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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Paul Jacksona49335c2005-09-06 15:18:09 -07009 * 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.
Linus Torvalds1da177e2005-04-16 15:20:36 -070011 *
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
Alexey Dobriyan8ac773b2006-10-19 23:28:32 -070018#include <linux/oom.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <linux/mm.h>
Alexey Dobriyan4e950f62007-07-30 02:36:13 +040020#include <linux/err.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include <linux/sched.h>
22#include <linux/swap.h>
23#include <linux/timex.h>
24#include <linux/jiffies.h>
Paul Jacksonef08e3b2005-09-06 15:18:13 -070025#include <linux/cpuset.h>
Martin Schwidefsky8bc719d2006-09-25 23:31:20 -070026#include <linux/module.h>
27#include <linux/notifier.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028
KAMEZAWA Hiroyukifadd8fb2006-06-23 02:03:13 -070029int sysctl_panic_on_oom;
Linus Torvalds1da177e2005-04-16 15:20:36 -070030/* #define DEBUG */
31
32/**
Dave Peterson6937a252006-06-23 02:03:13 -070033 * badness - calculate a numeric value for how bad this task has been
Linus Torvalds1da177e2005-04-16 15:20:36 -070034 * @p: task struct of which task we should calculate
Paul Jacksona49335c2005-09-06 15:18:09 -070035 * @uptime: current uptime in seconds
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 *
37 * The formula used is relatively simple and documented inline in the
38 * function. The main rationale is that we want to select a good task
39 * to kill when we run out of memory.
40 *
41 * Good in this context means that:
42 * 1) we lose the minimum amount of work done
43 * 2) we recover a large amount of memory
44 * 3) we don't kill anything innocent of eating tons of memory
45 * 4) we want to kill the minimum amount of processes (one)
46 * 5) we try to kill the process the user expects us to kill, this
47 * algorithm has been meticulously tuned to meet the principle
48 * of least surprise ... (be careful when you change it)
49 */
50
51unsigned long badness(struct task_struct *p, unsigned long uptime)
52{
53 unsigned long points, cpu_time, run_time, s;
Andrew Morton97c2c9b82006-04-18 22:20:38 -070054 struct mm_struct *mm;
55 struct task_struct *child;
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
Andrew Morton97c2c9b82006-04-18 22:20:38 -070057 task_lock(p);
58 mm = p->mm;
59 if (!mm) {
60 task_unlock(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 return 0;
Andrew Morton97c2c9b82006-04-18 22:20:38 -070062 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070063
64 /*
65 * The memory size of the process is the basis for the badness.
66 */
Andrew Morton97c2c9b82006-04-18 22:20:38 -070067 points = mm->total_vm;
68
69 /*
70 * After this unlock we can no longer dereference local variable `mm'
71 */
72 task_unlock(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -070073
74 /*
Hugh Dickins7ba34852007-01-05 16:37:03 -080075 * swapoff can easily use up all memory, so kill those first.
76 */
77 if (p->flags & PF_SWAPOFF)
78 return ULONG_MAX;
79
80 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -070081 * Processes which fork a lot of child processes are likely
Kurt Garloff9827b782006-02-20 18:27:51 -080082 * a good choice. We add half the vmsize of the children if they
Linus Torvalds1da177e2005-04-16 15:20:36 -070083 * have an own mm. This prevents forking servers to flood the
Kurt Garloff9827b782006-02-20 18:27:51 -080084 * machine with an endless amount of children. In case a single
85 * child is eating the vast majority of memory, adding only half
86 * to the parents will make the child our kill candidate of choice.
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 */
Andrew Morton97c2c9b82006-04-18 22:20:38 -070088 list_for_each_entry(child, &p->children, sibling) {
89 task_lock(child);
90 if (child->mm != mm && child->mm)
91 points += child->mm->total_vm/2 + 1;
92 task_unlock(child);
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 }
94
95 /*
96 * CPU time is in tens of seconds and run time is in thousands
97 * of seconds. There is no particular reason for this other than
98 * that it turned out to work very well in practice.
99 */
100 cpu_time = (cputime_to_jiffies(p->utime) + cputime_to_jiffies(p->stime))
101 >> (SHIFT_HZ + 3);
102
103 if (uptime >= p->start_time.tv_sec)
104 run_time = (uptime - p->start_time.tv_sec) >> 10;
105 else
106 run_time = 0;
107
108 s = int_sqrt(cpu_time);
109 if (s)
110 points /= s;
111 s = int_sqrt(int_sqrt(run_time));
112 if (s)
113 points /= s;
114
115 /*
116 * Niced processes are most likely less important, so double
117 * their badness points.
118 */
119 if (task_nice(p) > 0)
120 points *= 2;
121
122 /*
123 * Superuser processes are usually more important, so we make it
124 * less likely that we kill those.
125 */
126 if (cap_t(p->cap_effective) & CAP_TO_MASK(CAP_SYS_ADMIN) ||
127 p->uid == 0 || p->euid == 0)
128 points /= 4;
129
130 /*
131 * We don't want to kill a process with direct hardware access.
132 * Not only could that mess up the hardware, but usually users
133 * tend to only have this flag set on applications they think
134 * of as important.
135 */
136 if (cap_t(p->cap_effective) & CAP_TO_MASK(CAP_SYS_RAWIO))
137 points /= 4;
138
139 /*
Nick Piggin7887a3d2006-09-25 23:31:29 -0700140 * If p's nodes don't overlap ours, it may still help to kill p
141 * because p may have allocated or otherwise mapped memory on
142 * this node before. However it will be less likely.
143 */
144 if (!cpuset_excl_nodes_overlap(p))
145 points /= 8;
146
147 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 * Adjust the score by oomkilladj.
149 */
150 if (p->oomkilladj) {
Joshua N Pritikin9a827822007-05-06 14:49:07 -0700151 if (p->oomkilladj > 0) {
152 if (!points)
153 points = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 points <<= p->oomkilladj;
Joshua N Pritikin9a827822007-05-06 14:49:07 -0700155 } else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 points >>= -(p->oomkilladj);
157 }
158
159#ifdef DEBUG
160 printk(KERN_DEBUG "OOMkill: task %d (%s) got %d points\n",
161 p->pid, p->comm, points);
162#endif
163 return points;
164}
165
166/*
Christoph Lameter9b0f8b02006-02-20 18:27:52 -0800167 * Types of limitations to the nodes from which allocations may occur
168 */
169#define CONSTRAINT_NONE 1
170#define CONSTRAINT_MEMORY_POLICY 2
171#define CONSTRAINT_CPUSET 3
172
173/*
174 * Determine the type of allocation constraint.
175 */
176static inline int constrained_alloc(struct zonelist *zonelist, gfp_t gfp_mask)
177{
178#ifdef CONFIG_NUMA
179 struct zone **z;
KAMEZAWA Hiroyuki96ac5912006-12-29 16:47:20 -0800180 nodemask_t nodes;
181 int node;
Hugh Dickins3d124cb2007-04-23 14:41:02 -0700182
183 nodes_clear(nodes);
KAMEZAWA Hiroyuki96ac5912006-12-29 16:47:20 -0800184 /* node has memory ? */
185 for_each_online_node(node)
186 if (NODE_DATA(node)->node_present_pages)
187 node_set(node, nodes);
Christoph Lameter9b0f8b02006-02-20 18:27:52 -0800188
189 for (z = zonelist->zones; *z; z++)
Paul Jackson02a0e532006-12-13 00:34:25 -0800190 if (cpuset_zone_allowed_softwall(*z, gfp_mask))
Christoph Lameter89fa3022006-09-25 23:31:55 -0700191 node_clear(zone_to_nid(*z), nodes);
Christoph Lameter9b0f8b02006-02-20 18:27:52 -0800192 else
193 return CONSTRAINT_CPUSET;
194
195 if (!nodes_empty(nodes))
196 return CONSTRAINT_MEMORY_POLICY;
197#endif
198
199 return CONSTRAINT_NONE;
200}
201
202/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 * Simple selection loop. We chose the process with the highest
204 * number of 'points'. We expect the caller will lock the tasklist.
205 *
206 * (not docbooked, we don't want this one cluttering up the manual)
207 */
Kurt Garloff9827b782006-02-20 18:27:51 -0800208static struct task_struct *select_bad_process(unsigned long *ppoints)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210 struct task_struct *g, *p;
211 struct task_struct *chosen = NULL;
212 struct timespec uptime;
Kurt Garloff9827b782006-02-20 18:27:51 -0800213 *ppoints = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214
215 do_posix_clock_monotonic_gettime(&uptime);
Paul Jacksona49335c2005-09-06 15:18:09 -0700216 do_each_thread(g, p) {
217 unsigned long points;
Paul Jacksona49335c2005-09-06 15:18:09 -0700218
Oleg Nesterov28324d12006-09-29 02:01:12 -0700219 /*
220 * skip kernel threads and tasks which have already released
221 * their mm.
222 */
Nick Piggin5081dde2006-09-25 23:31:32 -0700223 if (!p->mm)
224 continue;
Oleg Nesterov28324d12006-09-29 02:01:12 -0700225 /* skip the init task */
226 if (is_init(p))
Paul Jacksona49335c2005-09-06 15:18:09 -0700227 continue;
Paul Jacksonef08e3b2005-09-06 15:18:13 -0700228
Paul Jacksona49335c2005-09-06 15:18:09 -0700229 /*
Nick Pigginb78483a2006-09-29 02:01:14 -0700230 * This task already has access to memory reserves and is
231 * being killed. Don't allow any other task access to the
232 * memory reserve.
233 *
234 * Note: this may have a chance of deadlock if it gets
235 * blocked waiting for another task which itself is waiting
236 * for memory. Is there a better alternative?
237 */
238 if (test_tsk_thread_flag(p, TIF_MEMDIE))
239 return ERR_PTR(-1UL);
240
241 /*
Dave Peterson6937a252006-06-23 02:03:13 -0700242 * This is in the process of releasing memory so wait for it
Paul Jacksona49335c2005-09-06 15:18:09 -0700243 * to finish before killing some other task by mistake.
Nick Piggin50ec3bb2006-09-25 23:31:29 -0700244 *
245 * However, if p is the current task, we allow the 'kill' to
246 * go ahead if it is exiting: this will simply set TIF_MEMDIE,
247 * which will allow it to gain access to memory reserves in
248 * the process of exiting and releasing its resources.
Nick Pigginb78483a2006-09-29 02:01:14 -0700249 * Otherwise we could get an easy OOM deadlock.
Paul Jacksona49335c2005-09-06 15:18:09 -0700250 */
Nick Pigginb78483a2006-09-29 02:01:14 -0700251 if (p->flags & PF_EXITING) {
252 if (p != current)
253 return ERR_PTR(-1UL);
254
Oleg Nesterov972c4ea2006-09-29 02:01:12 -0700255 chosen = p;
256 *ppoints = ULONG_MAX;
Nick Piggin50ec3bb2006-09-25 23:31:29 -0700257 }
Oleg Nesterov972c4ea2006-09-29 02:01:12 -0700258
Nick Piggin4a3ede12006-09-25 23:31:30 -0700259 if (p->oomkilladj == OOM_DISABLE)
260 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261
Paul Jacksona49335c2005-09-06 15:18:09 -0700262 points = badness(p, uptime.tv_sec);
Kurt Garloff9827b782006-02-20 18:27:51 -0800263 if (points > *ppoints || !chosen) {
Paul Jacksona49335c2005-09-06 15:18:09 -0700264 chosen = p;
Kurt Garloff9827b782006-02-20 18:27:51 -0800265 *ppoints = points;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 }
Paul Jacksona49335c2005-09-06 15:18:09 -0700267 } while_each_thread(g, p);
Oleg Nesterov972c4ea2006-09-29 02:01:12 -0700268
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 return chosen;
270}
271
272/**
Ram Gupta5a291b982006-09-25 23:31:54 -0700273 * Send SIGKILL to the selected process irrespective of CAP_SYS_RAW_IO
274 * flag though it's unlikely that we select a process with CAP_SYS_RAW_IO
275 * set.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276 */
Nick Pigginf3af38d2006-12-06 20:31:51 -0800277static void __oom_kill_task(struct task_struct *p, int verbose)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278{
Sukadev Bhattiproluf400e192006-09-29 02:00:07 -0700279 if (is_init(p)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 WARN_ON(1);
281 printk(KERN_WARNING "tried to kill init!\n");
282 return;
283 }
284
Oleg Nesterov01017a22006-09-29 02:01:13 -0700285 if (!p->mm) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286 WARN_ON(1);
287 printk(KERN_WARNING "tried to kill an mm-less task!\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 return;
289 }
Nick Piggin50ec3bb2006-09-25 23:31:29 -0700290
Nick Pigginf3af38d2006-12-06 20:31:51 -0800291 if (verbose)
292 printk(KERN_ERR "Killed process %d (%s)\n", p->pid, p->comm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293
294 /*
295 * We give our sacrificial lamb high priority and access to
296 * all the memory it needs. That way it should be able to
297 * exit() and clear out its resources quickly...
298 */
299 p->time_slice = HZ;
300 set_tsk_thread_flag(p, TIF_MEMDIE);
301
302 force_sig(SIGKILL, p);
303}
304
Nick Pigginf3af38d2006-12-06 20:31:51 -0800305static int oom_kill_task(struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306{
Dave Peterson01315922006-04-18 22:20:44 -0700307 struct mm_struct *mm;
Ingo Molnar36c8b582006-07-03 00:25:41 -0700308 struct task_struct *g, *q;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309
Dave Peterson01315922006-04-18 22:20:44 -0700310 mm = p->mm;
311
312 /* WARNING: mm may not be dereferenced since we did not obtain its
313 * value from get_task_mm(p). This is OK since all we need to do is
314 * compare mm to q->mm below.
315 *
316 * Furthermore, even if mm contains a non-NULL value, p->mm may
317 * change to NULL at any time since we do not hold task_lock(p).
318 * However, this is of no concern to us.
319 */
320
Oleg Nesterov01017a22006-09-29 02:01:13 -0700321 if (mm == NULL)
Dave Peterson01315922006-04-18 22:20:44 -0700322 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323
Nick Pigginc33e0fc2006-12-06 20:31:50 -0800324 /*
325 * Don't kill the process if any threads are set to OOM_DISABLE
326 */
327 do_each_thread(g, q) {
Ankita Garg35ae8342007-03-16 13:38:33 -0800328 if (q->mm == mm && q->oomkilladj == OOM_DISABLE)
Nick Pigginc33e0fc2006-12-06 20:31:50 -0800329 return 1;
330 } while_each_thread(g, q);
331
Nick Pigginf3af38d2006-12-06 20:31:51 -0800332 __oom_kill_task(p, 1);
Nick Pigginc33e0fc2006-12-06 20:31:50 -0800333
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 /*
335 * kill all processes that share the ->mm (i.e. all threads),
Nick Pigginf2a2a712006-12-06 20:31:52 -0800336 * but are in a different thread group. Don't let them have access
337 * to memory reserves though, otherwise we might deplete all memory.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 */
Nick Pigginc33e0fc2006-12-06 20:31:50 -0800339 do_each_thread(g, q) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340 if (q->mm == mm && q->tgid != p->tgid)
David Rientjes650a7c92007-04-23 21:36:13 -0700341 force_sig(SIGKILL, q);
Nick Pigginc33e0fc2006-12-06 20:31:50 -0800342 } while_each_thread(g, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343
Dave Peterson01315922006-04-18 22:20:44 -0700344 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345}
346
Dave Peterson01315922006-04-18 22:20:44 -0700347static int oom_kill_process(struct task_struct *p, unsigned long points,
348 const char *message)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 struct task_struct *c;
351 struct list_head *tsk;
352
Nick Piggin50ec3bb2006-09-25 23:31:29 -0700353 /*
354 * If the task is already exiting, don't alarm the sysadmin or kill
355 * its children or threads, just set TIF_MEMDIE so it can die quickly
356 */
357 if (p->flags & PF_EXITING) {
Nick Pigginf3af38d2006-12-06 20:31:51 -0800358 __oom_kill_task(p, 0);
Nick Piggin50ec3bb2006-09-25 23:31:29 -0700359 return 0;
360 }
361
Nick Pigginf3af38d2006-12-06 20:31:51 -0800362 printk(KERN_ERR "%s: kill process %d (%s) score %li or a child\n",
363 message, p->pid, p->comm, points);
364
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 /* Try to kill a child first */
366 list_for_each(tsk, &p->children) {
367 c = list_entry(tsk, struct task_struct, sibling);
368 if (c->mm == p->mm)
369 continue;
Nick Pigginf3af38d2006-12-06 20:31:51 -0800370 if (!oom_kill_task(c))
Dave Peterson01315922006-04-18 22:20:44 -0700371 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 }
Nick Pigginf3af38d2006-12-06 20:31:51 -0800373 return oom_kill_task(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374}
375
Martin Schwidefsky8bc719d2006-09-25 23:31:20 -0700376static BLOCKING_NOTIFIER_HEAD(oom_notify_list);
377
378int register_oom_notifier(struct notifier_block *nb)
379{
380 return blocking_notifier_chain_register(&oom_notify_list, nb);
381}
382EXPORT_SYMBOL_GPL(register_oom_notifier);
383
384int unregister_oom_notifier(struct notifier_block *nb)
385{
386 return blocking_notifier_chain_unregister(&oom_notify_list, nb);
387}
388EXPORT_SYMBOL_GPL(unregister_oom_notifier);
389
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390/**
Dave Peterson6937a252006-06-23 02:03:13 -0700391 * out_of_memory - kill the "best" process when we run out of memory
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 *
393 * If we run out of memory, we have the choice between either
394 * killing a random task (bad), letting the system crash (worse)
395 * OR try to be smart about which process to kill. Note that we
396 * don't have to be perfect here, we just have to be good.
397 */
Christoph Lameter9b0f8b02006-02-20 18:27:52 -0800398void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399{
Ingo Molnar36c8b582006-07-03 00:25:41 -0700400 struct task_struct *p;
Andrew Mortond6713e02006-02-28 16:59:19 -0800401 unsigned long points = 0;
Martin Schwidefsky8bc719d2006-09-25 23:31:20 -0700402 unsigned long freed = 0;
David Rientjes2b45ab32007-05-06 14:50:00 -0700403 int constraint;
Martin Schwidefsky8bc719d2006-09-25 23:31:20 -0700404
405 blocking_notifier_call_chain(&oom_notify_list, 0, &freed);
406 if (freed > 0)
407 /* Got some memory back in the last second. */
408 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409
Anton Blanchard42639262005-07-07 17:56:06 -0700410 if (printk_ratelimit()) {
Nick Pigginb72f1602006-09-25 23:31:32 -0700411 printk(KERN_WARNING "%s invoked oom-killer: "
412 "gfp_mask=0x%x, order=%d, oomkilladj=%d\n",
413 current->comm, gfp_mask, order, current->oomkilladj);
Andrew Mortonb958f7d2006-02-01 03:05:51 -0800414 dump_stack();
Anton Blanchard42639262005-07-07 17:56:06 -0700415 show_mem();
416 }
Janet Morgan578c2fd2005-06-21 17:14:56 -0700417
Yasunori Goto2b744c02007-05-06 14:49:59 -0700418 if (sysctl_panic_on_oom == 2)
419 panic("out of memory. Compulsory panic_on_oom is selected.\n");
420
Christoph Lameter9b0f8b02006-02-20 18:27:52 -0800421 /*
422 * Check if there were limitations on the allocation (only relevant for
423 * NUMA) that may require different handling.
424 */
David Rientjes2b45ab32007-05-06 14:50:00 -0700425 constraint = constrained_alloc(zonelist, gfp_mask);
426 cpuset_lock();
427 read_lock(&tasklist_lock);
428
429 switch (constraint) {
Christoph Lameter9b0f8b02006-02-20 18:27:52 -0800430 case CONSTRAINT_MEMORY_POLICY:
Dave Peterson01315922006-04-18 22:20:44 -0700431 oom_kill_process(current, points,
Christoph Lameter9b0f8b02006-02-20 18:27:52 -0800432 "No available memory (MPOL_BIND)");
433 break;
434
435 case CONSTRAINT_CPUSET:
Dave Peterson01315922006-04-18 22:20:44 -0700436 oom_kill_process(current, points,
Christoph Lameter9b0f8b02006-02-20 18:27:52 -0800437 "No available memory in cpuset");
438 break;
439
440 case CONSTRAINT_NONE:
KAMEZAWA Hiroyukifadd8fb2006-06-23 02:03:13 -0700441 if (sysctl_panic_on_oom)
442 panic("out of memory. panic_on_oom is selected\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443retry:
Christoph Lameter9b0f8b02006-02-20 18:27:52 -0800444 /*
445 * Rambo mode: Shoot down a process and hope it solves whatever
446 * issues we may have.
447 */
448 p = select_bad_process(&points);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449
Christoph Lameter9b0f8b02006-02-20 18:27:52 -0800450 if (PTR_ERR(p) == -1UL)
451 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452
Christoph Lameter9b0f8b02006-02-20 18:27:52 -0800453 /* Found nothing?!?! Either we hang forever, or we panic. */
454 if (!p) {
455 read_unlock(&tasklist_lock);
456 cpuset_unlock();
457 panic("Out of memory and no killable processes...\n");
458 }
459
Dave Peterson01315922006-04-18 22:20:44 -0700460 if (oom_kill_process(p, points, "Out of memory"))
Christoph Lameter9b0f8b02006-02-20 18:27:52 -0800461 goto retry;
462
463 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 }
465
Christoph Lameter9b0f8b02006-02-20 18:27:52 -0800466out:
Andrew Morton140ffce2006-03-02 02:54:28 -0800467 read_unlock(&tasklist_lock);
Paul Jackson505970b2006-01-14 13:21:06 -0800468 cpuset_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469
470 /*
471 * Give "p" a good chance of killing itself before we
Kirill Korotaev2f659f42006-01-08 01:01:05 -0800472 * retry to allocate memory unless "p" is current
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 */
Kirill Korotaev2f659f42006-01-08 01:01:05 -0800474 if (!test_thread_flag(TIF_MEMDIE))
Andrew Morton140ffce2006-03-02 02:54:28 -0800475 schedule_timeout_uninterruptible(1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476}