* [PATCH] virtio_balloon: fix shrinker count
@ 2019-11-19 10:18 Michael S. Tsirkin
2019-11-19 11:38 ` David Hildenbrand
0 siblings, 1 reply; 2+ messages in thread
From: Michael S. Tsirkin @ 2019-11-19 10:18 UTC (permalink / raw)
To: linux-kernel; +Cc: Wei Wang, stable, Jason Wang, virtualization
From: Wei Wang <wei.w.wang@intel.com>
Instead of multiplying by page order, virtio balloon divided by page
order. The result is that it can often return 0 if there are a bit less
than MAX_ORDER - 1 pages in use, and then shrinker scan won't be called.
Cc: stable@vger.kernel.org
Fixes: 71994620bb25 ("virtio_balloon: replace oom notifier with shrinker")
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
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 7cee05cdf3fb..65df40f261ab 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -825,7 +825,7 @@ static unsigned long virtio_balloon_shrinker_count(struct shrinker *shrinker,
unsigned long count;
count = vb->num_pages / VIRTIO_BALLOON_PAGES_PER_PAGE;
- count += vb->num_free_page_blocks >> VIRTIO_BALLOON_FREE_PAGE_ORDER;
+ count += vb->num_free_page_blocks << VIRTIO_BALLOON_FREE_PAGE_ORDER;
return count;
}
--
MST
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] virtio_balloon: fix shrinker count
2019-11-19 10:18 [PATCH] virtio_balloon: fix shrinker count Michael S. Tsirkin
@ 2019-11-19 11:38 ` David Hildenbrand
0 siblings, 0 replies; 2+ messages in thread
From: David Hildenbrand @ 2019-11-19 11:38 UTC (permalink / raw)
To: Michael S. Tsirkin, linux-kernel
Cc: Wei Wang, stable, Jason Wang, virtualization
On 19.11.19 11:18, Michael S. Tsirkin wrote:
> From: Wei Wang <wei.w.wang@intel.com>
>
> Instead of multiplying by page order, virtio balloon divided by page
> order. The result is that it can often return 0 if there are a bit less
> than MAX_ORDER - 1 pages in use, and then shrinker scan won't be called.
>
> Cc: stable@vger.kernel.org
> Fixes: 71994620bb25 ("virtio_balloon: replace oom notifier with shrinker")
> Signed-off-by: Wei Wang <wei.w.wang@intel.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> 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 7cee05cdf3fb..65df40f261ab 100644
> --- a/drivers/virtio/virtio_balloon.c
> +++ b/drivers/virtio/virtio_balloon.c
> @@ -825,7 +825,7 @@ static unsigned long virtio_balloon_shrinker_count(struct shrinker *shrinker,
> unsigned long count;
>
> count = vb->num_pages / VIRTIO_BALLOON_PAGES_PER_PAGE;
> - count += vb->num_free_page_blocks >> VIRTIO_BALLOON_FREE_PAGE_ORDER;
> + count += vb->num_free_page_blocks << VIRTIO_BALLOON_FREE_PAGE_ORDER;
>
> return count;
> }
>
Reviewed-by: David Hildenbrand <david@redhat.com>
--
Thanks,
David / dhildenb
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