Re: [PATCH] mm: don't defer freeing kernel page tables while booting

["Lorenzo Stoakes (ARM)" <ljs@kernel.org>]

On Thu, Sep 24, 2026 at 09:57:57AM +0100, Lorenzo Stoakes (ARM) wrote:
> On Thu, Sep 24, 2026 at 09:31:40AM +0200, David Hildenbrand (Arm) wrote:
> > On 9/24/26 09:28, Mikhail Gavrilov wrote:
> > > On 9/24/26 09:07, David Hildenbrand (Arm) wrote:
> > >> Should we instead simply skip the
> > >>
> > >> 	schedule_work(&kernel_pgtable_work.work);
> > >>
> > >> and rely on anybody freeing stuff later to just free that one alongside?
> > >>
> > >> That avoids throwing in more freeing handling.
> > >
> > > Yes, that is simpler, and the early table then goes through the same
> > > IOMMU flush as every other one, so there is no need to reason about
> > > what an IOMMU can see during boot.  The only cost is that it waits on
> > > the list until the next kernel page table is freed after boot.
> >
> > If we're worried about that actually causing problems we could drain the list at
> > a later part during the boot stage. I'd suspect we free something else later
> > already and simply drain the list ...

And on that, yes, I don't think there's anything to worry about there.

--
Cheers, Lorenzo