From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753018AbZHaQac (ORCPT ); Mon, 31 Aug 2009 12:30:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752183AbZHaQab (ORCPT ); Mon, 31 Aug 2009 12:30:31 -0400 Received: from e39.co.us.ibm.com ([32.97.110.160]:48076 "EHLO e39.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751695AbZHaQab (ORCPT ); Mon, 31 Aug 2009 12:30:31 -0400 Message-ID: <4A9BFA92.2030300@us.ibm.com> Date: Mon, 31 Aug 2009 09:30:10 -0700 From: Darren Hart User-Agent: Thunderbird 2.0.0.23 (X11/20090817) MIME-Version: 1.0 To: Arnd Bergmann CC: Michael Schnell , linux-kernel@vger.kernel.org, Mike Frysinger , Paul Mundt , Michael Kerrisk , Ingo Molnar , Jakub Jelinek , Thomas Chou Subject: Re: implementing Futex References: <4A842B32.5030401@lumino.de> <200908141438.01392.arnd@arndb.de> <4A855EE5.9010105@lumino.de> <200908141533.16714.arnd@arndb.de> In-Reply-To: <200908141533.16714.arnd@arndb.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Arnd Bergmann wrote: > On Friday 14 August 2009, Michael Schnell wrote: >> Arnd Bergmann wrote: >>> The man page says that the last parameter is ignored for op=FUTEX_WAKE, >>> which is correct. The code that you were looking at however is for >>> of=FUTEX_WAKE_OP, which is not documented as of manpages-3.22. >>> >>> It was added by Jakub back in 2005, but if he wrote a documentation >>> for it, it never went into the man pages package. On a similar >>> note, Ingo also added other futex operations that are not documented >>> yet. >>> >> Thus in any documented software, the quite complex stuff in >> "futex_atomic_op_inuser", which is provided in several different >> "futex.h" files for all those architectures never is used ? > > No, my point was that futex_atomic_op_inuser is indeed used > correctly, it's just not documented. > See http://lwn.net/Articles/148830/ for the initial posting > >> Is there any viable use for this ? > > glibc heavily uses it for the pthreads implementation. > >> Would it not be appropriate either to do a documentation or to remove it ? > > Adding documentation, yes. I also recently added two futex op codes which need to be added to the man page, but they are documented in Documentation/futex-requeue-pi.txt. Documentation/pi-futex.txt documents the FUTEX_(UN)LOCK_PI opcodes which aren't in the man pages either. -- Darren Hart IBM Linux Technology Center Real-Time Linux Team