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[INET6]: Reorganize struct inet6_dev to save 8 bytes

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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>
This commit is contained in:
Arnaldo Carvalho de Melo 2008-02-03 04:06:59 -08:00 committed by David S. Miller
parent ab1e0a13d7
commit 4e7e5cfe38
1 changed files with 2 additions and 2 deletions
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4
include/net/if_inet6.h
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@ -166,11 +166,11 @@ struct inet6_dev
struct ifmcaddr6 *mc_list;
struct ifmcaddr6 *mc_tomb;
rwlock_t mc_lock;
unsigned long mc_v1_seen;
unsigned long mc_maxdelay;
unsigned char mc_qrv;
unsigned char mc_gq_running;
unsigned char mc_ifc_count;
unsigned long mc_v1_seen;
unsigned long mc_maxdelay;
struct timer_list mc_gq_timer; /* general query timer */
struct timer_list mc_ifc_timer; /* interface change timer */