Re: [PATCH v1 13/13] kho: Introduce high-level memory allocation API

[Mike Rapoport <rppt@kernel.org>]

On Fri, Nov 14, 2025 at 10:53:58AM -0500, Pasha Tatashin wrote:
> Currently, clients of KHO must manually allocate memory (e.g., via
> alloc_pages), calculate the page order, and explicitly call
> kho_preserve_folio(). Similarly, cleanup requires separate calls to
> unpreserve and free the memory.
> 
> Introduce a high-level API to streamline this common pattern:
> 
> - kho_alloc_preserve(size): Allocates physically contiguous, zeroed
>   memory and immediately marks it for preservation.
> - kho_free_unpreserve(ptr, size): Unpreserves and frees the memory
>   in the current kernel.
> - kho_free_restore(ptr, size): Restores the struct page state of
>   preserved memory in the new kernel and immediately frees it to the
>   page allocator.

It would have been nice to have it before patch 3 (Preserve FDT folio only
once during initialization) and use kho_alloc_preserve() for KHO's own FDT.

> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
> ---
>  include/linux/kexec_handover.h     |  22 +++++--
>  kernel/liveupdate/kexec_handover.c | 101 +++++++++++++++++++++++++++++
>  2 files changed, 116 insertions(+), 7 deletions(-)

-- 
Sincerely yours,
Mike.