From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <dada1@cosmosbay.com>
Subject: Re: [PATCH] net: make sure struct dst_entry refcount is aligned on
 64 bytes
Date: Fri, 14 Nov 2008 14:37:38 +0100
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Cc: David Miller <davem@davemloft.net>, netdev@vger.kernel.org,
	shemminger@vyatta.com,
	"Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
To: Alexey Dobriyan <adobriyan@gmail.com>
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Alexey Dobriyan a =E9crit :

> Hmm, indeed.
>=20
> I tried moving __refcnt et al to the very beginning, but it seems to =
make
> things worse (on x86_64, almost within statistical error).
>=20
> And there is no way to use offset_of() inside struct definition. :-(

Yes, it is important that the beginning of structure contain read mostl=
y fields.

refcnt being the most written field (incremented / decremented for each=
 packet),
it is really important to move it outside of the first 128 bytes=20
(192 bytes on 64 bit arches) of dst_entry

I wonder if some real hot dst_entries could be splitted (one copy for e=
ach stream),
to reduce ping-pongs.