f2fs: shrink size of struct seg_entry
Restructure struct seg_entry to eliminate holes in it, after that,
in 32-bits machine, it reduces size from 32 bytes to 24 bytes; in
64-bits machine, it reduces size from 56 bytes to 40 bytes.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 975c33d..7a756ff 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -158,16 +158,17 @@
};
struct seg_entry {
- unsigned short valid_blocks; /* # of valid blocks */
+ unsigned int type:6; /* segment type like CURSEG_XXX_TYPE */
+ unsigned int valid_blocks:10; /* # of valid blocks */
+ unsigned int ckpt_valid_blocks:10; /* # of valid blocks last cp */
+ unsigned int padding:6; /* padding */
unsigned char *cur_valid_map; /* validity bitmap of blocks */
/*
* # of valid blocks and the validity bitmap stored in the the last
* checkpoint pack. This information is used by the SSR mode.
*/
- unsigned short ckpt_valid_blocks;
- unsigned char *ckpt_valid_map;
+ unsigned char *ckpt_valid_map; /* validity bitmap of blocks last cp */
unsigned char *discard_map;
- unsigned char type; /* segment type like CURSEG_XXX_TYPE */
unsigned long long mtime; /* modification time of the segment */
};