Re: [PATCH] mm: migrate: use thp_order instead of HPAGE_PMD_ORDER for new page allocation.
From: Andrew Morton
Date: Mon Apr 04 2022 - 18:01:16 EST
On Mon, 4 Apr 2022 12:53:25 -0400 Zi Yan <zi.yan@xxxxxxxx> wrote:
> From: Zi Yan <ziy@xxxxxxxxxx>
>
> With folios support, it is possible to have other than HPAGE_PMD_ORDER
> THPs, in the form of folios, in the system. Use thp_order() to correctly
> determine the source page order during migration.
Changelog doesn't describe the end user visible effects of the bug.
And it really should, because
> Link: https://lore.kernel.org/linux-mm/20220404132908.GA785673@u2004/
it fixes a kernel crash!