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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 DD1AFC43603 for ; Mon, 9 Dec 2019 22:04:12 +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 A5E1320637 for ; Mon, 9 Dec 2019 22:04:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="C5HN+E0M" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A5E1320637 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]:47792 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ieR8V-00082F-MM for qemu-devel@archiver.kernel.org; Mon, 09 Dec 2019 17:04:11 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:57064) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ieR7q-0007XE-JJ for qemu-devel@nongnu.org; Mon, 09 Dec 2019 17:03:31 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ieR7p-0006In-EW for qemu-devel@nongnu.org; Mon, 09 Dec 2019 17:03:30 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:46435 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ieR7p-0006FK-BV for qemu-devel@nongnu.org; Mon, 09 Dec 2019 17:03:29 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1575929008; 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=xe/5HCmd2rUcG7e6Lslz90H4wg9/YoajpdPrAoDnwkA=; b=C5HN+E0M8hbaNnaX3tGNd1Bw/AQpy8giiMP43cFqH69Lo3nZ1D0pVIzN+G6UZ+3HgGiw4m kOgO+QUWa2C+NTD994iALiv/4wDMHkWQKggBFgVEagC2ArZGEx3+e55QP+FvXZ00rUwref QxyTK7De+yRlLznsXx/Mjfkpbu7cAto= 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-279-G0ORfQboPd-J7ElE4Ky-dQ-1; Mon, 09 Dec 2019 17:03:25 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 50AA08017DF; Mon, 9 Dec 2019 22:03:24 +0000 (UTC) Received: from [10.3.116.171] (ovpn-116-171.phx2.redhat.com [10.3.116.171]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 06B6760BE0; Mon, 9 Dec 2019 22:03:19 +0000 (UTC) Subject: Re: [bugfix ping2] Re: [PATCH v2 0/2] fix qcow2_can_store_new_dirty_bitmap To: Max Reitz , Vladimir Sementsov-Ogievskiy , "qemu-block@nongnu.org" References: <20191014115126.15360-1-vsementsov@virtuozzo.com> <0db82122-ee0d-a346-cb49-d902d5d66b77@virtuozzo.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: <466a95d3-e808-02d1-94df-27bf1e4e13ee@redhat.com> Date: Mon, 9 Dec 2019 16:03:19 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: G0ORfQboPd-J7ElE4Ky-dQ-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 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: "kwolf@redhat.com" , "jsnow@redhat.com" , "qemu-devel@nongnu.org" , Denis Lunev Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 12/9/19 11:58 AM, Max Reitz wrote: > On 09.12.19 17:30, Max Reitz wrote: >> On 02.12.19 15:09, Vladimir Sementsov-Ogievskiy wrote: >>> Hi again! >>> >>> Still forgotten bug-fix :( >>> >>> Is it too late for 4.2? >> >> Sorry. :-/ >> >> Yes, I think I just forgot it. I don=E2=80=99t think it=E2=80=99s too i= mportant for >> 4.2, so, well, it isn=E2=80=99t too bad, but... Sorry. >> >>> I can't imagine better test, and it tests exactly what written in >>> https://bugzilla.redhat.com/show_bug.cgi?id=3D1712636 >>> >>> (Hmm, actually, I doubt that it is real use-case, more probably it's a = bug in management layer) >>> >>> So, take this with test or without test, to 4.2 or 5.0. >> >> I was thinking of seeing whether I could write a quicker test, but of >> course we should take the patch either way. >=20 > OK, I give up. It=E2=80=99s very much possible to create an image with 6= 5535 > bitmaps very quickly (like, under a second) outside of qemu, but just > opening it takes 2:30 min (because of the quadratic complexity of > checking whether a bitmap of the same name already exists). Can we fix that to use a hash table for amortized O(1) lookup rather=20 than the current O(n) lookup? But such a fix is 5.0 material. --=20 Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org