From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757524AbYE0JB0 (ORCPT ); Tue, 27 May 2008 05:01:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756685AbYE0JBQ (ORCPT ); Tue, 27 May 2008 05:01:16 -0400 Received: from smtp6.pp.htv.fi ([213.243.153.40]:58255 "EHLO smtp6.pp.htv.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755853AbYE0JBP (ORCPT ); Tue, 27 May 2008 05:01:15 -0400 Date: Tue, 27 May 2008 11:58:30 +0300 From: Adrian Bunk To: Mike Galbraith , Peter Zijlstra , Ingo Molnar , Andrew Morton , Linus Torvalds Cc: linux-kernel@vger.kernel.org Subject: [RFC: 2.6 patch] let GROUP_SCHED depend on BROKEN Message-ID: <20080527085830.GA20938@cs181133002.pp.htv.fi> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I know that this is controversial, for further background please see the discussion in http://bugzilla.kernel.org/show_bug.cgi?id=10761 Facts: - Bugzilla statistics (not counting duplicate bugs and bugs closed as INVALID): - 6 CPU scheduler regressions reported during 2.6.25-rc 1 of them still open as of 2.6.26-rc4 - 6 CPU scheduler regressions reported during 2.6.26-rc until now 5 of them still open as of 2.6.26-rc4 - at about half of the CPU scheduler regressions are related to group scheduling - Peter Zijlstra said in Bugzilla bug #10761: > Adrian Bunk said: > The CPU scheduler is currently regressing horribly often, and half of the > regressions are in group scheduling. That is because group scheduling is horribly complex and was never feature complete - trying to solve that is high on my list of priorities. My opinion: - features that alter existing kernel functionality should (different from drivers for previously not supported hardware) be in a very good state before being offered in stable kernels - Peter is wrong when he thinks that EXPERIMENTAL would somehow hide known-problematic features - in practice nearly everyone has to have EXPERIMENTAL enabled (e.g. for some hardware driver) - group scheduling already has a history of people accidentally enabling it and then running into problems I therefore suggest this patch to let GROUP_SCHED depend on BROKEN. Once it is feature complete and then got the usual testing through -next I'll have no objections against offering it again to users. Signed-off-by: Adrian Bunk --- c67cfbbb40895b72760865527dd1949631b1d183 diff --git a/init/Kconfig b/init/Kconfig index d9526b5..564deba 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -333,7 +333,7 @@ config HAVE_UNSTABLE_SCHED_CLOCK config GROUP_SCHED bool "Group CPU scheduler" - depends on EXPERIMENTAL + depends on BROKEN default n help This feature lets CPU scheduler recognize task groups and control CPU