Messages in this thread | | | Date | Mon, 18 Nov 2019 17:52:56 -0500 | From | "Michael S. Tsirkin" <> | Subject | Re: [PATCH 1/2] virtio_balloon: fix pages_to_free calculation |
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On Mon, Nov 18, 2019 at 01:38:10PM -0800, Khazhismel Kumykov wrote: > freed_pages was accumulating total freed pages, but was also subtracted > on each iteration from pages_to_free, which could potentially result in > attempting to free fewer pages than asked for. This change also makes > both freed_pages and pages_to_free in terms of "balloon pages", where > they were mismatched before.
And then patch 2/2 changes it back to both be regular pages. Which is good, but why do we have to go back and forth breaking then fixing it back?
> > Fixes: 71994620bb25 ("virtio_balloon: replace oom notifier with shrinker") > Cc: Wei Wang <wei.w.wang@intel.com> > Signed-off-by: Khazhismel Kumykov <khazhy@google.com> > --- > drivers/virtio/virtio_balloon.c | 7 ++----- > 1 file changed, 2 insertions(+), 5 deletions(-) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index 226fbb995fb0..7cf9540a40b8 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -782,11 +782,8 @@ static unsigned long shrink_balloon_pages(struct virtio_balloon *vb, > * VIRTIO_BALLOON_ARRAY_PFNS_MAX balloon pages, so we call it > * multiple times to deflate pages till reaching pages_to_free. > */ > - while (vb->num_pages && pages_to_free) { > - pages_freed += leak_balloon(vb, pages_to_free) / > - VIRTIO_BALLOON_PAGES_PER_PAGE; > - pages_to_free -= pages_freed; > - } > + while (vb->num_pages && pages_to_free > pages_freed) > + pages_freed += leak_balloon(vb, pages_to_free - pages_freed); > update_balloon_size(vb); > > return pages_freed; > -- > 2.24.0.432.g9d3f5f5b63-goog
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