Ingo Molnar <[EMAIL PROTECTED]> writes: > * Eric W. Biederman <[EMAIL PROTECTED]> wrote: > >> > on a second thought: the p->children list is needed for the whole >> > child/parent task tree, which is needed for sys_getppid(). >> >> Yes, something Oleg said made me realize that. >> >> As long as the reparent isn't to complex it isn't required that we >> have exactly one list . >> >> > The question is, does anything require us to reparent to within the >> > same thread group? >> >> I think my head is finally on straight about this question. >> >> Currently there is the silly linux specific parent death signal >> (pdeath_signal). Oleg's memory was a better than mine on this score. >> >> However there is no indication that the parent death signal being sent >> when a thread leader dies is actually correct, or even interesting. It >> probably should only be sent when getppid changes. >> >> So with pdeath_signal fixed that is nothing that requires us to >> reparent within the same thread group. >> >> I'm trying to remember what the story is now. There is a nasty race >> somewhere with reparenting, a threaded parent setting SIGCHLD to >> SIGIGN, and non-default signals that results in an zombie that no one >> can wait for and reap. It requires being reparented twice to trigger. >> >> Anyway it is a real mess and if we can remove the stupid multi-headed >> child lists things would become much simpler and the problem could not >> occur. >> >> Plus the code would become much simpler... >> >> utrace appears to have removed the ptrace_children list and the >> special cases that entailed. > > so ... is anyone pursuing this? This would allow us to make sys_wait4() > faster and more scalable: no tasklist_lock bouncing for example.
which part? Eric - 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/
