From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46335) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WD0JO-0008ID-Tw for qemu-devel@nongnu.org; Mon, 10 Feb 2014 18:30:55 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WD0JK-0008Fd-K4 for qemu-devel@nongnu.org; Mon, 10 Feb 2014 18:30:50 -0500 Received: from mx1.redhat.com ([209.132.183.28]:31086) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WD0JK-0008FK-CY for qemu-devel@nongnu.org; Mon, 10 Feb 2014 18:30:46 -0500 Message-ID: <52F9611D.7000808@redhat.com> Date: Tue, 11 Feb 2014 00:30:37 +0100 From: Laszlo Ersek MIME-Version: 1.0 References: <1390890126-17377-1-git-send-email-qiaonuohan@cn.fujitsu.com> <1390890126-17377-14-git-send-email-qiaonuohan@cn.fujitsu.com> <20140210141048.796e9c91@redhat.com> <52F94C84.20105@redhat.com> <52F95C46.3030701@redhat.com> In-Reply-To: <52F95C46.3030701@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v8 13/13] dump: add 'query-dump-guest-memory-capability' command List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: stefanha@gmail.com, qemu-devel@nongnu.org, Luiz Capitulino , qiaonuohan , kumagai-atsushi@mxc.nes.nec.co.jp, anderson@redhat.com, afaerber@suse.de On 02/11/14 00:09, Paolo Bonzini wrote: > Il 10/02/2014 23:02, Laszlo Ersek ha scritto: >> On 02/10/14 20:10, Luiz Capitulino wrote: >>> On Tue, 28 Jan 2014 14:22:06 +0800 >>> qiaonuohan wrote: >>> >>>> 'query-dump-guest-memory-capability' is used to query whether option >>>> 'format' >>>> is available for 'dump-guest-memory' and the available format. The >>>> output >>>> of the command will be like: >>>> >>>> -> { "execute": "query-dump-guest-memory-capability" } >>>> <- { "return": { >>>> "format-option": "optional", >>>> "capabilities": [ >>>> {"available": true, "format": "elf"}, >>>> {"available": true, "format": "kdump-zlib"}, >>>> {"available": true, "format": "kdump-lzo"}, >>>> {"available": true, "format": "kdump-snappy"} >>>> ] >>>> } >>> >>> I don't want to hold this series anymore, this series is long and I >>> know it >>> took you and Laszlo's a long time to get it right. On the other hand >>> we can't >>> allow every single command to have its own introspection protocol. >>> >>> I think I'm fine accepting this one now, as long as it's fine for >>> libvirt >>> too. Eric, can you confirm this please? >> >> We discussed this before, and Eric participated. In fact the custom >> introspection was one of his recommendations. >> >> http://thread.gmane.org/gmane.comp.emulators.qemu/221270/focus=246650 >> >> (Which I agreed with because it would give us the most independence.) >> >> Of course I'm not trying to imply that this one specific interface will >> doubtlessly serve all of libvirt's needs wrt. the kdump feature. We >> certainly need Eric to sign off on that. > > I think the justification here is that even if you defined an Enum for > ['elf','kdump-zlib', 'kdump-lzo', 'kdump-snappy'], it would not be > enough to describe which values were compiled in (as opposed to > supported by the particular QEMU version). > > However, I don't see the point in having the "format-option" field. What > about: > > -> { "execute": "query-dump-guest-memory-capabilities" } > <- { "return": { "formats": > ["elf", "kdump-zlib", "kdump-lzo", "kdump-snappy"] } Technically you might be right. However, this partial introspection feature is entirely a wart whose existence is exclusively justified by non-technical reasons, such as deadlines, and not wanting to be blocked indefinitely by architecture astronautics around full introspection. I don't see the point of polishing it beyond bare usability, at least not after I've reviewed three versions of the patchset. That's of course just my opinion... :) Laszlo