From patchwork Tue Nov 15 20:27:57 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Paul E. McKenney" X-Patchwork-Id: 5152 Return-Path: X-Original-To: patchwork@peony.canonical.com Delivered-To: patchwork@peony.canonical.com Received: from fiordland.canonical.com (fiordland.canonical.com [91.189.94.145]) by peony.canonical.com (Postfix) with ESMTP id AF9EC23E0F for ; Tue, 15 Nov 2011 20:28:35 +0000 (UTC) Received: from mail-fx0-f52.google.com (mail-fx0-f52.google.com [209.85.161.52]) by fiordland.canonical.com (Postfix) with ESMTP id A3BE7A1827D for ; Tue, 15 Nov 2011 20:28:35 +0000 (UTC) Received: by mail-fx0-f52.google.com with SMTP id a26so1226734faa.11 for ; Tue, 15 Nov 2011 12:28:35 -0800 (PST) Received: by 10.152.134.116 with SMTP id pj20mr18361609lab.5.1321388915494; Tue, 15 Nov 2011 12:28:35 -0800 (PST) X-Forwarded-To: linaro-patchwork@canonical.com X-Forwarded-For: patch@linaro.org linaro-patchwork@canonical.com Delivered-To: patches@linaro.org Received: by 10.152.41.198 with SMTP id h6cs55693lal; Tue, 15 Nov 2011 12:28:35 -0800 (PST) Received: by 10.52.27.72 with SMTP id r8mr44970495vdg.71.1321388912808; Tue, 15 Nov 2011 12:28:32 -0800 (PST) Received: from e1.ny.us.ibm.com (e1.ny.us.ibm.com. [32.97.182.141]) by mx.google.com with ESMTPS id p8si6937100yba.51.2011.11.15.12.28.32 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 15 Nov 2011 12:28:32 -0800 (PST) Received-SPF: pass (google.com: domain of paulmck@linux.vnet.ibm.com designates 32.97.182.141 as permitted sender) client-ip=32.97.182.141; Authentication-Results: mx.google.com; spf=pass (google.com: domain of paulmck@linux.vnet.ibm.com designates 32.97.182.141 as permitted sender) smtp.mail=paulmck@linux.vnet.ibm.com Received: from /spool/local by e1.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 15 Nov 2011 15:28:31 -0500 Received: from d01relay03.pok.ibm.com (9.56.227.235) by e1.ny.us.ibm.com (192.168.1.101) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Tue, 15 Nov 2011 15:28:14 -0500 Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay03.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id pAFKSC0c224682; Tue, 15 Nov 2011 15:28:13 -0500 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id pAFKS7gY008051; Tue, 15 Nov 2011 15:28:08 -0500 Received: from paulmck-ThinkPad-W500 ([9.47.24.246]) by d01av04.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id pAFKS7T1008039; Tue, 15 Nov 2011 15:28:07 -0500 Received: by paulmck-ThinkPad-W500 (Postfix, from userid 1000) id BA375EAA0C; Tue, 15 Nov 2011 12:28:06 -0800 (PST) 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: 11111520-6078-0000-0000-0000046E0AF8 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.