From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 40TvnY22PFzDr5X for ; Mon, 23 Apr 2018 15:16:17 +1000 (AEST) Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) by bilbo.ozlabs.org (Postfix) with ESMTP id 40TvnY1QCvz8svR for ; Mon, 23 Apr 2018 15:16:17 +1000 (AEST) Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 40TvnX4hKvz9s19 for ; Mon, 23 Apr 2018 15:16:16 +1000 (AEST) Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w3N5Dns1132790 for ; Mon, 23 Apr 2018 01:16:14 -0400 Received: from e06smtp13.uk.ibm.com (e06smtp13.uk.ibm.com [195.75.94.109]) by mx0b-001b2d01.pphosted.com with ESMTP id 2hh44ngxkp-1 (version=TLSv1.2 cipher=AES256-SHA256 bits=256 verify=NOT) for ; Mon, 23 Apr 2018 01:16:13 -0400 Received: from localhost by e06smtp13.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 23 Apr 2018 06:16:11 +0100 Subject: Re: [PATCH v4 1/7] powerpc/fadump: Move the metadata region to start of the reserved area. To: Nicholas Piggin Cc: linuxppc-dev , Ananth Narayan , kernelfans@gmail.com, "Aneesh Kumar K.V" , Hari Bathini , Nathan Fontenot , Anshuman Khandual , Srikar Dronamraju References: <152420062000.31037.770773018944092449.stgit@jupiter.in.ibm.com> <152420065839.31037.9373191008433546810.stgit@jupiter.in.ibm.com> <20180422115816.701d0837@roar.ozlabs.ibm.com> From: Mahesh Jagannath Salgaonkar Date: Mon, 23 Apr 2018 10:46:06 +0530 MIME-Version: 1.0 In-Reply-To: <20180422115816.701d0837@roar.ozlabs.ibm.com> Content-Type: text/plain; charset=utf-8 Message-Id: List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 04/22/2018 07:28 AM, Nicholas Piggin wrote: > On Fri, 20 Apr 2018 10:34:18 +0530 > Mahesh J Salgaonkar wrote: > >> From: Mahesh Salgaonkar >> >> Currently the metadata region that holds crash info structure and ELF core >> header is placed towards the end of reserved memory area. This patch places >> it at the beginning of the reserved memory area. It also introduces >> additional dump section called metadata section to communicate location >> of metadata region to 2nd kernel. This patch also maintains the >> compatibility between production/capture kernels irrespective of their >> kernel versions. Both combination older/newer and newer/older works fine. > > Trying to look at the patches it might help me if you document reasons > for why this change is made changelog, even if it may be obvious to > someone who knows the code better. Yeah, I should have mentioned that this patch provides the foundation for CMA patch 4. With CMA reservation we now allocate metadata region using cma_alloc() which always allocates metadata region at the start of CMA reserved region. Earlier in v1, I had this change included along with CMA reservation patch. But then to make things simpler for review I did a logical split of movement of metadata region and CMA reservation patch separately. I think I should order patch 1, 2 and 4 in a sequence and Move patch3 to patch 1. > > I thought you could include the documentation change in this patch as > well, but maybe that's a matter of preference. Yeah that's how I prefer it :-), but that just me. But if it helps in review I can fold it into 1. Thanks, -Mahesh.