Re: [RFC] fs, proc: Introduce /proc/<pid>/task/<tid>/children entryv6

From: KOSAKI Motohiro
Date: Tue Jan 17 2012 - 16:38:14 EST


(1/16/12 10:32 AM), Cyrill Gorcunov wrote:
When we do checkpoint of a task we need to know the list of children
the task, has but there is no easy and fast way to generate reverse
parent->children chain from arbitrary<pid> (while a parent pid is
provided in "PPid" field of /proc/<pid>/status).

So instead of walking over all pids in the system (creating one big process
tree in memory, just to figure out which children a task has) -- we add
explicit /proc/<pid>/task/<tid>/children entry, because the kernel already has
this kind of information but it is not yet exported.

I doubt this is good idea. It move some complexity to userland, but not reduce.
Again, if we add this interface, it should help pstree like process traversal
tools. Bare task hierarchy shouldn't be exposed userland. I believe users need
sub process, not sub threads.



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