From: Anton Blanchard <anton@samba.org>
Reduce size of struct dentry from 248 to 232 bytes on 64bit.
- Reduce size of qstr by 8 bytes, placing int hash and int len together.
We gain a further 4 byte saving when qstr is used in struct dentry
since qstr goes from 24 to 16 bytes and the next member (d_lru)
requires 8 byte alignment (which means 4 bytes of padding).
- Move d_mounted to the end, since char d_iname[] only requires 1 byte
alignment. This reduces struct dentry by another 4 bytes.
With these changes the number of objects we can fit into a 4kB slab
goes from 16 to 17 on ppc64.
Note the above assumes the architecture naturally aligns types.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/include/linux/dcache.h | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff -puN include/linux/dcache.h~reduce-size-of-struct-dentry-on-64bit include/linux/dcache.h
--- 25/include/linux/dcache.h~reduce-size-of-struct-dentry-on-64bit 2004-08-15 17:39:50.447563616 -0700
+++ 25-akpm/include/linux/dcache.h 2004-08-15 17:39:50.450563160 -0700
@@ -33,8 +33,8 @@ struct vfsmount;
*/
struct qstr {
unsigned int hash;
- const unsigned char *name;
unsigned int len;
+ const unsigned char *name;
};
struct dentry_stat_t {
@@ -101,11 +101,11 @@ struct dentry {
unsigned long d_time; /* used by d_revalidate */
struct dentry_operations *d_op;
struct super_block *d_sb; /* The root of the dentry tree */
- int d_mounted;
void *d_fsdata; /* fs-specific data */
struct rcu_head d_rcu;
struct dcookie_struct *d_cookie; /* cookie, if any */
struct hlist_node d_hash; /* lookup hash list */
+ int d_mounted;
unsigned char d_iname[DNAME_INLINE_LEN_MIN]; /* small names */
};
_