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

[Prasad Joshi <prasadjoshi.linux@xxxxxxxxx>]

Signed-off-by: Prasad Joshi <prasadjoshi.linux@xxxxxxxxx>
---
 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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