From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932257Ab1KOU2R (ORCPT ); Tue, 15 Nov 2011 15:28:17 -0500 Received: from e7.ny.us.ibm.com ([32.97.182.137]:54345 "EHLO e7.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757064Ab1KOU2O (ORCPT ); Tue, 15 Nov 2011 15:28:14 -0500 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com, patches@linaro.org, "Paul E. McKenney" , "Paul E. McKenney" Subject: [PATCH tip/core/rcu 1/9] rcu: Permit RCU_FAST_NO_HZ to be used by TREE_PREEMPT_RCU Date: Tue, 15 Nov 2011 12:27:57 -0800 Message-Id: <1321388885-11211-1-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.3.2 In-Reply-To: <20111115202736.GA11030@linux.vnet.ibm.com> References: <20111115202736.GA11030@linux.vnet.ibm.com> x-cbid: 11111520-5806-0000-0000-0000060E0078 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Paul E. McKenney The new implementation of RCU_FAST_NO_HZ is compatible with preemptible RCU, so this commit removes the Kconfig restriction that previously prohibited this. Signed-off-by: Paul E. McKenney --- init/Kconfig | 10 +++++----- 1 files changed, 5 insertions(+), 5 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index 43298f9..82b6a4c 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -469,14 +469,14 @@ config RCU_FANOUT_EXACT config RCU_FAST_NO_HZ bool "Accelerate last non-dyntick-idle CPU's grace periods" - depends on TREE_RCU && NO_HZ && SMP + depends on NO_HZ && SMP default n help This option causes RCU to attempt to accelerate grace periods - in order to allow the final CPU to enter dynticks-idle state - more quickly. On the other hand, this option increases the - overhead of the dynticks-idle checking, particularly on systems - with large numbers of CPUs. + in order to allow CPUs to enter dynticks-idle state more + quickly. On the other hand, this option increases the overhead + of the dynticks-idle checking, particularly on systems with + large numbers of CPUs. Say Y if energy efficiency is critically important, particularly if you have relatively few CPUs. -- 1.7.3.2