From patchwork Tue Sep 14 14:09:32 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eduardo Habkost X-Patchwork-Id: 64702 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 7E6A0B6EF0 for ; Wed, 15 Sep 2010 00:11:01 +1000 (EST) Received: from localhost ([127.0.0.1]:51615 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OvWDp-0004Zy-RJ for incoming@patchwork.ozlabs.org; Tue, 14 Sep 2010 10:10:57 -0400 Received: from [140.186.70.92] (port=58515 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OvWCZ-0004Ew-I3 for qemu-devel@nongnu.org; Tue, 14 Sep 2010 10:09:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OvWCY-0007M4-6X for qemu-devel@nongnu.org; Tue, 14 Sep 2010 10:09:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55044) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OvWCX-0007Lp-RQ for qemu-devel@nongnu.org; Tue, 14 Sep 2010 10:09:38 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o8EE9YQk015055 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 14 Sep 2010 10:09:34 -0400 Received: from blackpad.lan.raisama.net (ovpn-113-84.phx2.redhat.com [10.3.113.84]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o8EE9XWv021409; Tue, 14 Sep 2010 10:09:34 -0400 Received: by blackpad.lan.raisama.net (Postfix, from userid 500) id EE0CA17FA9B; Tue, 14 Sep 2010 11:09:32 -0300 (BRT) Date: Tue, 14 Sep 2010 11:09:32 -0300 From: Eduardo Habkost To: Adam Litke Subject: Re: [Qemu-devel] [PATCH] Disable virtio-balloon memory stats interface Message-ID: <20100914140932.GA12878@blackpad.lan.raisama.net> Mail-Followup-To: Adam Litke , Amit Shah , Anthony Liguori , Paolo Bonzini , Luiz Capitulino , qemu list , Markus Armbruster References: <1283955676-25119-1-git-send-email-agl@us.ibm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1283955676-25119-1-git-send-email-agl@us.ibm.com> X-Fnord: you can see the fnord User-Agent: Mutt/1.5.20 (2009-08-17) X-Scanned-By: MIMEDefang 2.67 on 10.5.11.11 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. Cc: Markus Armbruster , qemu list , Amit Shah , Paolo Bonzini , Luiz Capitulino X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org On Wed, Sep 08, 2010 at 09:21:16AM -0500, Adam Litke wrote: > The addition of memory stats reporting to the virtio balloon causes > the 'info balloon' command to become asynchronous. This is a regression > because in some cases it can hang the user monitor. > > Disable this feature until a better interface for asynchronous commands > can be worked out. > > Signed-off-by: Adam Litke > --- > hw/virtio-balloon.c | 12 +++++++++++- > 1 files changed, 11 insertions(+), 1 deletions(-) > > diff --git a/hw/virtio-balloon.c b/hw/virtio-balloon.c > index 9fe3886..dcdada6 100644 > --- a/hw/virtio-balloon.c > +++ b/hw/virtio-balloon.c > @@ -190,7 +190,17 @@ static void virtio_balloon_set_config(VirtIODevice *vdev, > > static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f) > { > - f |= (1 << VIRTIO_BALLOON_F_STATS_VQ); > + /* > + * The addition of memory stats reporting to the virtio balloon causes > + * the 'info balloon' command to become asynchronous. This is a regression > + * because in some cases it can hang the user monitor. > + * > + * Disable this feature until a better interface for asynchronous commands > + * can be worked out. > + * > + * -aglitke > + */ > + /* f |= (1 << VIRTIO_BALLOON_F_STATS_VQ); */ This field is guest-visible, won't this cause problems on migration? Isn't it better to disable it on the "info balloon" side, so the guest knows that the host may start requesting stat info eventually? I suggest doing this: Acked-by: Adam Litke diff --git a/hw/virtio-balloon.c b/hw/virtio-balloon.c index 1e4dfdd..92e9057 100644 --- a/hw/virtio-balloon.c +++ b/hw/virtio-balloon.c @@ -30,6 +30,10 @@ #include #endif +/* Disable guest-provided stats by now (bz#623903, bz#626544) */ +#define ENABLE_GUEST_STATS 0 + + typedef struct VirtIOBalloon { VirtIODevice vdev; @@ -84,12 +88,14 @@ static QObject *get_stats_qobject(VirtIOBalloon *dev) VIRTIO_BALLOON_PFN_SHIFT); stat_put(dict, "actual", actual); +#if ENABLE_GUEST_STATS stat_put(dict, "mem_swapped_in", dev->stats[VIRTIO_BALLOON_S_SWAP_IN]); stat_put(dict, "mem_swapped_out", dev->stats[VIRTIO_BALLOON_S_SWAP_OUT]); stat_put(dict, "major_page_faults", dev->stats[VIRTIO_BALLOON_S_MAJFLT]); stat_put(dict, "minor_page_faults", dev->stats[VIRTIO_BALLOON_S_MINFLT]); stat_put(dict, "free_mem", dev->stats[VIRTIO_BALLOON_S_MEMFREE]); stat_put(dict, "total_mem", dev->stats[VIRTIO_BALLOON_S_MEMTOT]); +#endif return QOBJECT(dict); } @@ -215,7 +221,7 @@ static void virtio_balloon_to_target(void *opaque, ram_addr_t target, } dev->stats_callback = cb; dev->stats_opaque_callback_data = cb_data; - if (dev->vdev.guest_features & (1 << VIRTIO_BALLOON_F_STATS_VQ)) { + if (ENABLE_GUEST_STATS && (dev->vdev.guest_features & (1 << VIRTIO_BALLOON_F_STATS_VQ))) { virtqueue_push(dev->svq, &dev->stats_vq_elem, dev->stats_vq_offset); virtio_notify(&dev->vdev, dev->svq); } else {