From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756517Ab3EXPGg (ORCPT ); Fri, 24 May 2013 11:06:36 -0400 Received: from e06smtp14.uk.ibm.com ([195.75.94.110]:35524 "EHLO e06smtp14.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755266Ab3EXPGe (ORCPT ); Fri, 24 May 2013 11:06:34 -0400 Date: Fri, 24 May 2013 17:06:26 +0200 From: Michael Holzheu To: Vivek Goyal Cc: HATAYAMA Daisuke , Jan Willeke , Martin Schwidefsky , Heiko Carstens , linux-kernel@vger.kernel.org, kexec@lists.infradead.org Subject: Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390 Message-ID: <20130524170626.2ac06efe@holzheu> In-Reply-To: <20130524143644.GD18218@redhat.com> References: <1369400889-11064-1-git-send-email-holzheu@linux.vnet.ibm.com> <20130524143644.GD18218@redhat.com> Organization: IBM X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13052415-1948-0000-0000-0000053EFBDA Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Vivek, On Fri, 24 May 2013 10:36:44 -0400 Vivek Goyal wrote: [snip] > Sorry, I don't understand the problem. If we swapped low memory and > crash reserved memory, that should have been taken care by prepared > ELF headers so that we map the right pfns. In x86 we swap 640K of low > memory with 640K of memory in reserved and we take care of this by > preparing elf headers accordingly. > > So why s390 can't do the same thing? I am not sure if I understand this. Currently we create the ELF header in a way that we have virtual=real. In the copy_oldmem_page() we do the swap so that for the /proc/vmcore code it looks like contiguous non-swapped memory. One reason why I thought this was necessary was that /dev/oldmem also uses the function and it should provide linear memory access like it is on the live system with /dev/mem. Is that implementation incorrect? Best Regards, Michael From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from e06smtp18.uk.ibm.com ([195.75.94.114]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Ufta4-0001HT-DW for kexec@lists.infradead.org; Fri, 24 May 2013 15:06:57 +0000 Received: from /spool/local by e06smtp18.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 24 May 2013 16:01:58 +0100 Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by d06dlp01.portsmouth.uk.ibm.com (Postfix) with ESMTP id 1503117D8025 for ; Fri, 24 May 2013 16:07:41 +0100 (BST) Received: from d06av08.portsmouth.uk.ibm.com (d06av08.portsmouth.uk.ibm.com [9.149.37.249]) by b06cxnps3074.portsmouth.uk.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r4OF6I8A52232262 for ; Fri, 24 May 2013 15:06:18 GMT Received: from d06av08.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av08.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id r4OF6SrF012861 for ; Fri, 24 May 2013 09:06:28 -0600 Date: Fri, 24 May 2013 17:06:26 +0200 From: Michael Holzheu Subject: Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390 Message-ID: <20130524170626.2ac06efe@holzheu> In-Reply-To: <20130524143644.GD18218@redhat.com> References: <1369400889-11064-1-git-send-email-holzheu@linux.vnet.ibm.com> <20130524143644.GD18218@redhat.com> Mime-Version: 1.0 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=twosheds.infradead.org@lists.infradead.org To: Vivek Goyal Cc: Heiko Carstens , kexec@lists.infradead.org, Jan Willeke , linux-kernel@vger.kernel.org, HATAYAMA Daisuke , Martin Schwidefsky Hello Vivek, On Fri, 24 May 2013 10:36:44 -0400 Vivek Goyal wrote: [snip] > Sorry, I don't understand the problem. If we swapped low memory and > crash reserved memory, that should have been taken care by prepared > ELF headers so that we map the right pfns. In x86 we swap 640K of low > memory with 640K of memory in reserved and we take care of this by > preparing elf headers accordingly. > > So why s390 can't do the same thing? I am not sure if I understand this. Currently we create the ELF header in a way that we have virtual=real. In the copy_oldmem_page() we do the swap so that for the /proc/vmcore code it looks like contiguous non-swapped memory. One reason why I thought this was necessary was that /dev/oldmem also uses the function and it should provide linear memory access like it is on the live system with /dev/mem. Is that implementation incorrect? Best Regards, Michael _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec