On Mon, Jun 12, 2023 at 09:45:38AM +0100, James Clark wrote:
[...]
> > @@ -609,8 +609,8 @@ static struct page *rb_alloc_aux_page(int node, int order)
> > {
> > struct page *page;
> >
> > - if (order > MAX_ORDER)
> > - order = MAX_ORDER;
> > + if (order >= MAX_ORDER)
> > + order = MAX_ORDER - 1;
> >
> > do {
> > page = alloc_pages_node(node, PERF_AUX_GFP, order);
>
>
> It seems like this was only just recently changed with this as the
> commit message (23baf83):
>
> mm, treewide: redefine MAX_ORDER sanely
>
> MAX_ORDER currently defined as number of orders page allocator
> supports: user can ask buddy allocator for page order between 0 and
> MAX_ORDER-1.
>
> This definition is counter-intuitive and lead to number of bugs all
> over the kernel.
>
> Change the definition of MAX_ORDER to be inclusive: the range of
> orders user can ask from buddy allocator is 0..MAX_ORDER now.
>
> It might be worth referring to this in the commit message or adding a
> fixes: reference. Or maybe this new change isn't quite right?
Good point. If so, we don't need this patch anymore.
Thanks for reminding, James.
Leo
