[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [RFC PATCH] xen/memory: Introduce a hypercall to provide unallocated space





On 17/08/2021 18:53, Julien Grall wrote:
Hi Oleksandr,

On 10/08/2021 18:03, Oleksandr wrote:

On 10.08.21 19:28, Julien Grall wrote:

Hi Julien.



On 09/08/2021 22:18, Oleksandr wrote:

On 09.08.21 23:45, Julien Grall wrote:


Hi Julien


Hi Oleksandr,

On 09/08/2021 19:24, Oleksandr wrote:

On 09.08.21 18:42, Julien Grall wrote:
1. If IOMMU is enabled for Dom0 -> provide holes found in Host DT as safe ranges

I would take into the account holes >= 1MB.

May I ask why 1MB?

Nothing special, just thinking to not bother with small regions which would not be too useful overall, but could bloat resulting reg property.

Anyway, I would be ok with any sizes.

I was more interesting with the reasoning behind your choice rather than saying we want more.

I agree that we may want to skip smaller region. I am guess that an high number of small regions will also increase the bookeeping in Linux.

But I would probably suggest to align the safe region to a 2MB (superpage for 4KB page granularity) just because the backend (or even Xen) may be able to do some optimization there.

OK, agree regarding the alignment. But, what about the size? I assume, it should be a multiple of 2MB.

I would say yes. In the documentation for the guest, I would just write "64KB" to give us some flexibility to reduce the alignment/size if we encounter platform where we can meet those limits (hopefully there is none...).

Whoops, I meant cannot rather than can.

Cheers,

--
Julien Grall



 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.