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Re: [Xen-devel] [PATCH] Make restore work properly with PV superpage flag

On Fri, Oct 12, 2012 at 6:32 PM, Dave McCracken <dcm@xxxxxxxx> wrote:
> For PV guests, the superpage flag means to unconditionally allocate all
> pages as superpages, which is required for Linux hugepages to work.  Support
> for this on restore was not supported.  This patch adds proper support for
> the superpage flag on restore.
> For HVM guests, the superpage flag has been used to mean attempt to allocate
> superpages if possible on restore.  This functionality has been preserved.
> Signed-off-by: Dave McCracken <dave.mccracken@xxxxxxxxxx>

Looks good -- boy, when you know that all of your pages have to be
superpages, it makes the logic a lot easier. :-)  Unfortunately that's
not the case for HVM guests, so we need to keep the complicated
detection logic.

I was trying to think of a way to make the "hvm" and "superpage" based
on the desired behavior (e.g, "detect_superpages",
"always_superpages", or something like that), rather than having to
encode "!hvm && superpage" all over the place, but I think in the end
the way you've written it is fine.

Acked-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>

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