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Subject: Re: [PATCH] Read THREAD_CPUTIME clock from other  processes.
From: Dario Faggioli <raistlin@linux.it>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
        linux-kernel <linux-kernel@vger.kernel.org>, torbenh <torbenh@gmx.de>,
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        Stanislaw Gruszka <sgruszka@redhat.com>,
        Dhaval Giani <dhaval.giani@gmail.com>
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On Thu, 2010-12-23 at 18:38 +0100, Dario Faggioli wrote:=20
> > >  	rcu_read_lock();
> > >  	p =3D find_task_by_vpid(pid);
> > > -	if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
> > > -		   same_thread_group(p, current) : has_group_leader_pid(p))) {
> > > +	if (!p)
> > >  		error =3D -EINVAL;
> > > -	}
> >=20
> > This changes the behaviour of sys_clock_settime(). Probably doesn't
> > matter since it does nothing, but perhaps !CPUCLOCK_PERTHREAD &&
> > !group_leader should result in -EINAVL as before.
> >=20
> Oops, sure, you're right, I can fix this. :-)
>=20
Mmm... This is trickier than I remembered expected. Apparently, glibc
always gives us a !CPUCLOCK_PERTHREAD() clockid, since it uses
MAKE_PROCESS_CLOCK() when clock_cpugetclockid is called.

Therefore, the take two of this thing will be a little different from
this first posting...

Thanks and Regards,
Dario

--=20
<<This happens because I choose it to happen!>> (Raistlin Majere)
----------------------------------------------------------------------
Dario Faggioli, ReTiS Lab, Scuola Superiore Sant'Anna, Pisa  (Italy)

http://retis.sssup.it/people/faggioli -- dario.faggioli@jabber.org


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