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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 5C752C4332F for ; Wed, 18 May 2022 15:31:57 +0000 (UTC) Received: from localhost ([::1]:34268 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nrLeW-0007Qc-6Y for qemu-devel@archiver.kernel.org; Wed, 18 May 2022 11:31:56 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37648) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nrLcu-0006Re-Ni for qemu-devel@nongnu.org; Wed, 18 May 2022 11:30:17 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:60999) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nrLcr-0005Lc-9B for qemu-devel@nongnu.org; Wed, 18 May 2022 11:30:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1652887811; 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: in-reply-to:in-reply-to:references:references; bh=oN2DZ/hfqciT6WibnrdMT/yneo3r7MGe7GuQDqBEVtI=; b=A3EBMeF8hhNaqimr/7wLwStfmJvYnNgBTFqLMQ3KkTlDUwv3LMlHJUUjzrfcbnemLJPP3t gXLtFwPyLRXqX/YckW8wD2c8oifxByYd4r2pu3ZyW/eb361+E5jzvWm8SNMMLB4yHybFjj JdTPTCaJW7FHGmT+Y5FmM2asYot6q4U= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-189-suBNv9HCOZ-1sWNVPy2RCg-1; Wed, 18 May 2022 11:30:09 -0400 X-MC-Unique: suBNv9HCOZ-1sWNVPy2RCg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 486AA800B21; Wed, 18 May 2022 15:30:09 +0000 (UTC) Received: from redhat.com (unknown [10.2.17.180]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A0A9840CF8EE; Wed, 18 May 2022 15:30:08 +0000 (UTC) Date: Wed, 18 May 2022 10:30:07 -0500 From: Eric Blake To: Vladimir Sementsov-Ogievskiy Cc: qemu-block@nongnu.org, qemu-devel@nongnu.org, hreitz@redhat.com, kwolf@redhat.com, jsnow@redhat.com, Vladimir Sementsov-Ogievskiy Subject: Re: [PATCH v4 2/3] block: improve block_dirty_bitmap_merge(): don't allocate extra bitmap Message-ID: <20220518153007.v2wfsflbrdminchs@redhat.com> References: <20220517111206.23585-1-v.sementsov-og@mail.ru> <20220517111206.23585-3-v.sementsov-og@mail.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220517111206.23585-3-v.sementsov-og@mail.ru> User-Agent: NeoMutt/20220429-71-6f7d3e X-Scanned-By: MIMEDefang 2.84 on 10.11.54.1 Received-SPF: pass client-ip=170.10.129.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, May 17, 2022 at 02:12:05PM +0300, Vladimir Sementsov-Ogievskiy wrote: > From: Vladimir Sementsov-Ogievskiy > > We don't need extra bitmap. All we need is to backup the original > bitmap when we do first merge. So, drop extra temporary bitmap and work > directly with target and backup. > > Still to keep old semantics, that on failure target is unchanged and > user don't need to restore, we need a local_backup variable and do > restore ourselves on failure path. > > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- > block/monitor/bitmap-qmp-cmds.c | 41 +++++++++++++++++---------------- > 1 file changed, 21 insertions(+), 20 deletions(-) Reviewed-by: Eric Blake > > diff --git a/block/monitor/bitmap-qmp-cmds.c b/block/monitor/bitmap-qmp-cmds.c > index bd10468596..282363606f 100644 > --- a/block/monitor/bitmap-qmp-cmds.c > +++ b/block/monitor/bitmap-qmp-cmds.c > @@ -261,8 +261,9 @@ BdrvDirtyBitmap *block_dirty_bitmap_merge(const char *node, const char *target, > HBitmap **backup, Error **errp) > { > BlockDriverState *bs; > - BdrvDirtyBitmap *dst, *src, *anon; > + BdrvDirtyBitmap *dst, *src; > BlockDirtyBitmapOrStrList *lst; > + HBitmap *local_backup = NULL; Basically, instead of tracking the backup via a full-featured BdrvDirtyBitmap, we are instead tracking it via a lightweight HBitmap. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org