Re: [PATCH] mm/migrate_device: fix cache flush when replacing huge zero PMD

Andrew Morton <[email protected]> Mon, 17 Aug 2026 15:12:04 -0700

Newsgroups	gmane.linux.kernel,gmane.linux.kernel.mm
Message-ID	<[email protected]>

On Mon, 17 Aug 2026 14:34:15 -0700 Andrew Morton <[email protected]> wrote:

> > Hi,
> > 
> > I took a closer look at this, there is no userspace-visible effect today.
> > 
> > The architectures that currently enable ARCH_ENABLE_THP_MIGRATION use
> > no-op implementations of flush_cache_page()/flush_cache_range().
> > 32-bit ARM has non-trivial implementations, but does not enable
> > ARCH_ENABLE_THP_MIGRATION.
> > 
> > So this appears to be a latent API misuse rather than a currently
> > observable bug, and I don't think a stable backport is necessary.
> 
> OK, thanks for checking.
> 
> > Should I resend a v2 clarifying the userspace-visible effect in the
> > changelog?
> 
> Yes please, after 7.3-rc1.

Actually, I updated the changelog and added it to next week's
queue-for-Linus.