Re: x86 swiotlb questions

["Jan Beulich" <jbeulich@novell.com>]

>>> Keir Fraser <keir@xensource.com> 15.12.06 15:03 >>>
>On 15/12/06 13:53, "Jan Beulich" <jbeulich@novell.com> wrote:
>
>> I already have patches ready to do this (the DMA thing really is a nice side
>> effect, I mostly wanted it for 32on64, so that I can restrict domain
>> allocations for 32-bit domains). Are you saying I should throw away the
>> DMA specialization then altogether (I already have no special DMA heap
>> anymore)? The leftovers from it are so that one can reserve some portion
>> of low memory to be returned only when the width restriction is low enough
>> (i.e. to retain dma_emergency_pool functionality), which certainly isn't
>> really appropriate anymore now (it should rather be a percentage or
>> something like that, so that the lower you get the more of the memory
>> remains reserved for specialized allocations).
>
>I think dma_emergency_pool as is can go. Possibly it should be replaced by
>allocator-management tools in dom0 to allow setting of limits on a
>per-bitwidth basis.

Okay, but I think I'll leave this as a separate change (that we probably first
should reach agreement on what it really ought to do and not do).

>Is this one of the patches you already sent in your 32-on-64 batch, or an
>additional one?

An additional one (or actually, a set of them, to make the individual steps
more clear). As a followup, I'm also planning to get rid of the Xen heaps
on those arches where they aren't needed (x86-64, not sure about ppc
and ia64, but I would assume it's really only x86-32 that needs it).

Jan