Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752283AbdC2Ozs (ORCPT ); Wed, 29 Mar 2017 10:55:48 -0400 Received: from cn.fujitsu.com ([59.151.112.132]:44098 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751583AbdC2Ozq (ORCPT ); Wed, 29 Mar 2017 10:55:46 -0400 X-IronPort-AV: E=Sophos;i="5.22,518,1449504000"; d="scan'208";a="17139546" From: Dou Liyang To: , CC: , , , , , , Dou Liyang Subject: [RFC PATCH 0/6] Unify the Interrupt Mode and setup it as soon as possible Date: Wed, 29 Mar 2017 22:55:27 +0800 Message-ID: <1490799333-18242-1-git-send-email-douly.fnst@cn.fujitsu.com> X-Mailer: git-send-email 2.5.5 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.167.226.106] X-yoursite-MailScanner-ID: BD15247EE1E3.A3A4D X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: douly.fnst@cn.fujitsu.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3223 Lines: 109 According to Ingo's and Eric's advice[1,2], Try my best to optimize the init of Interrupt Mode for x86. The MP specification defines three different interrupt modes as follows: 1. PIC Mode 2. Virtual Wire Mode 3. Symmetic I/O Mode Currently, In kernel, 1. Setup the Virtual Wire Mode during the IRQ initialization( step 1 in the following figure). 2. Enable and Setup the Symmetic I/O Mode either during the SMP-capabe system prepares CPUs(step 2) or during the UP system initializes itself(step 3). start_kernel +---------------+ | +--> ....... | | setup_arch +--> +-------+ | | init_IRQ +-> +--+-----+ | | init_ISA_irqs | +------> +-+--------+ | | +----------------+ +---> +------> | 1.init_bsp_APIC| | ....... +----------------+ +---> | rest_init +--->---+-----+ | | kernel_init | +> ----+-----+ | | kernel_init_freeable | +-> ----+-------------+ | | smp_prepare_cpus | +---> +----+---------+ | | | +-------------------+ | | +-> |2. apic_bsp_setup | | | +-------------------+ | | v | smp_init +---> +---+----+ | +-------------------+ +--> |3. apic_bsp_setup | +-------------------+ The purpose of this patchset is Unifing these setup steps and executing as soon as possible as follows: start_kernel ---------------+ | | | | init_IRQ +---->---+----+ | | | | +--------------------+ | +----> | 4. init_bsp_APIC | | +--------------------+ v By the way, Also fix a bug about kexec[3]. Some doubts, need help: 1. Patchset has influence on IOMMU in enable_IR_x2apic(). Not sure it can be in advance? 2. Due to Commit 8c3ba8d04924 ("x86, apic: ack all pending irqs when crashed/on kexec") ..., patchset also needs TSC and uses the "cpu_khz" in setup_local_APIC(). And a warning[4] will be triggered when crashed/on kexec. Not sure how to modify? [1]. https://lkml.org/lkml/2016/8/2/929 [2]. https://lkml.org/lkml/2016/8/1/506 [3]. https://lkml.org/lkml/2016/7/25/1118 [4]. WARN_ON(max_loops <= 0) in setup_local_APIC() Dou Liyang (6): x86/apic: Replace init_bsp_APIC() with apic_virture_wire_mode_setup() x86/apic: Construct a framework for setuping APIC mode as soon as possible x86/apic: Extract APIC timer related code from apic_bsp_setup() x86/apic: Make the APIC mode setup earlier for SMP-capable system x86/apic: Make the APIC mode setup earlier for UP system x86/apic: Remove the apic_virture_wire_mode_setup() arch/x86/include/asm/apic.h | 7 +- arch/x86/include/asm/io_apic.h | 2 + arch/x86/kernel/apic/apic.c | 218 ++++++++++++++++++++++++----------------- arch/x86/kernel/apic/io_apic.c | 4 +- arch/x86/kernel/irqinit.c | 6 +- arch/x86/kernel/smpboot.c | 68 ++----------- 6 files changed, 149 insertions(+), 156 deletions(-) -- 2.5.5