diff options
| -rw-r--r-- | mm/oom_kill.c | 31 |
1 files changed, 27 insertions, 4 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 21dd99eac..1a15cc0e1 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -44,6 +44,8 @@ int sysctl_oom_kill_allocating_task; int sysctl_oom_dump_tasks = 1; static DEFINE_SPINLOCK(zone_scan_lock); +static unsigned long last_victim; + #ifdef CONFIG_NUMA /** * has_intersects_mems_allowed() - check task eligiblity for kill @@ -264,14 +266,32 @@ enum oom_scan_t oom_scan_process_thread(struct task_struct *task, return OOM_SCAN_CONTINUE; /* - * This task already has access to memory reserves and is being killed. - * Don't allow any other task to have access to the reserves. + * We found a task that we already tried to kill, but it hasn't + * finished dying yet. Generally we want to avoid choosing another + * victim until it finishes. If we choose lots of victims then we'll + * use up our memory reserves and none of the tasks will be able to + * exit. + * + * ...but we can't wait forever. If a task persistently refuses to + * die then it might be waiting on a resource (mutex or whatever) that + * won't be released until _some other_ task runs. ...and maybe that + * other is blocked waiting on memory (deadlock!). If it's been + * "long enough" then we'll just skip over existing victims and pick + * someone new to kill. */ if (test_tsk_thread_flag(task, TIF_MEMDIE)) { if (unlikely(frozen(task))) __thaw_task(task); - if (!force_kill) - return OOM_SCAN_ABORT; + if (!force_kill) { + if (time_after(jiffies, + last_victim + msecs_to_jiffies(100))) { + pr_warn("Task %s:%d refused to die\n", + task->comm, task->pid); + return OOM_SCAN_CONTINUE; + } else { + return OOM_SCAN_ABORT; + } + } } if (!task->mm) return OOM_SCAN_CONTINUE; @@ -435,6 +455,7 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, */ if (p->flags & PF_EXITING) { set_tsk_thread_flag(p, TIF_MEMDIE); + last_victim = jiffies; put_task_struct(p); return; } @@ -538,6 +559,7 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, rcu_read_unlock(); set_tsk_thread_flag(victim, TIF_MEMDIE); + last_victim = jiffies; do_send_sig_info(SIGKILL, SEND_SIG_FORCED, victim, true); put_task_struct(victim); } @@ -670,6 +692,7 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, */ if (fatal_signal_pending(current) || current->flags & PF_EXITING) { set_thread_flag(TIF_MEMDIE); + last_victim = jiffies; return; } |