From 5a139296f872d438f17f7219411321b603c1622b Mon Sep 17 00:00:00 2001 From: "fan.du" Date: Mon, 5 Aug 2013 17:13:03 +0800 Subject: [PATCH] sctp: Pack dst_cookie into 1st cacheline hole for 64bit host As dst_cookie is used in fast path sctp_transport_dst_check. Before: struct sctp_transport { struct list_head transports; /* 0 16 */ atomic_t refcnt; /* 16 4 */ __u32 dead:1; /* 20:31 4 */ __u32 rto_pending:1; /* 20:30 4 */ __u32 hb_sent:1; /* 20:29 4 */ __u32 pmtu_pending:1; /* 20:28 4 */ /* XXX 28 bits hole, try to pack */ __u32 sack_generation; /* 24 4 */ /* XXX 4 bytes hole, try to pack */ struct flowi fl; /* 32 64 */ /* --- cacheline 1 boundary (64 bytes) was 32 bytes ago --- */ union sctp_addr ipaddr; /* 96 28 */ After: struct sctp_transport { struct list_head transports; /* 0 16 */ atomic_t refcnt; /* 16 4 */ __u32 dead:1; /* 20:31 4 */ __u32 rto_pending:1; /* 20:30 4 */ __u32 hb_sent:1; /* 20:29 4 */ __u32 pmtu_pending:1; /* 20:28 4 */ /* XXX 28 bits hole, try to pack */ __u32 sack_generation; /* 24 4 */ u32 dst_cookie; /* 28 4 */ struct flowi fl; /* 32 64 */ /* --- cacheline 1 boundary (64 bytes) was 32 bytes ago --- */ union sctp_addr ipaddr; /* 96 28 */ Signed-off-by: Fan Du Acked-by: Neil Horman Signed-off-by: David S. Miller --- include/net/sctp/structs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h index c0f4e29eedd5..d9c93a77b1a9 100644 --- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -782,6 +782,7 @@ struct sctp_transport { /* Has this transport moved the ctsn since we last sacked */ __u32 sack_generation; + u32 dst_cookie; struct flowi fl; @@ -946,7 +947,6 @@ struct sctp_transport { __u64 hb_nonce; struct rcu_head rcu; - u32 dst_cookie; }; struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,