Re: mmu notifiers

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Christoph Lameter wrote:
> On Wed, 9 Jan 2008, Andrea Arcangeli wrote:
>
>   
>> This patch is a first basic implementation of the mmu notifiers. More
>> methods can be added in the future.
>>
>> In short when the linux VM decides to free a page, it will unmap it
>> from the linux pagetables. However when a page is mapped not just by
>> the regular linux ptes, but also from the shadow pagetables, it's
>> currently unfreeable by the linux VM.
>>     
>
> Such a patch would also address issues that SGI has with exporting 
> mappings via XPMEM. Plus a variety of other uses. Go ahead and lets do 
> more in this area.
>
> Are the KVM folks interested in exporting memory from one guest to 
> another? That may also become possible with some of the work that we have 
> in progress and that also requires a patch like this.
>
>   

Actually sharing memory is possible even without this patch; one simply 
mmap()s a file into the address space of both guests.  Or are you 
referring to something else?

The patch does enable some nifty things; one example you may be familiar 
with is using page migration to move a guest from one numa node to another.

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


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