On 09/30, Tetsuo Handa wrote: > > David Rientjes wrote: > > On Tue, 29 Sep 2015, Oleg Nesterov wrote: > > > > > The fatal_signal_pending() was added to suppress unnecessary "sharing > > > same memory" message, but it can't 100% help anyway because it can be > > > false-negative; SIGKILL can be already dequeued. > > > > > > And worse, it can be false-positive due to exec or coredump. exec is > > > mostly fine, but coredump is not. It is possible that the group leader > > > has the pending SIGKILL because its sub-thread originated the coredump, > > > in this case we must not skip this process. > > > > > > We could probably add the additional ->group_exit_task check but this > > > pach just removes fatal_signal_pending(), the extra "Kill process" is > > > unlikely and doesn't really hurt. > > This fatal_signal_pending() check is about to be added by me because the OOM > killer spams the kernel log when the mm struct which the OOM victim is using > is shared by many threads. ( http://marc.info/?l=linux-mm&m=143256441501204 )
OK, I see, but it is wrong. But I don't really understand "shared by many threads", I mean "threads" is confusing word. I guess you mean CLONE_VM processes, otherwise we shouldn't see the additional spam. And 1000 CLONE_VM processes + "and the lock dependency prevents all threads except the OOM victim thread from terminating until they get TIF_MEMDIE flag" look like a really pathological case... > > In addition, I'm really debating whether we need the "sharing same memory" > > line or not. In the past, it has been helpful because there is no other > > way to determine what the kernel has killed other than to leave an > > artifact behind in the kernel log. I can imagine that this could easily > > spam the kernel log, though, accompanied by oom killer messages that are > > already very verbose. I wouldn't mind if it the printk were removed > > entirely. > > > > I was waiting for your comment about whether you depend on > the "sharing same memory" message with KERN_ERR level. > ( http://marc.info/?l=linux-mm&m=144120389203133 ) > > If nobody else objects, I think we can remove the "sharing same memory" > message. ( http://marc.info/?l=linux-mm&m=144119325831959 ) OK, will you agree with v2 which also removes pr_warn? Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
