ext4: reorder ext4_inode_info structure elements to remove unneeded padding
Theodore Ts'o [Mon, 10 Jan 2011 17:13:42 +0000 (12:13 -0500)]
By reordering the elements in the ext4_inode_info structure, we can
reduce the padding needed on an x86_64 system by 16 bytes.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/ext4.h

index de937fc..50e3d24 100644 (file)
@@ -763,10 +763,10 @@ struct ext4_inode_info {
         * near to their parent directory's inode.
         */
        ext4_group_t    i_block_group;
+       ext4_lblk_t     i_dir_start_lookup;
        unsigned long   i_state_flags;          /* Dynamic state flags */
        unsigned long   i_flags;
 
-       ext4_lblk_t             i_dir_start_lookup;
 #ifdef CONFIG_EXT4_FS_XATTR
        /*
         * Extended attributes can be read independently of the main file
@@ -835,7 +835,6 @@ struct ext4_inode_info {
        /* on-disk additional length */
        __u16 i_extra_isize;
 
-       spinlock_t i_block_reservation_lock;
 #ifdef CONFIG_QUOTA
        /* quota space reservation, managed internally by quota code */
        qsize_t i_reserved_quota;
@@ -844,9 +843,11 @@ struct ext4_inode_info {
        /* completed IOs that might need unwritten extents handling */
        struct list_head i_completed_io_list;
        spinlock_t i_completed_io_lock;
+       atomic_t i_ioend_count; /* Number of outstanding io_end structs */
        /* current io_end structure for async DIO write*/
        ext4_io_end_t *cur_aio_dio;
-       atomic_t i_ioend_count; /* Number of outstanding io_end structs */
+
+       spinlock_t i_block_reservation_lock;
 
        /*
         * Transactions that contain inode's metadata needed to complete