ipv6 fib: Make rt6_info{} more cache-line aware. (bd2c77a0) · Commits · 戴 / test

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:

YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by:

David S. Miller <davem@davemloft.net>

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)

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