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From:   Zi Yan <zi.yan@sent.com>
To:     linux-mm@kvack.org
Cc:     David Hildenbrand <david@redhat.com>,
        Matthew Wilcox <willy@infradead.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        John Hubbard <jhubbard@nvidia.com>,
        Yang Shi <shy828301@gmail.com>,
        David Rientjes <rientjes@google.com>,
        James Houghton <jthoughton@google.com>,
        Mike Rapoport <rppt@kernel.org>, linux-kernel@vger.kernel.org
Subject: [RFC PATCH v2 07/12] virtio: virtio_balloon: use pageblock_order instead of MAX_ORDER
Date:   Thu, 11 Aug 2022 19:16:38 -0400
Message-Id: <20220811231643.1012912-8-zi.yan@sent.com>
In-Reply-To: <20220811231643.1012912-1-zi.yan@sent.com>
References: <20220811231643.1012912-1-zi.yan@sent.com>
Reply-To: Zi Yan <ziy@nvidia.com>
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From: Zi Yan <ziy@nvidia.com>

virtio_balloon used MAX_ORDER to report free page blocks to host, as
MAX_ORDER becomes modifiable in later commits, the reported free size might
be too big. pageblock_order is either 1/2 of or the same as MAX_ORDER
currently. Use pageblock_order instead to make virtio_balloon have a
constant free page block report size when MAX_ORDER is changed in the later
commits.

Signed-off-by: Zi Yan <ziy@nvidia.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 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_balloo=
n.c
index 5b15936a5214..51447737538b 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -33,7 +33,7 @@
 #define VIRTIO_BALLOON_FREE_PAGE_ALLOC_FLAG (__GFP_NORETRY | __GFP_NOWARN =
| \
 					     __GFP_NOMEMALLOC)
 /* The order of free page blocks to report to host */
-#define VIRTIO_BALLOON_HINT_BLOCK_ORDER MAX_ORDER
+#define VIRTIO_BALLOON_HINT_BLOCK_ORDER pageblock_order
 /* The size of a free page block in bytes */
 #define VIRTIO_BALLOON_HINT_BLOCK_BYTES \
 	(1 << (VIRTIO_BALLOON_HINT_BLOCK_ORDER + PAGE_SHIFT))
--=20
2.35.1