The calculation of extent_buffer::pages size was done for 4k PAGE_SIZE,
but this wastes 15 unused pointers on arches with large page size. Eg.
on ppc64 this gives 15 * 8 = 120 bytes.
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
---
fs/btrfs/ctree.h | 6 ------
fs/btrfs/extent_io.c | 2 ++
fs/btrfs/extent_io.h | 8 +++++++-
3 files changed, 9 insertions(+), 7 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 4274a7bfdaed..f914f6187753 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -66,12 +66,6 @@ struct btrfs_ordered_sum;
#define BTRFS_COMPAT_EXTENT_TREE_V0
/*
- * the max metadata block size. This limit is somewhat artificial,
- * but the memmove costs go through the roof for larger blocks.
- */
-#define BTRFS_MAX_METADATA_BLOCKSIZE 65536
-
-/*
* we can actually store much bigger names, but lets not confuse the rest
* of linux
*/
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 75533adef998..6f468a1842e6 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4660,6 +4660,8 @@ __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
/*
* Sanity checks, currently the maximum is 64k covered by 16x 4k pages
*/
+ BUILD_BUG_ON(INLINE_EXTENT_BUFFER_PAGES * PAGE_SIZE
+ != BTRFS_MAX_METADATA_BLOCKSIZE);
BUILD_BUG_ON(BTRFS_MAX_METADATA_BLOCKSIZE
> MAX_INLINE_EXTENT_BUFFER_SIZE);
BUG_ON(len > MAX_INLINE_EXTENT_BUFFER_SIZE);
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index c0c1c4fef6ce..edfa1a0ab82b 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -4,6 +4,12 @@
#include <linux/rbtree.h>
#include "ulist.h"
+/*
+ * The maximum metadata block size. This limit is somewhat artificial,
+ * but the memmove costs go through the roof for larger blocks.
+ */
+#define BTRFS_MAX_METADATA_BLOCKSIZE (65536U)
+
/* bits for the extent state */
#define EXTENT_DIRTY (1U << 0)
#define EXTENT_WRITEBACK (1U << 1)
@@ -118,7 +124,7 @@ struct extent_state {
#endif
};
-#define INLINE_EXTENT_BUFFER_PAGES 16
+#define INLINE_EXTENT_BUFFER_PAGES (BTRFS_MAX_METADATA_BLOCKSIZE / PAGE_SIZE)
#define MAX_INLINE_EXTENT_BUFFER_SIZE (INLINE_EXTENT_BUFFER_PAGES * PAGE_SIZE)
struct extent_buffer {
u64 start;
--
2.7.1
--
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