[XFRM]: Pack struct xfrm_policy
[acme@newtoy net-2.6.20]$ pahole net/ipv4/tcp.o xfrm_policy
/* /pub/scm/linux/kernel/git/acme/net-2.6.20/include/linux/security.h:67 */
struct xfrm_policy {
struct xfrm_policy * next; /* 0 4 */
struct hlist_node bydst; /* 4 8 */
struct hlist_node byidx; /* 12 8 */
rwlock_t lock; /* 20 36 */
atomic_t refcnt; /* 56 4 */
struct timer_list timer; /* 60 24 */
u8 type; /* 84 1 */
/* XXX 3 bytes hole, try to pack */
u32 priority; /* 88 4 */
u32 index; /* 92 4 */
struct xfrm_selector selector; /* 96 56 */
struct xfrm_lifetime_cfg lft; /* 152 64 */
struct xfrm_lifetime_cur curlft; /* 216 32 */
struct dst_entry * bundles; /* 248 4 */
__u16 family; /* 252 2 */
__u8 action; /* 254 1 */
__u8 flags; /* 255 1 */
__u8 dead; /* 256 1 */
__u8 xfrm_nr; /* 257 1 */
/* XXX 2 bytes hole, try to pack */
struct xfrm_sec_ctx * security; /* 260 4 */
struct xfrm_tmpl xfrm_vec[6]; /* 264 360 */
}; /* size: 624, sum members: 619, holes: 2, sum holes: 5 */
So lets have just one hole instead of two, by moving 'type' to just before 'action',
end result:
[acme@newtoy net-2.6.20]$ codiff -s /tmp/tcp.o.before net/ipv4/tcp.o
/pub/scm/linux/kernel/git/acme/net-2.6.20/net/ipv4/tcp.c:
struct xfrm_policy | -4
1 struct changed
[acme@newtoy net-2.6.20]$
[acme@newtoy net-2.6.20]$ pahole -c 64 net/ipv4/tcp.o xfrm_policy
/* /pub/scm/linux/kernel/git/acme/net-2.6.20/include/linux/security.h:67 */
struct xfrm_policy {
struct xfrm_policy * next; /* 0 4 */
struct hlist_node bydst; /* 4 8 */
struct hlist_node byidx; /* 12 8 */
rwlock_t lock; /* 20 36 */
atomic_t refcnt; /* 56 4 */
struct timer_list timer; /* 60 24 */
u32 priority; /* 84 4 */
u32 index; /* 88 4 */
struct xfrm_selector selector; /* 92 56 */
struct xfrm_lifetime_cfg lft; /* 148 64 */
struct xfrm_lifetime_cur curlft; /* 212 32 */
struct dst_entry * bundles; /* 244 4 */
u16 family; /* 248 2 */
u8 type; /* 250 1 */
u8 action; /* 251 1 */
u8 flags; /* 252 1 */
u8 dead; /* 253 1 */
u8 xfrm_nr; /* 254 1 */
/* XXX 1 byte hole, try to pack */
struct xfrm_sec_ctx * security; /* 256 4 */
struct xfrm_tmpl xfrm_vec[6]; /* 260 360 */
}; /* size: 620, sum members: 619, holes: 1, sum holes: 1 */
Are there any fugly data dependencies here? None that I know.
In the process changed the removed the __ prefixed types, that are just for
userspace visible headers.
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
1 file changed