Re: [PATCH 06/12] kho: allow early-boot usage of the KHO radix tree

From: Mike Rapoport

Date: Mon May 11 2026 - 07:58:24 EST


On Wed, Apr 29, 2026 at 03:39:08PM +0200, Pratyush Yadav wrote:
> From: "Pratyush Yadav (Google)" <pratyush@xxxxxxxxxx>
>
> The KHO radix tree allocates memory for table pages from the buddy
> allocator using get_zeroed_page(). This is not available in early boot
> when memblock is still active.
>
> Using the radix tree in early boot is useful for KHO to track metadata
> about its memory. One such example is for tracking free blocks for
> memory allocation when scratch runs out of space. This feature will be
> added in the following commits.
>
> Add kho_radix_{alloc,free}_node() which allocate and free the table
> pages. They use slab_is_available() to decide which allocator to use.
> While slab_is_available() indicates availability of the slab allocator,
> it gets initialized right before buddy so it serves the same practical

^ after?

> purpose.
>
> Signed-off-by: Pratyush Yadav (Google) <pratyush@xxxxxxxxxx>
> ---
> kernel/liveupdate/kexec_handover.c | 24 ++++++++++++++++++++++--
> 1 file changed, 22 insertions(+), 2 deletions(-)

--
Sincerely yours,
Mike.