From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1A53BC32771 for ; Mon, 20 Jan 2020 19:17:33 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DBEED22525 for ; Mon, 20 Jan 2020 19:17:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Uc4v9DAQ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DBEED22525 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:43278 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1itcYG-0003ra-0q for qemu-devel@archiver.kernel.org; Mon, 20 Jan 2020 14:17:32 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:35241) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1itcXb-0003Lq-Ft for qemu-devel@nongnu.org; Mon, 20 Jan 2020 14:16:52 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1itcXZ-0004Pj-MP for qemu-devel@nongnu.org; Mon, 20 Jan 2020 14:16:51 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:25606 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1itcXZ-0004PK-JU for qemu-devel@nongnu.org; Mon, 20 Jan 2020 14:16:49 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579547809; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qndJVXZc//72XtzUTUAo0KSAzW6L/s0xG8oIGCWXZlQ=; b=Uc4v9DAQUea0cwfzTEKRj5kvvWL21K37b/oGe+ouz2D3itRwHP4rfZj/3x1vATNKcV0QcI vWiU1ZAk7QC4AWTVojCRl1gamOrVz2c2MsPDcLZ5DxR6O55j6hY3DoYwKm4xEGihCce5la i0BZJmfrwz2I0WV447/+57Ihv7kGva4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-69-rEuEGqggNOm7ZQvFRdZd0g-1; Mon, 20 Jan 2020 14:16:45 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8ABA6801E67; Mon, 20 Jan 2020 19:16:44 +0000 (UTC) Received: from [10.3.117.16] (ovpn-117-16.phx2.redhat.com [10.3.117.16]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D67085C299; Mon, 20 Jan 2020 19:16:43 +0000 (UTC) Subject: Re: [PATCH v2] qapi: Allow getting flat output from 'query-named-block-nodes' To: Peter Krempa , qemu-devel@nongnu.org References: <4470f8c779abc404dcf65e375db195cd91a80651.1579509782.git.pkrempa@redhat.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: <67719815-026e-6dba-aea8-0f3273df4fec@redhat.com> Date: Mon, 20 Jan 2020 13:16:43 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.1 MIME-Version: 1.0 In-Reply-To: <4470f8c779abc404dcf65e375db195cd91a80651.1579509782.git.pkrempa@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-MC-Unique: rEuEGqggNOm7ZQvFRdZd0g-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Markus Armbruster , qemu-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 1/20/20 2:50 AM, Peter Krempa wrote: > When a management application manages node names there's no reason to > recurse into backing images in the output of query-named-block-nodes. > > Add a parameter to the command which will return just the top level > structs. > > Signed-off-by: Peter Krempa > --- > > Diff to v1: > - rewrote setting of 'return_flat' in qmp_query_named_block_nodes > - tried to clarify the QMP schema docs for the new field > > This patch does not aim to fix the rather suboptimal original > documentation of the command as that is going to end up in a bunch of > bikeshedding. > > While I know that there are plans for a new command that should fix > this, the plans were already there for quite some time without much > happening. This is a quick fix to a real problem, because if you have > (maybe unpractically) deep backing chains, the returned JSON is getting > huge. (140 nesting levels exceeds 10MiB of JSON) Yep, O(n^2) output growth based on a depth of N is not ideal. > +++ b/qapi/block-core.json > @@ -1752,6 +1752,9 @@ > # > # Get the named block driver list > # > +# @flat: Omit the nested data about backing image ("backing-image" key) if true. > +# Default is false (Since 5.0) > +# > # Returns: the list of BlockDeviceInfo > # > # Since: 2.0 > @@ -1805,7 +1808,9 @@ > # } } ] } > # > ## > -{ 'command': 'query-named-block-nodes', 'returns': [ 'BlockDeviceInfo' ] } > +{ 'command': 'query-named-block-nodes', > + 'returns': [ 'BlockDeviceInfo' ], > + 'data': { '*flat': 'bool' } } Reviewed-by: Eric Blake -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org