From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263164AbUC3Fld (ORCPT ); Tue, 30 Mar 2004 00:41:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263205AbUC3Fld (ORCPT ); Tue, 30 Mar 2004 00:41:33 -0500 Received: from gate.crashing.org ([63.228.1.57]:55445 "EHLO gate.crashing.org") by vger.kernel.org with ESMTP id S263164AbUC3Fl2 (ORCPT ); Tue, 30 Mar 2004 00:41:28 -0500 Subject: [PATCH] ppc32: Allow PREEMPT with SMP in KConfig From: Benjamin Herrenschmidt To: Andrew Morton Cc: Linus Torvalds , Linux Kernel list Content-Type: text/plain Message-Id: <1080625278.1213.11.camel@gaston> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.5 Date: Tue, 30 Mar 2004 15:41:18 +1000 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi ! On ppc32, CONFIG_PREEMPT wasn't settable along with CONFIG_SMP for historical reasons (smp_processor_id() races). Those races have been fixes since then (well, should have been at least) so it's now safe to allow both options. Ben. ===== arch/ppc/Kconfig 1.56 vs edited ===== --- 1.56/arch/ppc/Kconfig Fri Mar 19 17:04:54 2004 +++ edited/arch/ppc/Kconfig Tue Mar 30 15:39:41 2004 @@ -696,14 +696,10 @@ config PREEMPT bool "Preemptible Kernel" - depends on !SMP help This option reduces the latency of the kernel when reacting to real-time or interactive events by allowing a low priority process to be preempted even if it is in kernel mode executing a system call. - Unfortunately the kernel code has some race conditions if both - CONFIG_SMP and CONFIG_PREEMPT are enabled, so this option is - currently disabled if you are building an SMP kernel. Say Y here if you are building a kernel for a desktop, embedded or real-time system. Say N if you are unsure.