From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id B1BF16B0253 for ; Wed, 3 Aug 2016 02:35:58 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id o124so379997710pfg.1 for ; Tue, 02 Aug 2016 23:35:58 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com. [148.163.156.1]) by mx.google.com with ESMTPS id lz7si7309101pab.147.2016.08.02.23.35.57 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 02 Aug 2016 23:35:57 -0700 (PDT) Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u736Y0VQ046880 for ; Wed, 3 Aug 2016 02:35:57 -0400 Received: from e28smtp04.in.ibm.com (e28smtp04.in.ibm.com [125.16.236.4]) by mx0a-001b2d01.pphosted.com with ESMTP id 24k0bp5n0f-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 03 Aug 2016 02:35:57 -0400 Received: from localhost by e28smtp04.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 3 Aug 2016 12:05:54 +0530 Received: from d28relay01.in.ibm.com (d28relay01.in.ibm.com [9.184.220.58]) by d28dlp01.in.ibm.com (Postfix) with ESMTP id A6CAEE0060 for ; Wed, 3 Aug 2016 12:10:09 +0530 (IST) Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay01.in.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u736ZmMk42074136 for ; Wed, 3 Aug 2016 12:05:48 +0530 Received: from d28av04.in.ibm.com (localhost [127.0.0.1]) by d28av04.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u736ZiHU030540 for ; Wed, 3 Aug 2016 12:05:47 +0530 Date: Wed, 3 Aug 2016 12:05:38 +0530 From: Srikar Dronamraju Subject: Re: [PATCH 2/2] fadump: Disable deferred page struct initialisation Reply-To: Srikar Dronamraju References: <1470143947-24443-1-git-send-email-srikar@linux.vnet.ibm.com> <1470143947-24443-3-git-send-email-srikar@linux.vnet.ibm.com> <1470201642.5034.3.camel@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1470201642.5034.3.camel@gmail.com> Message-Id: <20160803063538.GH6310@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Balbir Singh Cc: linux-mm@kvack.org, Mel Gorman , Vlastimil Babka , Michal Hocko , Andrew Morton , Michael Ellerman , mahesh@linux.vnet.ibm.com * Balbir Singh [2016-08-03 15:20:42]: > On Tue, 2016-08-02 at 18:49 +0530, Srikar Dronamraju wrote: > > Fadump kernel reserves significant number of memory blocks. On a multi-node > > machine, with CONFIG_DEFFERRED_STRUCT_PAGE support, fadump kernel fails to > > boot. Fix this by disabling deferred page struct initialisation. > > > > How much memory does a fadump kernel need? Can we bump up the limits depending > on the config. I presume when you say fadump kernel you mean kernel with > FADUMP in the config? On a regular kernel with CONFIG_FADUMP and fadump configured, 5% of the total memory is reserved for booting the kernel on crash. On crash, fadump kernel reserves the 95% memory and boots into the 5% memory that was reserved for it. It then parses the reserved 95% memory to collect the dump. The problem is not about the amount of memory thats reserved for fadump kernel. Even if we increase/decrease, we will still end up with the same issue. > BTW, I would much rather prefer a config based solution that does not select > DEFERRED_INIT if FADUMP is enabled. As Vlastimil rightly pointed out, for fadump, the same kernel is booted back at a different location when we crash. So we cannot have a config based solution. -- Thanks and Regards Srikar Dronamraju -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org