Re: [PATCH] ixgbe: Reduce memory consumption with larger page sizes

[Jeff Kirsher <jeffrey.t.kirsher@intel.com>]

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On Tue, 2013-10-22 at 10:37 +1100, Anton Blanchard wrote:
> The ixgbe driver allocates pages for its receive rings. It currently
> uses 512 pages, regardless of page size. During receive handling it
> adds the unused part of the page back into the rx ring, avoiding the
> need for a new allocation.
> 
> On a ppc64 box with 64 threads and 64kB pages, we end up with
> 512 entries * 64 rx queues * 64kB = 2GB memory used. Even more of a
> concern is that we use up 2GB of IOMMU space in order to map all this
> memory.
> 
> The driver makes a number of decisions based on if PAGE_SIZE is less
> than 8kB, so use this as the breakpoint and only allocate 128 entries
> on 8kB or larger page sizes.
> 
> Signed-off-by: Anton Blanchard <anton@samba.org>
> ---
> 
> Jeff: The breakpoint and the ring size I chose was pretty arbitrary,
> feel free to adjust as you see fit. Our main concern is we get that
> 2GB
> consumption down to something more reasonable :)

Thanks Anton, I will add your patch to my queue.

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