Re: [Qemu-devel] [PATCH] kvm: align ram_size to page boundary

[Blue Swirl]

On Sun, Jun 17, 2012 at 11:51 AM, Avi Kivity <address@hidden> wrote:
> On 06/17/2012 02:47 PM, Jan Kiszka wrote:
>>>>
>>>> I think this should rather go into generic code.
>>>
>>> To be honest, I put this in kvm-specific code because vl.c doesn't have
>>> TARGET_PAGE_ALIGN.  Maybe we should have machine->page_size or
>>> machine->ram_alignment.
>>>
>>>> What sense does it make
>>>> to have partial pages with TCG?
>>>
>>> Why impose an artificial restriction?
>>
>> Beca...
>>
>>>
>>> (answer: to reduce differences among various accelerators)
>>>
>>
>> Oh, you found the answer. :)
>
> Reducing round-trips across the Internet.
>
>>
>> At least, it should be enforce for the x86 target, independent of the
>> accelerator.
>
> Yeah.  So there's machine->page_size or machine->ram_alignment.  Not
> sure which is best.

The boards should make sure that the amount of RAM is feasible with
the board memory slots. It's not possible to put 256kb SIMMs to a slot
that expects 1GB DIMMs. We can allow some flexibility there though,
I'm not sure if the current chipsets would support very much memory if
we followed the docs to the letter.

Maybe strtosz() should just enforce 1MB granularity.

What about ballooning (memory hotplug?), can that reduce the memory by
smaller amount than page size?

>
> --
> error compiling committee.c: too many arguments to function
>
>
>