From mboxrd@z Thu Jan 1 00:00:00 1970 From: Darren Hart Subject: Re: Futex manpages out of date Date: Fri, 15 Jan 2010 09:13:12 -0800 Message-ID: <4B50A228.8070401@us.ibm.com> References: <4B509EA1.8060509@us.ibm.com> <1263575484.4244.445.camel@laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1263575484.4244.445.camel@laptop> Sender: linux-man-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Peter Zijlstra Cc: Michael Kerrisk , linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Thomas Gleixner , Ingo Molnar , Eric Dumazet , Dinakar Guniguntala , John Stultz , John Kacur List-Id: linux-man@vger.kernel.org Peter Zijlstra wrote: > On Fri, 2010-01-15 at 08:58 -0800, Darren Hart wrote: >> The futex man-pages (2,7) from version 3.15-1 and at least a few earlier >> versions are considerably out of date with respect to the current >> implementation. They don't document newer op codes, such as: >> >> FUTEX_WAIT_BITSET >> FUTEX_WAKE_BITSET >> FUTEX_WAKE_OP >> FUTEX_LOCK_PI >> FUTEX_UNLOCK_PI >> FUTEX_WAIT_REQUEUE_PI >> FUTEX_CMP_REQUEUE_PI >> >> These new wait op codes now use absolute timeouts, while the original >> FUTEX_WAIT uses a relative timeout. Lastly, and most importantly, glibc >> has removed the futex() wrapper to syscall(SYS_futex, ...). With that in >> mind, would people prefer that we simply remove the futex man-pages >> (2,7)? > > A readable text about the interaction between the futex value and the > various futex ops and how to build proper locking primitives with them > would be helpful I think, however doing that in the form of a locking > library (as has been suggested at KS) seems plenty fine to me. > > Readable code is much better than rambling English at conveying this > stuff. Perhaps as part of futex-test? An example set of locking primitives would be a good way to test the syscall independently of glibc... -- Darren Hart IBM Linux Technology Center Real-Time Linux Team -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html