Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 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. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Alexey Dobriyan | 8ac773b | 2006-10-19 23:28:32 -0700 | [diff] [blame] | 18 | #include <linux/oom.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | #include <linux/mm.h> |
Alexey Dobriyan | 4e950f6 | 2007-07-30 02:36:13 +0400 | [diff] [blame] | 20 | #include <linux/err.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | #include <linux/sched.h> |
| 22 | #include <linux/swap.h> |
| 23 | #include <linux/timex.h> |
| 24 | #include <linux/jiffies.h> |
Paul Jackson | ef08e3b | 2005-09-06 15:18:13 -0700 | [diff] [blame] | 25 | #include <linux/cpuset.h> |
Martin Schwidefsky | 8bc719d | 2006-09-25 23:31:20 -0700 | [diff] [blame] | 26 | #include <linux/module.h> |
| 27 | #include <linux/notifier.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | |
KAMEZAWA Hiroyuki | fadd8fb | 2006-06-23 02:03:13 -0700 | [diff] [blame] | 29 | int sysctl_panic_on_oom; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | /* #define DEBUG */ |
| 31 | |
| 32 | /** |
Dave Peterson | 6937a25 | 2006-06-23 02:03:13 -0700 | [diff] [blame] | 33 | * badness - calculate a numeric value for how bad this task has been |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | * @p: task struct of which task we should calculate |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 35 | * @uptime: current uptime in seconds |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | * |
| 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 | |
| 51 | unsigned long badness(struct task_struct *p, unsigned long uptime) |
| 52 | { |
| 53 | unsigned long points, cpu_time, run_time, s; |
Andrew Morton | 97c2c9b | 2006-04-18 22:20:38 -0700 | [diff] [blame] | 54 | struct mm_struct *mm; |
| 55 | struct task_struct *child; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 56 | |
Andrew Morton | 97c2c9b | 2006-04-18 22:20:38 -0700 | [diff] [blame] | 57 | task_lock(p); |
| 58 | mm = p->mm; |
| 59 | if (!mm) { |
| 60 | task_unlock(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 61 | return 0; |
Andrew Morton | 97c2c9b | 2006-04-18 22:20:38 -0700 | [diff] [blame] | 62 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | |
| 64 | /* |
| 65 | * The memory size of the process is the basis for the badness. |
| 66 | */ |
Andrew Morton | 97c2c9b | 2006-04-18 22:20:38 -0700 | [diff] [blame] | 67 | points = mm->total_vm; |
| 68 | |
| 69 | /* |
| 70 | * After this unlock we can no longer dereference local variable `mm' |
| 71 | */ |
| 72 | task_unlock(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 73 | |
| 74 | /* |
Hugh Dickins | 7ba3485 | 2007-01-05 16:37:03 -0800 | [diff] [blame] | 75 | * 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 Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | * Processes which fork a lot of child processes are likely |
Kurt Garloff | 9827b78 | 2006-02-20 18:27:51 -0800 | [diff] [blame] | 82 | * a good choice. We add half the vmsize of the children if they |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 83 | * have an own mm. This prevents forking servers to flood the |
Kurt Garloff | 9827b78 | 2006-02-20 18:27:51 -0800 | [diff] [blame] | 84 | * 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 Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | */ |
Andrew Morton | 97c2c9b | 2006-04-18 22:20:38 -0700 | [diff] [blame] | 88 | 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 Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 93 | } |
| 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 Piggin | 7887a3d | 2006-09-25 23:31:29 -0700 | [diff] [blame] | 140 | * 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 Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 148 | * Adjust the score by oomkilladj. |
| 149 | */ |
| 150 | if (p->oomkilladj) { |
Joshua N Pritikin | 9a82782 | 2007-05-06 14:49:07 -0700 | [diff] [blame] | 151 | if (p->oomkilladj > 0) { |
| 152 | if (!points) |
| 153 | points = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 154 | points <<= p->oomkilladj; |
Joshua N Pritikin | 9a82782 | 2007-05-06 14:49:07 -0700 | [diff] [blame] | 155 | } else |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 156 | points >>= -(p->oomkilladj); |
| 157 | } |
| 158 | |
| 159 | #ifdef DEBUG |
David Rientjes | a5e58a6 | 2007-07-31 00:37:32 -0700 | [diff] [blame] | 160 | printk(KERN_DEBUG "OOMkill: task %d (%s) got %lu points\n", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | p->pid, p->comm, points); |
| 162 | #endif |
| 163 | return points; |
| 164 | } |
| 165 | |
| 166 | /* |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 167 | * 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 | */ |
| 176 | static inline int constrained_alloc(struct zonelist *zonelist, gfp_t gfp_mask) |
| 177 | { |
| 178 | #ifdef CONFIG_NUMA |
| 179 | struct zone **z; |
Christoph Lameter | ee31af5 | 2007-10-16 01:25:30 -0700 | [diff] [blame] | 180 | nodemask_t nodes = node_states[N_HIGH_MEMORY]; |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 181 | |
| 182 | for (z = zonelist->zones; *z; z++) |
Paul Jackson | 02a0e53 | 2006-12-13 00:34:25 -0800 | [diff] [blame] | 183 | if (cpuset_zone_allowed_softwall(*z, gfp_mask)) |
Christoph Lameter | 89fa302 | 2006-09-25 23:31:55 -0700 | [diff] [blame] | 184 | node_clear(zone_to_nid(*z), nodes); |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 185 | else |
| 186 | return CONSTRAINT_CPUSET; |
| 187 | |
| 188 | if (!nodes_empty(nodes)) |
| 189 | return CONSTRAINT_MEMORY_POLICY; |
| 190 | #endif |
| 191 | |
| 192 | return CONSTRAINT_NONE; |
| 193 | } |
| 194 | |
| 195 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 196 | * Simple selection loop. We chose the process with the highest |
| 197 | * number of 'points'. We expect the caller will lock the tasklist. |
| 198 | * |
| 199 | * (not docbooked, we don't want this one cluttering up the manual) |
| 200 | */ |
Kurt Garloff | 9827b78 | 2006-02-20 18:27:51 -0800 | [diff] [blame] | 201 | static struct task_struct *select_bad_process(unsigned long *ppoints) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 203 | struct task_struct *g, *p; |
| 204 | struct task_struct *chosen = NULL; |
| 205 | struct timespec uptime; |
Kurt Garloff | 9827b78 | 2006-02-20 18:27:51 -0800 | [diff] [blame] | 206 | *ppoints = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 207 | |
| 208 | do_posix_clock_monotonic_gettime(&uptime); |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 209 | do_each_thread(g, p) { |
| 210 | unsigned long points; |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 211 | |
Oleg Nesterov | 28324d1 | 2006-09-29 02:01:12 -0700 | [diff] [blame] | 212 | /* |
| 213 | * skip kernel threads and tasks which have already released |
| 214 | * their mm. |
| 215 | */ |
Nick Piggin | 5081dde | 2006-09-25 23:31:32 -0700 | [diff] [blame] | 216 | if (!p->mm) |
| 217 | continue; |
Oleg Nesterov | 28324d1 | 2006-09-29 02:01:12 -0700 | [diff] [blame] | 218 | /* skip the init task */ |
| 219 | if (is_init(p)) |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 220 | continue; |
Paul Jackson | ef08e3b | 2005-09-06 15:18:13 -0700 | [diff] [blame] | 221 | |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 222 | /* |
Nick Piggin | b78483a | 2006-09-29 02:01:14 -0700 | [diff] [blame] | 223 | * This task already has access to memory reserves and is |
| 224 | * being killed. Don't allow any other task access to the |
| 225 | * memory reserve. |
| 226 | * |
| 227 | * Note: this may have a chance of deadlock if it gets |
| 228 | * blocked waiting for another task which itself is waiting |
| 229 | * for memory. Is there a better alternative? |
| 230 | */ |
| 231 | if (test_tsk_thread_flag(p, TIF_MEMDIE)) |
| 232 | return ERR_PTR(-1UL); |
| 233 | |
| 234 | /* |
Dave Peterson | 6937a25 | 2006-06-23 02:03:13 -0700 | [diff] [blame] | 235 | * This is in the process of releasing memory so wait for it |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 236 | * to finish before killing some other task by mistake. |
Nick Piggin | 50ec3bb | 2006-09-25 23:31:29 -0700 | [diff] [blame] | 237 | * |
| 238 | * However, if p is the current task, we allow the 'kill' to |
| 239 | * go ahead if it is exiting: this will simply set TIF_MEMDIE, |
| 240 | * which will allow it to gain access to memory reserves in |
| 241 | * the process of exiting and releasing its resources. |
Nick Piggin | b78483a | 2006-09-29 02:01:14 -0700 | [diff] [blame] | 242 | * Otherwise we could get an easy OOM deadlock. |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 243 | */ |
Nick Piggin | b78483a | 2006-09-29 02:01:14 -0700 | [diff] [blame] | 244 | if (p->flags & PF_EXITING) { |
| 245 | if (p != current) |
| 246 | return ERR_PTR(-1UL); |
| 247 | |
Oleg Nesterov | 972c4ea | 2006-09-29 02:01:12 -0700 | [diff] [blame] | 248 | chosen = p; |
| 249 | *ppoints = ULONG_MAX; |
Nick Piggin | 50ec3bb | 2006-09-25 23:31:29 -0700 | [diff] [blame] | 250 | } |
Oleg Nesterov | 972c4ea | 2006-09-29 02:01:12 -0700 | [diff] [blame] | 251 | |
Nick Piggin | 4a3ede1 | 2006-09-25 23:31:30 -0700 | [diff] [blame] | 252 | if (p->oomkilladj == OOM_DISABLE) |
| 253 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 254 | |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 255 | points = badness(p, uptime.tv_sec); |
Kurt Garloff | 9827b78 | 2006-02-20 18:27:51 -0800 | [diff] [blame] | 256 | if (points > *ppoints || !chosen) { |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 257 | chosen = p; |
Kurt Garloff | 9827b78 | 2006-02-20 18:27:51 -0800 | [diff] [blame] | 258 | *ppoints = points; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 259 | } |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 260 | } while_each_thread(g, p); |
Oleg Nesterov | 972c4ea | 2006-09-29 02:01:12 -0700 | [diff] [blame] | 261 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 262 | return chosen; |
| 263 | } |
| 264 | |
| 265 | /** |
Ram Gupta | 5a291b98 | 2006-09-25 23:31:54 -0700 | [diff] [blame] | 266 | * Send SIGKILL to the selected process irrespective of CAP_SYS_RAW_IO |
| 267 | * flag though it's unlikely that we select a process with CAP_SYS_RAW_IO |
| 268 | * set. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 269 | */ |
Nick Piggin | f3af38d | 2006-12-06 20:31:51 -0800 | [diff] [blame] | 270 | static void __oom_kill_task(struct task_struct *p, int verbose) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 271 | { |
Sukadev Bhattiprolu | f400e19 | 2006-09-29 02:00:07 -0700 | [diff] [blame] | 272 | if (is_init(p)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 273 | WARN_ON(1); |
| 274 | printk(KERN_WARNING "tried to kill init!\n"); |
| 275 | return; |
| 276 | } |
| 277 | |
Oleg Nesterov | 01017a2 | 2006-09-29 02:01:13 -0700 | [diff] [blame] | 278 | if (!p->mm) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 279 | WARN_ON(1); |
| 280 | printk(KERN_WARNING "tried to kill an mm-less task!\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 281 | return; |
| 282 | } |
Nick Piggin | 50ec3bb | 2006-09-25 23:31:29 -0700 | [diff] [blame] | 283 | |
Nick Piggin | f3af38d | 2006-12-06 20:31:51 -0800 | [diff] [blame] | 284 | if (verbose) |
| 285 | printk(KERN_ERR "Killed process %d (%s)\n", p->pid, p->comm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 286 | |
| 287 | /* |
| 288 | * We give our sacrificial lamb high priority and access to |
| 289 | * all the memory it needs. That way it should be able to |
| 290 | * exit() and clear out its resources quickly... |
| 291 | */ |
| 292 | p->time_slice = HZ; |
| 293 | set_tsk_thread_flag(p, TIF_MEMDIE); |
| 294 | |
| 295 | force_sig(SIGKILL, p); |
| 296 | } |
| 297 | |
Nick Piggin | f3af38d | 2006-12-06 20:31:51 -0800 | [diff] [blame] | 298 | static int oom_kill_task(struct task_struct *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 299 | { |
Dave Peterson | 0131592 | 2006-04-18 22:20:44 -0700 | [diff] [blame] | 300 | struct mm_struct *mm; |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 301 | struct task_struct *g, *q; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 302 | |
Dave Peterson | 0131592 | 2006-04-18 22:20:44 -0700 | [diff] [blame] | 303 | mm = p->mm; |
| 304 | |
| 305 | /* WARNING: mm may not be dereferenced since we did not obtain its |
| 306 | * value from get_task_mm(p). This is OK since all we need to do is |
| 307 | * compare mm to q->mm below. |
| 308 | * |
| 309 | * Furthermore, even if mm contains a non-NULL value, p->mm may |
| 310 | * change to NULL at any time since we do not hold task_lock(p). |
| 311 | * However, this is of no concern to us. |
| 312 | */ |
| 313 | |
Oleg Nesterov | 01017a2 | 2006-09-29 02:01:13 -0700 | [diff] [blame] | 314 | if (mm == NULL) |
Dave Peterson | 0131592 | 2006-04-18 22:20:44 -0700 | [diff] [blame] | 315 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 316 | |
Nick Piggin | c33e0fc | 2006-12-06 20:31:50 -0800 | [diff] [blame] | 317 | /* |
| 318 | * Don't kill the process if any threads are set to OOM_DISABLE |
| 319 | */ |
| 320 | do_each_thread(g, q) { |
Ankita Garg | 35ae834 | 2007-03-16 13:38:33 -0800 | [diff] [blame] | 321 | if (q->mm == mm && q->oomkilladj == OOM_DISABLE) |
Nick Piggin | c33e0fc | 2006-12-06 20:31:50 -0800 | [diff] [blame] | 322 | return 1; |
| 323 | } while_each_thread(g, q); |
| 324 | |
Nick Piggin | f3af38d | 2006-12-06 20:31:51 -0800 | [diff] [blame] | 325 | __oom_kill_task(p, 1); |
Nick Piggin | c33e0fc | 2006-12-06 20:31:50 -0800 | [diff] [blame] | 326 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 327 | /* |
| 328 | * kill all processes that share the ->mm (i.e. all threads), |
Nick Piggin | f2a2a71 | 2006-12-06 20:31:52 -0800 | [diff] [blame] | 329 | * but are in a different thread group. Don't let them have access |
| 330 | * to memory reserves though, otherwise we might deplete all memory. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 331 | */ |
Nick Piggin | c33e0fc | 2006-12-06 20:31:50 -0800 | [diff] [blame] | 332 | do_each_thread(g, q) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 333 | if (q->mm == mm && q->tgid != p->tgid) |
David Rientjes | 650a7c9 | 2007-04-23 21:36:13 -0700 | [diff] [blame] | 334 | force_sig(SIGKILL, q); |
Nick Piggin | c33e0fc | 2006-12-06 20:31:50 -0800 | [diff] [blame] | 335 | } while_each_thread(g, q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | |
Dave Peterson | 0131592 | 2006-04-18 22:20:44 -0700 | [diff] [blame] | 337 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 338 | } |
| 339 | |
Dave Peterson | 0131592 | 2006-04-18 22:20:44 -0700 | [diff] [blame] | 340 | static int oom_kill_process(struct task_struct *p, unsigned long points, |
| 341 | const char *message) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 342 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 343 | struct task_struct *c; |
| 344 | struct list_head *tsk; |
| 345 | |
Nick Piggin | 50ec3bb | 2006-09-25 23:31:29 -0700 | [diff] [blame] | 346 | /* |
| 347 | * If the task is already exiting, don't alarm the sysadmin or kill |
| 348 | * its children or threads, just set TIF_MEMDIE so it can die quickly |
| 349 | */ |
| 350 | if (p->flags & PF_EXITING) { |
Nick Piggin | f3af38d | 2006-12-06 20:31:51 -0800 | [diff] [blame] | 351 | __oom_kill_task(p, 0); |
Nick Piggin | 50ec3bb | 2006-09-25 23:31:29 -0700 | [diff] [blame] | 352 | return 0; |
| 353 | } |
| 354 | |
Nick Piggin | f3af38d | 2006-12-06 20:31:51 -0800 | [diff] [blame] | 355 | printk(KERN_ERR "%s: kill process %d (%s) score %li or a child\n", |
| 356 | message, p->pid, p->comm, points); |
| 357 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 358 | /* Try to kill a child first */ |
| 359 | list_for_each(tsk, &p->children) { |
| 360 | c = list_entry(tsk, struct task_struct, sibling); |
| 361 | if (c->mm == p->mm) |
| 362 | continue; |
Nick Piggin | f3af38d | 2006-12-06 20:31:51 -0800 | [diff] [blame] | 363 | if (!oom_kill_task(c)) |
Dave Peterson | 0131592 | 2006-04-18 22:20:44 -0700 | [diff] [blame] | 364 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 365 | } |
Nick Piggin | f3af38d | 2006-12-06 20:31:51 -0800 | [diff] [blame] | 366 | return oom_kill_task(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 367 | } |
| 368 | |
Martin Schwidefsky | 8bc719d | 2006-09-25 23:31:20 -0700 | [diff] [blame] | 369 | static BLOCKING_NOTIFIER_HEAD(oom_notify_list); |
| 370 | |
| 371 | int register_oom_notifier(struct notifier_block *nb) |
| 372 | { |
| 373 | return blocking_notifier_chain_register(&oom_notify_list, nb); |
| 374 | } |
| 375 | EXPORT_SYMBOL_GPL(register_oom_notifier); |
| 376 | |
| 377 | int unregister_oom_notifier(struct notifier_block *nb) |
| 378 | { |
| 379 | return blocking_notifier_chain_unregister(&oom_notify_list, nb); |
| 380 | } |
| 381 | EXPORT_SYMBOL_GPL(unregister_oom_notifier); |
| 382 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 383 | /** |
Dave Peterson | 6937a25 | 2006-06-23 02:03:13 -0700 | [diff] [blame] | 384 | * out_of_memory - kill the "best" process when we run out of memory |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 385 | * |
| 386 | * If we run out of memory, we have the choice between either |
| 387 | * killing a random task (bad), letting the system crash (worse) |
| 388 | * OR try to be smart about which process to kill. Note that we |
| 389 | * don't have to be perfect here, we just have to be good. |
| 390 | */ |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 391 | void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | { |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 393 | struct task_struct *p; |
Andrew Morton | d6713e0 | 2006-02-28 16:59:19 -0800 | [diff] [blame] | 394 | unsigned long points = 0; |
Martin Schwidefsky | 8bc719d | 2006-09-25 23:31:20 -0700 | [diff] [blame] | 395 | unsigned long freed = 0; |
David Rientjes | 2b45ab3 | 2007-05-06 14:50:00 -0700 | [diff] [blame] | 396 | int constraint; |
Martin Schwidefsky | 8bc719d | 2006-09-25 23:31:20 -0700 | [diff] [blame] | 397 | |
| 398 | blocking_notifier_call_chain(&oom_notify_list, 0, &freed); |
| 399 | if (freed > 0) |
| 400 | /* Got some memory back in the last second. */ |
| 401 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 402 | |
Anton Blanchard | 4263926 | 2005-07-07 17:56:06 -0700 | [diff] [blame] | 403 | if (printk_ratelimit()) { |
Nick Piggin | b72f160 | 2006-09-25 23:31:32 -0700 | [diff] [blame] | 404 | printk(KERN_WARNING "%s invoked oom-killer: " |
| 405 | "gfp_mask=0x%x, order=%d, oomkilladj=%d\n", |
| 406 | current->comm, gfp_mask, order, current->oomkilladj); |
Andrew Morton | b958f7d | 2006-02-01 03:05:51 -0800 | [diff] [blame] | 407 | dump_stack(); |
Anton Blanchard | 4263926 | 2005-07-07 17:56:06 -0700 | [diff] [blame] | 408 | show_mem(); |
| 409 | } |
Janet Morgan | 578c2fd | 2005-06-21 17:14:56 -0700 | [diff] [blame] | 410 | |
Yasunori Goto | 2b744c0 | 2007-05-06 14:49:59 -0700 | [diff] [blame] | 411 | if (sysctl_panic_on_oom == 2) |
| 412 | panic("out of memory. Compulsory panic_on_oom is selected.\n"); |
| 413 | |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 414 | /* |
| 415 | * Check if there were limitations on the allocation (only relevant for |
| 416 | * NUMA) that may require different handling. |
| 417 | */ |
David Rientjes | 2b45ab3 | 2007-05-06 14:50:00 -0700 | [diff] [blame] | 418 | constraint = constrained_alloc(zonelist, gfp_mask); |
| 419 | cpuset_lock(); |
| 420 | read_lock(&tasklist_lock); |
| 421 | |
| 422 | switch (constraint) { |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 423 | case CONSTRAINT_MEMORY_POLICY: |
Dave Peterson | 0131592 | 2006-04-18 22:20:44 -0700 | [diff] [blame] | 424 | oom_kill_process(current, points, |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 425 | "No available memory (MPOL_BIND)"); |
| 426 | break; |
| 427 | |
| 428 | case CONSTRAINT_CPUSET: |
Dave Peterson | 0131592 | 2006-04-18 22:20:44 -0700 | [diff] [blame] | 429 | oom_kill_process(current, points, |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 430 | "No available memory in cpuset"); |
| 431 | break; |
| 432 | |
| 433 | case CONSTRAINT_NONE: |
KAMEZAWA Hiroyuki | fadd8fb | 2006-06-23 02:03:13 -0700 | [diff] [blame] | 434 | if (sysctl_panic_on_oom) |
| 435 | panic("out of memory. panic_on_oom is selected\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 436 | retry: |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 437 | /* |
| 438 | * Rambo mode: Shoot down a process and hope it solves whatever |
| 439 | * issues we may have. |
| 440 | */ |
| 441 | p = select_bad_process(&points); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 442 | |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 443 | if (PTR_ERR(p) == -1UL) |
| 444 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 445 | |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 446 | /* Found nothing?!?! Either we hang forever, or we panic. */ |
| 447 | if (!p) { |
| 448 | read_unlock(&tasklist_lock); |
| 449 | cpuset_unlock(); |
| 450 | panic("Out of memory and no killable processes...\n"); |
| 451 | } |
| 452 | |
Dave Peterson | 0131592 | 2006-04-18 22:20:44 -0700 | [diff] [blame] | 453 | if (oom_kill_process(p, points, "Out of memory")) |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 454 | goto retry; |
| 455 | |
| 456 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 457 | } |
| 458 | |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 459 | out: |
Andrew Morton | 140ffce | 2006-03-02 02:54:28 -0800 | [diff] [blame] | 460 | read_unlock(&tasklist_lock); |
Paul Jackson | 505970b | 2006-01-14 13:21:06 -0800 | [diff] [blame] | 461 | cpuset_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 462 | |
| 463 | /* |
| 464 | * Give "p" a good chance of killing itself before we |
Kirill Korotaev | 2f659f4 | 2006-01-08 01:01:05 -0800 | [diff] [blame] | 465 | * retry to allocate memory unless "p" is current |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 466 | */ |
Kirill Korotaev | 2f659f4 | 2006-01-08 01:01:05 -0800 | [diff] [blame] | 467 | if (!test_thread_flag(TIF_MEMDIE)) |
Andrew Morton | 140ffce | 2006-03-02 02:54:28 -0800 | [diff] [blame] | 468 | schedule_timeout_uninterruptible(1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 469 | } |