[PATCH] virtio-balloon: Change balloon page size to 1MB

[Prasad Joshi]

Signed-off-by: Prasad Joshi <prasadjoshi.li...@gmail.com>
---
 drivers/virtio/virtio_balloon.c |   18 +++++++++---------
 include/linux/virtio_balloon.h  |    4 +++-
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 95aeedf..e352448 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -64,9 +64,8 @@ static u32 page_to_balloon_pfn(struct page *page)
 {
        unsigned long pfn = page_to_pfn(page);
 
-       BUILD_BUG_ON(PAGE_SHIFT < VIRTIO_BALLOON_PFN_SHIFT);
        /* Convert pfn from Linux page size to balloon page size. */
-       return pfn >> (PAGE_SHIFT - VIRTIO_BALLOON_PFN_SHIFT);
+       return pfn >> VIRTIO_BALLOON_PAGE_ORDER;
 }
 
 static void balloon_ack(struct virtqueue *vq)
@@ -102,8 +101,9 @@ static void fill_balloon(struct virtio_balloon *vb, size_t 
num)
        num = min(num, ARRAY_SIZE(vb->pfns));
 
        for (vb->num_pfns = 0; vb->num_pfns < num; vb->num_pfns++) {
-               struct page *page = alloc_page(GFP_HIGHUSER | __GFP_NORETRY |
-                                       __GFP_NOMEMALLOC | __GFP_NOWARN);
+               struct page *page = alloc_pages(GFP_HIGHUSER | __GFP_NORETRY |
+                               __GFP_NOMEMALLOC | __GFP_NOWARN,
+                               VIRTIO_BALLOON_PAGE_ORDER);
                if (!page) {
                        if (printk_ratelimit())
                                dev_printk(KERN_INFO, &vb->vdev->dev,
@@ -114,7 +114,7 @@ static void fill_balloon(struct virtio_balloon *vb, size_t 
num)
                        break;
                }
                vb->pfns[vb->num_pfns] = page_to_balloon_pfn(page);
-               totalram_pages--;
+               totalram_pages -= VIRTIO_BALLOON_PAGES;
                vb->num_pages++;
                list_add(&page->lru, &vb->pages);
        }
@@ -131,8 +131,8 @@ static void release_pages_by_pfn(const u32 pfns[], unsigned 
int num)
        unsigned int i;
 
        for (i = 0; i < num; i++) {
-               __free_page(pfn_to_page(pfns[i]));
-               totalram_pages++;
+               __free_pages(pfn_to_page(pfns[i]), VIRTIO_BALLOON_PAGE_ORDER);
+               totalram_pages += VIRTIO_BALLOON_PAGES;
        }
 }
 
@@ -146,7 +146,7 @@ static void leak_balloon(struct virtio_balloon *vb, size_t 
num)
        for (vb->num_pfns = 0; vb->num_pfns < num; vb->num_pfns++) {
                page = list_first_entry(&vb->pages, struct page, lru);
                list_del(&page->lru);
-               vb->pfns[vb->num_pfns] = page_to_balloon_pfn(page);
+               vb->pfns[vb->num_pfns] = page_to_pfn(page);
                vb->num_pages--;
        }
 
@@ -400,7 +400,7 @@ static int virtballoon_restore(struct virtio_device *vdev)
        /* We don't have these pages in the balloon anymore! */
        list_for_each_entry_safe(page, page2, &vb->pages, lru) {
                list_del(&page->lru);
-               totalram_pages++;
+               totalram_pages += VIRTIO_BALLOON_PAGES;
        }
        return init_vqs(vdev->priv);
 }
diff --git a/include/linux/virtio_balloon.h b/include/linux/virtio_balloon.h
index 652dc8b..86840fe 100644
--- a/include/linux/virtio_balloon.h
+++ b/include/linux/virtio_balloon.h
@@ -33,7 +33,9 @@
 #define VIRTIO_BALLOON_F_STATS_VQ      1 /* Memory Stats virtqueue */
 
 /* Size of a PFN in the balloon interface. */
-#define VIRTIO_BALLOON_PFN_SHIFT 12
+#define VIRTIO_BALLOON_PFN_SHIFT  20
+#define VIRTIO_BALLOON_PAGE_ORDER (VIRTIO_BALLOON_PFN_SHIFT - PAGE_SHIFT)
+#define VIRTIO_BALLOON_PAGES      (1U << VIRTIO_BALLOON_PAGE_ORDER)
 
 struct virtio_balloon_config
 {
-- 
1.7.4.1

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