diff options
| -rw-r--r-- | include/linux/oom.h | 2 | ||||
| -rw-r--r-- | kernel/exit.c | 2 | ||||
| -rw-r--r-- | mm/oom_kill.c | 73 |
3 files changed, 50 insertions, 27 deletions
diff --git a/include/linux/oom.h b/include/linux/oom.h index 03e6257321f0..45993b840ed6 100644 --- a/include/linux/oom.h +++ b/include/linux/oom.h @@ -91,7 +91,7 @@ extern enum oom_scan_t oom_scan_process_thread(struct oom_control *oc, extern bool out_of_memory(struct oom_control *oc); -extern void exit_oom_victim(void); +extern void exit_oom_victim(struct task_struct *tsk); extern int register_oom_notifier(struct notifier_block *nb); extern int unregister_oom_notifier(struct notifier_block *nb); diff --git a/kernel/exit.c b/kernel/exit.c index 953d1a1c0387..fd90195667e1 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -435,7 +435,7 @@ static void exit_mm(struct task_struct *tsk) mm_update_next_owner(mm); mmput(mm); if (test_thread_flag(TIF_MEMDIE)) - exit_oom_victim(); + exit_oom_victim(tsk); } static struct task_struct *find_alive_thread(struct task_struct *p) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index f7ed6ece0719..2830b1c6483e 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -416,20 +416,36 @@ bool oom_killer_disabled __read_mostly; * victim (if that is possible) to help the OOM killer to move on. */ static struct task_struct *oom_reaper_th; -static struct mm_struct *mm_to_reap; +static struct task_struct *task_to_reap; static DECLARE_WAIT_QUEUE_HEAD(oom_reaper_wait); -static bool __oom_reap_vmas(struct mm_struct *mm) +static bool __oom_reap_task(struct task_struct *tsk) { struct mmu_gather tlb; struct vm_area_struct *vma; + struct mm_struct *mm; + struct task_struct *p; struct zap_details details = {.check_swap_entries = true, .ignore_dirty = true}; bool ret = true; - /* We might have raced with exit path */ - if (!atomic_inc_not_zero(&mm->mm_users)) + /* + * Make sure we find the associated mm_struct even when the particular + * thread has already terminated and cleared its mm. + * We might have race with exit path so consider our work done if there + * is no mm. + */ + p = find_lock_task_mm(tsk); + if (!p) + return true; + + mm = p->mm; + if (!atomic_inc_not_zero(&mm->mm_users)) { + task_unlock(p); return true; + } + + task_unlock(p); if (!down_read_trylock(&mm->mmap_sem)) { ret = false; @@ -464,60 +480,66 @@ static bool __oom_reap_vmas(struct mm_struct *mm) } tlb_finish_mmu(&tlb, 0, -1); up_read(&mm->mmap_sem); + + /* + * Clear TIF_MEMDIE because the task shouldn't be sitting on a + * reasonably reclaimable memory anymore. OOM killer can continue + * by selecting other victim if unmapping hasn't led to any + * improvements. This also means that selecting this task doesn't + * make any sense. + */ + tsk->signal->oom_score_adj = OOM_SCORE_ADJ_MIN; + exit_oom_victim(tsk); out: mmput(mm); return ret; } -static void oom_reap_vmas(struct mm_struct *mm) +static void oom_reap_task(struct task_struct *tsk) { int attempts = 0; /* Retry the down_read_trylock(mmap_sem) a few times */ - while (attempts++ < 10 && !__oom_reap_vmas(mm)) + while (attempts++ < 10 && !__oom_reap_task(tsk)) schedule_timeout_idle(HZ/10); /* Drop a reference taken by wake_oom_reaper */ - mmdrop(mm); + put_task_struct(tsk); } static int oom_reaper(void *unused) { while (true) { - struct mm_struct *mm; + struct task_struct *tsk; wait_event_freezable(oom_reaper_wait, - (mm = READ_ONCE(mm_to_reap))); - oom_reap_vmas(mm); - WRITE_ONCE(mm_to_reap, NULL); + (tsk = READ_ONCE(task_to_reap))); + oom_reap_task(tsk); + WRITE_ONCE(task_to_reap, NULL); } return 0; } -static void wake_oom_reaper(struct mm_struct *mm) +static void wake_oom_reaper(struct task_struct *tsk) { - struct mm_struct *old_mm; + struct task_struct *old_tsk; if (!oom_reaper_th) return; - /* - * Pin the given mm. Use mm_count instead of mm_users because - * we do not want to delay the address space tear down. - */ - atomic_inc(&mm->mm_count); + get_task_struct(tsk); /* * Make sure that only a single mm is ever queued for the reaper * because multiple are not necessary and the operation might be * disruptive so better reduce it to the bare minimum. */ - old_mm = cmpxchg(&mm_to_reap, NULL, mm); - if (!old_mm) + old_tsk = cmpxchg(&task_to_reap, NULL, tsk); + if (!old_tsk) wake_up(&oom_reaper_wait); else - mmdrop(mm); + put_task_struct(tsk); } static int __init oom_init(void) @@ -532,7 +554,7 @@ static int __init oom_init(void) } subsys_initcall(oom_init) #else -static void wake_oom_reaper(struct mm_struct *mm) +static void wake_oom_reaper(struct task_struct *tsk) { } #endif @@ -563,9 +585,10 @@ void mark_oom_victim(struct task_struct *tsk) /** * exit_oom_victim - note the exit of an OOM victim */ -void exit_oom_victim(void) +void exit_oom_victim(struct task_struct *tsk) { - clear_thread_flag(TIF_MEMDIE); + if (!test_and_clear_tsk_thread_flag(tsk, TIF_MEMDIE)) + return; if (!atomic_dec_return(&oom_victims)) wake_up_all(&oom_victims_wait); @@ -748,7 +771,7 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p, rcu_read_unlock(); if (can_oom_reap) - wake_oom_reaper(mm); + wake_oom_reaper(victim); mmdrop(mm); put_task_struct(victim); |