Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752486Ab3HAAjy (ORCPT ); Wed, 31 Jul 2013 20:39:54 -0400 Received: from mail-wi0-f179.google.com ([209.85.212.179]:51816 "EHLO mail-wi0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752124Ab3HAAb4 (ORCPT ); Wed, 31 Jul 2013 20:31:56 -0400 From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Steven Rostedt , "Paul E. McKenney" , Ingo Molnar , Thomas Gleixner , Peter Zijlstra , Borislav Petkov , Li Zhong , Mike Galbraith , Kevin Hilman Subject: [PATCH 06/23] context_tracking: Remove full dynticks' hacky dependency on wide context tracking Date: Thu, 1 Aug 2013 02:31:23 +0200 Message-Id: <1375317100-20651-7-git-send-email-fweisbec@gmail.com> X-Mailer: git-send-email 1.7.5.4 In-Reply-To: <1375317100-20651-1-git-send-email-fweisbec@gmail.com> References: <1375317100-20651-1-git-send-email-fweisbec@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3413 Lines: 88 Now that the full dynticks subsystem only enables the context tracking on full dynticks CPUs, lets remove the dependency on CONTEXT_TRACKING_FORCE This dependency was a hack to enable the context tracking widely for the full dynticks susbsystem until the latter becomes able to enable it in a more CPU-finegrained fashion. Now CONTEXT_TRACKING_FORCE only stands for testing on archs that work on support for the context tracking while full dynticks can't be used yet due to unmet dependencies. It simulates a system where all CPUs are full dynticks so that RCU user extended quiescent states and dynticks cputime accounting can be tested on the given arch. Signed-off-by: Frederic Weisbecker Cc: Steven Rostedt Cc: Paul E. McKenney Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Borislav Petkov Cc: Li Zhong Cc: Mike Galbraith Cc: Kevin Hilman --- init/Kconfig | 28 ++++++++++++++++++++++------ kernel/time/Kconfig | 1 - 2 files changed, 22 insertions(+), 7 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index 247084b..ffbf5d7 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -527,13 +527,29 @@ config RCU_USER_QS config CONTEXT_TRACKING_FORCE bool "Force context tracking" depends on CONTEXT_TRACKING - default CONTEXT_TRACKING + default y if !NO_HZ_FULL help - Probe on user/kernel boundaries by default in order to - test the features that rely on it such as userspace RCU extended - quiescent states. - This test is there for debugging until we have a real user like the - full dynticks mode. + The major pre-requirement for full dynticks to work is to + support the context tracking subsystem. But there are also + other dependencies to provide in order to make the full + dynticks working. + + This option stands for testing when an arch implements the + context tracking backend but doesn't yet fullfill all the + requirements to make the full dynticks feature working. + Without the full dynticks, there is no way to test the support + for context tracking and the subsystems that rely on it: RCU + userspace extended quiescent state and tickless cputime + accounting. This option copes with the absence of the full + dynticks subsystem by forcing the context tracking on all + CPUs in the system. + + Say Y only if you're working on the developpement of an + architecture backend for the context tracking. + + Say N otherwise, this option brings an overhead that you + don't want in production. + config RCU_FANOUT int "Tree-based hierarchical RCU fanout value" diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig index 70f27e8..747bbc7 100644 --- a/kernel/time/Kconfig +++ b/kernel/time/Kconfig @@ -105,7 +105,6 @@ config NO_HZ_FULL select RCU_USER_QS select RCU_NOCB_CPU select VIRT_CPU_ACCOUNTING_GEN - select CONTEXT_TRACKING_FORCE select IRQ_WORK help Adaptively try to shutdown the tick whenever possible, even when -- 1.7.5.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/