From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751501AbeAED1B (ORCPT + 1 other); Thu, 4 Jan 2018 22:27:01 -0500 Received: from mx1.redhat.com ([209.132.183.28]:36622 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751298AbeAED1A (ORCPT ); Thu, 4 Jan 2018 22:27:00 -0500 Date: Fri, 5 Jan 2018 11:26:57 +0800 From: Baoquan He To: linux-kernel@vger.kernel.org Cc: mingo@redhat.com, tglx@linutronix.de, hpa@zytor.com, x86@kernel.org, douly.fnst@cn.fujitsu.com, rostedt@goodmis.org, jgross@suse.com, peterz@infradead.org, uobergfe@redhat.com, joro@8bytes.org Subject: Re: [PATCH 1/3] x86/apic: Set up through LAPIC on boot CPU's LINT0 if ioapic is disabled to kexec/kdump kernel Message-ID: <20180105032657.GH7235@x1> References: <1515120933-27414-1-git-send-email-bhe@redhat.com> <20180105032226.GE7235@x1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180105032226.GE7235@x1> User-Agent: Mutt/1.7.0 (2016-08-17) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Fri, 05 Jan 2018 03:27:00 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: Sorry, my git send-email config seems incorrect. The patch subject is not right. So NACK this series, will repost v2. On 01/05/18 at 11:22am, Baoquan He wrote: > Kdump kernel will become very slow if 'noapic' is specified in kernel > command line. Normal kernel doesn't have this issue. > > This is because the legacy irq mode is disabled in crashed kernel before > jump jump to kdump kernel since commit 522e66464467 ("x86/apic: Disable I/O > APIC before shutdown of the local APIC") is merged. While in normal kernel, > the legacy irq mode has been set in BIOS. > > So we need set the delivery mode AS ExtINT for LVT0 of boot CPU's LAPIC > explicitly if IO-APIC is disabled, to set up through-local-APIC. > > Signed-off-by: Baoquan He > --- > arch/x86/kernel/apic/apic.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c > index 880441f24146..7e613fb90630 100644 > --- a/arch/x86/kernel/apic/apic.c > +++ b/arch/x86/kernel/apic/apic.c > @@ -1521,7 +1521,7 @@ void setup_local_APIC(void) > * TODO: set up through-local-APIC from through-I/O-APIC? --macro > */ > value = apic_read(APIC_LVT0) & APIC_LVT_MASKED; > - if (!cpu && (pic_mode || !value)) { > + if (!cpu && (pic_mode || !value || skip_ioapic_setup)) { > value = APIC_DM_EXTINT; > apic_printk(APIC_VERBOSE, "enabled ExtINT on CPU#%d\n", cpu); > } else { > -- > 2.5.5 >