Re: [PATCH 0/5] rtcache remove respin

[Eric Dumazet <eric.dumazet@gmail.com>]

On Sun, 2012-07-01 at 05:02 -0700, David Miller wrote:
> It's been a while and there were of course a lot of merge hassles with
> the most recent set I posted, so I respun these patches tonight
> because I wanted to see the effects of the recent rpfilter hacks on an
> rtcache-less system.
> 
> On a SPARC T3-1:
> 
> 1) Output route lookup: ~2800 cycles
> 2) Input route lookups: ~3000 cycles (rpfilter=0)
>                         ~4300 cycles (rpfilter=1)
> 
> Another nice part is how small struct rtable is after this patch set:
> 
> struct rtable {
> 	struct dst_entry        dst;
> 	int                     rt_genid;
> 	unsigned int            rt_flags;
> 	__u16                   rt_type;
> 	__be32                  rt_dst;
> 	int                     rt_route_iif;
> 	int                     rt_iif;
> 	int                     rt_oif;
> 	__be32                  rt_gateway;
> 	u32                     rt_peer_genid;
> 	unsigned long           _peer;
> 	struct fib_info         *fi;
> };
> 
> which is about 208 bytes on sparc64.
> 
> Signed-off-by: David S. Miller <davem@davemloft.net>

Can be <= 192 actually

rcu_head not needed anymore in dst_entry

If we still want __refcnt being on cache line boundary, we might find a
better way to accomplish this.