On Thu, 29 Jul 2010, Dave Hansen wrote:
quoted text > SPARSEMEM_EXTREME would be a bit different. It's a 2-level lookup.
> You'd have 16 "section roots", each representing 256MB of address space.
> Each time we put memory under one of those roots, we'd fill in a
> 512-section second-level table, which is designed to always fit into one
> page. If you start at 256MB, you won't waste all those entries.
That is certain a solution to the !MMU case and it would work very much
like a page table. If you have an MMU then the vmemmap sparsemem
configuration can take advantage of of that to avoid the 2 level lookup.
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Re: [PATCH] Tight check of pfn_valid on sparsemem - v4 , Christoph Lameter , (Fri Jul 30, 5:48 am)
