Dave Hansen wrote:
quoted text
> Oh, once we've let Linux establish ptes to it, we've required that the
> hypervisor have it around?  How does that work with the balloon driver?
> Do we destroy the ptes when giving balloon memory back to the
> hypervisor?
>   

Yep.  It removes any mapping before handing it back to the hypervisor.

quoted text
> If we're talking about i386, then we're set.  We don't map the hot-added
> memory at all because we only add highmem on i386.  The only time we map
> these pages is *after* we actually allocate them when they get mapped
> into userspace or used as vmalloc() or they're kmap()'d.
>   

Well, the balloon driver can balloon out lowmem pages, so we have to 
deal with mappings either way.  But balloon+hotplug would work 
identically on x86-64, so all pages are mapped.

quoted text
>> I think we're getting off track here; this is a lot of extra complexity 
>> to justify allowing usermode to use /sys to online a chunk of hotplugged 
>> memory.
>>     
>
> Either that, or we're going to develop the entire Xen/kvm memory hotplug
> architecture around the soon-to-be-legacy i386 limitations. :)

Everything also applies to x86-64.


    J
--
unsubscribe notice
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/