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virtio_balloon: divide/multiply instead of shifts

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We managed to get confused about the shift direction at least once.
Let's switch to division/multiplcation instead. Add a number of pages
macro for this purpose.  We still keep the order macro around too since
this is what alloc/free pages want.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Wei Wang <wei.w.wang@intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
This commit is contained in:
Michael S. Tsirkin 2019-11-19 05:25:24 -05:00
parent 2a946fa1c8
commit 63b9b80e9f
1 changed files with 5 additions and 4 deletions
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9
drivers/virtio/virtio_balloon.c
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@ -36,6 +36,7 @@
/* The size of a free page block in bytes */
#define VIRTIO_BALLOON_HINT_BLOCK_BYTES \
(1 << (VIRTIO_BALLOON_HINT_BLOCK_ORDER + PAGE_SHIFT))
#define VIRTIO_BALLOON_HINT_BLOCK_PAGES (1 << VIRTIO_BALLOON_HINT_BLOCK_ORDER)
#ifdef CONFIG_BALLOON_COMPACTION
static struct vfsmount *balloon_mnt;
@ -776,11 +777,11 @@ static unsigned long shrink_free_pages(struct virtio_balloon *vb,
unsigned long blocks_to_free, blocks_freed;
pages_to_free = round_up(pages_to_free,
1 << VIRTIO_BALLOON_HINT_BLOCK_ORDER);
blocks_to_free = pages_to_free >> VIRTIO_BALLOON_HINT_BLOCK_ORDER;
VIRTIO_BALLOON_HINT_BLOCK_PAGES);
blocks_to_free = pages_to_free / VIRTIO_BALLOON_HINT_BLOCK_PAGES;
blocks_freed = return_free_pages_to_mm(vb, blocks_to_free);
return blocks_freed << VIRTIO_BALLOON_HINT_BLOCK_ORDER;
return blocks_freed * VIRTIO_BALLOON_HINT_BLOCK_PAGES;
}
static unsigned long leak_balloon_pages(struct virtio_balloon *vb,
@ -837,7 +838,7 @@ 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_HINT_BLOCK_ORDER;
count += vb->num_free_page_blocks * VIRTIO_BALLOON_HINT_BLOCK_PAGES;
return count;
}