From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752408AbcAEPbn (ORCPT ); Tue, 5 Jan 2016 10:31:43 -0500 Received: from mx1.redhat.com ([209.132.183.28]:36931 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751815AbcAEPbk (ORCPT ); Tue, 5 Jan 2016 10:31:40 -0500 Date: Tue, 5 Jan 2016 17:31:36 +0200 From: "Michael S. Tsirkin" To: Petr Mladek Cc: linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Jeff Epler , Tejun Heo , Jiri Kosina Subject: Re: [PATCH RFC] virtio_balloon: refill by config handler Message-ID: <20160105164041-mutt-send-email-mst@redhat.com> References: <1451643122-21561-1-git-send-email-mst@redhat.com> <20160105143733.GE3178@pathway.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160105143733.GE3178@pathway.suse.cz> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 05, 2016 at 03:37:33PM +0100, Petr Mladek wrote: > On Fri 2016-01-01 12:13:48, Michael S. Tsirkin wrote: > > Peter Mladek reported that balloon might never refill completely after > > restore. This is because fill_balloon is only called once there. > > Calling fill_balloon repeatedly seems too aggressive, > > especially in light of the fact that it sleeps on failure: let's > > wake the config change handler and fill it asynchronously. > > > > Reported-by: Petr Mladek > > Signed-off-by: Michael S. Tsirkin > > --- > > > > I was unable to test this - for some reason my test VM > > doesn't resume (with or without the patch). > > Petr, does this work for you? > > Ah, I have just realized that the problem happens only after the > conversion to the workqueue. It works without this patch with the > current code. The balloon kthread is waken when released from > __refrigerator(). In fact, maybe we should drop fill_balloon and update_balloon_size here? Resume will finish faster ... > I am sorry for the noise. I wanted to split the conversion to > workqueues into two patches to make it better readable. We need to > queue the balloon resizing work here. I wrongly assumed that the > original kthread must have the same problem. > > Best Regards, > Petr > > > drivers/virtio/virtio_balloon.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > > index 7efc329..ee29473 100644 > > --- a/drivers/virtio/virtio_balloon.c > > +++ b/drivers/virtio/virtio_balloon.c > > @@ -589,7 +589,7 @@ static int virtballoon_restore(struct virtio_device *vdev) > > > > virtio_device_ready(vdev); > > > > - fill_balloon(vb, towards_target(vb)); > > + wake_up(&vb->config_change); > > update_balloon_size(vb); > > return 0; > > } > > -- > > MST