This series introduces the LUO, a kernel subsystem designed to
facilitate live kernel updates with minimal downtime,
particularly in cloud delplyoments aiming to update without fully
disrupting running virtual machines.

This series builds upon KHO framework by adding programmatic
control over KHO's lifecycle and leveraging KHO for persisting LUO's
own metadata across the kexec boundary. The git branch for this series
can be found at:

https://github.com/googleprodkernel/linux-liveupdate/tree/luo/v1

Changelog from rfc-v2:
- Addressed review comments from Mike Rapoport, Pratyush Yadav,
  David Matlack
- Moved everything under kernel/liveupdate including KHO.
- Added a number fixes to KHO that were discovered.
- luo_files is not a registred as a subsystem.
- Added sessions support to preserved files.
- Added support for memfd (Pratyush Yadav)
- Added libluo (proposed as RFC) (Pratyush Yadav)
- Removed notifiers from KHO (Mike Rapoport)

What is Live Update?
Live Update is a kexec based reboot process where selected kernel
resources (memory, file descriptors, and eventually devices) are kept
operational or their state preserved across a kernel transition. For
certain resources, DMA and interrupt activity might continue with
minimal interruption during the kernel reboot.

LUO provides a framework for coordinating live updates. It features:
State Machine: Manages the live update process through states:
NORMAL, PREPARED, FROZEN, UPDATED.

KHO Integration:

LUO programmatically drives KHO's finalization and abort sequences.
KHO's debugfs interface is now optional configured via
CONFIG_KEXEC_HANDOVER_DEBUG.

LUO preserves its own metadata via KHO's kho_add_subtree and
kho_preserve_phys() mechanisms.

Subsystem Participation: A callback API liveupdate_register_subsystem()
allows kernel subsystems (e.g., KVM, IOMMU, VFIO, PCI) to register
handlers for LUO events (PREPARE, FREEZE, FINISH, CANCEL) and persist a
u64 payload via the LUO FDT.

File Descriptor Preservation: Infrastructure
liveupdate_register_filesystem, luo_register_file, luo_retrieve_file to
allow specific types of file descriptors (e.g., memfd, vfio) to be
preserved and restored.

Handlers for specific file types can be registered to manage their
preservation and restoration, storing a u64 payload in the LUO FDT.

User-space Interface:

ioctl (/dev/liveupdate): The primary control interface for
triggering LUO state transitions (prepare, freeze, finish, cancel)
and managing the preservation/restoration of file descriptors.
Access requires CAP_SYS_ADMIN.

sysfs (/sys/kernel/liveupdate/state): A read-only interface for
monitoring the current LUO state. This allows userspace services to
track progress and coordinate actions.

Selftests: Includes kernel-side hooks and userspace selftests to
verify core LUO functionality, particularly subsystem registration and
basic state transitions.

LUO State Machine and Events:

NORMAL:   Default operational state.
PREPARED: Initial preparation complete after LIVEUPDATE_PREPARE
          event. Subsystems have saved initial state.
FROZEN:   Final "blackout window" state after LIVEUPDATE_FREEZE
          event, just before kexec. Workloads must be suspended.
UPDATED:  Next kernel has booted via live update. Awaiting restoration
          and LIVEUPDATE_FINISH.

Events:
LIVEUPDATE_PREPARE: Prepare for reboot, serialize state.
LIVEUPDATE_FREEZE:  Final opportunity to save state before kexec.
LIVEUPDATE_FINISH:  Post-reboot cleanup in the next kernel.
LIVEUPDATE_CANCEL:  Abort prepare or freeze, revert changes.

RFC v1: https://lore.kernel.org/all/20250320024011.2995837-1-pasha.tatashin@soleen.com
RFC v2: https://lore.kernel.org/all/20250515182322.117840-1-pasha.tatashin@soleen.com/

Changyuan Lyu (1):
  kho: add interfaces to unpreserve folios and physical memory ranges

Mike Rapoport (Microsoft) (1):
  kho: drop notifiers

Pasha Tatashin (22):
  kho: init new_physxa->phys_bits to fix lockdep
  kho: mm: Don't allow deferred struct page with KHO
  kho: warn if KHO is disabled due to an error
  kho: allow to drive kho from within kernel
  kho: make debugfs interface optional
  kho: don't unpreserve memory during abort
  liveupdate: kho: move to kernel/liveupdate
  liveupdate: luo_core: Live Update Orchestrator
  liveupdate: luo_core: integrate with KHO
  liveupdate: luo_subsystems: add subsystem registration
  liveupdate: luo_subsystems: implement subsystem callbacks
  liveupdate: luo_files: add infrastructure for FDs
  liveupdate: luo_files: implement file systems callbacks
  liveupdate: luo_ioctl: add ioctl interface
  liveupdate: luo_sysfs: add sysfs state monitoring
  reboot: call liveupdate_reboot() before kexec
  liveupdate: luo_files: luo_ioctl: session-based file descriptor
    tracking
  kho: move kho debugfs directory to liveupdate
  liveupdate: add selftests for subsystems un/registration
  selftests/liveupdate: add subsystem/state tests
  docs: add luo documentation
  MAINTAINERS: add liveupdate entry

Pratyush Yadav (8):
  mm: shmem: use SHMEM_F_* flags instead of VM_* flags
  mm: shmem: allow freezing inode mapping
  mm: shmem: export some functions to internal.h
  luo: allow preserving memfd
  docs: add documentation for memfd preservation via LUO
  tools: introduce libluo
  libluo: introduce luoctl
  libluo: add tests

 .../ABI/testing/sysfs-kernel-liveupdate       |  51 +
 Documentation/admin-guide/index.rst           |   1 +
 Documentation/admin-guide/liveupdate.rst      |  16 +
 Documentation/core-api/index.rst              |   1 +
 Documentation/core-api/kho/concepts.rst       |   2 +-
 Documentation/core-api/liveupdate.rst         |  57 ++
 Documentation/mm/index.rst                    |   1 +
 Documentation/mm/memfd_preservation.rst       | 138 +++
 Documentation/userspace-api/index.rst         |   1 +
 .../userspace-api/ioctl/ioctl-number.rst      |   2 +
 Documentation/userspace-api/liveupdate.rst    |  25 +
 MAINTAINERS                                   |  20 +-
 include/linux/kexec_handover.h                |  53 +-
 include/linux/liveupdate.h                    | 235 +++++
 include/linux/shmem_fs.h                      |  23 +
 include/uapi/linux/liveupdate.h               | 265 +++++
 init/Kconfig                                  |   2 +
 kernel/Kconfig.kexec                          |  14 -
 kernel/Makefile                               |   2 +-
 kernel/liveupdate/Kconfig                     |  90 ++
 kernel/liveupdate/Makefile                    |  13 +
 kernel/{ => liveupdate}/kexec_handover.c      | 556 +++++-----
 kernel/liveupdate/kexec_handover_debug.c      | 222 ++++
 kernel/liveupdate/kexec_handover_internal.h   |  45 +
 kernel/liveupdate/luo_core.c                  | 525 ++++++++++
 kernel/liveupdate/luo_files.c                 | 946 ++++++++++++++++++
 kernel/liveupdate/luo_internal.h              |  47 +
 kernel/liveupdate/luo_ioctl.c                 | 192 ++++
 kernel/liveupdate/luo_selftests.c             | 344 +++++++
 kernel/liveupdate/luo_selftests.h             |  84 ++
 kernel/liveupdate/luo_subsystems.c            | 420 ++++++++
 kernel/liveupdate/luo_sysfs.c                 |  92 ++
 kernel/reboot.c                               |   4 +
 mm/Makefile                                   |   1 +
 mm/internal.h                                 |   6 +
 mm/memblock.c                                 |  56 +-
 mm/memfd_luo.c                                | 501 ++++++++++
 mm/shmem.c                                    |  46 +-
 tools/lib/luo/LICENSE                         | 165 +++
 tools/lib/luo/Makefile                        |  45 +
 tools/lib/luo/README.md                       | 166 +++
 tools/lib/luo/cli/.gitignore                  |   1 +
 tools/lib/luo/cli/Makefile                    |  18 +
 tools/lib/luo/cli/luoctl.c                    | 178 ++++
 tools/lib/luo/include/libluo.h                | 128 +++
 tools/lib/luo/include/liveupdate.h            | 265 +++++
 tools/lib/luo/libluo.c                        | 203 ++++
 tools/lib/luo/tests/.gitignore                |   1 +
 tools/lib/luo/tests/Makefile                  |  18 +
 tools/lib/luo/tests/test.c                    | 848 ++++++++++++++++
 tools/testing/selftests/Makefile              |   1 +
 tools/testing/selftests/liveupdate/.gitignore |   1 +
 tools/testing/selftests/liveupdate/Makefile   |   7 +
 tools/testing/selftests/liveupdate/config     |   6 +
 .../testing/selftests/liveupdate/liveupdate.c | 356 +++++++
 55 files changed, 7091 insertions(+), 415 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-kernel-liveupdate
 create mode 100644 Documentation/admin-guide/liveupdate.rst
 create mode 100644 Documentation/core-api/liveupdate.rst
 create mode 100644 Documentation/mm/memfd_preservation.rst
 create mode 100644 Documentation/userspace-api/liveupdate.rst
 create mode 100644 include/linux/liveupdate.h
 create mode 100644 include/uapi/linux/liveupdate.h
 create mode 100644 kernel/liveupdate/Kconfig
 create mode 100644 kernel/liveupdate/Makefile
 rename kernel/{ => liveupdate}/kexec_handover.c (74%)
 create mode 100644 kernel/liveupdate/kexec_handover_debug.c
 create mode 100644 kernel/liveupdate/kexec_handover_internal.h
 create mode 100644 kernel/liveupdate/luo_core.c
 create mode 100644 kernel/liveupdate/luo_files.c
 create mode 100644 kernel/liveupdate/luo_internal.h
 create mode 100644 kernel/liveupdate/luo_ioctl.c
 create mode 100644 kernel/liveupdate/luo_selftests.c
 create mode 100644 kernel/liveupdate/luo_selftests.h
 create mode 100644 kernel/liveupdate/luo_subsystems.c
 create mode 100644 kernel/liveupdate/luo_sysfs.c
 create mode 100644 mm/memfd_luo.c
 create mode 100644 tools/lib/luo/LICENSE
 create mode 100644 tools/lib/luo/Makefile
 create mode 100644 tools/lib/luo/README.md
 create mode 100644 tools/lib/luo/cli/.gitignore
 create mode 100644 tools/lib/luo/cli/Makefile
 create mode 100644 tools/lib/luo/cli/luoctl.c
 create mode 100644 tools/lib/luo/include/libluo.h
 create mode 100644 tools/lib/luo/include/liveupdate.h
 create mode 100644 tools/lib/luo/libluo.c
 create mode 100644 tools/lib/luo/tests/.gitignore
 create mode 100644 tools/lib/luo/tests/Makefile
 create mode 100644 tools/lib/luo/tests/test.c
 create mode 100644 tools/testing/selftests/liveupdate/.gitignore
 create mode 100644 tools/testing/selftests/liveupdate/Makefile
 create mode 100644 tools/testing/selftests/liveupdate/config
 create mode 100644 tools/testing/selftests/liveupdate/liveupdate.c

-- 
2.50.0.727.gbf7dc18ff4-goog

FYI: Every one of your emails to the list for this series was bounced by
all the recipients using @gmail.com email addresses.

		-ben (owner-linux-mm)

On Wed, Jun 25, 2025 at 11:17:47PM +0000, Pasha Tatashin wrote:
> This series introduces the LUO, a kernel subsystem designed to
> facilitate live kernel updates with minimal downtime,
> particularly in cloud delplyoments aiming to update without fully
> disrupting running virtual machines.
> 
> This series builds upon KHO framework by adding programmatic
> control over KHO's lifecycle and leveraging KHO for persisting LUO's
> own metadata across the kexec boundary. The git branch for this series
> can be found at:
> 
> https://github.com/googleprodkernel/linux-liveupdate/tree/luo/v1
> 
> Changelog from rfc-v2:
> - Addressed review comments from Mike Rapoport, Pratyush Yadav,
>   David Matlack
> - Moved everything under kernel/liveupdate including KHO.
> - Added a number fixes to KHO that were discovered.
> - luo_files is not a registred as a subsystem.
> - Added sessions support to preserved files.
> - Added support for memfd (Pratyush Yadav)
> - Added libluo (proposed as RFC) (Pratyush Yadav)
> - Removed notifiers from KHO (Mike Rapoport)
> 
> What is Live Update?
> Live Update is a kexec based reboot process where selected kernel
> resources (memory, file descriptors, and eventually devices) are kept
> operational or their state preserved across a kernel transition. For
> certain resources, DMA and interrupt activity might continue with
> minimal interruption during the kernel reboot.
> 
> LUO provides a framework for coordinating live updates. It features:
> State Machine: Manages the live update process through states:
> NORMAL, PREPARED, FROZEN, UPDATED.
> 
> KHO Integration:
> 
> LUO programmatically drives KHO's finalization and abort sequences.
> KHO's debugfs interface is now optional configured via
> CONFIG_KEXEC_HANDOVER_DEBUG.
> 
> LUO preserves its own metadata via KHO's kho_add_subtree and
> kho_preserve_phys() mechanisms.
> 
> Subsystem Participation: A callback API liveupdate_register_subsystem()
> allows kernel subsystems (e.g., KVM, IOMMU, VFIO, PCI) to register
> handlers for LUO events (PREPARE, FREEZE, FINISH, CANCEL) and persist a
> u64 payload via the LUO FDT.
> 
> File Descriptor Preservation: Infrastructure
> liveupdate_register_filesystem, luo_register_file, luo_retrieve_file to
> allow specific types of file descriptors (e.g., memfd, vfio) to be
> preserved and restored.
> 
> Handlers for specific file types can be registered to manage their
> preservation and restoration, storing a u64 payload in the LUO FDT.
> 
> User-space Interface:
> 
> ioctl (/dev/liveupdate): The primary control interface for
> triggering LUO state transitions (prepare, freeze, finish, cancel)
> and managing the preservation/restoration of file descriptors.
> Access requires CAP_SYS_ADMIN.
> 
> sysfs (/sys/kernel/liveupdate/state): A read-only interface for
> monitoring the current LUO state. This allows userspace services to
> track progress and coordinate actions.
> 
> Selftests: Includes kernel-side hooks and userspace selftests to
> verify core LUO functionality, particularly subsystem registration and
> basic state transitions.
> 
> LUO State Machine and Events:
> 
> NORMAL:   Default operational state.
> PREPARED: Initial preparation complete after LIVEUPDATE_PREPARE
>           event. Subsystems have saved initial state.
> FROZEN:   Final "blackout window" state after LIVEUPDATE_FREEZE
>           event, just before kexec. Workloads must be suspended.
> UPDATED:  Next kernel has booted via live update. Awaiting restoration
>           and LIVEUPDATE_FINISH.
> 
> Events:
> LIVEUPDATE_PREPARE: Prepare for reboot, serialize state.
> LIVEUPDATE_FREEZE:  Final opportunity to save state before kexec.
> LIVEUPDATE_FINISH:  Post-reboot cleanup in the next kernel.
> LIVEUPDATE_CANCEL:  Abort prepare or freeze, revert changes.
> 
> RFC v1: https://lore.kernel.org/all/20250320024011.2995837-1-pasha.tatashin@soleen.com
> RFC v2: https://lore.kernel.org/all/20250515182322.117840-1-pasha.tatashin@soleen.com/
> 
> Changyuan Lyu (1):
>   kho: add interfaces to unpreserve folios and physical memory ranges
> 
> Mike Rapoport (Microsoft) (1):
>   kho: drop notifiers
> 
> Pasha Tatashin (22):
>   kho: init new_physxa->phys_bits to fix lockdep
>   kho: mm: Don't allow deferred struct page with KHO
>   kho: warn if KHO is disabled due to an error
>   kho: allow to drive kho from within kernel
>   kho: make debugfs interface optional
>   kho: don't unpreserve memory during abort
>   liveupdate: kho: move to kernel/liveupdate
>   liveupdate: luo_core: Live Update Orchestrator
>   liveupdate: luo_core: integrate with KHO
>   liveupdate: luo_subsystems: add subsystem registration
>   liveupdate: luo_subsystems: implement subsystem callbacks
>   liveupdate: luo_files: add infrastructure for FDs
>   liveupdate: luo_files: implement file systems callbacks
>   liveupdate: luo_ioctl: add ioctl interface
>   liveupdate: luo_sysfs: add sysfs state monitoring
>   reboot: call liveupdate_reboot() before kexec
>   liveupdate: luo_files: luo_ioctl: session-based file descriptor
>     tracking
>   kho: move kho debugfs directory to liveupdate
>   liveupdate: add selftests for subsystems un/registration
>   selftests/liveupdate: add subsystem/state tests
>   docs: add luo documentation
>   MAINTAINERS: add liveupdate entry
> 
> Pratyush Yadav (8):
>   mm: shmem: use SHMEM_F_* flags instead of VM_* flags
>   mm: shmem: allow freezing inode mapping
>   mm: shmem: export some functions to internal.h
>   luo: allow preserving memfd
>   docs: add documentation for memfd preservation via LUO
>   tools: introduce libluo
>   libluo: introduce luoctl
>   libluo: add tests
> 
>  .../ABI/testing/sysfs-kernel-liveupdate       |  51 +
>  Documentation/admin-guide/index.rst           |   1 +
>  Documentation/admin-guide/liveupdate.rst      |  16 +
>  Documentation/core-api/index.rst              |   1 +
>  Documentation/core-api/kho/concepts.rst       |   2 +-
>  Documentation/core-api/liveupdate.rst         |  57 ++
>  Documentation/mm/index.rst                    |   1 +
>  Documentation/mm/memfd_preservation.rst       | 138 +++
>  Documentation/userspace-api/index.rst         |   1 +
>  .../userspace-api/ioctl/ioctl-number.rst      |   2 +
>  Documentation/userspace-api/liveupdate.rst    |  25 +
>  MAINTAINERS                                   |  20 +-
>  include/linux/kexec_handover.h                |  53 +-
>  include/linux/liveupdate.h                    | 235 +++++
>  include/linux/shmem_fs.h                      |  23 +
>  include/uapi/linux/liveupdate.h               | 265 +++++
>  init/Kconfig                                  |   2 +
>  kernel/Kconfig.kexec                          |  14 -
>  kernel/Makefile                               |   2 +-
>  kernel/liveupdate/Kconfig                     |  90 ++
>  kernel/liveupdate/Makefile                    |  13 +
>  kernel/{ => liveupdate}/kexec_handover.c      | 556 +++++-----
>  kernel/liveupdate/kexec_handover_debug.c      | 222 ++++
>  kernel/liveupdate/kexec_handover_internal.h   |  45 +
>  kernel/liveupdate/luo_core.c                  | 525 ++++++++++
>  kernel/liveupdate/luo_files.c                 | 946 ++++++++++++++++++
>  kernel/liveupdate/luo_internal.h              |  47 +
>  kernel/liveupdate/luo_ioctl.c                 | 192 ++++
>  kernel/liveupdate/luo_selftests.c             | 344 +++++++
>  kernel/liveupdate/luo_selftests.h             |  84 ++
>  kernel/liveupdate/luo_subsystems.c            | 420 ++++++++
>  kernel/liveupdate/luo_sysfs.c                 |  92 ++
>  kernel/reboot.c                               |   4 +
>  mm/Makefile                                   |   1 +
>  mm/internal.h                                 |   6 +
>  mm/memblock.c                                 |  56 +-
>  mm/memfd_luo.c                                | 501 ++++++++++
>  mm/shmem.c                                    |  46 +-
>  tools/lib/luo/LICENSE                         | 165 +++
>  tools/lib/luo/Makefile                        |  45 +
>  tools/lib/luo/README.md                       | 166 +++
>  tools/lib/luo/cli/.gitignore                  |   1 +
>  tools/lib/luo/cli/Makefile                    |  18 +
>  tools/lib/luo/cli/luoctl.c                    | 178 ++++
>  tools/lib/luo/include/libluo.h                | 128 +++
>  tools/lib/luo/include/liveupdate.h            | 265 +++++
>  tools/lib/luo/libluo.c                        | 203 ++++
>  tools/lib/luo/tests/.gitignore                |   1 +
>  tools/lib/luo/tests/Makefile                  |  18 +
>  tools/lib/luo/tests/test.c                    | 848 ++++++++++++++++
>  tools/testing/selftests/Makefile              |   1 +
>  tools/testing/selftests/liveupdate/.gitignore |   1 +
>  tools/testing/selftests/liveupdate/Makefile   |   7 +
>  tools/testing/selftests/liveupdate/config     |   6 +
>  .../testing/selftests/liveupdate/liveupdate.c | 356 +++++++
>  55 files changed, 7091 insertions(+), 415 deletions(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-kernel-liveupdate
>  create mode 100644 Documentation/admin-guide/liveupdate.rst
>  create mode 100644 Documentation/core-api/liveupdate.rst
>  create mode 100644 Documentation/mm/memfd_preservation.rst
>  create mode 100644 Documentation/userspace-api/liveupdate.rst
>  create mode 100644 include/linux/liveupdate.h
>  create mode 100644 include/uapi/linux/liveupdate.h
>  create mode 100644 kernel/liveupdate/Kconfig
>  create mode 100644 kernel/liveupdate/Makefile
>  rename kernel/{ => liveupdate}/kexec_handover.c (74%)
>  create mode 100644 kernel/liveupdate/kexec_handover_debug.c
>  create mode 100644 kernel/liveupdate/kexec_handover_internal.h
>  create mode 100644 kernel/liveupdate/luo_core.c
>  create mode 100644 kernel/liveupdate/luo_files.c
>  create mode 100644 kernel/liveupdate/luo_internal.h
>  create mode 100644 kernel/liveupdate/luo_ioctl.c
>  create mode 100644 kernel/liveupdate/luo_selftests.c
>  create mode 100644 kernel/liveupdate/luo_selftests.h
>  create mode 100644 kernel/liveupdate/luo_subsystems.c
>  create mode 100644 kernel/liveupdate/luo_sysfs.c
>  create mode 100644 mm/memfd_luo.c
>  create mode 100644 tools/lib/luo/LICENSE
>  create mode 100644 tools/lib/luo/Makefile
>  create mode 100644 tools/lib/luo/README.md
>  create mode 100644 tools/lib/luo/cli/.gitignore
>  create mode 100644 tools/lib/luo/cli/Makefile
>  create mode 100644 tools/lib/luo/cli/luoctl.c
>  create mode 100644 tools/lib/luo/include/libluo.h
>  create mode 100644 tools/lib/luo/include/liveupdate.h
>  create mode 100644 tools/lib/luo/libluo.c
>  create mode 100644 tools/lib/luo/tests/.gitignore
>  create mode 100644 tools/lib/luo/tests/Makefile
>  create mode 100644 tools/lib/luo/tests/test.c
>  create mode 100644 tools/testing/selftests/liveupdate/.gitignore
>  create mode 100644 tools/testing/selftests/liveupdate/Makefile
>  create mode 100644 tools/testing/selftests/liveupdate/config
>  create mode 100644 tools/testing/selftests/liveupdate/liveupdate.c
> 
> -- 
> 2.50.0.727.gbf7dc18ff4-goog
> 

-- 
"Thought is the essence of where you are now."

On Wed, Jun 25, 2025 at 7:26 PM Benjamin LaHaise <bcrl@kvack.org> wrote:
>
> FYI: Every one of your emails to the list for this series was bounced by
> all the recipients using @gmail.com email addresses.
>
>                 -ben (owner-linux-mm)

This is extremely annoying, I will need to figure out why this is
happening. soleen.com uses google workspace.

Pasha

>
> On Wed, Jun 25, 2025 at 11:17:47PM +0000, Pasha Tatashin wrote:
> > This series introduces the LUO, a kernel subsystem designed to
> > facilitate live kernel updates with minimal downtime,
> > particularly in cloud delplyoments aiming to update without fully
> > disrupting running virtual machines.
> >
> > This series builds upon KHO framework by adding programmatic
> > control over KHO's lifecycle and leveraging KHO for persisting LUO's
> > own metadata across the kexec boundary. The git branch for this series
> > can be found at:
> >
> > https://github.com/googleprodkernel/linux-liveupdate/tree/luo/v1
> >
> > Changelog from rfc-v2:
> > - Addressed review comments from Mike Rapoport, Pratyush Yadav,
> >   David Matlack
> > - Moved everything under kernel/liveupdate including KHO.
> > - Added a number fixes to KHO that were discovered.
> > - luo_files is not a registred as a subsystem.
> > - Added sessions support to preserved files.
> > - Added support for memfd (Pratyush Yadav)
> > - Added libluo (proposed as RFC) (Pratyush Yadav)
> > - Removed notifiers from KHO (Mike Rapoport)
> >
> > What is Live Update?
> > Live Update is a kexec based reboot process where selected kernel
> > resources (memory, file descriptors, and eventually devices) are kept
> > operational or their state preserved across a kernel transition. For
> > certain resources, DMA and interrupt activity might continue with
> > minimal interruption during the kernel reboot.
> >
> > LUO provides a framework for coordinating live updates. It features:
> > State Machine: Manages the live update process through states:
> > NORMAL, PREPARED, FROZEN, UPDATED.
> >
> > KHO Integration:
> >
> > LUO programmatically drives KHO's finalization and abort sequences.
> > KHO's debugfs interface is now optional configured via
> > CONFIG_KEXEC_HANDOVER_DEBUG.
> >
> > LUO preserves its own metadata via KHO's kho_add_subtree and
> > kho_preserve_phys() mechanisms.
> >
> > Subsystem Participation: A callback API liveupdate_register_subsystem()
> > allows kernel subsystems (e.g., KVM, IOMMU, VFIO, PCI) to register
> > handlers for LUO events (PREPARE, FREEZE, FINISH, CANCEL) and persist a
> > u64 payload via the LUO FDT.
> >
> > File Descriptor Preservation: Infrastructure
> > liveupdate_register_filesystem, luo_register_file, luo_retrieve_file to
> > allow specific types of file descriptors (e.g., memfd, vfio) to be
> > preserved and restored.
> >
> > Handlers for specific file types can be registered to manage their
> > preservation and restoration, storing a u64 payload in the LUO FDT.
> >
> > User-space Interface:
> >
> > ioctl (/dev/liveupdate): The primary control interface for
> > triggering LUO state transitions (prepare, freeze, finish, cancel)
> > and managing the preservation/restoration of file descriptors.
> > Access requires CAP_SYS_ADMIN.
> >
> > sysfs (/sys/kernel/liveupdate/state): A read-only interface for
> > monitoring the current LUO state. This allows userspace services to
> > track progress and coordinate actions.
> >
> > Selftests: Includes kernel-side hooks and userspace selftests to
> > verify core LUO functionality, particularly subsystem registration and
> > basic state transitions.
> >
> > LUO State Machine and Events:
> >
> > NORMAL:   Default operational state.
> > PREPARED: Initial preparation complete after LIVEUPDATE_PREPARE
> >           event. Subsystems have saved initial state.
> > FROZEN:   Final "blackout window" state after LIVEUPDATE_FREEZE
> >           event, just before kexec. Workloads must be suspended.
> > UPDATED:  Next kernel has booted via live update. Awaiting restoration
> >           and LIVEUPDATE_FINISH.
> >
> > Events:
> > LIVEUPDATE_PREPARE: Prepare for reboot, serialize state.
> > LIVEUPDATE_FREEZE:  Final opportunity to save state before kexec.
> > LIVEUPDATE_FINISH:  Post-reboot cleanup in the next kernel.
> > LIVEUPDATE_CANCEL:  Abort prepare or freeze, revert changes.
> >
> > RFC v1: https://lore.kernel.org/all/20250320024011.2995837-1-pasha.tatashin@soleen.com
> > RFC v2: https://lore.kernel.org/all/20250515182322.117840-1-pasha.tatashin@soleen.com/
> >
> > Changyuan Lyu (1):
> >   kho: add interfaces to unpreserve folios and physical memory ranges
> >
> > Mike Rapoport (Microsoft) (1):
> >   kho: drop notifiers
> >
> > Pasha Tatashin (22):
> >   kho: init new_physxa->phys_bits to fix lockdep
> >   kho: mm: Don't allow deferred struct page with KHO
> >   kho: warn if KHO is disabled due to an error
> >   kho: allow to drive kho from within kernel
> >   kho: make debugfs interface optional
> >   kho: don't unpreserve memory during abort
> >   liveupdate: kho: move to kernel/liveupdate
> >   liveupdate: luo_core: Live Update Orchestrator
> >   liveupdate: luo_core: integrate with KHO
> >   liveupdate: luo_subsystems: add subsystem registration
> >   liveupdate: luo_subsystems: implement subsystem callbacks
> >   liveupdate: luo_files: add infrastructure for FDs
> >   liveupdate: luo_files: implement file systems callbacks
> >   liveupdate: luo_ioctl: add ioctl interface
> >   liveupdate: luo_sysfs: add sysfs state monitoring
> >   reboot: call liveupdate_reboot() before kexec
> >   liveupdate: luo_files: luo_ioctl: session-based file descriptor
> >     tracking
> >   kho: move kho debugfs directory to liveupdate
> >   liveupdate: add selftests for subsystems un/registration
> >   selftests/liveupdate: add subsystem/state tests
> >   docs: add luo documentation
> >   MAINTAINERS: add liveupdate entry
> >
> > Pratyush Yadav (8):
> >   mm: shmem: use SHMEM_F_* flags instead of VM_* flags
> >   mm: shmem: allow freezing inode mapping
> >   mm: shmem: export some functions to internal.h
> >   luo: allow preserving memfd
> >   docs: add documentation for memfd preservation via LUO
> >   tools: introduce libluo
> >   libluo: introduce luoctl
> >   libluo: add tests
> >
> >  .../ABI/testing/sysfs-kernel-liveupdate       |  51 +
> >  Documentation/admin-guide/index.rst           |   1 +
> >  Documentation/admin-guide/liveupdate.rst      |  16 +
> >  Documentation/core-api/index.rst              |   1 +
> >  Documentation/core-api/kho/concepts.rst       |   2 +-
> >  Documentation/core-api/liveupdate.rst         |  57 ++
> >  Documentation/mm/index.rst                    |   1 +
> >  Documentation/mm/memfd_preservation.rst       | 138 +++
> >  Documentation/userspace-api/index.rst         |   1 +
> >  .../userspace-api/ioctl/ioctl-number.rst      |   2 +
> >  Documentation/userspace-api/liveupdate.rst    |  25 +
> >  MAINTAINERS                                   |  20 +-
> >  include/linux/kexec_handover.h                |  53 +-
> >  include/linux/liveupdate.h                    | 235 +++++
> >  include/linux/shmem_fs.h                      |  23 +
> >  include/uapi/linux/liveupdate.h               | 265 +++++
> >  init/Kconfig                                  |   2 +
> >  kernel/Kconfig.kexec                          |  14 -
> >  kernel/Makefile                               |   2 +-
> >  kernel/liveupdate/Kconfig                     |  90 ++
> >  kernel/liveupdate/Makefile                    |  13 +
> >  kernel/{ => liveupdate}/kexec_handover.c      | 556 +++++-----
> >  kernel/liveupdate/kexec_handover_debug.c      | 222 ++++
> >  kernel/liveupdate/kexec_handover_internal.h   |  45 +
> >  kernel/liveupdate/luo_core.c                  | 525 ++++++++++
> >  kernel/liveupdate/luo_files.c                 | 946 ++++++++++++++++++
> >  kernel/liveupdate/luo_internal.h              |  47 +
> >  kernel/liveupdate/luo_ioctl.c                 | 192 ++++
> >  kernel/liveupdate/luo_selftests.c             | 344 +++++++
> >  kernel/liveupdate/luo_selftests.h             |  84 ++
> >  kernel/liveupdate/luo_subsystems.c            | 420 ++++++++
> >  kernel/liveupdate/luo_sysfs.c                 |  92 ++
> >  kernel/reboot.c                               |   4 +
> >  mm/Makefile                                   |   1 +
> >  mm/internal.h                                 |   6 +
> >  mm/memblock.c                                 |  56 +-
> >  mm/memfd_luo.c                                | 501 ++++++++++
> >  mm/shmem.c                                    |  46 +-
> >  tools/lib/luo/LICENSE                         | 165 +++
> >  tools/lib/luo/Makefile                        |  45 +
> >  tools/lib/luo/README.md                       | 166 +++
> >  tools/lib/luo/cli/.gitignore                  |   1 +
> >  tools/lib/luo/cli/Makefile                    |  18 +
> >  tools/lib/luo/cli/luoctl.c                    | 178 ++++
> >  tools/lib/luo/include/libluo.h                | 128 +++
> >  tools/lib/luo/include/liveupdate.h            | 265 +++++
> >  tools/lib/luo/libluo.c                        | 203 ++++
> >  tools/lib/luo/tests/.gitignore                |   1 +
> >  tools/lib/luo/tests/Makefile                  |  18 +
> >  tools/lib/luo/tests/test.c                    | 848 ++++++++++++++++
> >  tools/testing/selftests/Makefile              |   1 +
> >  tools/testing/selftests/liveupdate/.gitignore |   1 +
> >  tools/testing/selftests/liveupdate/Makefile   |   7 +
> >  tools/testing/selftests/liveupdate/config     |   6 +
> >  .../testing/selftests/liveupdate/liveupdate.c | 356 +++++++
> >  55 files changed, 7091 insertions(+), 415 deletions(-)
> >  create mode 100644 Documentation/ABI/testing/sysfs-kernel-liveupdate
> >  create mode 100644 Documentation/admin-guide/liveupdate.rst
> >  create mode 100644 Documentation/core-api/liveupdate.rst
> >  create mode 100644 Documentation/mm/memfd_preservation.rst
> >  create mode 100644 Documentation/userspace-api/liveupdate.rst
> >  create mode 100644 include/linux/liveupdate.h
> >  create mode 100644 include/uapi/linux/liveupdate.h
> >  create mode 100644 kernel/liveupdate/Kconfig
> >  create mode 100644 kernel/liveupdate/Makefile
> >  rename kernel/{ => liveupdate}/kexec_handover.c (74%)
> >  create mode 100644 kernel/liveupdate/kexec_handover_debug.c
> >  create mode 100644 kernel/liveupdate/kexec_handover_internal.h
> >  create mode 100644 kernel/liveupdate/luo_core.c
> >  create mode 100644 kernel/liveupdate/luo_files.c
> >  create mode 100644 kernel/liveupdate/luo_internal.h
> >  create mode 100644 kernel/liveupdate/luo_ioctl.c
> >  create mode 100644 kernel/liveupdate/luo_selftests.c
> >  create mode 100644 kernel/liveupdate/luo_selftests.h
> >  create mode 100644 kernel/liveupdate/luo_subsystems.c
> >  create mode 100644 kernel/liveupdate/luo_sysfs.c
> >  create mode 100644 mm/memfd_luo.c
> >  create mode 100644 tools/lib/luo/LICENSE
> >  create mode 100644 tools/lib/luo/Makefile
> >  create mode 100644 tools/lib/luo/README.md
> >  create mode 100644 tools/lib/luo/cli/.gitignore
> >  create mode 100644 tools/lib/luo/cli/Makefile
> >  create mode 100644 tools/lib/luo/cli/luoctl.c
> >  create mode 100644 tools/lib/luo/include/libluo.h
> >  create mode 100644 tools/lib/luo/include/liveupdate.h
> >  create mode 100644 tools/lib/luo/libluo.c
> >  create mode 100644 tools/lib/luo/tests/.gitignore
> >  create mode 100644 tools/lib/luo/tests/Makefile
> >  create mode 100644 tools/lib/luo/tests/test.c
> >  create mode 100644 tools/testing/selftests/liveupdate/.gitignore
> >  create mode 100644 tools/testing/selftests/liveupdate/Makefile
> >  create mode 100644 tools/testing/selftests/liveupdate/config
> >  create mode 100644 tools/testing/selftests/liveupdate/liveupdate.c
> >
> > --
> > 2.50.0.727.gbf7dc18ff4-goog
> >
>
> --
> "Thought is the essence of where you are now."

On Wed, Jun 25, 2025 at 07:44:12PM -0400, pasha.tatashin wrote:
> On Wed, Jun 25, 2025 at 7:26 PM Benjamin LaHaise <bcrl@kvack.org> wrote:
> >
> > FYI: Every one of your emails to the list for this series was bounced by
> > all the recipients using @gmail.com email addresses.
> >
> >                 -ben (owner-linux-mm)
> 
> This is extremely annoying, I will need to figure out why this is
> happening. soleen.com uses google workspace.

b4 also seems unhappy with your mail:

  X [PATCH v1 1/32] kho: init new_physxa->phys_bits to fix lockdep
    X BADSIG: DKIM/soleen-com.20230601.gappssmtp.com

Though I spent a few mins trying to guess why and came up empty. The
mail servers thought the DKIM was OK when they accepted it..

ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=soleen.com; spf=pass smtp.mailfrom=soleen.com; dkim=pass (2048-bit key) header.d=soleen-com.20230601.gappssmtp.com header.i=@soleen-com.20230601.gappssmtp.com header.b=VxWLPP8s; arc=none smtp.client-ip=209.85.219.177
Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=soleen.com
Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=soleen.com
Authentication-Results: smtp.subspace.kernel.org;
	dkim=pass (2048-bit key) header.d=soleen-com.20230601.gappssmtp.com header.i=@soleen-com.20230601.gappssmtp.com header.b="VxWLPP8s"
Received: by mail-yb1-f177.google.com with SMTP id 3f1490d57ef6-e8259b783f6so264959276.3
        for <linux-doc@vger.kernel.org>; Wed, 25 Jun 2025 16:18:45 -0700 (PDT)

Jason

On Fri, Jul 4, 2025 at 1:33 PM Jason Gunthorpe <jgg@ziepe.ca> wrote:
>
> On Wed, Jun 25, 2025 at 07:44:12PM -0400, pasha.tatashin wrote:
> > On Wed, Jun 25, 2025 at 7:26 PM Benjamin LaHaise <bcrl@kvack.org> wrote:
> > >
> > > FYI: Every one of your emails to the list for this series was bounced by
> > > all the recipients using @gmail.com email addresses.
> > >
> > >                 -ben (owner-linux-mm)
> >
> > This is extremely annoying, I will need to figure out why this is
> > happening. soleen.com uses google workspace.
>
> b4 also seems unhappy with your mail:
>
>   X [PATCH v1 1/32] kho: init new_physxa->phys_bits to fix lockdep
>     X BADSIG: DKIM/soleen-com.20230601.gappssmtp.com
>
> Though I spent a few mins trying to guess why and came up empty. The
> mail servers thought the DKIM was OK when they accepted it..
>
> ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=soleen.com; spf=pass smtp.mailfrom=soleen.com; dkim=pass (2048-bit key) header.d=soleen-com.20230601.gappssmtp.com header.i=@soleen-com.20230601.gappssmtp.com header.b=VxWLPP8s; arc=none smtp.client-ip=209.85.219.177
> Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=soleen.com
> Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=soleen.com
> Authentication-Results: smtp.subspace.kernel.org;
>         dkim=pass (2048-bit key) header.d=soleen-com.20230601.gappssmtp.com header.i=@soleen-com.20230601.gappssmtp.com header.b="VxWLPP8s"
> Received: by mail-yb1-f177.google.com with SMTP id 3f1490d57ef6-e8259b783f6so264959276.3
>         for <linux-doc@vger.kernel.org>; Wed, 25 Jun 2025 16:18:45 -0700 (PDT)

Thank you Jason, I think I found the reason why this happened:

While DMARC itself was enabled, the Quarantine/Reject policy was set to none.

I will resend this series.

Pasha

On Wed, Jun 25, 2025 at 07:44:12PM -0400, pasha.tatashin wrote:
> On Wed, Jun 25, 2025 at 7:26 PM Benjamin LaHaise <bcrl@kvack.org> wrote:
> >
> > FYI: Every one of your emails to the list for this series was bounced by
> > all the recipients using @gmail.com email addresses.
> >
> >                 -ben (owner-linux-mm)
> 
> This is extremely annoying, I will need to figure out why this is
> happening. soleen.com uses google workspace.

I'm close to kicking all the @gmail.com subscribers off the mailing lists
given how bad this is getting.  My general advice to anyone posting to
mailing lists these days is to assume that anyone reading email via any of
Google's service isn't going to see your mailing list posts.  It keeps
getting worse, and nobody at the platform companies seems to care.

		-ben

> Pasha
> 
> >
> > On Wed, Jun 25, 2025 at 11:17:47PM +0000, Pasha Tatashin wrote:
> > > This series introduces the LUO, a kernel subsystem designed to
> > > facilitate live kernel updates with minimal downtime,
> > > particularly in cloud delplyoments aiming to update without fully
> > > disrupting running virtual machines.
> > >
> > > This series builds upon KHO framework by adding programmatic
> > > control over KHO's lifecycle and leveraging KHO for persisting LUO's
> > > own metadata across the kexec boundary. The git branch for this series
> > > can be found at:
> > >
> > > https://github.com/googleprodkernel/linux-liveupdate/tree/luo/v1
> > >
> > > Changelog from rfc-v2:
> > > - Addressed review comments from Mike Rapoport, Pratyush Yadav,
> > >   David Matlack
> > > - Moved everything under kernel/liveupdate including KHO.
> > > - Added a number fixes to KHO that were discovered.
> > > - luo_files is not a registred as a subsystem.
> > > - Added sessions support to preserved files.
> > > - Added support for memfd (Pratyush Yadav)
> > > - Added libluo (proposed as RFC) (Pratyush Yadav)
> > > - Removed notifiers from KHO (Mike Rapoport)
> > >
> > > What is Live Update?
> > > Live Update is a kexec based reboot process where selected kernel
> > > resources (memory, file descriptors, and eventually devices) are kept
> > > operational or their state preserved across a kernel transition. For
> > > certain resources, DMA and interrupt activity might continue with
> > > minimal interruption during the kernel reboot.
> > >
> > > LUO provides a framework for coordinating live updates. It features:
> > > State Machine: Manages the live update process through states:
> > > NORMAL, PREPARED, FROZEN, UPDATED.
> > >
> > > KHO Integration:
> > >
> > > LUO programmatically drives KHO's finalization and abort sequences.
> > > KHO's debugfs interface is now optional configured via
> > > CONFIG_KEXEC_HANDOVER_DEBUG.
> > >
> > > LUO preserves its own metadata via KHO's kho_add_subtree and
> > > kho_preserve_phys() mechanisms.
> > >
> > > Subsystem Participation: A callback API liveupdate_register_subsystem()
> > > allows kernel subsystems (e.g., KVM, IOMMU, VFIO, PCI) to register
> > > handlers for LUO events (PREPARE, FREEZE, FINISH, CANCEL) and persist a
> > > u64 payload via the LUO FDT.
> > >
> > > File Descriptor Preservation: Infrastructure
> > > liveupdate_register_filesystem, luo_register_file, luo_retrieve_file to
> > > allow specific types of file descriptors (e.g., memfd, vfio) to be
> > > preserved and restored.
> > >
> > > Handlers for specific file types can be registered to manage their
> > > preservation and restoration, storing a u64 payload in the LUO FDT.
> > >
> > > User-space Interface:
> > >
> > > ioctl (/dev/liveupdate): The primary control interface for
> > > triggering LUO state transitions (prepare, freeze, finish, cancel)
> > > and managing the preservation/restoration of file descriptors.
> > > Access requires CAP_SYS_ADMIN.
> > >
> > > sysfs (/sys/kernel/liveupdate/state): A read-only interface for
> > > monitoring the current LUO state. This allows userspace services to
> > > track progress and coordinate actions.
> > >
> > > Selftests: Includes kernel-side hooks and userspace selftests to
> > > verify core LUO functionality, particularly subsystem registration and
> > > basic state transitions.
> > >
> > > LUO State Machine and Events:
> > >
> > > NORMAL:   Default operational state.
> > > PREPARED: Initial preparation complete after LIVEUPDATE_PREPARE
> > >           event. Subsystems have saved initial state.
> > > FROZEN:   Final "blackout window" state after LIVEUPDATE_FREEZE
> > >           event, just before kexec. Workloads must be suspended.
> > > UPDATED:  Next kernel has booted via live update. Awaiting restoration
> > >           and LIVEUPDATE_FINISH.
> > >
> > > Events:
> > > LIVEUPDATE_PREPARE: Prepare for reboot, serialize state.
> > > LIVEUPDATE_FREEZE:  Final opportunity to save state before kexec.
> > > LIVEUPDATE_FINISH:  Post-reboot cleanup in the next kernel.
> > > LIVEUPDATE_CANCEL:  Abort prepare or freeze, revert changes.
> > >
> > > RFC v1: https://lore.kernel.org/all/20250320024011.2995837-1-pasha.tatashin@soleen.com
> > > RFC v2: https://lore.kernel.org/all/20250515182322.117840-1-pasha.tatashin@soleen.com/
> > >
> > > Changyuan Lyu (1):
> > >   kho: add interfaces to unpreserve folios and physical memory ranges
> > >
> > > Mike Rapoport (Microsoft) (1):
> > >   kho: drop notifiers
> > >
> > > Pasha Tatashin (22):
> > >   kho: init new_physxa->phys_bits to fix lockdep
> > >   kho: mm: Don't allow deferred struct page with KHO
> > >   kho: warn if KHO is disabled due to an error
> > >   kho: allow to drive kho from within kernel
> > >   kho: make debugfs interface optional
> > >   kho: don't unpreserve memory during abort
> > >   liveupdate: kho: move to kernel/liveupdate
> > >   liveupdate: luo_core: Live Update Orchestrator
> > >   liveupdate: luo_core: integrate with KHO
> > >   liveupdate: luo_subsystems: add subsystem registration
> > >   liveupdate: luo_subsystems: implement subsystem callbacks
> > >   liveupdate: luo_files: add infrastructure for FDs
> > >   liveupdate: luo_files: implement file systems callbacks
> > >   liveupdate: luo_ioctl: add ioctl interface
> > >   liveupdate: luo_sysfs: add sysfs state monitoring
> > >   reboot: call liveupdate_reboot() before kexec
> > >   liveupdate: luo_files: luo_ioctl: session-based file descriptor
> > >     tracking
> > >   kho: move kho debugfs directory to liveupdate
> > >   liveupdate: add selftests for subsystems un/registration
> > >   selftests/liveupdate: add subsystem/state tests
> > >   docs: add luo documentation
> > >   MAINTAINERS: add liveupdate entry
> > >
> > > Pratyush Yadav (8):
> > >   mm: shmem: use SHMEM_F_* flags instead of VM_* flags
> > >   mm: shmem: allow freezing inode mapping
> > >   mm: shmem: export some functions to internal.h
> > >   luo: allow preserving memfd
> > >   docs: add documentation for memfd preservation via LUO
> > >   tools: introduce libluo
> > >   libluo: introduce luoctl
> > >   libluo: add tests
> > >
> > >  .../ABI/testing/sysfs-kernel-liveupdate       |  51 +
> > >  Documentation/admin-guide/index.rst           |   1 +
> > >  Documentation/admin-guide/liveupdate.rst      |  16 +
> > >  Documentation/core-api/index.rst              |   1 +
> > >  Documentation/core-api/kho/concepts.rst       |   2 +-
> > >  Documentation/core-api/liveupdate.rst         |  57 ++
> > >  Documentation/mm/index.rst                    |   1 +
> > >  Documentation/mm/memfd_preservation.rst       | 138 +++
> > >  Documentation/userspace-api/index.rst         |   1 +
> > >  .../userspace-api/ioctl/ioctl-number.rst      |   2 +
> > >  Documentation/userspace-api/liveupdate.rst    |  25 +
> > >  MAINTAINERS                                   |  20 +-
> > >  include/linux/kexec_handover.h                |  53 +-
> > >  include/linux/liveupdate.h                    | 235 +++++
> > >  include/linux/shmem_fs.h                      |  23 +
> > >  include/uapi/linux/liveupdate.h               | 265 +++++
> > >  init/Kconfig                                  |   2 +
> > >  kernel/Kconfig.kexec                          |  14 -
> > >  kernel/Makefile                               |   2 +-
> > >  kernel/liveupdate/Kconfig                     |  90 ++
> > >  kernel/liveupdate/Makefile                    |  13 +
> > >  kernel/{ => liveupdate}/kexec_handover.c      | 556 +++++-----
> > >  kernel/liveupdate/kexec_handover_debug.c      | 222 ++++
> > >  kernel/liveupdate/kexec_handover_internal.h   |  45 +
> > >  kernel/liveupdate/luo_core.c                  | 525 ++++++++++
> > >  kernel/liveupdate/luo_files.c                 | 946 ++++++++++++++++++
> > >  kernel/liveupdate/luo_internal.h              |  47 +
> > >  kernel/liveupdate/luo_ioctl.c                 | 192 ++++
> > >  kernel/liveupdate/luo_selftests.c             | 344 +++++++
> > >  kernel/liveupdate/luo_selftests.h             |  84 ++
> > >  kernel/liveupdate/luo_subsystems.c            | 420 ++++++++
> > >  kernel/liveupdate/luo_sysfs.c                 |  92 ++
> > >  kernel/reboot.c                               |   4 +
> > >  mm/Makefile                                   |   1 +
> > >  mm/internal.h                                 |   6 +
> > >  mm/memblock.c                                 |  56 +-
> > >  mm/memfd_luo.c                                | 501 ++++++++++
> > >  mm/shmem.c                                    |  46 +-
> > >  tools/lib/luo/LICENSE                         | 165 +++
> > >  tools/lib/luo/Makefile                        |  45 +
> > >  tools/lib/luo/README.md                       | 166 +++
> > >  tools/lib/luo/cli/.gitignore                  |   1 +
> > >  tools/lib/luo/cli/Makefile                    |  18 +
> > >  tools/lib/luo/cli/luoctl.c                    | 178 ++++
> > >  tools/lib/luo/include/libluo.h                | 128 +++
> > >  tools/lib/luo/include/liveupdate.h            | 265 +++++
> > >  tools/lib/luo/libluo.c                        | 203 ++++
> > >  tools/lib/luo/tests/.gitignore                |   1 +
> > >  tools/lib/luo/tests/Makefile                  |  18 +
> > >  tools/lib/luo/tests/test.c                    | 848 ++++++++++++++++
> > >  tools/testing/selftests/Makefile              |   1 +
> > >  tools/testing/selftests/liveupdate/.gitignore |   1 +
> > >  tools/testing/selftests/liveupdate/Makefile   |   7 +
> > >  tools/testing/selftests/liveupdate/config     |   6 +
> > >  .../testing/selftests/liveupdate/liveupdate.c | 356 +++++++
> > >  55 files changed, 7091 insertions(+), 415 deletions(-)
> > >  create mode 100644 Documentation/ABI/testing/sysfs-kernel-liveupdate
> > >  create mode 100644 Documentation/admin-guide/liveupdate.rst
> > >  create mode 100644 Documentation/core-api/liveupdate.rst
> > >  create mode 100644 Documentation/mm/memfd_preservation.rst
> > >  create mode 100644 Documentation/userspace-api/liveupdate.rst
> > >  create mode 100644 include/linux/liveupdate.h
> > >  create mode 100644 include/uapi/linux/liveupdate.h
> > >  create mode 100644 kernel/liveupdate/Kconfig
> > >  create mode 100644 kernel/liveupdate/Makefile
> > >  rename kernel/{ => liveupdate}/kexec_handover.c (74%)
> > >  create mode 100644 kernel/liveupdate/kexec_handover_debug.c
> > >  create mode 100644 kernel/liveupdate/kexec_handover_internal.h
> > >  create mode 100644 kernel/liveupdate/luo_core.c
> > >  create mode 100644 kernel/liveupdate/luo_files.c
> > >  create mode 100644 kernel/liveupdate/luo_internal.h
> > >  create mode 100644 kernel/liveupdate/luo_ioctl.c
> > >  create mode 100644 kernel/liveupdate/luo_selftests.c
> > >  create mode 100644 kernel/liveupdate/luo_selftests.h
> > >  create mode 100644 kernel/liveupdate/luo_subsystems.c
> > >  create mode 100644 kernel/liveupdate/luo_sysfs.c
> > >  create mode 100644 mm/memfd_luo.c
> > >  create mode 100644 tools/lib/luo/LICENSE
> > >  create mode 100644 tools/lib/luo/Makefile
> > >  create mode 100644 tools/lib/luo/README.md
> > >  create mode 100644 tools/lib/luo/cli/.gitignore
> > >  create mode 100644 tools/lib/luo/cli/Makefile
> > >  create mode 100644 tools/lib/luo/cli/luoctl.c
> > >  create mode 100644 tools/lib/luo/include/libluo.h
> > >  create mode 100644 tools/lib/luo/include/liveupdate.h
> > >  create mode 100644 tools/lib/luo/libluo.c
> > >  create mode 100644 tools/lib/luo/tests/.gitignore
> > >  create mode 100644 tools/lib/luo/tests/Makefile
> > >  create mode 100644 tools/lib/luo/tests/test.c
> > >  create mode 100644 tools/testing/selftests/liveupdate/.gitignore
> > >  create mode 100644 tools/testing/selftests/liveupdate/Makefile
> > >  create mode 100644 tools/testing/selftests/liveupdate/config
> > >  create mode 100644 tools/testing/selftests/liveupdate/liveupdate.c
> > >
> > > --
> > > 2.50.0.727.gbf7dc18ff4-goog
> > >
> >
> > --
> > "Thought is the essence of where you are now."
> 

-- 
"Thought is the essence of where you are now."