From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752571AbdJaHI1 (ORCPT ); Tue, 31 Oct 2017 03:08:27 -0400 Received: from mga07.intel.com ([134.134.136.100]:43248 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751487AbdJaHIZ (ORCPT ); Tue, 31 Oct 2017 03:08:25 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.44,322,1505804400"; d="scan'208";a="915724899" Date: Tue, 31 Oct 2017 08:08:19 +0100 From: Fengguang Wu To: Dan Williams Cc: Linus Torvalds , Linux Kernel Mailing List , Vishal Verma , Huang Ying , Aaron Lu Subject: Re: [pmem_attach_disk] WARNING: CPU: 46 PID: 518 at kernel/memremap.c:363 devm_memremap_pages+0x350/0x4b0 Message-ID: <20171031070819.favx7xdsxqzsmuoc@wfg-t540p.sh.intel.com> References: <20171029225155.qcum5i75awrt5tzm@wfg-t540p.sh.intel.com> <20171030074055.wd56v3wiy2aveh2p@wfg-t540p.sh.intel.com> <20171031000053.gdn5jbxhlrxqmxfq@wfg-t540p.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org CC Ying and Aaron for Dan's tips on nvdimm testing. On Mon, Oct 30, 2017 at 05:24:42PM -0700, Dan Williams wrote: >On Mon, Oct 30, 2017 at 5:00 PM, Fengguang Wu wrote: >> Hi Dan, >> >> On Mon, Oct 30, 2017 at 08:59:46AM -0700, Dan Williams wrote: >>> >>> On Mon, Oct 30, 2017 at 12:40 AM, Fengguang Wu >>> wrote: >>>> >>>> >>>> CC nvdimm maintainers. >>>> >>>> On Sun, Oct 29, 2017 at 11:51:55PM +0100, Fengguang Wu wrote: >>>>> >>>>> >>>>> Hi Linus, >>>>> >>>>> Up to now we see the below boot error/warnings when testing v4.14-rc6. >>>>> >>>>> They hit the RC release mainly due to various imperfections in 0day's >>>>> auto bisection. So I manually list them here and CC the likely easy to >>>>> debug ones to the corresponding maintainers in the followup emails. >>>>> >>>>> boot_successes: 4700 >>>>> boot_failures: 247 >>>> >>>> >>>> >>>> [...] >>>> >>>>> WARNING:at_kernel/memremap.c:#devm_memremap_pages: 1 >>>> >>>> >>>> >>>> Bisect failed, hope it's not hard to debug: >>>> >>>> Start >>>> [ 18.989316] devm_memremap_pages attempted on mixed region [mem >>>> 0x680000000-0x103dffffff flags 0x200] >>> >>> >>> >>> This appears to be a problem in the test environment. "Persistent >>> Memory" can only be specified on a minimum of a 128MB boundary if it >>> intersects "System RAM". Assuming I did my math right this appears to >>> end on 16MB boundary. Fixing this problem in the kernel would require >>> this patch set: >>> >>> "mm: sub-section memory hotplug support": >>> https://lwn.net/Articles/707908/ >> >> >> Good to know that! >> >>> ...but I have abandoned / pushed that to the back of my queue since >>> BIOS induced version of this problem does not appear to trigger in >>> practice. I assume this test is using memmap=ss!nn? >> >> >> Yes, we used >> >> memmap=104G!26G memmap=104G!154G >> The warning showed up only once -- attached is the full dmesg. >> > >Something is going wrong with memmap= because you are not getting 1G >aligned address ranges. I think you would have better luck switching >to the official nvdimm emulation in qemu-kvm rather than relying on >memmap= which is just a fragile / unreliable interface. In fact we >should look to deprecate it and point everyone to use the standard >methods. We just have a problem of legacy pre-ACPI6 platforms that >have no other way than a kernel command line to identify persistent >memory ranges. Got it. Thank you for the tips! Thanks, Fengguang