From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752721AbaLSOC4 (ORCPT ); Fri, 19 Dec 2014 09:02:56 -0500 Received: from terminus.zytor.com ([198.137.202.10]:45749 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752163AbaLSOCx (ORCPT ); Fri, 19 Dec 2014 09:02:53 -0500 Date: Fri, 19 Dec 2014 06:02:29 -0800 From: tip-bot for Thomas Gleixner Message-ID: Cc: hpa@zytor.com, tglx@linutronix.de, joro@8bytes.org, bp@alien8.de, jiang.liu@linux.intel.com, linux-kernel@vger.kernel.org, mingo@kernel.org Reply-To: jiang.liu@linux.intel.com, mingo@kernel.org, linux-kernel@vger.kernel.org, joro@8bytes.org, bp@alien8.de, tglx@linutronix.de, hpa@zytor.com In-Reply-To: <20141205084147.153643952@linutronix.de> References: <20141205084147.153643952@linutronix.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/apic] x86, smpboot: Remove pointless preempt_disable() in native_smp_prepare_cpus() Git-Commit-ID: 250a1ac685f147d4f4b2f132cfaffcce1a6792c1 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 250a1ac685f147d4f4b2f132cfaffcce1a6792c1 Gitweb: http://git.kernel.org/tip/250a1ac685f147d4f4b2f132cfaffcce1a6792c1 Author: Thomas Gleixner AuthorDate: Fri, 5 Dec 2014 08:48:29 +0000 Committer: Thomas Gleixner CommitDate: Tue, 16 Dec 2014 14:08:14 +0100 x86, smpboot: Remove pointless preempt_disable() in native_smp_prepare_cpus() There is no reason to keep preemption disabled in this function. We only have two other threads live: kthreadd and idle. Neither of them is going to preempt. But that preempt_disable forces all the code inside to do GFP_ATOMIC allocations which is just insane. Remove it. Signed-off-by: Thomas Gleixner Tested-by: Borislav Petkov Cc: Jiang Liu Cc: Joerg Roedel Cc: x86@kernel.org Link: http://lkml.kernel.org/r/20141205084147.153643952@linutronix.de Signed-off-by: Thomas Gleixner --- arch/x86/kernel/smpboot.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 7a8f584..6d7022c 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1084,7 +1084,6 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus) { unsigned int i; - preempt_disable(); smp_cpu_index_default(); /* @@ -1102,22 +1101,19 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus) } set_cpu_sibling_map(0); - if (smp_sanity_check(max_cpus) < 0) { pr_info("SMP disabled\n"); disable_smp(); - goto out; + return; } default_setup_apic_routing(); - preempt_disable(); if (read_apic_id() != boot_cpu_physical_apicid) { panic("Boot APIC ID in local APIC unexpected (%d vs %d)", read_apic_id(), boot_cpu_physical_apicid); /* Or can we switch back to PIC here? */ } - preempt_enable(); connect_bsp_APIC(); @@ -1151,8 +1147,6 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus) uv_system_init(); set_mtrr_aps_delayed_init(); -out: - preempt_enable(); } void arch_enable_nonboot_cpus_begin(void)