Hi Jason,
On Thu, Jan 15, 2026 at 07:44:30PM -0800, Jason Miu wrote:
> This series transitions KHO from an xarray-based metadata tracking system
> with serialization to a radix tree data structure that can be passed
> directly to the next kernel.
>
> The key motivations for this change are to:
> - Eliminate the need for data serialization before kexec.
> - Remove the KHO finalize state.
> - Pass preservation metadata more directly to the next kernel via the FDT.
>
> The new approach uses a radix tree to mark preserved pages. A page's
> physical address and its order are encoded into a single value. The tree
> is composed of multiple levels of page-sized tables, with leaf nodes
> being bitmaps where each set bit represents a preserved page. The
> physical address of the radix tree's root is passed in the FDT, allowing
> the next kernel to reconstruct the preserved memory map.
>
> This series is broken down into the following patches:
>
> 1. kho: Adopt radix tree for preserved memory tracking:
> Replaces the xarray-based tracker with the new radix tree
> implementation and increments the ABI version.
>
> 2. kho: Remove finalize state and clients:
> Removes the now-obsolete kho_finalize() function and its usage
> from client code and debugfs.
>
> ---
>
> Changelog since v6 [1]:
> - Fixed a potential dangling pointer in kho_radix_add_page() on allocation failure
> - Fixed a premature return in __kho_radix_walk_tree()
> - Corrected the size type in kho_preserved_memory_reserve() to match memblock_reserve()
git range-diff claims that v5, v6 and v7 are identical.
Can you please verify that it's the latest version you intended to send?
> [1] https://lore.kernel.org/lkml/20260115230047.1220580-1-jasonmiu@google.com/
>
> ---
>
> Jason Miu (2):
> kho: Adopt radix tree for preserved memory tracking
> kho: Remove finalize state and clients
>
> Documentation/admin-guide/mm/kho.rst | 53 +-
> Documentation/core-api/kho/abi.rst | 6 +
> Documentation/core-api/kho/index.rst | 18 +-
> include/linux/kho/abi/kexec_handover.h | 144 +++-
> include/linux/kho_radix_tree.h | 70 ++
> kernel/liveupdate/kexec_handover.c | 695 ++++++++++----------
> kernel/liveupdate/kexec_handover_debugfs.c | 23 -
> kernel/liveupdate/kexec_handover_internal.h | 3 -
> kernel/liveupdate/luo_core.c | 12 +-
> kernel/liveupdate/luo_flb.c | 2 +-
> tools/testing/selftests/kho/init.c | 20 -
> 11 files changed, 573 insertions(+), 473 deletions(-)
> create mode 100644 include/linux/kho_radix_tree.h
>
>
> base-commit: 9b7977f9e39b7768c70c2aa497f04e7569fd3e00
> --
> 2.52.0.457.g6b5491de43-goog
>
--
Sincerely yours,
Mike.