On 01/06, Mandeep Singh Baines wrote: > > Oleg Nesterov (oleg@xxxxxxxxxx) wrote: > > > > > > in particular, http://marc.info/?l=linux-kernel&m=127714242731448 > > > > I think this should work, but then we should do something with the > > > > users like zap_threads(). > > > > > > > > > > With that patch, won't you potentially miss the exec thread if an exec > > > occurs while you're iterating over the list? Is that OK? > > > > Of course it is not OK ;) Note the "we should do something with" above. > > > > So requirements should be something like this: (I assume, you mean the lockless case) > * Any task alive for the duration of the iteration MUST be visited > * No task should be visited more than once > * Any task born or exiting after starting the iteration MAY be skipped > * You can start at any task in the thread group Well yes, but it is not easy to exactly define what after/before means in this case. > Would something like this work: > > #define while_each_thread(g, t, o) \ > while (t->group_leader == o && (t = next_thread(t)) != g) > > Where o should have the value of g->group_leader. I don't understand how this helps... and how this can work even ignoring the barriers. OK, we have the main thream M and the sub-thread T, we are doing do { do_something(t); } while_each_thread(M, t, M); why we can't miss T if it does exec? Oleg. -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
