From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Gleixner Subject: Re: Next round: revised futex(2) man page for review Date: Tue, 28 Jul 2015 23:03:52 +0200 (CEST) Message-ID: References: <55B61EF3.7080302@gmail.com> <20150728204508.GG19282@twins.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="8323329-1673709282-1438117434=:3825" Return-path: In-Reply-To: <20150728204508.GG19282-ndre7Fmf5hadTX5a5knrm8zTDFooKrT+cvkQGrU6aU0@public.gmane.org> Sender: linux-man-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Peter Zijlstra Cc: "Michael Kerrisk (man-pages)" , Darren Hart , Torvald Riegel , Carlos O'Donell , Ingo Molnar , Jakub Jelinek , linux-man , lkml , Davidlohr Bueso , Arnd Bergmann , Steven Rostedt , Linux API , Roland McGrath , Anton Blanchard , Eric Dumazet , bill o gallmeister , Jan Kiszka , Daniel Wagner , Rich Felker , Andy Lutomirski , bert hubert , Rusty Russell , Heinrich Schuchardt List-Id: linux-api@vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323329-1673709282-1438117434=:3825 Content-Type: TEXT/PLAIN; charset=utf-8 Content-Transfer-Encoding: 8BIT On Tue, 28 Jul 2015, Peter Zijlstra wrote: > On Tue, Jul 28, 2015 at 10:23:51PM +0200, Thomas Gleixner wrote: > > > > FUTEX_WAKE (since Linux 2.6.0) > > > This operation wakes at most val of the waiters that are > > > waiting (e.g., inside FUTEX_WAIT) on the futex word at the > > > address uaddr. Most commonly, val is specified as either > > > 1 (wake up a single waiter) or INT_MAX (wake up all wait‐ > > > ers). No guarantee is provided about which waiters are > > > awoken (e.g., a waiter with a higher scheduling priority > > > is not guaranteed to be awoken in preference to a waiter > > > with a lower priority). > > > > That's only correct up to Linux 2.6.21. > > > > Since 2.6.22 we have a priority ordered wakeup. For SCHED_OTHER > > threads this takes the nice level into account. Threads with the same > > priority are woken in FIFO order. > > Maybe don't mention the effects of SCHED_OTHER, order by nice value is > 'wrong'. Indeed. > Also, this code seems to use plist, which means it won't do the right > thing for SCHED_DEADLINE either. > > Do we want to go fix that? I think so. Thanks, tglx --8323329-1673709282-1438117434=:3825-- -- 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