linux-kernel - Re: [rfc] do not place sub-threads on task

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 30 Jun 2009 12:30:37 -0700 (PDT)
From:	Roland McGrath <roland@...hat.com>
To:	Oleg Nesterov <oleg@...hat.com>
Cc:	Ratan Nalumasu <rnalumasu@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Ingo Molnar <mingo@...e.hu>,
	Vitaly Mayatskikh <vmayatsk@...hat.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [rfc] do not place sub-threads on task_struct->children list

> Currently we add sub-threads to ->real_parent->children list. This
> buys nothing but slows down do_wait().
> 
> With this patch ->children contains only main threads (group leaders).
> The only complication is that forget_original_parent() should iterate
> over sub-threads by hand.

This seems right to me, though I'll admit I haven't really walked through
all the exit/reparent paths afresh with this in mind.

Note that this naturally suggests moving ->sibling to signal_struct.  (Of
course that can come later.)  The abuse of sibling in reparent_leader adds
a wrinkle to that, but off hand it looks like it could do the same with it
living in signal_struct with a bit of contortion.

Oh, and what about the de_thread() leader-replacement case?

Thanks,
Roland
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/