From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44650) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UpUSp-0001rQ-PE for qemu-devel@nongnu.org; Wed, 19 Jun 2013 22:19:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UpUSn-00007n-3N for qemu-devel@nongnu.org; Wed, 19 Jun 2013 22:19:07 -0400 Received: from [222.73.24.84] (port=28639 helo=song.cn.fujitsu.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UpUSm-00006i-OE for qemu-devel@nongnu.org; Wed, 19 Jun 2013 22:19:05 -0400 Message-ID: <51C2667B.4030600@cn.fujitsu.com> Date: Thu, 20 Jun 2013 10:18:35 +0800 From: Qiao Nuohan MIME-Version: 1.0 References: <1369709437-24969-1-git-send-email-qiaonuohan@cn.fujitsu.com> <20130619134952.GE31475@stefanha-thinkpad.muc.redhat.com> In-Reply-To: <20130619134952.GE31475@stefanha-thinkpad.muc.redhat.com> Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1; format=flowed Subject: Re: [Qemu-devel] [PATCH v4 0/9] Make 'dump-guest-memory' dump in kdump-compressed format List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: zhangxh@cn.fujitsu.com, qemu-devel@nongnu.org, lcapitulino@redhat.com, anderson@redhat.com, kumagai-atsushi@mxc.nes.nec.co.jp, afaerber@suse.de On 06/19/2013 09:49 PM, Stefan Hajnoczi wrote: > Where does that code live that writes DISKDUMP files? I can see the > diskdump.[ch] code. Sorry, I cannot catch what do you mean here. > > The file format is pretty bad: we need 4 temporary files and a lot of > data copying to write it out. > > Why not just compress an ELF file and teach the crash utility how to > decompress while reading the ELF? > > Also, did you look into simply outputting the ELF file without zero > pages? What I want is a dump file with smaller size. And compressed format and with zero pages excluded can make it. I choose kdump-compressed format because it is a standard format and it can realize what I want. Why 4 temporary files are need? dump-guest-memory may be called with a fd which is supposed to send data of dump to. If fd is opened on a pipe or etc which is unable to seek, then I need to cache the data. -- Regards Qiao Nuohan