From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: SRS0=cDPr=PQ=linuxfoundation.org=gregkh@kernel.org Date: Tue, 08 Jan 2019 00:10:43 -0700 From: Greg KH Subject: Re: [PATCH v4 2/3] virtio-balloon: improve update_balloon_size_func Message-ID: <20190108071043.GB32048@kroah.com> References: <1546923005-40517-1-git-send-email-wei.w.wang@intel.com> <1546923005-40517-3-git-send-email-wei.w.wang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1546923005-40517-3-git-send-email-wei.w.wang@intel.com> To: Wei Wang Cc: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, mst@redhat.com, cohuck@redhat.com, borntraeger@de.ibm.com, pbonzini@redhat.com, dgilbert@redhat.com, pasic@linux.ibm.com List-ID: On Tue, Jan 08, 2019 at 12:50:04PM +0800, Wei Wang wrote: > There is no need to update the balloon actual register when there is no > ballooning request. This patch avoids update_balloon_size when diff is 0. > > Signed-off-by: Wei Wang > Reviewed-by: Cornelia Huck > Reviewed-by: Halil Pasic > Tested-by: Christian Borntraeger > --- > drivers/virtio/virtio_balloon.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index 45d32f5..d48c12c 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -457,9 +457,12 @@ static void update_balloon_size_func(struct work_struct *work) > update_balloon_size_work); > diff = towards_target(vb); > > + if (!diff) > + return; > + > if (diff > 0) > diff -= fill_balloon(vb, diff); > - else if (diff < 0) > + else > diff += leak_balloon(vb, -diff); > update_balloon_size(vb); > > -- > 2.7.4 > This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for how to do this properly.