Messages in this thread | | | Date | Fri, 16 Jul 1999 22:33:55 +0200 | From | Andi Kleen <> | Subject | Re: kernel thread support - LWP's |
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On Fri, Jul 16, 1999 at 03:12:37PM -0400, Zack Weinberg wrote: > >Linus has very strong feelings against this, and i think he is right there. > >Stack management should be done in user space. You would just move some stuff > >that can be equally well done in user space into a giant system call. > > You're right about stack management being done in user space, but this > forces the libc clone() stub to be coded in such a way that it can't be used > without CLONE_VM. (Or you could write one that only works without it. You > just can't have it both ways.) This is because clone() with CLONE_VM > returns twice on the same stack, and will die horribly if allowed to do > anything at the C level afterward. Like vfork, only worse.
I think that is reasonable, as long as that complexity is hidden in libc.
> > >> It would also be handy to have a "disown" call which had the effect of > >> immediately reparenting the target process to init. Currently "detached > >> threads" have to be waited for too. > > > >This already exists. Do prctl(PR_SET_DEATHSIG, SOME_NEW_SIGNAL) in the child > >and ignore that signal in the parent (at least it should work in theory, > >I haven't tested it) > > I think if you do that then the zombie never gets reaped.
True, it needs SA_NOCLDWAIT too (which does not work ATM)
-Andi
-- This is like TV. I don't like TV.
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