Re: skb data uncacheable ??

From: Henrik Nordstrom
Date: Wed Apr 14 2004 - 03:53:14 EST


On Wed, 14 Apr 2004, Nagendra Singh Tomar wrote:

> This way we can set the P1 (page containing the header) as cacheable and
> P2 as noncacheable. I know it looks ugly but we can make use of the
> remaining of P1 for some slab.

Very doubtful about this. You will need very many of these kinds of pages,
and I see it very unlikely the relative huge amounts of leftovers will
find any valuable use elsewhere in the kernel. Basically you increase the
memory usage per skb from about the packet size plus skbuff header to at
minimum 2 pages (1 cacheable, one normal), and I do not think many will
find this acceptable, But maybe?

You also need to worry about tlb flushing and other negative impacts each
time a new skbuff needs to be allocated / freed.

Regards
Henrik

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