Re: init's children list is long and slows reaping children.

[Ingo Molnar]

* Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

> I'd almost prefer to just not add kernel threads to any parent process 
> list *at*all*.

i think part of the problem is the legacy that the list is artificially 
unified: tasks that 'will possibly exit' are on the same list as tasks 
that 'have already exited'. If we split it up into its natural data 
structure, having a list of tasks that are there and do not intend to 
exit, plus a separate list of tasks that are exiting and want to notify 
their parent, all this scanning goes away. I can see no real reason for 
this other than legacy - i dont think the semantics of the wait4() API 
force us to scan all those threads.

putting the freshly reaped tasks at the 'head' of the list is just a 
fancy (and incomplete) way of splitting the list up into two lists, and 
i'd advocate a clean split. Just like have have split the ptrace_list 
away from the main list too.

	Ingo
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/