From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 36689C31E40 for ; Tue, 13 Aug 2019 02:54:52 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 12EB4206C1 for ; Tue, 13 Aug 2019 02:54:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 12EB4206C1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id F0E49DBC; Tue, 13 Aug 2019 02:54:51 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 0600EDB8 for ; Tue, 13 Aug 2019 02:54:50 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id A2FD38B for ; Tue, 13 Aug 2019 02:54:49 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 01593155DB; Tue, 13 Aug 2019 02:54:49 +0000 (UTC) Received: from dhcp-128-65.nay.redhat.com (ovpn-12-72.pek2.redhat.com [10.72.12.72]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E5ACB7BE42; Tue, 13 Aug 2019 02:54:44 +0000 (UTC) Date: Tue, 13 Aug 2019 10:54:41 +0800 From: Dave Young To: Michal Hocko Subject: Re: Crash kernel with 256 MB reserved memory runs into OOM condition Message-ID: <20190813025441.GA2979@dhcp-128-65.nay.redhat.com> References: <20190812095029.GE5117@dhcp22.suse.cz> <20190813024317.GA2862@dhcp-128-65.nay.redhat.com> <20190813024600.GA2944@dhcp-128-65.nay.redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190813024600.GA2944@dhcp-128-65.nay.redhat.com> User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Tue, 13 Aug 2019 02:54:49 +0000 (UTC) Cc: Paul Menzel , kasong@redhat.com, linux-pci@vger.kernel.org, "x86@kernel.org" , kexec@lists.infradead.org, Linux Kernel Mailing List , iommu@lists.linux-foundation.org, Donald Buczek , lijiang@redhat.com X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org On 08/13/19 at 10:46am, Dave Young wrote: > Add more cc. > On 08/13/19 at 10:43am, Dave Young wrote: > > Hi, > > > > On 08/12/19 at 11:50am, Michal Hocko wrote: > > > On Mon 12-08-19 11:42:33, Paul Menzel wrote: > > > > Dear Linux folks, > > > > > > > > > > > > On a Dell PowerEdge R7425 with two AMD EPYC 7601 (total 128 threads) and > > > > 1 TB RAM, the crash kernel with 256 MB of space reserved crashes. > > > > > > > > Please find the messages of the normal and the crash kernel attached. > > > > > > You will need more memory to reserve for the crash kernel because ... > > > > > > > [ 4.548703] Node 0 DMA free:484kB min:4kB low:4kB high:4kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:568kB managed:484kB mlocked:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB > > > > [ 4.573612] lowmem_reserve[]: 0 125 125 125 > > > > [ 4.577799] Node 0 DMA32 free:1404kB min:1428kB low:1784kB high:2140kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:15720kB writepending:0kB present:261560kB managed:133752kB mlocked:0kB kernel_stack:2496kB pagetables:0kB bounce:0kB free_pcp:212kB local_pcp:212kB free_cma:0kB > > > > > > ... the memory is really depleted and nothing to be reclaimed (no anon. > > > file pages) Look how tht free memory is below min watermark (node zone DMA has > > > lowmem protection for GFP_KERNEL allocation). > > > > We found similar issue on our side while working on kdump on SME enabled > > systemd. Kairui is working on some patches. > > > > Actually on those SME/SEV enabled machines, swiotlb is enabled > > automatically so at least we need extra 64M+ memory for kdump other > > than the normal expectation. > > > > Can you check if this is also your case? > > The question is to Paul, also it would be always good to cc kexec mail > list for kexec and kdump issues. Looks like hardware iommu is used, maybe you do not enable SME? Also replace maxcpus=1 with nr_cpus=1 can save some memory, can have a try. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu