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=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 DEB04C76186 for ; Wed, 17 Jul 2019 10:49:03 +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 A2EC620880 for ; Wed, 17 Jul 2019 10:49:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A2EC620880 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]:55858 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hnhUc-0005yc-P0 for qemu-devel@archiver.kernel.org; Wed, 17 Jul 2019 06:49:02 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59931) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hnhUO-0005WF-B1 for qemu-devel@nongnu.org; Wed, 17 Jul 2019 06:48:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hnhUM-0001My-AA for qemu-devel@nongnu.org; Wed, 17 Jul 2019 06:48:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55340) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hnhUI-0001Hr-UW; Wed, 17 Jul 2019 06:48:44 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1F34A3092651; Wed, 17 Jul 2019 10:48:40 +0000 (UTC) Received: from redhat.com (ovpn-120-247.rdu2.redhat.com [10.10.120.247]) by smtp.corp.redhat.com (Postfix) with SMTP id CA6EC611DC; Wed, 17 Jul 2019 10:48:29 +0000 (UTC) Date: Wed, 17 Jul 2019 06:48:28 -0400 From: "Michael S. Tsirkin" To: David Hildenbrand Message-ID: <20190717063902-mutt-send-email-mst@kernel.org> References: <20190717103550.24657-1-david@redhat.com> <20190717103550.24657-4-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190717103550.24657-4-david@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Wed, 17 Jul 2019 10:48:40 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH-for-4.1 v2 3/3] virtio-balloon: reset pbp on device resets 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: Igor Mammedov , qemu-stable@nongnu.org, qemu-devel@nongnu.org, Stefan Hajnoczi , David Gibson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Jul 17, 2019 at 12:35:50PM +0200, David Hildenbrand wrote: > When a guest reboots (ordinary reboots, but also via kexec), it will > happily reuse any system memory, including previously inflated memory. > > We could have tracking data for a pbp (PartiallyBalloonedPage). It could > happen that a new inflation request from the guest will result in a > discard of such a pbp, although the guest is (again) reusing some > memory. > > We should reset the pbp on any device resets. > > Fixes: ed48c59875b6 ("virtio-balloon: Safely handle BALLOON_PAGE_SIZE < > host page size") > Cc: qemu-stable@nongnu.org #v4.0.0 > Cc: Stefan Hajnoczi > Cc: David Gibson > Cc: Michael S. Tsirkin > Cc: Igor Mammedov > Signed-off-by: David Hildenbrand Can't something else remove a ramblock besides a reset? > --- > hw/virtio/virtio-balloon.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c > index 84d01bceb3..9de3c030bf 100644 > --- a/hw/virtio/virtio-balloon.c > +++ b/hw/virtio/virtio-balloon.c > @@ -847,6 +847,7 @@ static void virtio_balloon_device_reset(VirtIODevice *vdev) > if (virtio_balloon_free_page_support(s)) { > virtio_balloon_free_page_stop(s); > } > + virtio_balloon_reset_pbp(s); > > if (s->stats_vq_elem != NULL) { > virtqueue_unpop(s->svq, s->stats_vq_elem, 0); > -- > 2.21.0