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Commit bd2c77a0 authored by YOSHIFUJI Hideaki / 吉藤英明's avatar YOSHIFUJI Hideaki / 吉藤英明 Committed by David S. Miller
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ipv6 fib: Make rt6_info{} more cache-line aware. 



The head element of rt6_info{} is dst_entry{}, and
IPv6 specific elements follow.

Because elements at the end of dst_entry{} are frequently
updated, it is not good to put frequently-used static
elements, such as rt6i_idev, rt6i_dst or rt6i_flags in the
same cache line.

On the other hand, fib6_table, rt6i_node or rt6i_gateway are
rarely used, so it is okay to stay in the same cache line.

Let's rearrange rt6_info{}.

Signed-off-by: default avatarYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 152102c7

include/net/ip6_fib.h

+16 −13
Original line number Diff line number Diff line
@@ -88,34 +88,37 @@ struct rt6_info { 
		struct dst_entry	dst;

	} u;



	struct inet6_dev		*rt6i_idev;



#define rt6i_dev			u.dst.dev

#define rt6i_nexthop			u.dst.neighbour

#define rt6i_expires			u.dst.expires



	/*

	 * Tail elements of dst_entry (__refcnt etc.)

	 * and these elements (rarely used in hot path) are in

	 * the same cache line.

	 */

	struct fib6_table		*rt6i_table;

	struct fib6_node		*rt6i_node;



	struct in6_addr			rt6i_gateway;



	u32				rt6i_flags;

	u32				rt6i_metric;

	atomic_t			rt6i_ref;



	/* more non-fragment space at head required */

	unsigned short			rt6i_nfheader_len;



	u8				rt6i_protocol;



	struct fib6_table		*rt6i_table;

	/* These are in a separate cache line. */

	struct rt6key			rt6i_dst ____cacheline_aligned_in_smp;

	u32				rt6i_flags;

	struct rt6key			rt6i_src;

	u32				rt6i_metric;



	struct rt6key			rt6i_dst;

	struct inet6_dev		*rt6i_idev;



#ifdef CONFIG_XFRM

	u32				rt6i_flow_cache_genid;

#endif

	/* more non-fragment space at head required */

	unsigned short			rt6i_nfheader_len;



	struct rt6key			rt6i_src;

	u8				rt6i_protocol;

};



static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)