Re: [patch] O(1) sys_exit(), threading, scalable-exit-2.5.31-A6

From: Dave McCracken (
Date: Mon Aug 19 2002 - 13:31:38 EST

--On Monday, August 19, 2002 08:08:10 PM +0200 Ingo Molnar <>

> the problem is that the tracing task wants to do a wait4() on all traced
> children, and the only way to get that is to have the traced tasks in the
> child list. Eg. strace -f traces a random number of tasks, and after the
> PTRACE_CONTINUE call, the wait4 done by strace must be able to 'get
> events' from pretty much any of the traced tasks. So unless the ptrace
> interface is reworked in an incompatible way, i cannot see how this would
> work. wait4 could perhaps somehow search the whole tasklist, but that
> could be a pretty big pain even for something like strace.

It seems to me it would be worth adding list_heads in the task struct for
ptraced tasks and ptraced siblings if it gets rid of the reparenting.

Dave McCracken

Dave McCracken IBM Linux Base Kernel Team 1-512-838-3059 T/L 678-3059

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