]> err.no Git - linux-2.6/commit
[INET6]: Reorganize struct inet6_dev to save 8 bytes
authorArnaldo Carvalho de Melo <acme@redhat.com>
Sun, 3 Feb 2008 12:06:59 +0000 (04:06 -0800)
committerDavid S. Miller <davem@davemloft.net>
Sun, 3 Feb 2008 12:28:52 +0000 (04:28 -0800)
commit4e7e5cfe3825b4d854fc005d784a6f551b3c039f
tree0facec726e4a8f410e74d30234bb8f4894f8c186
parentab1e0a13d70299e792fd0527cefd070c1405fa5b
[INET6]: Reorganize struct inet6_dev to save 8 bytes

And make it a multiple of a 64 bytes, reducing cacheline trashing:

Before:

[acme@doppio net-2.6]$ pahole -C inet6_dev net/dccp/ipv6.o
struct inet6_dev {
<SNIP>
long unsigned int          mc_maxdelay;          /*    48     8 */
unsigned char              mc_qrv;               /*    56     1 */
unsigned char              mc_gq_running;        /*    57     1 */
unsigned char              mc_ifc_count;         /*    58     1 */

/* XXX 5 bytes hole, try to pack */

/* --- cacheline 1 boundary (64 bytes) --- */
struct timer_list          mc_gq_timer;          /*    64    48 */
<SNIP>
__u32                      if_flags;             /*   180     4 */
int                        dead;                 /*   184     4 */
u8                         rndid[8];             /*   188     8 */

/* XXX 4 bytes hole, try to pack */

/* --- cacheline 3 boundary (192 bytes) was 8 bytes ago --- */
struct timer_list          regen_timer;          /*   200    48 */

<SNIP>

/* size: 456, cachelines: 8 */
/* sum members: 447, holes: 2, sum holes: 9 */
/* last cacheline: 8 bytes */
};

After:

net-2.6/net/ipv6/af_inet6.c:
  struct inet6_dev |   -8
 1 struct changed

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
include/net/if_inet6.h