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Commit 5f8e1e8b authored by Jesper Dangaard Brouer's avatar Jesper Dangaard Brouer Committed by David S. Miller
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net: cacheline adjust struct inet_frags for better frag performance 



The globally shared rwlock, of struct inet_frags, shares
cacheline with the 'rnd' number, which is used by the hash
calculations.  Fix this, as this obviously is a bad idea, as
unnecessary cache-misses will occur when accessing the 'rnd'
number.

Also small note that, moving function ptr (*match) up in struct,
is to avoid it lands on the next cacheline (on 64-bit).

Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cd39a789

include/net/inet_frag.h

+7 −4
Original line number Diff line number Diff line
@@ -40,18 +40,21 @@ struct inet_frag_queue { 


struct inet_frags {

	struct hlist_head	hash[INETFRAGS_HASHSZ];

	rwlock_t		lock;

	u32			rnd;

	int			qsize;

	/* This rwlock is a global lock (seperate per IPv4, IPv6 and

	 * netfilter). Important to keep this on a seperate cacheline.

	 */

	rwlock_t		lock ____cacheline_aligned_in_smp;

	int			secret_interval;

	struct timer_list	secret_timer;

	u32			rnd;

	int			qsize;



	unsigned int		(*hashfn)(struct inet_frag_queue *);

	bool			(*match)(struct inet_frag_queue *q, void *arg);

	void			(*constructor)(struct inet_frag_queue *q,

						void *arg);

	void			(*destructor)(struct inet_frag_queue *);

	void			(*skb_free)(struct sk_buff *);

	bool			(*match)(struct inet_frag_queue *q, void *arg);

	void			(*frag_expire)(unsigned long data);

};