On Wed, 21 Sep 2011, Jeremy Fitzhardinge wrote:
> On 09/21/2011 03:42 AM, Stefano Stabellini wrote:
> > On Thu, 15 Sep 2011, Jeremy Fitzhardinge wrote:
> >> This series is relying on regular ram mappings are already synced to all
> >> tasks, but I'm not sure that's necessarily guaranteed (for example, if
> >> you hotplug new memory into the domain, the new pages won't be mapped
> >> into every mm unless they're synced).
> > the series is using GFP_KERNEL, so this problem shouldn't occur, right?
>
> What properties do you think GFP_KERNEL guarantees?
That the memory is below 4G and always mapped in the kernel 1:1 region.
Regarding memory hotplug it looks like that x86_32 is mapping new memory
ZONE_HIGHMEM, therefore avoiding any problems with GFP_KERNEL allocations.
On the other hand x86_64 is mapping the memory ZONE_NORMAL and calling
init_memory_mapping on the new range right away. AFAICT changes to
the 1:1 mapping in init_mm are automatically synced across all mm's
because the pgd is shared?
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
Home