| /* |
| * linux/mm/oom_kill.c |
| * |
| * Copyright (C) 1998,2000 Rik van Riel |
| * Thanks go out to Claus Fischer for some serious inspiration and |
| * for goading me into coding this file... |
| * |
| * The routines in this file are used to kill a process when |
| * we're seriously out of memory. This gets called from __alloc_pages() |
| * in mm/page_alloc.c when we really run out of memory. |
| * |
| * Since we won't call these routines often (on a well-configured |
| * machine) this file will double as a 'coding guide' and a signpost |
| * for newbie kernel hackers. It features several pointers to major |
| * kernel subsystems and hints as to where to find out what things do. |
| */ |
| |
| #include <linux/oom.h> |
| #include <linux/mm.h> |
| #include <linux/err.h> |
| #include <linux/gfp.h> |
| #include <linux/sched.h> |
| #include <linux/swap.h> |
| #include <linux/timex.h> |
| #include <linux/jiffies.h> |
| #include <linux/cpuset.h> |
| #include <linux/module.h> |
| #include <linux/notifier.h> |
| #include <linux/memcontrol.h> |
| #include <linux/mempolicy.h> |
| #include <linux/security.h> |
| |
| int sysctl_panic_on_oom; |
| int sysctl_oom_kill_allocating_task; |
| int sysctl_oom_dump_tasks = 1; |
| static DEFINE_SPINLOCK(zone_scan_lock); |
| /* #define DEBUG */ |
| |
| #ifdef CONFIG_NUMA |
| /** |
| * has_intersects_mems_allowed() - check task eligiblity for kill |
| * @tsk: task struct of which task to consider |
| * @mask: nodemask passed to page allocator for mempolicy ooms |
| * |
| * Task eligibility is determined by whether or not a candidate task, @tsk, |
| * shares the same mempolicy nodes as current if it is bound by such a policy |
| * and whether or not it has the same set of allowed cpuset nodes. |
| */ |
| static bool has_intersects_mems_allowed(struct task_struct *tsk, |
| const nodemask_t *mask) |
| { |
| struct task_struct *start = tsk; |
| |
| do { |
| if (mask) { |
| /* |
| * If this is a mempolicy constrained oom, tsk's |
| * cpuset is irrelevant. Only return true if its |
| * mempolicy intersects current, otherwise it may be |
| * needlessly killed. |
| */ |
| if (mempolicy_nodemask_intersects(tsk, mask)) |
| return true; |
| } else { |
| /* |
| * This is not a mempolicy constrained oom, so only |
| * check the mems of tsk's cpuset. |
| */ |
| if (cpuset_mems_allowed_intersects(current, tsk)) |
| return true; |
| } |
| tsk = next_thread(tsk); |
| } while (tsk != start); |
| return false; |
| } |
| #else |
| static bool has_intersects_mems_allowed(struct task_struct *tsk, |
| const nodemask_t *mask) |
| { |
| return true; |
| } |
| #endif /* CONFIG_NUMA */ |
| |
| /* |
| * The process p may have detached its own ->mm while exiting or through |
| * use_mm(), but one or more of its subthreads may still have a valid |
| * pointer. Return p, or any of its subthreads with a valid ->mm, with |
| * task_lock() held. |
| */ |
| static struct task_struct *find_lock_task_mm(struct task_struct *p) |
| { |
| struct task_struct *t = p; |
| |
| do { |
| task_lock(t); |
| if (likely(t->mm)) |
| return t; |
| task_unlock(t); |
| } while_each_thread(p, t); |
| |
| return NULL; |
| } |
| |
| /** |
| * badness - calculate a numeric value for how bad this task has been |
| * @p: task struct of which task we should calculate |
| * @uptime: current uptime in seconds |
| * |
| * The formula used is relatively simple and documented inline in the |
| * function. The main rationale is that we want to select a good task |
| * to kill when we run out of memory. |
| * |
| * Good in this context means that: |
| * 1) we lose the minimum amount of work done |
| * 2) we recover a large amount of memory |
| * 3) we don't kill anything innocent of eating tons of memory |
| * 4) we want to kill the minimum amount of processes (one) |
| * 5) we try to kill the process the user expects us to kill, this |
| * algorithm has been meticulously tuned to meet the principle |
| * of least surprise ... (be careful when you change it) |
| */ |
| |
| unsigned long badness(struct task_struct *p, unsigned long uptime) |
| { |
| unsigned long points, cpu_time, run_time; |
| struct task_struct *child; |
| struct task_struct *c, *t; |
| int oom_adj = p->signal->oom_adj; |
| struct task_cputime task_time; |
| unsigned long utime; |
| unsigned long stime; |
| |
| if (oom_adj == OOM_DISABLE) |
| return 0; |
| |
| p = find_lock_task_mm(p); |
| if (!p) |
| return 0; |
| |
| /* |
| * The memory size of the process is the basis for the badness. |
| */ |
| points = p->mm->total_vm; |
| task_unlock(p); |
| |
| /* |
| * swapoff can easily use up all memory, so kill those first. |
| */ |
| if (p->flags & PF_OOM_ORIGIN) |
| return ULONG_MAX; |
| |
| /* |
| * Processes which fork a lot of child processes are likely |
| * a good choice. We add half the vmsize of the children if they |
| * have an own mm. This prevents forking servers to flood the |
| * machine with an endless amount of children. In case a single |
| * child is eating the vast majority of memory, adding only half |
| * to the parents will make the child our kill candidate of choice. |
| */ |
| t = p; |
| do { |
| list_for_each_entry(c, &t->children, sibling) { |
| child = find_lock_task_mm(c); |
| if (child) { |
| if (child->mm != p->mm) |
| points += child->mm->total_vm/2 + 1; |
| task_unlock(child); |
| } |
| } |
| } while_each_thread(p, t); |
| |
| /* |
| * CPU time is in tens of seconds and run time is in thousands |
| * of seconds. There is no particular reason for this other than |
| * that it turned out to work very well in practice. |
| */ |
| thread_group_cputime(p, &task_time); |
| utime = cputime_to_jiffies(task_time.utime); |
| stime = cputime_to_jiffies(task_time.stime); |
| cpu_time = (utime + stime) >> (SHIFT_HZ + 3); |
| |
| |
| if (uptime >= p->start_time.tv_sec) |
| run_time = (uptime - p->start_time.tv_sec) >> 10; |
| else |
| run_time = 0; |
| |
| if (cpu_time) |
| points /= int_sqrt(cpu_time); |
| if (run_time) |
| points /= int_sqrt(int_sqrt(run_time)); |
| |
| /* |
| * Niced processes are most likely less important, so double |
| * their badness points. |
| */ |
| if (task_nice(p) > 0) |
| points *= 2; |
| |
| /* |
| * Superuser processes are usually more important, so we make it |
| * less likely that we kill those. |
| */ |
| if (has_capability_noaudit(p, CAP_SYS_ADMIN) || |
| has_capability_noaudit(p, CAP_SYS_RESOURCE)) |
| points /= 4; |
| |
| /* |
| * We don't want to kill a process with direct hardware access. |
| * Not only could that mess up the hardware, but usually users |
| * tend to only have this flag set on applications they think |
| * of as important. |
| */ |
| if (has_capability_noaudit(p, CAP_SYS_RAWIO)) |
| points /= 4; |
| |
| /* |
| * Adjust the score by oom_adj. |
| */ |
| if (oom_adj) { |
| if (oom_adj > 0) { |
| if (!points) |
| points = 1; |
| points <<= oom_adj; |
| } else |
| points >>= -(oom_adj); |
| } |
| |
| #ifdef DEBUG |
| printk(KERN_DEBUG "OOMkill: task %d (%s) got %lu points\n", |
| p->pid, p->comm, points); |
| #endif |
| return points; |
| } |
| |
| /* |
| * Determine the type of allocation constraint. |
| */ |
| #ifdef CONFIG_NUMA |
| static enum oom_constraint constrained_alloc(struct zonelist *zonelist, |
| gfp_t gfp_mask, nodemask_t *nodemask) |
| { |
| struct zone *zone; |
| struct zoneref *z; |
| enum zone_type high_zoneidx = gfp_zone(gfp_mask); |
| |
| /* |
| * Reach here only when __GFP_NOFAIL is used. So, we should avoid |
| * to kill current.We have to random task kill in this case. |
| * Hopefully, CONSTRAINT_THISNODE...but no way to handle it, now. |
| */ |
| if (gfp_mask & __GFP_THISNODE) |
| return CONSTRAINT_NONE; |
| |
| /* |
| * The nodemask here is a nodemask passed to alloc_pages(). Now, |
| * cpuset doesn't use this nodemask for its hardwall/softwall/hierarchy |
| * feature. mempolicy is an only user of nodemask here. |
| * check mempolicy's nodemask contains all N_HIGH_MEMORY |
| */ |
| if (nodemask && !nodes_subset(node_states[N_HIGH_MEMORY], *nodemask)) |
| return CONSTRAINT_MEMORY_POLICY; |
| |
| /* Check this allocation failure is caused by cpuset's wall function */ |
| for_each_zone_zonelist_nodemask(zone, z, zonelist, |
| high_zoneidx, nodemask) |
| if (!cpuset_zone_allowed_softwall(zone, gfp_mask)) |
| return CONSTRAINT_CPUSET; |
| |
| return CONSTRAINT_NONE; |
| } |
| #else |
| static enum oom_constraint constrained_alloc(struct zonelist *zonelist, |
| gfp_t gfp_mask, nodemask_t *nodemask) |
| { |
| return CONSTRAINT_NONE; |
| } |
| #endif |
| |
| /* |
| * Simple selection loop. We chose the process with the highest |
| * number of 'points'. We expect the caller will lock the tasklist. |
| * |
| * (not docbooked, we don't want this one cluttering up the manual) |
| */ |
| static struct task_struct *select_bad_process(unsigned long *ppoints, |
| struct mem_cgroup *mem, const nodemask_t *nodemask) |
| { |
| struct task_struct *p; |
| struct task_struct *chosen = NULL; |
| struct timespec uptime; |
| *ppoints = 0; |
| |
| do_posix_clock_monotonic_gettime(&uptime); |
| for_each_process(p) { |
| unsigned long points; |
| |
| /* skip the init task and kthreads */ |
| if (is_global_init(p) || (p->flags & PF_KTHREAD)) |
| continue; |
| if (mem && !task_in_mem_cgroup(p, mem)) |
| continue; |
| if (!has_intersects_mems_allowed(p, nodemask)) |
| continue; |
| |
| /* |
| * This task already has access to memory reserves and is |
| * being killed. Don't allow any other task access to the |
| * memory reserve. |
| * |
| * Note: this may have a chance of deadlock if it gets |
| * blocked waiting for another task which itself is waiting |
| * for memory. Is there a better alternative? |
| */ |
| if (test_tsk_thread_flag(p, TIF_MEMDIE)) |
| return ERR_PTR(-1UL); |
| |
| /* |
| * This is in the process of releasing memory so wait for it |
| * to finish before killing some other task by mistake. |
| * |
| * However, if p is the current task, we allow the 'kill' to |
| * go ahead if it is exiting: this will simply set TIF_MEMDIE, |
| * which will allow it to gain access to memory reserves in |
| * the process of exiting and releasing its resources. |
| * Otherwise we could get an easy OOM deadlock. |
| */ |
| if ((p->flags & PF_EXITING) && p->mm) { |
| if (p != current) |
| return ERR_PTR(-1UL); |
| |
| chosen = p; |
| *ppoints = ULONG_MAX; |
| } |
| |
| if (p->signal->oom_adj == OOM_DISABLE) |
| continue; |
| |
| points = badness(p, uptime.tv_sec); |
| if (points > *ppoints || !chosen) { |
| chosen = p; |
| *ppoints = points; |
| } |
| } |
| |
| return chosen; |
| } |
| |
| /** |
| * dump_tasks - dump current memory state of all system tasks |
| * @mem: current's memory controller, if constrained |
| * |
| * Dumps the current memory state of all system tasks, excluding kernel threads. |
| * State information includes task's pid, uid, tgid, vm size, rss, cpu, oom_adj |
| * score, and name. |
| * |
| * If the actual is non-NULL, only tasks that are a member of the mem_cgroup are |
| * shown. |
| * |
| * Call with tasklist_lock read-locked. |
| */ |
| static void dump_tasks(const struct mem_cgroup *mem) |
| { |
| struct task_struct *p; |
| struct task_struct *task; |
| |
| printk(KERN_INFO "[ pid ] uid tgid total_vm rss cpu oom_adj " |
| "name\n"); |
| for_each_process(p) { |
| if (p->flags & PF_KTHREAD) |
| continue; |
| if (mem && !task_in_mem_cgroup(p, mem)) |
| continue; |
| |
| task = find_lock_task_mm(p); |
| if (!task) { |
| /* |
| * This is a kthread or all of p's threads have already |
| * detached their mm's. There's no need to report |
| * them; they can't be oom killed anyway. |
| */ |
| continue; |
| } |
| |
| printk(KERN_INFO "[%5d] %5d %5d %8lu %8lu %3u %3d %s\n", |
| task->pid, __task_cred(task)->uid, task->tgid, |
| task->mm->total_vm, get_mm_rss(task->mm), |
| task_cpu(task), task->signal->oom_adj, task->comm); |
| task_unlock(task); |
| } |
| } |
| |
| static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order, |
| struct mem_cgroup *mem) |
| { |
| task_lock(current); |
| pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, " |
| "oom_adj=%d\n", |
| current->comm, gfp_mask, order, current->signal->oom_adj); |
| cpuset_print_task_mems_allowed(current); |
| task_unlock(current); |
| dump_stack(); |
| mem_cgroup_print_oom_info(mem, p); |
| show_mem(); |
| if (sysctl_oom_dump_tasks) |
| dump_tasks(mem); |
| } |
| |
| #define K(x) ((x) << (PAGE_SHIFT-10)) |
| static int oom_kill_task(struct task_struct *p) |
| { |
| p = find_lock_task_mm(p); |
| if (!p || p->signal->oom_adj == OOM_DISABLE) { |
| task_unlock(p); |
| return 1; |
| } |
| pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB\n", |
| task_pid_nr(p), p->comm, K(p->mm->total_vm), |
| K(get_mm_counter(p->mm, MM_ANONPAGES)), |
| K(get_mm_counter(p->mm, MM_FILEPAGES))); |
| task_unlock(p); |
| |
| p->rt.time_slice = HZ; |
| set_tsk_thread_flag(p, TIF_MEMDIE); |
| force_sig(SIGKILL, p); |
| return 0; |
| } |
| #undef K |
| |
| static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, |
| unsigned long points, struct mem_cgroup *mem, |
| const char *message) |
| { |
| struct task_struct *victim = p; |
| struct task_struct *child; |
| struct task_struct *t = p; |
| unsigned long victim_points = 0; |
| struct timespec uptime; |
| |
| if (printk_ratelimit()) |
| dump_header(p, gfp_mask, order, mem); |
| |
| /* |
| * If the task is already exiting, don't alarm the sysadmin or kill |
| * its children or threads, just set TIF_MEMDIE so it can die quickly |
| */ |
| if (p->flags & PF_EXITING) { |
| set_tsk_thread_flag(p, TIF_MEMDIE); |
| return 0; |
| } |
| |
| task_lock(p); |
| pr_err("%s: Kill process %d (%s) score %lu or sacrifice child\n", |
| message, task_pid_nr(p), p->comm, points); |
| task_unlock(p); |
| |
| /* |
| * If any of p's children has a different mm and is eligible for kill, |
| * the one with the highest badness() score is sacrificed for its |
| * parent. This attempts to lose the minimal amount of work done while |
| * still freeing memory. |
| */ |
| do_posix_clock_monotonic_gettime(&uptime); |
| do { |
| list_for_each_entry(child, &t->children, sibling) { |
| unsigned long child_points; |
| |
| if (child->mm == p->mm) |
| continue; |
| if (mem && !task_in_mem_cgroup(child, mem)) |
| continue; |
| |
| /* badness() returns 0 if the thread is unkillable */ |
| child_points = badness(child, uptime.tv_sec); |
| if (child_points > victim_points) { |
| victim = child; |
| victim_points = child_points; |
| } |
| } |
| } while_each_thread(p, t); |
| |
| return oom_kill_task(victim); |
| } |
| |
| /* |
| * Determines whether the kernel must panic because of the panic_on_oom sysctl. |
| */ |
| static void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask, |
| int order) |
| { |
| if (likely(!sysctl_panic_on_oom)) |
| return; |
| if (sysctl_panic_on_oom != 2) { |
| /* |
| * panic_on_oom == 1 only affects CONSTRAINT_NONE, the kernel |
| * does not panic for cpuset, mempolicy, or memcg allocation |
| * failures. |
| */ |
| if (constraint != CONSTRAINT_NONE) |
| return; |
| } |
| read_lock(&tasklist_lock); |
| dump_header(NULL, gfp_mask, order, NULL); |
| read_unlock(&tasklist_lock); |
| panic("Out of memory: %s panic_on_oom is enabled\n", |
| sysctl_panic_on_oom == 2 ? "compulsory" : "system-wide"); |
| } |
| |
| #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
| void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask) |
| { |
| unsigned long points = 0; |
| struct task_struct *p; |
| |
| check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, 0); |
| read_lock(&tasklist_lock); |
| retry: |
| p = select_bad_process(&points, mem, NULL); |
| if (!p || PTR_ERR(p) == -1UL) |
| goto out; |
| |
| if (oom_kill_process(p, gfp_mask, 0, points, mem, |
| "Memory cgroup out of memory")) |
| goto retry; |
| out: |
| read_unlock(&tasklist_lock); |
| } |
| #endif |
| |
| static BLOCKING_NOTIFIER_HEAD(oom_notify_list); |
| |
| int register_oom_notifier(struct notifier_block *nb) |
| { |
| return blocking_notifier_chain_register(&oom_notify_list, nb); |
| } |
| EXPORT_SYMBOL_GPL(register_oom_notifier); |
| |
| int unregister_oom_notifier(struct notifier_block *nb) |
| { |
| return blocking_notifier_chain_unregister(&oom_notify_list, nb); |
| } |
| EXPORT_SYMBOL_GPL(unregister_oom_notifier); |
| |
| /* |
| * Try to acquire the OOM killer lock for the zones in zonelist. Returns zero |
| * if a parallel OOM killing is already taking place that includes a zone in |
| * the zonelist. Otherwise, locks all zones in the zonelist and returns 1. |
| */ |
| int try_set_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask) |
| { |
| struct zoneref *z; |
| struct zone *zone; |
| int ret = 1; |
| |
| spin_lock(&zone_scan_lock); |
| for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) { |
| if (zone_is_oom_locked(zone)) { |
| ret = 0; |
| goto out; |
| } |
| } |
| |
| for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) { |
| /* |
| * Lock each zone in the zonelist under zone_scan_lock so a |
| * parallel invocation of try_set_zonelist_oom() doesn't succeed |
| * when it shouldn't. |
| */ |
| zone_set_flag(zone, ZONE_OOM_LOCKED); |
| } |
| |
| out: |
| spin_unlock(&zone_scan_lock); |
| return ret; |
| } |
| |
| /* |
| * Clears the ZONE_OOM_LOCKED flag for all zones in the zonelist so that failed |
| * allocation attempts with zonelists containing them may now recall the OOM |
| * killer, if necessary. |
| */ |
| void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask) |
| { |
| struct zoneref *z; |
| struct zone *zone; |
| |
| spin_lock(&zone_scan_lock); |
| for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) { |
| zone_clear_flag(zone, ZONE_OOM_LOCKED); |
| } |
| spin_unlock(&zone_scan_lock); |
| } |
| |
| /* |
| * Try to acquire the oom killer lock for all system zones. Returns zero if a |
| * parallel oom killing is taking place, otherwise locks all zones and returns |
| * non-zero. |
| */ |
| static int try_set_system_oom(void) |
| { |
| struct zone *zone; |
| int ret = 1; |
| |
| spin_lock(&zone_scan_lock); |
| for_each_populated_zone(zone) |
| if (zone_is_oom_locked(zone)) { |
| ret = 0; |
| goto out; |
| } |
| for_each_populated_zone(zone) |
| zone_set_flag(zone, ZONE_OOM_LOCKED); |
| out: |
| spin_unlock(&zone_scan_lock); |
| return ret; |
| } |
| |
| /* |
| * Clears ZONE_OOM_LOCKED for all system zones so that failed allocation |
| * attempts or page faults may now recall the oom killer, if necessary. |
| */ |
| static void clear_system_oom(void) |
| { |
| struct zone *zone; |
| |
| spin_lock(&zone_scan_lock); |
| for_each_populated_zone(zone) |
| zone_clear_flag(zone, ZONE_OOM_LOCKED); |
| spin_unlock(&zone_scan_lock); |
| } |
| |
| |
| /* |
| * Must be called with tasklist_lock held for read. |
| */ |
| static void __out_of_memory(gfp_t gfp_mask, int order, const nodemask_t *mask) |
| { |
| struct task_struct *p; |
| unsigned long points; |
| |
| if (sysctl_oom_kill_allocating_task) |
| if (!oom_kill_process(current, gfp_mask, order, 0, NULL, |
| "Out of memory (oom_kill_allocating_task)")) |
| return; |
| retry: |
| /* |
| * Rambo mode: Shoot down a process and hope it solves whatever |
| * issues we may have. |
| */ |
| p = select_bad_process(&points, NULL, mask); |
| |
| if (PTR_ERR(p) == -1UL) |
| return; |
| |
| /* Found nothing?!?! Either we hang forever, or we panic. */ |
| if (!p) { |
| dump_header(NULL, gfp_mask, order, NULL); |
| read_unlock(&tasklist_lock); |
| panic("Out of memory and no killable processes...\n"); |
| } |
| |
| if (oom_kill_process(p, gfp_mask, order, points, NULL, |
| "Out of memory")) |
| goto retry; |
| } |
| |
| /** |
| * out_of_memory - kill the "best" process when we run out of memory |
| * @zonelist: zonelist pointer |
| * @gfp_mask: memory allocation flags |
| * @order: amount of memory being requested as a power of 2 |
| * @nodemask: nodemask passed to page allocator |
| * |
| * If we run out of memory, we have the choice between either |
| * killing a random task (bad), letting the system crash (worse) |
| * OR try to be smart about which process to kill. Note that we |
| * don't have to be perfect here, we just have to be good. |
| */ |
| void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, |
| int order, nodemask_t *nodemask) |
| { |
| unsigned long freed = 0; |
| enum oom_constraint constraint = CONSTRAINT_NONE; |
| |
| blocking_notifier_call_chain(&oom_notify_list, 0, &freed); |
| if (freed > 0) |
| /* Got some memory back in the last second. */ |
| return; |
| |
| /* |
| * If current has a pending SIGKILL, then automatically select it. The |
| * goal is to allow it to allocate so that it may quickly exit and free |
| * its memory. |
| */ |
| if (fatal_signal_pending(current)) { |
| set_thread_flag(TIF_MEMDIE); |
| return; |
| } |
| |
| /* |
| * Check if there were limitations on the allocation (only relevant for |
| * NUMA) that may require different handling. |
| */ |
| if (zonelist) |
| constraint = constrained_alloc(zonelist, gfp_mask, nodemask); |
| check_panic_on_oom(constraint, gfp_mask, order); |
| read_lock(&tasklist_lock); |
| __out_of_memory(gfp_mask, order, |
| constraint == CONSTRAINT_MEMORY_POLICY ? nodemask : |
| NULL); |
| read_unlock(&tasklist_lock); |
| |
| /* |
| * Give "p" a good chance of killing itself before we |
| * retry to allocate memory unless "p" is current |
| */ |
| if (!test_thread_flag(TIF_MEMDIE)) |
| schedule_timeout_uninterruptible(1); |
| } |
| |
| /* |
| * The pagefault handler calls here because it is out of memory, so kill a |
| * memory-hogging task. If a populated zone has ZONE_OOM_LOCKED set, a parallel |
| * oom killing is already in progress so do nothing. If a task is found with |
| * TIF_MEMDIE set, it has been killed so do nothing and allow it to exit. |
| */ |
| void pagefault_out_of_memory(void) |
| { |
| if (try_set_system_oom()) { |
| out_of_memory(NULL, 0, 0, NULL); |
| clear_system_oom(); |
| } |
| if (!test_thread_flag(TIF_MEMDIE)) |
| schedule_timeout_uninterruptible(1); |
| } |