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; |
David Rientjes | fe071d7 | 2007-10-16 23:25:56 -0700 | [diff] [blame] | 30 | int sysctl_oom_kill_allocating_task; |
David Rientjes | 098d7f1 | 2007-10-16 23:25:55 -0700 | [diff] [blame] | 31 | static DEFINE_MUTEX(zone_scan_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | /* #define DEBUG */ |
| 33 | |
| 34 | /** |
Dave Peterson | 6937a25 | 2006-06-23 02:03:13 -0700 | [diff] [blame] | 35 | * badness - calculate a numeric value for how bad this task has been |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | * @p: task struct of which task we should calculate |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 37 | * @uptime: current uptime in seconds |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | * |
| 39 | * The formula used is relatively simple and documented inline in the |
| 40 | * function. The main rationale is that we want to select a good task |
| 41 | * to kill when we run out of memory. |
| 42 | * |
| 43 | * Good in this context means that: |
| 44 | * 1) we lose the minimum amount of work done |
| 45 | * 2) we recover a large amount of memory |
| 46 | * 3) we don't kill anything innocent of eating tons of memory |
| 47 | * 4) we want to kill the minimum amount of processes (one) |
| 48 | * 5) we try to kill the process the user expects us to kill, this |
| 49 | * algorithm has been meticulously tuned to meet the principle |
| 50 | * of least surprise ... (be careful when you change it) |
| 51 | */ |
| 52 | |
| 53 | unsigned long badness(struct task_struct *p, unsigned long uptime) |
| 54 | { |
| 55 | unsigned long points, cpu_time, run_time, s; |
Andrew Morton | 97c2c9b | 2006-04-18 22:20:38 -0700 | [diff] [blame] | 56 | struct mm_struct *mm; |
| 57 | struct task_struct *child; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 58 | |
Andrew Morton | 97c2c9b | 2006-04-18 22:20:38 -0700 | [diff] [blame] | 59 | task_lock(p); |
| 60 | mm = p->mm; |
| 61 | if (!mm) { |
| 62 | task_unlock(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | return 0; |
Andrew Morton | 97c2c9b | 2006-04-18 22:20:38 -0700 | [diff] [blame] | 64 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 65 | |
| 66 | /* |
| 67 | * The memory size of the process is the basis for the badness. |
| 68 | */ |
Andrew Morton | 97c2c9b | 2006-04-18 22:20:38 -0700 | [diff] [blame] | 69 | points = mm->total_vm; |
| 70 | |
| 71 | /* |
| 72 | * After this unlock we can no longer dereference local variable `mm' |
| 73 | */ |
| 74 | task_unlock(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 75 | |
| 76 | /* |
Hugh Dickins | 7ba3485 | 2007-01-05 16:37:03 -0800 | [diff] [blame] | 77 | * swapoff can easily use up all memory, so kill those first. |
| 78 | */ |
| 79 | if (p->flags & PF_SWAPOFF) |
| 80 | return ULONG_MAX; |
| 81 | |
| 82 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 83 | * Processes which fork a lot of child processes are likely |
Kurt Garloff | 9827b78 | 2006-02-20 18:27:51 -0800 | [diff] [blame] | 84 | * 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] | 85 | * have an own mm. This prevents forking servers to flood the |
Kurt Garloff | 9827b78 | 2006-02-20 18:27:51 -0800 | [diff] [blame] | 86 | * machine with an endless amount of children. In case a single |
| 87 | * child is eating the vast majority of memory, adding only half |
| 88 | * to the parents will make the child our kill candidate of choice. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 89 | */ |
Andrew Morton | 97c2c9b | 2006-04-18 22:20:38 -0700 | [diff] [blame] | 90 | list_for_each_entry(child, &p->children, sibling) { |
| 91 | task_lock(child); |
| 92 | if (child->mm != mm && child->mm) |
| 93 | points += child->mm->total_vm/2 + 1; |
| 94 | task_unlock(child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 95 | } |
| 96 | |
| 97 | /* |
| 98 | * CPU time is in tens of seconds and run time is in thousands |
| 99 | * of seconds. There is no particular reason for this other than |
| 100 | * that it turned out to work very well in practice. |
| 101 | */ |
| 102 | cpu_time = (cputime_to_jiffies(p->utime) + cputime_to_jiffies(p->stime)) |
| 103 | >> (SHIFT_HZ + 3); |
| 104 | |
| 105 | if (uptime >= p->start_time.tv_sec) |
| 106 | run_time = (uptime - p->start_time.tv_sec) >> 10; |
| 107 | else |
| 108 | run_time = 0; |
| 109 | |
| 110 | s = int_sqrt(cpu_time); |
| 111 | if (s) |
| 112 | points /= s; |
| 113 | s = int_sqrt(int_sqrt(run_time)); |
| 114 | if (s) |
| 115 | points /= s; |
| 116 | |
| 117 | /* |
| 118 | * Niced processes are most likely less important, so double |
| 119 | * their badness points. |
| 120 | */ |
| 121 | if (task_nice(p) > 0) |
| 122 | points *= 2; |
| 123 | |
| 124 | /* |
| 125 | * Superuser processes are usually more important, so we make it |
| 126 | * less likely that we kill those. |
| 127 | */ |
| 128 | if (cap_t(p->cap_effective) & CAP_TO_MASK(CAP_SYS_ADMIN) || |
| 129 | p->uid == 0 || p->euid == 0) |
| 130 | points /= 4; |
| 131 | |
| 132 | /* |
| 133 | * We don't want to kill a process with direct hardware access. |
| 134 | * Not only could that mess up the hardware, but usually users |
| 135 | * tend to only have this flag set on applications they think |
| 136 | * of as important. |
| 137 | */ |
| 138 | if (cap_t(p->cap_effective) & CAP_TO_MASK(CAP_SYS_RAWIO)) |
| 139 | points /= 4; |
| 140 | |
| 141 | /* |
Nick Piggin | 7887a3d | 2006-09-25 23:31:29 -0700 | [diff] [blame] | 142 | * If p's nodes don't overlap ours, it may still help to kill p |
| 143 | * because p may have allocated or otherwise mapped memory on |
| 144 | * this node before. However it will be less likely. |
| 145 | */ |
| 146 | if (!cpuset_excl_nodes_overlap(p)) |
| 147 | points /= 8; |
| 148 | |
| 149 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 150 | * Adjust the score by oomkilladj. |
| 151 | */ |
| 152 | if (p->oomkilladj) { |
Joshua N Pritikin | 9a82782 | 2007-05-06 14:49:07 -0700 | [diff] [blame] | 153 | if (p->oomkilladj > 0) { |
| 154 | if (!points) |
| 155 | points = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 156 | points <<= p->oomkilladj; |
Joshua N Pritikin | 9a82782 | 2007-05-06 14:49:07 -0700 | [diff] [blame] | 157 | } else |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | points >>= -(p->oomkilladj); |
| 159 | } |
| 160 | |
| 161 | #ifdef DEBUG |
David Rientjes | a5e58a6 | 2007-07-31 00:37:32 -0700 | [diff] [blame] | 162 | printk(KERN_DEBUG "OOMkill: task %d (%s) got %lu points\n", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 163 | p->pid, p->comm, points); |
| 164 | #endif |
| 165 | return points; |
| 166 | } |
| 167 | |
| 168 | /* |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 169 | * Determine the type of allocation constraint. |
| 170 | */ |
David Rientjes | 70e24bd | 2007-10-16 23:25:53 -0700 | [diff] [blame] | 171 | static inline enum oom_constraint constrained_alloc(struct zonelist *zonelist, |
| 172 | gfp_t gfp_mask) |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 173 | { |
| 174 | #ifdef CONFIG_NUMA |
| 175 | struct zone **z; |
Christoph Lameter | ee31af5 | 2007-10-16 01:25:30 -0700 | [diff] [blame] | 176 | nodemask_t nodes = node_states[N_HIGH_MEMORY]; |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 177 | |
| 178 | for (z = zonelist->zones; *z; z++) |
Paul Jackson | 02a0e53 | 2006-12-13 00:34:25 -0800 | [diff] [blame] | 179 | if (cpuset_zone_allowed_softwall(*z, gfp_mask)) |
Christoph Lameter | 89fa302 | 2006-09-25 23:31:55 -0700 | [diff] [blame] | 180 | node_clear(zone_to_nid(*z), nodes); |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 181 | else |
| 182 | return CONSTRAINT_CPUSET; |
| 183 | |
| 184 | if (!nodes_empty(nodes)) |
| 185 | return CONSTRAINT_MEMORY_POLICY; |
| 186 | #endif |
| 187 | |
| 188 | return CONSTRAINT_NONE; |
| 189 | } |
| 190 | |
| 191 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 192 | * Simple selection loop. We chose the process with the highest |
| 193 | * number of 'points'. We expect the caller will lock the tasklist. |
| 194 | * |
| 195 | * (not docbooked, we don't want this one cluttering up the manual) |
| 196 | */ |
Kurt Garloff | 9827b78 | 2006-02-20 18:27:51 -0800 | [diff] [blame] | 197 | static struct task_struct *select_bad_process(unsigned long *ppoints) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 198 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | struct task_struct *g, *p; |
| 200 | struct task_struct *chosen = NULL; |
| 201 | struct timespec uptime; |
Kurt Garloff | 9827b78 | 2006-02-20 18:27:51 -0800 | [diff] [blame] | 202 | *ppoints = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 203 | |
| 204 | do_posix_clock_monotonic_gettime(&uptime); |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 205 | do_each_thread(g, p) { |
| 206 | unsigned long points; |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 207 | |
Oleg Nesterov | 28324d1 | 2006-09-29 02:01:12 -0700 | [diff] [blame] | 208 | /* |
| 209 | * skip kernel threads and tasks which have already released |
| 210 | * their mm. |
| 211 | */ |
Nick Piggin | 5081dde | 2006-09-25 23:31:32 -0700 | [diff] [blame] | 212 | if (!p->mm) |
| 213 | continue; |
Oleg Nesterov | 28324d1 | 2006-09-29 02:01:12 -0700 | [diff] [blame] | 214 | /* skip the init task */ |
| 215 | if (is_init(p)) |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 216 | continue; |
Paul Jackson | ef08e3b | 2005-09-06 15:18:13 -0700 | [diff] [blame] | 217 | |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 218 | /* |
Nick Piggin | b78483a | 2006-09-29 02:01:14 -0700 | [diff] [blame] | 219 | * This task already has access to memory reserves and is |
| 220 | * being killed. Don't allow any other task access to the |
| 221 | * memory reserve. |
| 222 | * |
| 223 | * Note: this may have a chance of deadlock if it gets |
| 224 | * blocked waiting for another task which itself is waiting |
| 225 | * for memory. Is there a better alternative? |
| 226 | */ |
| 227 | if (test_tsk_thread_flag(p, TIF_MEMDIE)) |
| 228 | return ERR_PTR(-1UL); |
| 229 | |
| 230 | /* |
Dave Peterson | 6937a25 | 2006-06-23 02:03:13 -0700 | [diff] [blame] | 231 | * This is in the process of releasing memory so wait for it |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 232 | * to finish before killing some other task by mistake. |
Nick Piggin | 50ec3bb | 2006-09-25 23:31:29 -0700 | [diff] [blame] | 233 | * |
| 234 | * However, if p is the current task, we allow the 'kill' to |
| 235 | * go ahead if it is exiting: this will simply set TIF_MEMDIE, |
| 236 | * which will allow it to gain access to memory reserves in |
| 237 | * the process of exiting and releasing its resources. |
Nick Piggin | b78483a | 2006-09-29 02:01:14 -0700 | [diff] [blame] | 238 | * Otherwise we could get an easy OOM deadlock. |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 239 | */ |
Nick Piggin | b78483a | 2006-09-29 02:01:14 -0700 | [diff] [blame] | 240 | if (p->flags & PF_EXITING) { |
| 241 | if (p != current) |
| 242 | return ERR_PTR(-1UL); |
| 243 | |
Oleg Nesterov | 972c4ea | 2006-09-29 02:01:12 -0700 | [diff] [blame] | 244 | chosen = p; |
| 245 | *ppoints = ULONG_MAX; |
Nick Piggin | 50ec3bb | 2006-09-25 23:31:29 -0700 | [diff] [blame] | 246 | } |
Oleg Nesterov | 972c4ea | 2006-09-29 02:01:12 -0700 | [diff] [blame] | 247 | |
Nick Piggin | 4a3ede1 | 2006-09-25 23:31:30 -0700 | [diff] [blame] | 248 | if (p->oomkilladj == OOM_DISABLE) |
| 249 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 250 | |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 251 | points = badness(p, uptime.tv_sec); |
Kurt Garloff | 9827b78 | 2006-02-20 18:27:51 -0800 | [diff] [blame] | 252 | if (points > *ppoints || !chosen) { |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 253 | chosen = p; |
Kurt Garloff | 9827b78 | 2006-02-20 18:27:51 -0800 | [diff] [blame] | 254 | *ppoints = points; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 255 | } |
Paul Jackson | a49335c | 2005-09-06 15:18:09 -0700 | [diff] [blame] | 256 | } while_each_thread(g, p); |
Oleg Nesterov | 972c4ea | 2006-09-29 02:01:12 -0700 | [diff] [blame] | 257 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | return chosen; |
| 259 | } |
| 260 | |
| 261 | /** |
Ram Gupta | 5a291b98 | 2006-09-25 23:31:54 -0700 | [diff] [blame] | 262 | * Send SIGKILL to the selected process irrespective of CAP_SYS_RAW_IO |
| 263 | * flag though it's unlikely that we select a process with CAP_SYS_RAW_IO |
| 264 | * set. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 265 | */ |
Nick Piggin | f3af38d | 2006-12-06 20:31:51 -0800 | [diff] [blame] | 266 | static void __oom_kill_task(struct task_struct *p, int verbose) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 267 | { |
Sukadev Bhattiprolu | f400e19 | 2006-09-29 02:00:07 -0700 | [diff] [blame] | 268 | if (is_init(p)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 269 | WARN_ON(1); |
| 270 | printk(KERN_WARNING "tried to kill init!\n"); |
| 271 | return; |
| 272 | } |
| 273 | |
Oleg Nesterov | 01017a2 | 2006-09-29 02:01:13 -0700 | [diff] [blame] | 274 | if (!p->mm) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 275 | WARN_ON(1); |
| 276 | printk(KERN_WARNING "tried to kill an mm-less task!\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 277 | return; |
| 278 | } |
Nick Piggin | 50ec3bb | 2006-09-25 23:31:29 -0700 | [diff] [blame] | 279 | |
Nick Piggin | f3af38d | 2006-12-06 20:31:51 -0800 | [diff] [blame] | 280 | if (verbose) |
| 281 | printk(KERN_ERR "Killed process %d (%s)\n", p->pid, p->comm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 282 | |
| 283 | /* |
| 284 | * We give our sacrificial lamb high priority and access to |
| 285 | * all the memory it needs. That way it should be able to |
| 286 | * exit() and clear out its resources quickly... |
| 287 | */ |
| 288 | p->time_slice = HZ; |
| 289 | set_tsk_thread_flag(p, TIF_MEMDIE); |
| 290 | |
| 291 | force_sig(SIGKILL, p); |
| 292 | } |
| 293 | |
Nick Piggin | f3af38d | 2006-12-06 20:31:51 -0800 | [diff] [blame] | 294 | static int oom_kill_task(struct task_struct *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 295 | { |
Dave Peterson | 0131592 | 2006-04-18 22:20:44 -0700 | [diff] [blame] | 296 | struct mm_struct *mm; |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 297 | struct task_struct *g, *q; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 298 | |
Dave Peterson | 0131592 | 2006-04-18 22:20:44 -0700 | [diff] [blame] | 299 | mm = p->mm; |
| 300 | |
| 301 | /* WARNING: mm may not be dereferenced since we did not obtain its |
| 302 | * value from get_task_mm(p). This is OK since all we need to do is |
| 303 | * compare mm to q->mm below. |
| 304 | * |
| 305 | * Furthermore, even if mm contains a non-NULL value, p->mm may |
| 306 | * change to NULL at any time since we do not hold task_lock(p). |
| 307 | * However, this is of no concern to us. |
| 308 | */ |
| 309 | |
Oleg Nesterov | 01017a2 | 2006-09-29 02:01:13 -0700 | [diff] [blame] | 310 | if (mm == NULL) |
Dave Peterson | 0131592 | 2006-04-18 22:20:44 -0700 | [diff] [blame] | 311 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 312 | |
Nick Piggin | c33e0fc | 2006-12-06 20:31:50 -0800 | [diff] [blame] | 313 | /* |
| 314 | * Don't kill the process if any threads are set to OOM_DISABLE |
| 315 | */ |
| 316 | do_each_thread(g, q) { |
Ankita Garg | 35ae834 | 2007-03-16 13:38:33 -0800 | [diff] [blame] | 317 | if (q->mm == mm && q->oomkilladj == OOM_DISABLE) |
Nick Piggin | c33e0fc | 2006-12-06 20:31:50 -0800 | [diff] [blame] | 318 | return 1; |
| 319 | } while_each_thread(g, q); |
| 320 | |
Nick Piggin | f3af38d | 2006-12-06 20:31:51 -0800 | [diff] [blame] | 321 | __oom_kill_task(p, 1); |
Nick Piggin | c33e0fc | 2006-12-06 20:31:50 -0800 | [diff] [blame] | 322 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 323 | /* |
| 324 | * kill all processes that share the ->mm (i.e. all threads), |
Nick Piggin | f2a2a71 | 2006-12-06 20:31:52 -0800 | [diff] [blame] | 325 | * but are in a different thread group. Don't let them have access |
| 326 | * to memory reserves though, otherwise we might deplete all memory. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 327 | */ |
Nick Piggin | c33e0fc | 2006-12-06 20:31:50 -0800 | [diff] [blame] | 328 | do_each_thread(g, q) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 329 | if (q->mm == mm && q->tgid != p->tgid) |
David Rientjes | 650a7c9 | 2007-04-23 21:36:13 -0700 | [diff] [blame] | 330 | force_sig(SIGKILL, q); |
Nick Piggin | c33e0fc | 2006-12-06 20:31:50 -0800 | [diff] [blame] | 331 | } while_each_thread(g, q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 332 | |
Dave Peterson | 0131592 | 2006-04-18 22:20:44 -0700 | [diff] [blame] | 333 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 334 | } |
| 335 | |
David Rientjes | 7213f50 | 2007-10-16 23:25:57 -0700 | [diff] [blame^] | 336 | static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, |
| 337 | unsigned long points, const char *message) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 338 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 339 | struct task_struct *c; |
| 340 | struct list_head *tsk; |
| 341 | |
David Rientjes | 7213f50 | 2007-10-16 23:25:57 -0700 | [diff] [blame^] | 342 | if (printk_ratelimit()) { |
| 343 | printk(KERN_WARNING "%s invoked oom-killer: " |
| 344 | "gfp_mask=0x%x, order=%d, oomkilladj=%d\n", |
| 345 | current->comm, gfp_mask, order, current->oomkilladj); |
| 346 | dump_stack(); |
| 347 | show_mem(); |
| 348 | } |
| 349 | |
Nick Piggin | 50ec3bb | 2006-09-25 23:31:29 -0700 | [diff] [blame] | 350 | /* |
| 351 | * If the task is already exiting, don't alarm the sysadmin or kill |
| 352 | * its children or threads, just set TIF_MEMDIE so it can die quickly |
| 353 | */ |
| 354 | if (p->flags & PF_EXITING) { |
Nick Piggin | f3af38d | 2006-12-06 20:31:51 -0800 | [diff] [blame] | 355 | __oom_kill_task(p, 0); |
Nick Piggin | 50ec3bb | 2006-09-25 23:31:29 -0700 | [diff] [blame] | 356 | return 0; |
| 357 | } |
| 358 | |
Nick Piggin | f3af38d | 2006-12-06 20:31:51 -0800 | [diff] [blame] | 359 | printk(KERN_ERR "%s: kill process %d (%s) score %li or a child\n", |
| 360 | message, p->pid, p->comm, points); |
| 361 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 362 | /* Try to kill a child first */ |
| 363 | list_for_each(tsk, &p->children) { |
| 364 | c = list_entry(tsk, struct task_struct, sibling); |
| 365 | if (c->mm == p->mm) |
| 366 | continue; |
Nick Piggin | f3af38d | 2006-12-06 20:31:51 -0800 | [diff] [blame] | 367 | if (!oom_kill_task(c)) |
Dave Peterson | 0131592 | 2006-04-18 22:20:44 -0700 | [diff] [blame] | 368 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 369 | } |
Nick Piggin | f3af38d | 2006-12-06 20:31:51 -0800 | [diff] [blame] | 370 | return oom_kill_task(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 371 | } |
| 372 | |
Martin Schwidefsky | 8bc719d | 2006-09-25 23:31:20 -0700 | [diff] [blame] | 373 | static BLOCKING_NOTIFIER_HEAD(oom_notify_list); |
| 374 | |
| 375 | int register_oom_notifier(struct notifier_block *nb) |
| 376 | { |
| 377 | return blocking_notifier_chain_register(&oom_notify_list, nb); |
| 378 | } |
| 379 | EXPORT_SYMBOL_GPL(register_oom_notifier); |
| 380 | |
| 381 | int unregister_oom_notifier(struct notifier_block *nb) |
| 382 | { |
| 383 | return blocking_notifier_chain_unregister(&oom_notify_list, nb); |
| 384 | } |
| 385 | EXPORT_SYMBOL_GPL(unregister_oom_notifier); |
| 386 | |
David Rientjes | 098d7f1 | 2007-10-16 23:25:55 -0700 | [diff] [blame] | 387 | /* |
| 388 | * Try to acquire the OOM killer lock for the zones in zonelist. Returns zero |
| 389 | * if a parallel OOM killing is already taking place that includes a zone in |
| 390 | * the zonelist. Otherwise, locks all zones in the zonelist and returns 1. |
| 391 | */ |
| 392 | int try_set_zone_oom(struct zonelist *zonelist) |
| 393 | { |
| 394 | struct zone **z; |
| 395 | int ret = 1; |
| 396 | |
| 397 | z = zonelist->zones; |
| 398 | |
| 399 | mutex_lock(&zone_scan_mutex); |
| 400 | do { |
| 401 | if (zone_is_oom_locked(*z)) { |
| 402 | ret = 0; |
| 403 | goto out; |
| 404 | } |
| 405 | } while (*(++z) != NULL); |
| 406 | |
| 407 | /* |
| 408 | * Lock each zone in the zonelist under zone_scan_mutex so a parallel |
| 409 | * invocation of try_set_zone_oom() doesn't succeed when it shouldn't. |
| 410 | */ |
| 411 | z = zonelist->zones; |
| 412 | do { |
| 413 | zone_set_flag(*z, ZONE_OOM_LOCKED); |
| 414 | } while (*(++z) != NULL); |
| 415 | out: |
| 416 | mutex_unlock(&zone_scan_mutex); |
| 417 | return ret; |
| 418 | } |
| 419 | |
| 420 | /* |
| 421 | * Clears the ZONE_OOM_LOCKED flag for all zones in the zonelist so that failed |
| 422 | * allocation attempts with zonelists containing them may now recall the OOM |
| 423 | * killer, if necessary. |
| 424 | */ |
| 425 | void clear_zonelist_oom(struct zonelist *zonelist) |
| 426 | { |
| 427 | struct zone **z; |
| 428 | |
| 429 | z = zonelist->zones; |
| 430 | |
| 431 | mutex_lock(&zone_scan_mutex); |
| 432 | do { |
| 433 | zone_clear_flag(*z, ZONE_OOM_LOCKED); |
| 434 | } while (*(++z) != NULL); |
| 435 | mutex_unlock(&zone_scan_mutex); |
| 436 | } |
| 437 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 438 | /** |
Dave Peterson | 6937a25 | 2006-06-23 02:03:13 -0700 | [diff] [blame] | 439 | * 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] | 440 | * |
| 441 | * If we run out of memory, we have the choice between either |
| 442 | * killing a random task (bad), letting the system crash (worse) |
| 443 | * OR try to be smart about which process to kill. Note that we |
| 444 | * don't have to be perfect here, we just have to be good. |
| 445 | */ |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 446 | 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] | 447 | { |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 448 | struct task_struct *p; |
Andrew Morton | d6713e0 | 2006-02-28 16:59:19 -0800 | [diff] [blame] | 449 | unsigned long points = 0; |
Martin Schwidefsky | 8bc719d | 2006-09-25 23:31:20 -0700 | [diff] [blame] | 450 | unsigned long freed = 0; |
David Rientjes | 70e24bd | 2007-10-16 23:25:53 -0700 | [diff] [blame] | 451 | enum oom_constraint constraint; |
Martin Schwidefsky | 8bc719d | 2006-09-25 23:31:20 -0700 | [diff] [blame] | 452 | |
| 453 | blocking_notifier_call_chain(&oom_notify_list, 0, &freed); |
| 454 | if (freed > 0) |
| 455 | /* Got some memory back in the last second. */ |
| 456 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 457 | |
Yasunori Goto | 2b744c0 | 2007-05-06 14:49:59 -0700 | [diff] [blame] | 458 | if (sysctl_panic_on_oom == 2) |
| 459 | panic("out of memory. Compulsory panic_on_oom is selected.\n"); |
| 460 | |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 461 | /* |
| 462 | * Check if there were limitations on the allocation (only relevant for |
| 463 | * NUMA) that may require different handling. |
| 464 | */ |
David Rientjes | 2b45ab3 | 2007-05-06 14:50:00 -0700 | [diff] [blame] | 465 | constraint = constrained_alloc(zonelist, gfp_mask); |
| 466 | cpuset_lock(); |
| 467 | read_lock(&tasklist_lock); |
| 468 | |
| 469 | switch (constraint) { |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 470 | case CONSTRAINT_MEMORY_POLICY: |
David Rientjes | 7213f50 | 2007-10-16 23:25:57 -0700 | [diff] [blame^] | 471 | oom_kill_process(current, gfp_mask, order, points, |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 472 | "No available memory (MPOL_BIND)"); |
| 473 | break; |
| 474 | |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 475 | case CONSTRAINT_NONE: |
KAMEZAWA Hiroyuki | fadd8fb | 2006-06-23 02:03:13 -0700 | [diff] [blame] | 476 | if (sysctl_panic_on_oom) |
| 477 | panic("out of memory. panic_on_oom is selected\n"); |
David Rientjes | fe071d7 | 2007-10-16 23:25:56 -0700 | [diff] [blame] | 478 | /* Fall-through */ |
| 479 | case CONSTRAINT_CPUSET: |
| 480 | if (sysctl_oom_kill_allocating_task) { |
David Rientjes | 7213f50 | 2007-10-16 23:25:57 -0700 | [diff] [blame^] | 481 | oom_kill_process(current, gfp_mask, order, points, |
David Rientjes | fe071d7 | 2007-10-16 23:25:56 -0700 | [diff] [blame] | 482 | "Out of memory (oom_kill_allocating_task)"); |
| 483 | break; |
| 484 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 485 | retry: |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 486 | /* |
| 487 | * Rambo mode: Shoot down a process and hope it solves whatever |
| 488 | * issues we may have. |
| 489 | */ |
| 490 | p = select_bad_process(&points); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 491 | |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 492 | if (PTR_ERR(p) == -1UL) |
| 493 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 494 | |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 495 | /* Found nothing?!?! Either we hang forever, or we panic. */ |
| 496 | if (!p) { |
| 497 | read_unlock(&tasklist_lock); |
| 498 | cpuset_unlock(); |
| 499 | panic("Out of memory and no killable processes...\n"); |
| 500 | } |
| 501 | |
David Rientjes | 7213f50 | 2007-10-16 23:25:57 -0700 | [diff] [blame^] | 502 | if (oom_kill_process(p, points, gfp_mask, order, |
| 503 | "Out of memory")) |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 504 | goto retry; |
| 505 | |
| 506 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 507 | } |
| 508 | |
Christoph Lameter | 9b0f8b0 | 2006-02-20 18:27:52 -0800 | [diff] [blame] | 509 | out: |
Andrew Morton | 140ffce | 2006-03-02 02:54:28 -0800 | [diff] [blame] | 510 | read_unlock(&tasklist_lock); |
Paul Jackson | 505970b | 2006-01-14 13:21:06 -0800 | [diff] [blame] | 511 | cpuset_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 512 | |
| 513 | /* |
| 514 | * Give "p" a good chance of killing itself before we |
Kirill Korotaev | 2f659f4 | 2006-01-08 01:01:05 -0800 | [diff] [blame] | 515 | * retry to allocate memory unless "p" is current |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 516 | */ |
Kirill Korotaev | 2f659f4 | 2006-01-08 01:01:05 -0800 | [diff] [blame] | 517 | if (!test_thread_flag(TIF_MEMDIE)) |
Andrew Morton | 140ffce | 2006-03-02 02:54:28 -0800 | [diff] [blame] | 518 | schedule_timeout_uninterruptible(1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 519 | } |