diff options
| -rw-r--r-- | include/linux/oom.h | 26 | ||||
| -rw-r--r-- | mm/memcontrol.c | 4 | ||||
| -rw-r--r-- | mm/oom_kill.c | 133 |
3 files changed, 85 insertions, 78 deletions
diff --git a/include/linux/oom.h b/include/linux/oom.h index 606137b3b778..5bc0457ee3a8 100644 --- a/include/linux/oom.h +++ b/include/linux/oom.h @@ -73,9 +73,9 @@ static inline bool oom_task_origin(const struct task_struct *p) extern void mark_oom_victim(struct task_struct *tsk); #ifdef CONFIG_MMU -extern void try_oom_reaper(struct task_struct *tsk); +extern void wake_oom_reaper(struct task_struct *tsk); #else -static inline void try_oom_reaper(struct task_struct *tsk) +static inline void wake_oom_reaper(struct task_struct *tsk) { } #endif @@ -107,27 +107,7 @@ extern void oom_killer_enable(void); extern struct task_struct *find_lock_task_mm(struct task_struct *p); -static inline bool task_will_free_mem(struct task_struct *task) -{ - struct signal_struct *sig = task->signal; - - /* - * A coredumping process may sleep for an extended period in exit_mm(), - * so the oom killer cannot assume that the process will promptly exit - * and release memory. - */ - if (sig->flags & SIGNAL_GROUP_COREDUMP) - return false; - - if (!(task->flags & PF_EXITING)) - return false; - - /* Make sure that the whole thread group is going down */ - if (!thread_group_empty(task) && !(sig->flags & SIGNAL_GROUP_EXIT)) - return false; - - return true; -} +bool task_will_free_mem(struct task_struct *task); /* sysctls */ extern int sysctl_oom_dump_tasks; diff --git a/mm/memcontrol.c b/mm/memcontrol.c index f3a84c64f35c..3e8f9e5e9291 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1276,9 +1276,9 @@ static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, * 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) || task_will_free_mem(current)) { + if (task_will_free_mem(current)) { mark_oom_victim(current); - try_oom_reaper(current); + wake_oom_reaper(current); goto unlock; } diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 38f89ac2df7f..8ee92fb76968 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -596,7 +596,7 @@ static int oom_reaper(void *unused) return 0; } -static void wake_oom_reaper(struct task_struct *tsk) +void wake_oom_reaper(struct task_struct *tsk) { if (!oom_reaper_th) return; @@ -614,46 +614,6 @@ static void wake_oom_reaper(struct task_struct *tsk) wake_up(&oom_reaper_wait); } -/* Check if we can reap the given task. This has to be called with stable - * tsk->mm - */ -void try_oom_reaper(struct task_struct *tsk) -{ - struct mm_struct *mm = tsk->mm; - struct task_struct *p; - - if (!mm) - return; - - /* - * There might be other threads/processes which are either not - * dying or even not killable. - */ - if (atomic_read(&mm->mm_users) > 1) { - rcu_read_lock(); - for_each_process(p) { - if (!process_shares_mm(p, mm)) - continue; - if (fatal_signal_pending(p)) - continue; - - /* - * If the task is exiting make sure the whole thread group - * is exiting and cannot acces mm anymore. - */ - if (signal_group_exit(p->signal)) - continue; - - /* Give up */ - rcu_read_unlock(); - return; - } - rcu_read_unlock(); - } - - wake_oom_reaper(tsk); -} - static int __init oom_init(void) { oom_reaper_th = kthread_run(oom_reaper, NULL, "oom_reaper"); @@ -665,10 +625,6 @@ static int __init oom_init(void) return 0; } subsys_initcall(oom_init) -#else -static void wake_oom_reaper(struct task_struct *tsk) -{ -} #endif /** @@ -745,6 +701,81 @@ void oom_killer_enable(void) oom_killer_disabled = false; } +static inline bool __task_will_free_mem(struct task_struct *task) +{ + struct signal_struct *sig = task->signal; + + /* + * A coredumping process may sleep for an extended period in exit_mm(), + * so the oom killer cannot assume that the process will promptly exit + * and release memory. + */ + if (sig->flags & SIGNAL_GROUP_COREDUMP) + return false; + + if (sig->flags & SIGNAL_GROUP_EXIT) + return true; + + if (thread_group_empty(task) && (task->flags & PF_EXITING)) + return true; + + return false; +} + +/* + * Checks whether the given task is dying or exiting and likely to + * release its address space. This means that all threads and processes + * sharing the same mm have to be killed or exiting. + */ +bool task_will_free_mem(struct task_struct *task) +{ + struct mm_struct *mm; + struct task_struct *p; + bool ret; + + if (!__task_will_free_mem(task)) + return false; + + /* + * If the process has passed exit_mm we have to skip it because + * we have lost a link to other tasks sharing this mm, we do not + * have anything to reap and the task might then get stuck waiting + * for parent as zombie and we do not want it to hold TIF_MEMDIE + */ + p = find_lock_task_mm(task); + if (!p) + return false; + + mm = p->mm; + if (atomic_read(&mm->mm_users) <= 1) { + task_unlock(p); + return true; + } + + /* pin the mm to not get freed and reused */ + atomic_inc(&mm->mm_count); + task_unlock(p); + + /* + * This is really pessimistic but we do not have any reliable way + * to check that external processes share with our mm + */ + rcu_read_lock(); + for_each_process(p) { + if (!process_shares_mm(p, mm)) + continue; + if (same_thread_group(task, p)) + continue; + ret = __task_will_free_mem(p); + if (!ret) + break; + } + rcu_read_unlock(); + mmdrop(mm); + + return ret; +} + /* * Must be called while holding a reference to p, which will be released upon * returning. @@ -766,15 +797,12 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p, * 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 */ - task_lock(p); - if (p->mm && task_will_free_mem(p)) { + if (task_will_free_mem(p)) { mark_oom_victim(p); - try_oom_reaper(p); - task_unlock(p); + wake_oom_reaper(p); put_task_struct(p); return; } - task_unlock(p); if (__ratelimit(&oom_rs)) dump_header(oc, p); @@ -944,10 +972,9 @@ bool out_of_memory(struct oom_control *oc) * But don't select if current has already released its mm and cleared * TIF_MEMDIE flag at exit_mm(), otherwise an OOM livelock may occur. */ - if (current->mm && - (fatal_signal_pending(current) || task_will_free_mem(current))) { + if (current->mm && task_will_free_mem(current)) { mark_oom_victim(current); - try_oom_reaper(current); + wake_oom_reaper(current); return true; } |