the old value in the caller, and then reinstate it later. | |
49 | */ | |
50 | int test_set_oom_score_adj(int new_val) | |
51 | { | |
52 | struct sighand_struct *sighand = current->sighand; | |
53 | int old_val; | |
54 | ||
55 | spin_lock_irq(&sighand->siglock); | |
56 | old_val = current->signal->oom_score_adj; | |
c9f01245 | 57 | current->signal->oom_score_adj = new_val; |
72788c38 DR |
58 | spin_unlock_irq(&sighand->siglock); |
59 | ||
60 | return old_val; | |
61 | } | |
62 | ||
6f48d0eb DR |
63 | #ifdef CONFIG_NUMA |
64 | /** | |
65 | * has_intersects_mems_allowed() - check task eligiblity for kill | |
66 | * @tsk: task struct of which task to consider | |
67 | * @mask: nodemask passed to page allocator for mempolicy ooms | |
68 | * | |
69 | * Task eligibility is determined by whether or not a candidate task, @tsk, | |
70 | * shares the same mempolicy nodes as current if it is bound by such a policy | |
71 | * and whether or not it has the same set of allowed cpuset nodes. | |
495789a5 | 72 | */ |
6f48d0eb DR |
73 | static bool has_intersects_mems_allowed(struct task_struct *tsk, |
74 | const nodemask_t *mask) | |
495789a5 | 75 | { |
6f48d0eb | 76 | struct task_struct *start = tsk; |
495789a5 | 77 | |
495789a5 | 78 | do { |
6f48d0eb DR |
79 | if (mask) { |
80 | /* | |
81 | * If this is a mempolicy constrained oom, tsk's | |
82 | * cpuset is irrelevant. Only return true if its | |
83 | * mempolicy intersects current, otherwise it may be | |
84 | * needlessly killed. | |
85 | */ | |
86 | if (mempolicy_nodemask_intersects(tsk, mask)) | |
87 | return true; | |
88 | } else { | |
89 | /* | |
90 | * This is not a mempolicy constrained oom, so only | |
91 | * check the mems of tsk's cpuset. | |
92 | */ | |
93 | if (cpuset_mems_allowed_intersects(current, tsk)) | |
94 | return true; | |
95 | } | |
df1090a8 KM |
96 | } while_each_thread(start, tsk); |
97 | ||
6f48d0eb DR |
98 | return false; |
99 | } | |
100 | #else | |
101 | static bool has_intersects_mems_allowed(struct task_struct *tsk, | |
102 | const nodemask_t *mask) | |
103 | { | |
104 | return true; | |
495789a5 | 105 | } |
6f48d0eb | 106 | #endif /* CONFIG_NUMA */ |
495789a5 | 107 | |
6f48d0eb DR |
108 | /* |
109 | * The process p may have detached its own ->mm while exiting or through | |
110 | * use_mm(), but one or more of its subthreads may still have a valid | |
111 | * pointer. Return p, or any of its subthreads with a valid ->mm, with | |
112 | * task_lock() held. | |
113 | */ | |
158e0a2d | 114 | struct task_struct *find_lock_task_mm(struct task_struct *p) |
dd8e8f40 ON |
115 | { |
116 | struct task_struct *t = p; | |
117 | ||
118 | do { | |
119 | task_lock(t); | |
120 | if (likely(t->mm)) | |
121 | return t; | |
122 | task_unlock(t); | |
123 | } while_each_thread(p, t); | |
124 | ||
125 | return NULL; | |
126 | } | |
127 | ||
ab290adb | 128 | /* return true if the task is not adequate as candidate victim task. */ |
e85bfd3a DR |
129 | static bool oom_unkillable_task(struct task_struct *p, |
130 | const struct mem_cgroup *mem, const nodemask_t *nodemask) | |
ab290adb KM |
131 | { |
132 | if (is_global_init(p)) | |
133 | return true; | |
134 | if (p->flags & PF_KTHREAD) | |
135 | return true; | |
136 | ||
137 | /* When mem_cgroup_out_of_memory() and p is not member of the group */ | |
138 | if (mem && !task_in_mem_cgroup(p, mem)) | |
139 | return true; | |
140 | ||
141 | /* p may not have freeable memory in nodemask */ | |
142 | if (!has_intersects_mems_allowed(p, nodemask)) | |
143 | return true; | |
144 | ||
145 | return false; | |
146 | } | |
147 | ||
1da177e4 | 148 | /** |
a63d83f4 | 149 | * oom_badness - heuristic function to determine which candidate task to kill |
1da177e4 | 150 | * @p: task struct of which task we should calculate |
a63d83f4 | 151 | * @totalpages: total present RAM allowed for page allocation |
1da177e4 | 152 | * |
a63d83f4 DR |
153 | * The heuristic for determining which task to kill is made to be as simple and |
154 | * predictable as possible. The goal is to return the highest value for the | |
155 | * task consuming the most memory to avoid subsequent oom failures. | |
1da177e4 | 156 | */ |
a63d83f4 DR |
157 | unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *mem, |
158 | const nodemask_t *nodemask, unsigned long totalpages) | |
1da177e4 | 159 | { |
a63d83f4 | 160 | int points; |
28b83c51 | 161 | |
26ebc984 KM |
162 | if (oom_unkillable_task(p, mem, nodemask)) |
163 | return 0; | |
1da177e4 | 164 | |
dd8e8f40 ON |
165 | p = find_lock_task_mm(p); |
166 | if (!p) | |
1da177e4 LT |
167 | return 0; |
168 | ||
1da177e4 | 169 | /* |
a63d83f4 DR |
170 | * The memory controller may have a limit of 0 bytes, so avoid a divide |
171 | * by zero, if necessary. | |
1da177e4 | 172 | */ |
a63d83f4 DR |
173 | if (!totalpages) |
174 | totalpages = 1; | |
1da177e4 LT |
175 | |
176 | /* | |
a63d83f4 | 177 | * The baseline for the badness score is the proportion of RAM that each |
f755a042 | 178 | * task's rss, pagetable and swap space use. |
1da177e4 | 179 | */ |
f755a042 KM |
180 | points = get_mm_rss(p->mm) + p->mm->nr_ptes; |
181 | points += get_mm_counter(p->mm, MM_SWAPENTS); | |
182 | ||
183 | points *= 1000; | |
184 | points /= totalpages; | |
a63d83f4 | 185 | task_unlock(p); |
1da177e4 LT |
186 | |
187 | /* | |
a63d83f4 DR |
188 | * Root processes get 3% bonus, just like the __vm_enough_memory() |
189 | * implementation used by LSMs. | |
1da177e4 | 190 | */ |
a63d83f4 DR |
191 | if (has_capability_noaudit(p, CAP_SYS_ADMIN)) |
192 | points -= 30; | |
1da177e4 LT |
193 | |
194 | /* | |
a63d83f4 DR |
195 | * /proc/pid/oom_score_adj ranges from -1000 to +1000 such that it may |
196 | * either completely disable oom killing or always prefer a certain | |
197 | * task. | |
1da177e4 | 198 | */ |
a63d83f4 | 199 | points += p->signal->oom_score_adj; |
1da177e4 | 200 | |
f19e8aa1 DR |
201 | /* |
202 | * Never return 0 for an eligible task that may be killed since it's | |
203 | * possible that no single user task uses more than 0.1% of memory and | |
204 | * no single admin tasks uses more than 3.0%. | |
205 | */ | |
206 | if (points <= 0) | |
207 | return 1; | |
a63d83f4 | 208 | return (points < 1000) ? points : 1000; |
1da177e4 LT |
209 | } |
210 | ||
9b0f8b04 CL |
211 | /* |
212 | * Determine the type of allocation constraint. | |
213 | */ | |
9b0f8b04 | 214 | #ifdef CONFIG_NUMA |
4365a567 | 215 | static enum oom_constraint constrained_alloc(struct zonelist *zonelist, |
a63d83f4 DR |
216 | gfp_t gfp_mask, nodemask_t *nodemask, |
217 | unsigned long *totalpages) | |
4365a567 | 218 | { |
54a6eb5c | 219 | struct zone *zone; |
dd1a239f | 220 | struct zoneref *z; |
54a6eb5c | 221 | enum zone_type high_zoneidx = gfp_zone(gfp_mask); |
a63d83f4 DR |
222 | bool cpuset_limited = false; |
223 | int nid; | |
9b0f8b04 | 224 | |
a63d83f4 DR |
225 | /* Default to all available memory */ |
226 | *totalpages = totalram_pages + total_swap_pages; | |
227 | ||
228 | if (!zonelist) | |
229 | return CONSTRAINT_NONE; | |
4365a567 KH |
230 | /* |
231 | * Reach here only when __GFP_NOFAIL is used. So, we should avoid | |
232 | * to kill current.We have to random task kill in this case. | |
233 | * Hopefully, CONSTRAINT_THISNODE...but no way to handle it, now. | |
234 | */ | |
235 | if (gfp_mask & __GFP_THISNODE) | |
236 | return CONSTRAINT_NONE; | |
9b0f8b04 | 237 | |
4365a567 | 238 | /* |
a63d83f4 DR |
239 | * This is not a __GFP_THISNODE allocation, so a truncated nodemask in |
240 | * the page allocator means a mempolicy is in effect. Cpuset policy | |
241 | * is enforced in get_page_from_freelist(). | |
4365a567 | 242 | */ |
a63d83f4 DR |
243 | if (nodemask && !nodes_subset(node_states[N_HIGH_MEMORY], *nodemask)) { |
244 | *totalpages = total_swap_pages; | |
245 | for_each_node_mask(nid, *nodemask) | |
246 | *totalpages += node_spanned_pages(nid); | |
9b0f8b04 | 247 | return CONSTRAINT_MEMORY_POLICY; |
a63d83f4 | 248 | } |
4365a567 KH |
249 | |
250 | /* Check this allocation failure is caused by cpuset's wall function */ | |
251 | for_each_zone_zonelist_nodemask(zone, z, zonelist, | |
252 | high_zoneidx, nodemask) | |
253 | if (!cpuset_zone_allowed_softwall(zone, gfp_mask)) | |
a63d83f4 | 254 | cpuset_limited = true; |
9b0f8b04 | 255 | |
a63d83f4 DR |
256 | if (cpuset_limited) { |
257 | *totalpages = total_swap_pages; | |
258 | for_each_node_mask(nid, cpuset_current_mems_allowed) | |
259 | *totalpages += node_spanned_pages(nid); | |
260 | return CONSTRAINT_CPUSET; | |
261 | } | |
9b0f8b04 CL |
262 | return CONSTRAINT_NONE; |
263 | } | |
4365a567 KH |
264 | #else |
265 | static enum oom_constraint constrained_alloc(struct zonelist *zonelist, | |
a63d83f4 DR |
266 | gfp_t gfp_mask, nodemask_t *nodemask, |
267 | unsigned long *totalpages) | |
4365a567 | 268 | { |
a63d83f4 | 269 | *totalpages = totalram_pages + total_swap_pages; |
4365a567 KH |
270 | return CONSTRAINT_NONE; |
271 | } | |
272 | #endif | |
9b0f8b04 | 273 | |
1da177e4 LT |
274 | /* |
275 | * Simple selection loop. We chose the process with the highest | |
276 | * number of 'points'. We expect the caller will lock the tasklist. | |
277 | * | |
278 | * (not docbooked, we don't want this one cluttering up the manual) | |
279 | */ | |
a63d83f4 DR |
280 | static struct task_struct *select_bad_process(unsigned int *ppoints, |
281 | unsigned long totalpages, struct mem_cgroup *mem, | |
282 | const nodemask_t *nodemask) | |
1da177e4 | 283 | { |
3a5dda7a | 284 | struct task_struct *g, *p; |
1da177e4 | 285 | struct task_struct *chosen = NULL; |
9827b781 | 286 | *ppoints = 0; |
1da177e4 | 287 | |
3a5dda7a | 288 | do_each_thread(g, p) { |
a63d83f4 | 289 | unsigned int points; |
a49335cc | 290 | |
c027a474 | 291 | if (p->exit_state) |
30e2b41f | 292 | continue; |
ab290adb | 293 | if (oom_unkillable_task(p, mem, nodemask)) |
6cf86ac6 | 294 | continue; |
ef08e3b4 | 295 | |
b78483a4 NP |
296 | /* |
297 | * This task already has access to memory reserves and is | |
298 | * being killed. Don't allow any other task access to the | |
299 | * memory reserve. | |
300 | * | |
301 | * Note: this may have a chance of deadlock if it gets | |
302 | * blocked waiting for another task which itself is waiting | |
303 | * for memory. Is there a better alternative? | |
304 | */ | |
f660daac DR |
305 | if (test_tsk_thread_flag(p, TIF_MEMDIE)) { |
306 | if (unlikely(frozen(p))) | |
307 | thaw_process(p); | |
b78483a4 | 308 | return ERR_PTR(-1UL); |
f660daac | 309 | } |
c027a474 ON |
310 | if (!p->mm) |
311 | continue; | |
b78483a4 | 312 | |
30e2b41f | 313 | if (p->flags & PF_EXITING) { |
edd45544 DR |
314 | /* |
315 | * If p is the current task and is in the process of | |
316 | * releasing memory, we allow the "kill" to set | |
317 | * TIF_MEMDIE, which will allow it to gain access to | |
318 | * memory reserves. Otherwise, it may stall forever. | |
319 | * | |
320 | * The loop isn't broken here, however, in case other | |
321 | * threads are found to have already been oom killed. | |
322 | */ | |
323 | if (p == current) { | |
324 | chosen = p; | |
325 | *ppoints = 1000; | |
326 | } else { | |
327 | /* | |
328 | * If this task is not being ptraced on exit, | |
329 | * then wait for it to finish before killing | |
330 | * some other task unnecessarily. | |
331 | */ | |
d21142ec | 332 | if (!(p->group_leader->ptrace & PT_TRACE_EXIT)) |
edd45544 DR |
333 | return ERR_PTR(-1UL); |
334 | } | |
50ec3bbf | 335 | } |
972c4ea5 | 336 | |
a63d83f4 DR |
337 | points = oom_badness(p, mem, nodemask, totalpages); |
338 | if (points > *ppoints) { | |
a49335cc | 339 | chosen = p; |
9827b781 | 340 | *ppoints = points; |
1da177e4 | 341 | } |
3a5dda7a | 342 | } while_each_thread(g, p); |
972c4ea5 | 343 | |
1da177e4 LT |
344 | return chosen; |
345 | } | |
346 | ||
fef1bdd6 | 347 | /** |
1b578df0 | 348 | * dump_tasks - dump current memory state of all system tasks |
74ab7f1d | 349 | * @mem: current's memory controller, if constrained |
e85bfd3a | 350 | * @nodemask: nodemask passed to page allocator for mempolicy ooms |
1b578df0 | 351 | * |
e85bfd3a DR |
352 | * Dumps the current memory state of all eligible tasks. Tasks not in the same |
353 | * memcg, not in the same cpuset, or bound to a disjoint set of mempolicy nodes | |
354 | * are not shown. | |
fef1bdd6 | 355 | * State information includes task's pid, uid, tgid, vm size, rss, cpu, oom_adj |
a63d83f4 | 356 | * value, oom_score_adj value, and name. |
fef1bdd6 | 357 | * |
fef1bdd6 DR |
358 | * Call with tasklist_lock read-locked. |
359 | */ | |
e85bfd3a | 360 | static void dump_tasks(const struct mem_cgroup *mem, const nodemask_t *nodemask) |
fef1bdd6 | 361 | { |
c55db957 KM |
362 | struct task_struct *p; |
363 | struct task_struct *task; | |
fef1bdd6 | 364 | |
a63d83f4 | 365 | pr_info("[ pid ] uid tgid total_vm rss cpu oom_adj oom_score_adj name\n"); |
c55db957 | 366 | for_each_process(p) { |
e85bfd3a | 367 | if (oom_unkillable_task(p, mem, nodemask)) |
b4416d2b | 368 | continue; |
fef1bdd6 | 369 | |
c55db957 KM |
370 | task = find_lock_task_mm(p); |
371 | if (!task) { | |
6d2661ed | 372 | /* |
74ab7f1d DR |
373 | * This is a kthread or all of p's threads have already |
374 | * detached their mm's. There's no need to report | |
c55db957 | 375 | * them; they can't be oom killed anyway. |
6d2661ed | 376 | */ |
6d2661ed DR |
377 | continue; |
378 | } | |
c55db957 | 379 | |
a63d83f4 | 380 | pr_info("[%5d] %5d %5d %8lu %8lu %3u %3d %5d %s\n", |
8d6c83f0 | 381 | task->pid, task_uid(task), task->tgid, |
a63d83f4 DR |
382 | task->mm->total_vm, get_mm_rss(task->mm), |
383 | task_cpu(task), task->signal->oom_adj, | |
384 | task->signal->oom_score_adj, task->comm); | |
c55db957 KM |
385 | task_unlock(task); |
386 | } | |
fef1bdd6 DR |
387 | } |
388 | ||
d31f56db | 389 | static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order, |
e85bfd3a | 390 | struct mem_cgroup *mem, const nodemask_t *nodemask) |
1b604d75 | 391 | { |
5e9d834a | 392 | task_lock(current); |
1b604d75 | 393 | pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, " |
a63d83f4 DR |
394 | "oom_adj=%d, oom_score_adj=%d\n", |
395 | current->comm, gfp_mask, order, current->signal->oom_adj, | |
396 | current->signal->oom_score_adj); | |
1b604d75 DR |
397 | cpuset_print_task_mems_allowed(current); |
398 | task_unlock(current); | |
399 | dump_stack(); | |
d31f56db | 400 | mem_cgroup_print_oom_info(mem, p); |
b2b755b5 | 401 | show_mem(SHOW_MEM_FILTER_NODES); |
1b604d75 | 402 | if (sysctl_oom_dump_tasks) |
e85bfd3a | 403 | dump_tasks(mem, nodemask); |
1b604d75 DR |
404 | } |
405 | ||
3b4798cb | 406 | #define K(x) ((x) << (PAGE_SHIFT-10)) |
93b43fa5 | 407 | static int oom_kill_task(struct task_struct *p, struct mem_cgroup *mem) |
1da177e4 | 408 | { |
1e99bad0 DR |
409 | struct task_struct *q; |
410 | struct mm_struct *mm; | |
411 | ||
dd8e8f40 | 412 | p = find_lock_task_mm(p); |
be71cf22 | 413 | if (!p) |
b940fd70 | 414 | return 1; |
be71cf22 | 415 | |
1e99bad0 DR |
416 | /* mm cannot be safely dereferenced after task_unlock(p) */ |
417 | mm = p->mm; | |
418 | ||
b940fd70 DR |
419 | pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB\n", |
420 | task_pid_nr(p), p->comm, K(p->mm->total_vm), | |
421 | K(get_mm_counter(p->mm, MM_ANONPAGES)), | |
422 | K(get_mm_counter(p->mm, MM_FILEPAGES))); | |
3b4798cb | 423 | task_unlock(p); |
1da177e4 | 424 | |
1e99bad0 | 425 | /* |
7b0d44fa | 426 | * Kill all user processes sharing p->mm in other thread groups, if any. |
1e99bad0 DR |
427 | * They don't get access to memory reserves or a higher scheduler |
428 | * priority, though, to avoid depletion of all memory or task | |
429 | * starvation. This prevents mm->mmap_sem livelock when an oom killed | |
430 | * task cannot exit because it requires the semaphore and its contended | |
431 | * by another thread trying to allocate memory itself. That thread will | |
432 | * now get access to memory reserves since it has a pending fatal | |
433 | * signal. | |
434 | */ | |
435 | for_each_process(q) | |
7b0d44fa DR |
436 | if (q->mm == mm && !same_thread_group(q, p) && |
437 | !(q->flags & PF_KTHREAD)) { | |
c9f01245 DR |
438 | if (q->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) |
439 | continue; | |
440 | ||
1e99bad0 DR |
441 | task_lock(q); /* Protect ->comm from prctl() */ |
442 | pr_err("Kill process %d (%s) sharing same memory\n", | |
443 | task_pid_nr(q), q->comm); | |
444 | task_unlock(q); | |
445 | force_sig(SIGKILL, q); | |
446 | } | |
93b43fa5 | 447 | |
1da177e4 | 448 | set_tsk_thread_flag(p, TIF_MEMDIE); |
1da177e4 | 449 | force_sig(SIGKILL, p); |
93b43fa5 | 450 | |
01315922 | 451 | return 0; |
1da177e4 | 452 | } |
b940fd70 | 453 | #undef K |
1da177e4 | 454 | |
7213f506 | 455 | static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, |
a63d83f4 DR |
456 | unsigned int points, unsigned long totalpages, |
457 | struct mem_cgroup *mem, nodemask_t *nodemask, | |
458 | const char *message) | |
1da177e4 | 459 | { |
52d3c036 | 460 | struct task_struct *victim = p; |
5e9d834a | 461 | struct task_struct *child; |
52d3c036 LT |
462 | struct task_struct *t = p; |
463 | unsigned int victim_points = 0; | |
1da177e4 | 464 | |
1b604d75 | 465 | if (printk_ratelimit()) |
e85bfd3a | 466 | dump_header(p, gfp_mask, order, mem, nodemask); |
7213f506 | 467 | |
50ec3bbf NP |
468 | /* |
469 | * If the task is already exiting, don't alarm the sysadmin or kill | |
470 | * its children or threads, just set TIF_MEMDIE so it can die quickly | |
471 | */ | |
0753ba01 | 472 | if (p->flags & PF_EXITING) { |
4358997a | 473 | set_tsk_thread_flag(p, TIF_MEMDIE); |
50ec3bbf NP |
474 | return 0; |
475 | } | |
476 | ||
5e9d834a | 477 | task_lock(p); |
a63d83f4 | 478 | pr_err("%s: Kill process %d (%s) score %d or sacrifice child\n", |
5e9d834a DR |
479 | message, task_pid_nr(p), p->comm, points); |
480 | task_unlock(p); | |
f3af38d3 | 481 | |
5e9d834a DR |
482 | /* |
483 | * If any of p's children has a different mm and is eligible for kill, | |
11239836 | 484 | * the one with the highest oom_badness() score is sacrificed for its |
5e9d834a DR |
485 | * parent. This attempts to lose the minimal amount of work done while |
486 | * still freeing memory. | |
487 | */ | |
dd8e8f40 | 488 | do { |
5e9d834a | 489 | list_for_each_entry(child, &t->children, sibling) { |
a63d83f4 | 490 | unsigned int child_points; |
5e9d834a | 491 | |
edd45544 DR |
492 | if (child->mm == p->mm) |
493 | continue; | |
a63d83f4 DR |
494 | /* |
495 | * oom_badness() returns 0 if the thread is unkillable | |
496 | */ | |
497 | child_points = oom_badness(child, mem, nodemask, | |
498 | totalpages); | |
5e9d834a DR |
499 | if (child_points > victim_points) { |
500 | victim = child; | |
501 | victim_points = child_points; | |
502 | } | |
dd8e8f40 ON |
503 | } |
504 | } while_each_thread(p, t); | |
505 | ||
93b43fa5 | 506 | return oom_kill_task(victim, mem); |
1da177e4 LT |
507 | } |
508 | ||
309ed882 DR |
509 | /* |
510 | * Determines whether the kernel must panic because of the panic_on_oom sysctl. | |
511 | */ | |
512 | static void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask, | |
e85bfd3a | 513 | int order, const nodemask_t *nodemask) |
309ed882 DR |
514 | { |
515 | if (likely(!sysctl_panic_on_oom)) | |
516 | return; | |
517 | if (sysctl_panic_on_oom != 2) { | |
518 | /* | |
519 | * panic_on_oom == 1 only affects CONSTRAINT_NONE, the kernel | |
520 | * does not panic for cpuset, mempolicy, or memcg allocation | |
521 | * failures. | |
522 | */ | |
523 | if (constraint != CONSTRAINT_NONE) | |
524 | return; | |
525 | } | |
526 | read_lock(&tasklist_lock); | |
e85bfd3a | 527 | dump_header(NULL, gfp_mask, order, NULL, nodemask); |
309ed882 DR |
528 | read_unlock(&tasklist_lock); |
529 | panic("Out of memory: %s panic_on_oom is enabled\n", | |
530 | sysctl_panic_on_oom == 2 ? "compulsory" : "system-wide"); | |
531 | } | |
532 | ||
00f0b825 | 533 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
c7ba5c9e PE |
534 | void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask) |
535 | { | |
a63d83f4 DR |
536 | unsigned long limit; |
537 | unsigned int points = 0; | |
c7ba5c9e PE |
538 | struct task_struct *p; |
539 | ||
f9434ad1 DR |
540 | /* |
541 | * If current has a pending SIGKILL, then automatically select it. The | |
542 | * goal is to allow it to allocate so that it may quickly exit and free | |
543 | * its memory. | |
544 | */ | |
545 | if (fatal_signal_pending(current)) { | |
546 | set_thread_flag(TIF_MEMDIE); | |
f9434ad1 DR |
547 | return; |
548 | } | |
549 | ||
e85bfd3a | 550 | check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, 0, NULL); |
a63d83f4 | 551 | limit = mem_cgroup_get_limit(mem) >> PAGE_SHIFT; |
e115f2d8 | 552 | read_lock(&tasklist_lock); |
c7ba5c9e | 553 | retry: |
a63d83f4 | 554 | p = select_bad_process(&points, limit, mem, NULL); |
df64f81b | 555 | if (!p || PTR_ERR(p) == -1UL) |
c7ba5c9e PE |
556 | goto out; |
557 | ||
a63d83f4 | 558 | if (oom_kill_process(p, gfp_mask, 0, points, limit, mem, NULL, |
c7ba5c9e PE |
559 | "Memory cgroup out of memory")) |
560 | goto retry; | |
561 | out: | |
e115f2d8 | 562 | read_unlock(&tasklist_lock); |
c7ba5c9e PE |
563 | } |
564 | #endif | |
565 | ||
8bc719d3 MS |
566 | static BLOCKING_NOTIFIER_HEAD(oom_notify_list); |
567 | ||
568 | int register_oom_notifier(struct notifier_block *nb) | |
569 | { | |
570 | return blocking_notifier_chain_register(&oom_notify_list, nb); | |
571 | } | |
572 | EXPORT_SYMBOL_GPL(register_oom_notifier); | |
573 | ||
574 | int unregister_oom_notifier(struct notifier_block *nb) | |
575 | { | |
576 | return blocking_notifier_chain_unregister(&oom_notify_list, nb); | |
577 | } | |
578 | EXPORT_SYMBOL_GPL(unregister_oom_notifier); | |
579 | ||
098d7f12 DR |
580 | /* |
581 | * Try to acquire the OOM killer lock for the zones in zonelist. Returns zero | |
582 | * if a parallel OOM killing is already taking place that includes a zone in | |
583 | * the zonelist. Otherwise, locks all zones in the zonelist and returns 1. | |
584 | */ | |
ff321fea | 585 | int try_set_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask) |
098d7f12 | 586 | { |
dd1a239f MG |
587 | struct zoneref *z; |
588 | struct zone *zone; | |
098d7f12 DR |
589 | int ret = 1; |
590 | ||
c7d4caeb | 591 | spin_lock(&zone_scan_lock); |
dd1a239f MG |
592 | for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) { |
593 | if (zone_is_oom_locked(zone)) { | |
098d7f12 DR |
594 | ret = 0; |
595 | goto out; | |
596 | } | |
dd1a239f MG |
597 | } |
598 | ||
599 | for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) { | |
600 | /* | |
c7d4caeb | 601 | * Lock each zone in the zonelist under zone_scan_lock so a |
ff321fea | 602 | * parallel invocation of try_set_zonelist_oom() doesn't succeed |
dd1a239f MG |
603 | * when it shouldn't. |
604 | */ | |
605 | zone_set_flag(zone, ZONE_OOM_LOCKED); | |
606 | } | |
098d7f12 | 607 | |
098d7f12 | 608 | out: |
c7d4caeb | 609 | spin_unlock(&zone_scan_lock); |
098d7f12 DR |
610 | return ret; |
611 | } | |
612 | ||
613 | /* | |
614 | * Clears the ZONE_OOM_LOCKED flag for all zones in the zonelist so that failed | |
615 | * allocation attempts with zonelists containing them may now recall the OOM | |
616 | * killer, if necessary. | |
617 | */ | |
dd1a239f | 618 | void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask) |
098d7f12 | 619 | { |
dd1a239f MG |
620 | struct zoneref *z; |
621 | struct zone *zone; | |
098d7f12 | 622 | |
c7d4caeb | 623 | spin_lock(&zone_scan_lock); |
dd1a239f MG |
624 | for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) { |
625 | zone_clear_flag(zone, ZONE_OOM_LOCKED); | |
626 | } | |
c7d4caeb | 627 | spin_unlock(&zone_scan_lock); |
098d7f12 DR |
628 | } |
629 | ||
e3658932 DR |
630 | /* |
631 | * Try to acquire the oom killer lock for all system zones. Returns zero if a | |
632 | * parallel oom killing is taking place, otherwise locks all zones and returns | |
633 | * non-zero. | |
634 | */ | |
635 | static int try_set_system_oom(void) | |
636 | { | |
637 | struct zone *zone; | |
638 | int ret = 1; | |
639 | ||
640 | spin_lock(&zone_scan_lock); | |
641 | for_each_populated_zone(zone) | |
642 | if (zone_is_oom_locked(zone)) { | |
643 | ret = 0; | |
644 | goto out; | |
645 | } | |
646 | for_each_populated_zone(zone) | |
647 | zone_set_flag(zone, ZONE_OOM_LOCKED); | |
648 | out: | |
649 | spin_unlock(&zone_scan_lock); | |
650 | return ret; | |
651 | } | |
652 | ||
653 | /* | |
654 | * Clears ZONE_OOM_LOCKED for all system zones so that failed allocation | |
655 | * attempts or page faults may now recall the oom killer, if necessary. | |
656 | */ | |
657 | static void clear_system_oom(void) | |
658 | { | |
659 | struct zone *zone; | |
660 | ||
661 | spin_lock(&zone_scan_lock); | |
662 | for_each_populated_zone(zone) | |
663 | zone_clear_flag(zone, ZONE_OOM_LOCKED); | |
664 | spin_unlock(&zone_scan_lock); | |
665 | } | |
666 | ||
1da177e4 | 667 | /** |
6937a25c | 668 | * out_of_memory - kill the "best" process when we run out of memory |
1b578df0 RD |
669 | * @zonelist: zonelist pointer |
670 | * @gfp_mask: memory allocation flags | |
671 | * @order: amount of memory being requested as a power of 2 | |
6f48d0eb | 672 | * @nodemask: nodemask passed to page allocator |
1da177e4 LT |
673 | * |
674 | * If we run out of memory, we have the choice between either | |
675 | * killing a random task (bad), letting the system crash (worse) | |
676 | * OR try to be smart about which process to kill. Note that we | |
677 | * don't have to be perfect here, we just have to be good. | |
678 | */ | |
4365a567 KH |
679 | void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, |
680 | int order, nodemask_t *nodemask) | |
1da177e4 | 681 | { |
e85bfd3a | 682 | const nodemask_t *mpol_mask; |
0aad4b31 | 683 | struct task_struct *p; |
a63d83f4 | 684 | unsigned long totalpages; |
8bc719d3 | 685 | unsigned long freed = 0; |
a63d83f4 | 686 | unsigned int points; |
e3658932 | 687 | enum oom_constraint constraint = CONSTRAINT_NONE; |
b52723c5 | 688 | int killed = 0; |
8bc719d3 MS |
689 | |
690 | blocking_notifier_call_chain(&oom_notify_list, 0, &freed); | |
691 | if (freed > 0) | |
692 | /* Got some memory back in the last second. */ | |
693 | return; | |
1da177e4 | 694 | |
7b98c2e4 DR |
695 | /* |
696 | * If current has a pending SIGKILL, then automatically select it. The | |
697 | * goal is to allow it to allocate so that it may quickly exit and free | |
698 | * its memory. | |
699 | */ | |
700 | if (fatal_signal_pending(current)) { | |
701 | set_thread_flag(TIF_MEMDIE); | |
702 | return; | |
703 | } | |
704 | ||
9b0f8b04 CL |
705 | /* |
706 | * Check if there were limitations on the allocation (only relevant for | |
707 | * NUMA) that may require different handling. | |
708 | */ | |
a63d83f4 DR |
709 | constraint = constrained_alloc(zonelist, gfp_mask, nodemask, |
710 | &totalpages); | |
e85bfd3a DR |
711 | mpol_mask = (constraint == CONSTRAINT_MEMORY_POLICY) ? nodemask : NULL; |
712 | check_panic_on_oom(constraint, gfp_mask, order, mpol_mask); | |
0aad4b31 | 713 | |
2b45ab33 | 714 | read_lock(&tasklist_lock); |
f88ccad5 | 715 | if (sysctl_oom_kill_allocating_task && |
a96cfd6e | 716 | !oom_unkillable_task(current, NULL, nodemask) && |
c9f01245 | 717 | current->mm) { |
0aad4b31 DR |
718 | /* |
719 | * oom_kill_process() needs tasklist_lock held. If it returns | |
720 | * non-zero, current could not be killed so we must fallback to | |
721 | * the tasklist scan. | |
722 | */ | |
a63d83f4 DR |
723 | if (!oom_kill_process(current, gfp_mask, order, 0, totalpages, |
724 | NULL, nodemask, | |
0aad4b31 | 725 | "Out of memory (oom_kill_allocating_task)")) |
b52723c5 | 726 | goto out; |
0aad4b31 DR |
727 | } |
728 | ||
729 | retry: | |
e85bfd3a | 730 | p = select_bad_process(&points, totalpages, NULL, mpol_mask); |
0aad4b31 | 731 | if (PTR_ERR(p) == -1UL) |
b52723c5 | 732 | goto out; |
0aad4b31 DR |
733 | |
734 | /* Found nothing?!?! Either we hang forever, or we panic. */ | |
735 | if (!p) { | |
e85bfd3a | 736 | dump_header(NULL, gfp_mask, order, NULL, mpol_mask); |
0aad4b31 DR |
737 | read_unlock(&tasklist_lock); |
738 | panic("Out of memory and no killable processes...\n"); | |
739 | } | |
740 | ||
a63d83f4 DR |
741 | if (oom_kill_process(p, gfp_mask, order, points, totalpages, NULL, |
742 | nodemask, "Out of memory")) | |
0aad4b31 | 743 | goto retry; |
b52723c5 KM |
744 | killed = 1; |
745 | out: | |
140ffcec | 746 | read_unlock(&tasklist_lock); |
1da177e4 LT |
747 | |
748 | /* | |
749 | * Give "p" a good chance of killing itself before we | |
2f659f46 | 750 | * retry to allocate memory unless "p" is current |
1da177e4 | 751 | */ |
b52723c5 | 752 | if (killed && !test_thread_flag(TIF_MEMDIE)) |
140ffcec | 753 | schedule_timeout_uninterruptible(1); |
1da177e4 | 754 | } |
e3658932 DR |
755 | |
756 | /* | |
757 | * The pagefault handler calls here because it is out of memory, so kill a | |
758 | * memory-hogging task. If a populated zone has ZONE_OOM_LOCKED set, a parallel | |
759 | * oom killing is already in progress so do nothing. If a task is found with | |
760 | * TIF_MEMDIE set, it has been killed so do nothing and allow it to exit. | |
761 | */ | |
762 | void pagefault_out_of_memory(void) | |
763 | { | |
764 | if (try_set_system_oom()) { | |
765 | out_of_memory(NULL, 0, 0, NULL); | |
766 | clear_system_oom(); | |
767 | } | |
768 | if (!test_thread_flag(TIF_MEMDIE)) | |
769 | schedule_timeout_uninterruptible(1); | |
770 | } |