[PATCH] reduce size of struct inode on 64bit

Reduce the size of struct inode on 64bit architectures by reducing padding.
This assumes spinlocks are 32bit or less which is the case on most
architectures.

This reduces inode structs by 24 bytes on ppc64, and on ext2 increases the
number of inodes in a 4kB slab from 5 to 6.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/include/linux/fs.h b/include/linux/fs.h
index aecce55e4f88fa77d167811c8e14705d6fb413c6..68d486024d562bd544c742c3dc151be735865753 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -335,14 +335,14 @@ struct address_space {
        struct inode            *host;          /* owner: inode, block_device */
        struct radix_tree_root  page_tree;      /* radix tree of all pages */
        spinlock_t              tree_lock;      /* and spinlock protecting it */
-       unsigned long           nrpages;        /* number of total pages */
-       pgoff_t                 writeback_index;/* writeback starts here */
-       struct address_space_operations *a_ops; /* methods */
-       struct prio_tree_root   i_mmap;         /* tree of private mappings */
        unsigned int            i_mmap_writable;/* count VM_SHARED mappings */
+       struct prio_tree_root   i_mmap;         /* tree of private mappings */
        struct list_head        i_mmap_nonlinear;/*list VM_NONLINEAR mappings */
        spinlock_t              i_mmap_lock;    /* protect tree, count, list */
        atomic_t                truncate_count; /* Cover race condition with truncate */
+       unsigned long           nrpages;        /* number of total pages */
+       pgoff_t                 writeback_index;/* writeback starts here */
+       struct address_space_operations *a_ops; /* methods */
        unsigned long           flags;          /* error bits/gfp mask */
        struct backing_dev_info *backing_dev_info; /* device readahead, etc */
        spinlock_t              private_lock;   /* for use by the address_space */
@@ -437,6 +437,7 @@ struct inode {
        unsigned long           i_version;
        unsigned long           i_blocks;
        unsigned short          i_bytes;
+       unsigned char           i_sock;
        spinlock_t              i_lock; /* i_blocks, i_bytes, maybe i_size */
        struct semaphore        i_sem;
        struct rw_semaphore     i_alloc_sem;
@@ -456,6 +457,8 @@ struct inode {
        struct cdev             *i_cdev;
        int                     i_cindex;
 
+       __u32                   i_generation;
+
        unsigned long           i_dnotify_mask; /* Directory notify events */
        struct dnotify_struct   *i_dnotify; /* for directory notifications */
 
@@ -463,11 +466,9 @@ struct inode {
        unsigned long           dirtied_when;   /* jiffies of first dirtying */
 
        unsigned int            i_flags;
-       unsigned char           i_sock;
 
        atomic_t                i_writecount;
        void                    *i_security;
-       __u32                   i_generation;
        union {
                void            *generic_ip;
        } u;