[PATCH v3] kho: add support for deferred struct page init

[Michał Cłapiński]

On Wed, Feb 11, 2026 at 8:40 PM Pasha Tatashin
<pasha.tatashin at soleen.com> wrote:
>
> On Wed, Feb 11, 2026 at 12:40 PM Michal Clapinski <mclapinski at google.com> wrote:
> >
> > From: Evangelos Petrongonas <epetron at amazon.de>
> >
> > When CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled, struct page
> > initialization is deferred to parallel kthreads that run later
> > in the boot process.
> >
> > During KHO restoration, deserialize_bitmap() writes metadata for
> > each preserved memory region. However, if the struct page has not been
> > initialized, this write targets uninitialized memory, potentially
> > leading to errors like:
> > BUG: unable to handle page fault for address: ...
> >
> > Fix this by introducing kho_get_preserved_page(),  which ensures
> > all struct pages in a preserved region are initialized by calling
> > init_deferred_page() which is a no-op when deferred init is disabled
> > or when the struct page is already initialized.
> >
>
> Co-developed-by: Michal Clapinski <mclapinski at google.com>
>
> > Signed-off-by: Evangelos Petrongonas <epetron at amazon.de>
> > Signed-off-by: Michal Clapinski <mclapinski at google.com>
> > Reviewed-by: Pratyush Yadav (Google) <pratyush at kernel.org>
> > ---
> > v3:
> > - changed commit msg
> > - don't invoke early_pfn_to_nid if CONFIG_DEFERRED_STRUCT_PAGE_INIT=n
>
> Reviewed-by: Pasha Tatashin <pasha.tatashin at soleen.com>

Hello Andrew,
could you please apply this with the added Co-developed-by tag?

Thanks,
Michal