Messages in this thread | | | Date | Fri, 30 Oct 2009 18:56:20 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] ptrace: cleanup ptrace_init_task()->ptrace_link() path |
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On Sat, 31 Oct 2009 01:55:07 +0100 Oleg Nesterov <oleg@redhat.com> wrote:
> On 10/30, Andrew Morton wrote: > > > > On Fri, 30 Oct 2009 00:56:56 +0100 > > Oleg Nesterov <oleg@redhat.com> wrote: > > > > > ptrace > > > > Speaking of which, I'm still sitting on > > do_wait-optimization-do-not-place-sub-threads-on-task_struct-children-list.patch. > > (this patch has nothing to do with ptrace) > > > Should I drop it? > > Why? I think this is good optimization and imho cleanup. > > There is no point to have sub-thread in ->children list and this > slows down do_wait() if a child has a lot of threads, it has to > iterate over all sub-threads just to filter them out. >
On 17 Sep you said:
: Yes, risky... God knows who can do list_for_each(->children) and expect to : find the sub-threads. But this is obviously good optimization/simplification. : : It is just ugly to place sub-threads on ->children list, this buys nothing : but slown downs do_wait(). (this was needed, afaics, to handle ptraced but : not re-parented threads a long ago).
so that's why I didn't merge it into 2.6.32. Is the patch still considered "risky"?
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