From nobody Mon Nov 3 20:06:04 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1505995954279658.3503908250275; Thu, 21 Sep 2017 05:12:34 -0700 (PDT) Received: from localhost ([::1]:53397 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dv0LJ-0005rq-Hy for importer@patchew.org; Thu, 21 Sep 2017 08:12:33 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39266) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dv0Gs-0002GT-FK for qemu-devel@nongnu.org; Thu, 21 Sep 2017 08:08:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dv0Gq-00026C-QQ for qemu-devel@nongnu.org; Thu, 21 Sep 2017 08:07:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53126) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dv0Gq-00024j-Ke for qemu-devel@nongnu.org; Thu, 21 Sep 2017 08:07:56 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B0A112CE907; Thu, 21 Sep 2017 12:07:55 +0000 (UTC) Received: from donizetti.redhat.com (ovpn-117-52.ams2.redhat.com [10.36.117.52]) by smtp.corp.redhat.com (Postfix) with ESMTP id E967C5EDF8; Thu, 21 Sep 2017 12:07:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com B0A112CE907 Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=pbonzini@redhat.com From: Paolo Bonzini To: qemu-devel@nongnu.org Date: Thu, 21 Sep 2017 14:07:50 +0200 Message-Id: <20170921120751.3027-3-pbonzini@redhat.com> In-Reply-To: <20170921120751.3027-1-pbonzini@redhat.com> References: <20170921120751.3027-1-pbonzini@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Thu, 21 Sep 2017 12:07:55 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH 2/3] memory: seek FlatView sharing candidates among children subregions X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: aik@ozlabs.ru Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" A container can be used instead of an alias to allow switching between multiple subregions. In this case we cannot directly share the subregions (since they only belong to a single parent), but if the subregions are aliases we can in turn walk those. While this does not reduce much the number of FlatViews that are created, it makes it possible to share the PCI bus master FlatViews and their AddressSpaceDispatch structures. For 112 virtio-net-pci devices, boot time is reduced from 25 to 10 seconds and memory consumption from 1.4 to 1 G. Signed-off-by: Paolo Bonzini --- memory.c | 41 +++++++++++++++++++++++++++++++++++------ 1 file changed, 35 insertions(+), 6 deletions(-) diff --git a/memory.c b/memory.c index 4952cc5d84..3207ae55e2 100644 --- a/memory.c +++ b/memory.c @@ -733,12 +733,41 @@ static void render_memory_region(FlatView *view, =20 static MemoryRegion *memory_region_get_flatview_root(MemoryRegion *mr) { - while (mr->alias && !mr->alias_offset && - int128_ge(mr->size, mr->alias->size)) { - /* The alias is included in its entirety. Use it as - * the "real" root, so that we can share more FlatViews. - */ - mr =3D mr->alias; + while (mr->enabled) { + if (mr->alias && !mr->alias_offset && + int128_ge(mr->size, mr->alias->size)) { + /* The alias is included in its entirety. Use it as + * the "real" root, so that we can share more FlatViews. + */ + mr =3D mr->alias; + continue; + } + + if (!mr->terminates) { + unsigned int found =3D 0; + MemoryRegion *child, *next =3D NULL; + QTAILQ_FOREACH(child, &mr->subregions, subregions_link) { + if (child->enabled) { + if (++found > 1) { + next =3D NULL; + break; + } + if (!child->addr && int128_ge(mr->size, child->size)) { + /* A child is included in its entirety. If it's t= he only + * enabled one, use it in the hope of finding an a= lias down the + * way. This will also let us share FlatViews. + */ + next =3D child; + } + } + } + if (next) { + mr =3D next; + continue; + } + } + + break; } =20 return mr; --=20 2.13.5