diff options
Diffstat (limited to 'mm/oom_kill.c')
| -rw-r--r-- | mm/oom_kill.c | 24 |
1 files changed, 10 insertions, 14 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 9e8b4f030c1c..99736e026712 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -495,11 +495,12 @@ static bool __oom_reap_task_mm(struct task_struct *tsk, struct mm_struct *mm) } /* - * increase mm_users only after we know we will reap something so - * that the mmput_async is called only when we have reaped something - * and delayed __mmput doesn't matter that much + * MMF_OOM_SKIP is set by exit_mmap when the OOM reaper can't + * work on the mm anymore. The check for MMF_OOM_SKIP must run + * under mmap_sem for reading because it serializes against the + * down_write();up_write() cycle in exit_mmap(). */ - if (!mmget_not_zero(mm)) { + if (test_bit(MMF_OOM_SKIP, &mm->flags)) { up_read(&mm->mmap_sem); trace_skip_task_reaping(tsk->pid); goto unlock_oom; @@ -542,12 +543,6 @@ static bool __oom_reap_task_mm(struct task_struct *tsk, struct mm_struct *mm) K(get_mm_counter(mm, MM_SHMEMPAGES))); up_read(&mm->mmap_sem); - /* - * Drop our reference but make sure the mmput slow path is called from a - * different context because we shouldn't risk we get stuck there and - * put the oom_reaper out of the way. - */ - mmput_async(mm); trace_finish_task_reaping(tsk->pid); unlock_oom: mutex_unlock(&oom_lock); @@ -824,7 +819,8 @@ static void oom_kill_process(struct oom_control *oc, const char *message) /* * 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 + * its children or threads, just give it access to memory reserves + * so it can die quickly */ task_lock(p); if (task_will_free_mem(p)) { @@ -889,9 +885,9 @@ static void oom_kill_process(struct oom_control *oc, const char *message) count_memcg_event_mm(mm, OOM_KILL); /* - * We should send SIGKILL before setting TIF_MEMDIE in order to prevent - * the OOM victim from depleting the memory reserves from the user - * space under its control. + * We should send SIGKILL before granting access to memory reserves + * in order to prevent the OOM victim from depleting the memory + * reserves from the user space under its control. */ do_send_sig_info(SIGKILL, SEND_SIG_FORCED, victim, true); mark_oom_victim(victim); |