From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-io0-x235.google.com ([2607:f8b0:4001:c06::235]) by bombadil.infradead.org with esmtps (Exim 4.89 #1 (Red Hat Linux)) id 1eYmIG-0003Iw-CT for kexec@lists.infradead.org; Tue, 09 Jan 2018 05:17:50 +0000 Received: by mail-io0-x235.google.com with SMTP id z130so17119206ioe.13 for ; Mon, 08 Jan 2018 21:17:37 -0800 (PST) Date: Tue, 9 Jan 2018 14:22:38 +0900 From: AKASHI Takahiro Subject: Re: arm64 crashkernel fails to boot on acpi-only machines due to ACPI regions being no longer mapped as NOMAP Message-ID: <20180109052237.GC18820@linaro.org> References: <20171222083308.cy3vwlyhig22q5ee@fireball> <20171225032500.GA8877@linaro.org> <20171226013217.GA2119@dhcp-128-65.nay.redhat.com> <20171226013517.GA2186@dhcp-128-65.nay.redhat.com> <20171226022807.GB8877@linaro.org> <20171226065845.GB5354@dhcp-128-65.nay.redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20171226065845.GB5354@dhcp-128-65.nay.redhat.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Dave Young Cc: Mark Rutland , "linux-efi@vger.kernel.org" , Ard Biesheuvel , Matt Fleming , Bhupesh Sharma , kexec@lists.infradead.org, James Morse , Bhupesh SHARMA , "linux-arm-kernel@lists.infradead.org" On Tue, Dec 26, 2017 at 02:58:45PM +0800, Dave Young wrote: > On 12/26/17 at 08:26am, Bhupesh Sharma wrote: > > On Tue, Dec 26, 2017 at 7:58 AM, AKASHI Takahiro > > wrote: > > > On Tue, Dec 26, 2017 at 09:35:17AM +0800, Dave Young wrote: > > >> [snip] > > >> > > > Well, we may be able to change pr_warn() to pr_warn_once() here, but > > >> > > > I hope that adding "numa=off" to kernel command line should also work. > > >> > > > > >> > > Hmm, adding "numa=off" to crashkernel bootargs works, and TBH it was > > >> > > my initial thought process as well, but I am not sure if this will > > >> > > cause any regressions on aarch64 systems which use crashdump feature. > > >> > > > >> > It should be fine since we use numa=off by default for all other arches > > >> > ie. x86, ppc64 and s390. Actually disabling numa in kdump kernel can save > > >> > mm component memory usage. > > >> > > > >> > > >> Forgot to say I means in RHEL and Fedora we use numa=off for kdump.. > > > > > > Thank you for the clarification. > > > (It might be better to make numa off automatically if maxcpus == 0 (and 1?).) > > > > > > > Not sure if we can leave this to the distribution-specific kdump > > scripts (as the crashkernel boot can be held up for sufficient time > > and may appear stuck). The distribution scripts may be different (for > > e.g. ubuntu and RHEL/fedora) across distributions and may have > > different bootarg options. > > Personally I think distribution should take care of this param as for > kdump. But as AKASHI said it could be a issue for 1st kernel with > nr_cpus=1 booting. Problem is why we do not see this issue on other > machines. The issue won't be kdump-specific. Theoretically, it also takes place when "mem=" is specified on numa. Since we can avoid annoying messages by adding "numa=off", I'm reluctant to suppress most of messages but the first. My suggestion here is to add some notes in Documentation/kdump/kdump.txt regarding NUMA case. Thanks, Takahiro AKASHI > > > > So how about considering a kernel fix only which doesn't require > > relying on changing the distribution-specific kdump scripts, as we > > should avoid introducing a regression while trying to fix a regression > > :) > > > > Just my 2 cents. > > > > Thanks, > > Bhupesh > > Thanks > Dave _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec