On 11/25, Michael Holzheu wrote: > > Hello Oleg, > > On Tue, 2010-11-23 at 17:59 +0100, Oleg Nesterov wrote: > > On 11/19, Michael Holzheu wrote: > > > TODO: > > > ----- > > > With this patch we take the siglock twice. First for the dead task > > > and second for the parent of the dead task. This give the following > > > lockdep warning (probably a lockdep annotation is needed here): > > > > And we already discussed this ;) We do not need 2 siglock's, only > > parent's. Just move the callsite in __exit_signal() down, under > > another (lockless) group_dead check. > > > > Or I missed something? > > The problem with moving this down to the second group_dead check is that > after __unhash_process() is called, pid_alive(tsk) which is checked in > thread_group_cputime() returns false. Therefore we always get zero CPU > times. I see, thanks. > So I probably have to introduce a second group_dead check at the > beginning of __exit_signal(): Probably... But in fact this reminds we should cleanup this code somehow. By the time we call thread_group_times() there are no other threads. > My personal feeling is that probably the only acceptable thing would be > to make the new behavior configurable with a sysctl and define the > default as it currently is (POSIX compliant). > > This would only introduce two additional checks in __exit_signal() and > wait_task_zombie() and would not add any new fields to the > signal_struct. Yeah, it would be nice to avoid new fields. Hmm. Somehow I forgot about 4/4, please see another email... Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
