On Thu, Feb 04, 2021 at 06:19:36PM +0000, Quentin Perret wrote:

On Thursday 04 Feb 2021 at 14:31:08 (+0000), Will Deacon wrote:

quoted

Just feels a bit backwards having __find_buddy() take an order parameter,
yet then return a page of the wrong order! __hyp_extract_page() always
passes the p->order as the order,

Gotcha, so maybe this is just a naming problem. __find_buddy() is simply
a helper to lookup/index the vmemmap, but it's perfectly possible that
the 'destination' page that is being indexed has already been allocated,
and split up multiple time (and so at a different order), etc ... And
that is the caller's job to decide.

How about __lookup_potential_buddy() ? Any suggestion?

Hey, my job here is to waffle incoherently and hope that you find bugs in
your own code. Now you want me to _name_ something! Jeez...

Ok, how about __find_buddy() does what it does today but doesn't take an
order argument, whereas __find_buddy_of_order() takes the order argument
and checks the page order before returning?

Will