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From: David Miller <davem@davemloft.net>
To: netdev@vger.kernel.org
Subject: RT metric sharing...
Date: Thu, 10 Dec 2009 14:14:38 -0800 (PST)	[thread overview]
Message-ID: <20091210.141438.78359022.davem@davemloft.net> (raw)


This topic has come up a few times, but I had a reason to
consider it again.

The routing metrics take up quite a bit of space in the
dst_entry and thus every routing cache entry.

We could save some space with indirection.

Basically my idea is:

1) dst_metrics are maintained in external structure

2) when cache entry is created, read-only dst_metrics object
   is allocated for it

3) any attempt to change the metrics of such a read-only dst_entry
   cow's it, all further writes proceed as normal

We currently have 13 (so 13 * sizeof(u32) == 52) and we're probably
about to get a 14th (for the initial receive window stuff).


             reply	other threads:[~2009-12-10 22:14 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-12-10 22:14 David Miller [this message]
2009-12-11  0:22 ` RT metric sharing Eric Dumazet

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