On 03/09, David Rientjes wrote: > > On Wed, 9 Mar 2011, Oleg Nesterov wrote: > > > > Using for_each_process() does not consider threads that have failed to > > > exit after the oom killed parent and, thus, we select another innocent > > > task to kill when we're really just waiting for those threads to exit > > > > How so? select_bad_process() checks TIF_MEMDIE and returns ERR_PTR() > > if it is set. > > > > TIF_MEMDIE is quite obviously a per-thread flag Yes, and this is why I think it should be replaced. > That leader may exit and leave behind several other > threads No, it can't. More precisely, it can, and it can even exit _before_ this process starts to use a lot of memory, then later this process can be oom-killed. But, until all threads disappear, the leader can't go away and for_each_process() must see it. IOW. If for_each_process() doesn't see the leader, there are no threads from its thread group. If it does see, the process is not dead yet. It may be exiting, and the current check tries to detect this case but it is not perfect. And btw "if (p != current)" code is wrong. I told this many times. This was one of the reasons why initial ->mm != NULL in select_bad_process() were completely wrong. Now we are going to re-introduce them, although Andrey's patch is not that wrong (but should be dropped anyway imho). However, > > And, exactly because we use for_each_process() we do not need to check > > other threads. The main thread can't disappear until they all exit. > > > > That's obviously false, I still can't convince you ;) Oleg. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>