Re: large page patch (fwd) (fwd)

David Mosberger
2002-08-06T05:15:59Z

>>>>> On Mon, 05 Aug 2002 21:58:17 -0700 (PDT), "David S. Miller" <davem@redhat.com> said:

>> From: David Mosberger <davidm@napali.hpl.hp.com> Date:
>> Mon, 5 Aug 2002 22:01:16 -0700

>> In my opinion, this is perhaps the strongest argument
>> *for* a separate "giant page" syscall interface. It will be
>> very hard (perhaps impossible) to optimize superpages to work
>> efficiently when the ratio of superpage/basepage grows huge
>> (as, by definition, the kernel would manage them as a set of
>> basepages).

DaveM> Actually, this is one of the reasons there was a lot of
DaveM> research into using sub-page clustering for large mappings in
DaveM> the TLB. Basically how this worked is that for a superpage,
DaveM> you could stick multiple sub-mappings into the entry such
DaveM> that you didn't need a fully physically contiguous superpage.

Sounds great if you have the hardware that can do it. Not too many
CPUs I know of support it.

--david