Messages in this thread | | | Date | Fri, 16 Mar 2007 13:59:52 -0700 | From | Martin Bligh <> | Subject | Re: [PATCH 00/18] Make common x86 arch area for i386 and x86_64 - Take 2 |
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Christoph Lameter wrote: > On Fri, 16 Mar 2007, Martin Bligh wrote: > >> You have to do some sort of lookup anyway, and Andy seemed to have them >> all folded into one. > > What lookup would you need to do? On x86_64 even the TLB use is > hidden by the existing 2M entries for 1-1 mappings. > >> Or are you trying to avoid this by going to back to the crud we had >> in 2.4 where we pretend mem_map is one big array, indexed by pfn with >> huge sparsely mapped holes in it? > > Yes that the advanced way of doing it rather than adding useless custom > lookups.
For starters, you can't do that sparse a mapping on a 32 bit system. I'll let Andy explain the rest of it.
>> Would be nice to work out (and document somewhere) what the pros and >> cons of virtual memmap vs sparsemem were - ISTR one of the arguments >> was extremely sparsely layed out machines, and you needed sparsemem >> for that. But right now we have 3 solutions, which is not a good >> situation. > > Please read my posts to linux-mm on that subject. We discussed it last > year in detail and the agreement was that the sparsemem crud needs to be > taken out. Kame-san posted patches to do that.
"the agreement"? So Andy agreed to taking it out? Or you and Kame did?
M.
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