Re: [rfc][patch] Avoid taking global tasklist_lock for single threadedprocess at getrusage()

Ravikiran G Thirumalai
2005-12-28T18:33:48Z

On Wed, Dec 28, 2005 at 03:38:39PM +0300, Oleg Nesterov wrote:
> Christoph Lameter wrote:
> >
> > On Sat, 24 Dec 2005, Oleg Nesterov wrote:
> >
> > > I can't understand this. 'p' can do clone(CLONE_THREAD) immediately
> > > after 'if (!thread_group_empty(p))' check.
> >
> > Only if p != current. As discussed later the lockless approach is
> > intened to only be used if p == current.
>
> Unless I missed something this function (getrusage_both) is called
> from wait_noreap_copyout,

Hi Oleg,
Yes, this patch needs to be reworked. I am on it. I'd also missed that
p->signal was protected by the tasklist_lock. Thanks for pointing it out.
I will put out the modified version soon.

Thanks,
Kiran