* [PATCH v2] liveupdate: separate memfd support into LIVEUPDATE_MEMFD
@ 2025-12-30 14:53 Pasha Tatashin
2025-12-30 15:30 ` Mike Rapoport
0 siblings, 1 reply; 3+ messages in thread
From: Pasha Tatashin @ 2025-12-30 14:53 UTC (permalink / raw)
To: akpm, pasha.tatashin, rppt, linux-kernel, linux-mm, pratyush
Decouple memfd preservation support from the core Live Update
Orchestrator configuration.
Previously, enabling CONFIG_LIVEUPDATE forced a dependency on
CONFIG_SHMEM and unconditionally compiled memfd_luo.o. However, Live
Update may be used for purposes that do not require memfd-backed memory
preservation.
Introduce CONFIG_LIVEUPDATE_MEMFD to gate memfd_luo.o. This moves the
SHMEM and MEMFD_CREATE dependencies to the specific feature that needs
them, allowing the base LIVEUPDATE option to be selected independently
of shared memory support.
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
---
Changes v2:
- Updated testing config
- Added review-by
kernel/liveupdate/Kconfig | 16 +++++++++++++++-
mm/Makefile | 2 +-
tools/testing/selftests/liveupdate/config | 1 +
3 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/kernel/liveupdate/Kconfig b/kernel/liveupdate/Kconfig
index d2aeaf13c3ac..9a1a8cdcf16c 100644
--- a/kernel/liveupdate/Kconfig
+++ b/kernel/liveupdate/Kconfig
@@ -54,7 +54,6 @@ config KEXEC_HANDOVER_ENABLE_DEFAULT
config LIVEUPDATE
bool "Live Update Orchestrator"
depends on KEXEC_HANDOVER
- depends on SHMEM
help
Enable the Live Update Orchestrator. Live Update is a mechanism,
typically based on kexec, that allows the kernel to be updated
@@ -73,4 +72,19 @@ config LIVEUPDATE
If unsure, say N.
+config LIVEUPDATE_MEMFD
+ bool "Live update support for memfd"
+ depends on LIVEUPDATE
+ depends on MEMFD_CREATE
+ depends on SHMEM
+ help
+ Enable live update support for memfd regions. This allows preserving
+ memfd-backed memory across kernel live updates.
+
+ This can be used to back VM memory with memfds, allowing the guest
+ memory to persist, or for other user workloads needing to preserve
+ pages.
+
+ If unsure, say N.
+
endmenu
diff --git a/mm/Makefile b/mm/Makefile
index 9175f8cc6565..798f04233d71 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -100,7 +100,7 @@ obj-$(CONFIG_NUMA) += memory-tiers.o
obj-$(CONFIG_DEVICE_MIGRATION) += migrate_device.o
obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o khugepaged.o
obj-$(CONFIG_PAGE_COUNTER) += page_counter.o
-obj-$(CONFIG_LIVEUPDATE) += memfd_luo.o
+obj-$(CONFIG_LIVEUPDATE_MEMFD) += memfd_luo.o
obj-$(CONFIG_MEMCG_V1) += memcontrol-v1.o
obj-$(CONFIG_MEMCG) += memcontrol.o vmpressure.o
ifdef CONFIG_SWAP
diff --git a/tools/testing/selftests/liveupdate/config b/tools/testing/selftests/liveupdate/config
index 91d03f9a6a39..1bfc708041bd 100644
--- a/tools/testing/selftests/liveupdate/config
+++ b/tools/testing/selftests/liveupdate/config
@@ -5,6 +5,7 @@ CONFIG_KEXEC_HANDOVER_ENABLE_DEFAULT=y
CONFIG_KEXEC_HANDOVER_DEBUGFS=y
CONFIG_KEXEC_HANDOVER_DEBUG=y
CONFIG_LIVEUPDATE=y
+CONFIG_LIVEUPDATE_MEMFD=y
CONFIG_LIVEUPDATE_TEST=y
CONFIG_MEMFD_CREATE=y
CONFIG_TMPFS=y
--
2.52.0.351.gbe84eed79e-goog
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] liveupdate: separate memfd support into LIVEUPDATE_MEMFD
2025-12-30 14:53 [PATCH v2] liveupdate: separate memfd support into LIVEUPDATE_MEMFD Pasha Tatashin
@ 2025-12-30 15:30 ` Mike Rapoport
2025-12-30 16:07 ` Pasha Tatashin
0 siblings, 1 reply; 3+ messages in thread
From: Mike Rapoport @ 2025-12-30 15:30 UTC (permalink / raw)
To: Pasha Tatashin; +Cc: akpm, linux-kernel, linux-mm, pratyush
On Tue, Dec 30, 2025 at 09:53:21AM -0500, Pasha Tatashin wrote:
> Decouple memfd preservation support from the core Live Update
> Orchestrator configuration.
>
> Previously, enabling CONFIG_LIVEUPDATE forced a dependency on
> CONFIG_SHMEM and unconditionally compiled memfd_luo.o. However, Live
> Update may be used for purposes that do not require memfd-backed memory
> preservation.
>
> Introduce CONFIG_LIVEUPDATE_MEMFD to gate memfd_luo.o. This moves the
> SHMEM and MEMFD_CREATE dependencies to the specific feature that needs
> them, allowing the base LIVEUPDATE option to be selected independently
> of shared memory support.
>
> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
> Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
> ---
> Changes v2:
> - Updated testing config
> - Added review-by
>
> kernel/liveupdate/Kconfig | 16 +++++++++++++++-
> mm/Makefile | 2 +-
> tools/testing/selftests/liveupdate/config | 1 +
> 3 files changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/liveupdate/Kconfig b/kernel/liveupdate/Kconfig
> index d2aeaf13c3ac..9a1a8cdcf16c 100644
> --- a/kernel/liveupdate/Kconfig
> +++ b/kernel/liveupdate/Kconfig
> @@ -54,7 +54,6 @@ config KEXEC_HANDOVER_ENABLE_DEFAULT
> config LIVEUPDATE
> bool "Live Update Orchestrator"
> depends on KEXEC_HANDOVER
> - depends on SHMEM
> help
> Enable the Live Update Orchestrator. Live Update is a mechanism,
> typically based on kexec, that allows the kernel to be updated
> @@ -73,4 +72,19 @@ config LIVEUPDATE
>
> If unsure, say N.
>
> +config LIVEUPDATE_MEMFD
> + bool "Live update support for memfd"
> + depends on LIVEUPDATE
> + depends on MEMFD_CREATE
> + depends on SHMEM
Maybe also
default LIVEUPDATE
> + help
> + Enable live update support for memfd regions. This allows preserving
> + memfd-backed memory across kernel live updates.
> +
> + This can be used to back VM memory with memfds, allowing the guest
> + memory to persist, or for other user workloads needing to preserve
> + pages.
> +
> + If unsure, say N.
> +
> endmenu
> diff --git a/mm/Makefile b/mm/Makefile
> index 9175f8cc6565..798f04233d71 100644
> --- a/mm/Makefile
> +++ b/mm/Makefile
> @@ -100,7 +100,7 @@ obj-$(CONFIG_NUMA) += memory-tiers.o
> obj-$(CONFIG_DEVICE_MIGRATION) += migrate_device.o
> obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o khugepaged.o
> obj-$(CONFIG_PAGE_COUNTER) += page_counter.o
> -obj-$(CONFIG_LIVEUPDATE) += memfd_luo.o
> +obj-$(CONFIG_LIVEUPDATE_MEMFD) += memfd_luo.o
> obj-$(CONFIG_MEMCG_V1) += memcontrol-v1.o
> obj-$(CONFIG_MEMCG) += memcontrol.o vmpressure.o
> ifdef CONFIG_SWAP
> diff --git a/tools/testing/selftests/liveupdate/config b/tools/testing/selftests/liveupdate/config
> index 91d03f9a6a39..1bfc708041bd 100644
> --- a/tools/testing/selftests/liveupdate/config
> +++ b/tools/testing/selftests/liveupdate/config
> @@ -5,6 +5,7 @@ CONFIG_KEXEC_HANDOVER_ENABLE_DEFAULT=y
> CONFIG_KEXEC_HANDOVER_DEBUGFS=y
> CONFIG_KEXEC_HANDOVER_DEBUG=y
> CONFIG_LIVEUPDATE=y
> +CONFIG_LIVEUPDATE_MEMFD=y
then this is not needed :)
> CONFIG_LIVEUPDATE_TEST=y
> CONFIG_MEMFD_CREATE=y
> CONFIG_TMPFS=y
> --
> 2.52.0.351.gbe84eed79e-goog
>
--
Sincerely yours,
Mike.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] liveupdate: separate memfd support into LIVEUPDATE_MEMFD
2025-12-30 15:30 ` Mike Rapoport
@ 2025-12-30 16:07 ` Pasha Tatashin
0 siblings, 0 replies; 3+ messages in thread
From: Pasha Tatashin @ 2025-12-30 16:07 UTC (permalink / raw)
To: Mike Rapoport; +Cc: akpm, linux-kernel, linux-mm, pratyush
On Tue, Dec 30, 2025 at 10:30 AM Mike Rapoport <rppt@kernel.org> wrote:
>
> On Tue, Dec 30, 2025 at 09:53:21AM -0500, Pasha Tatashin wrote:
> > Decouple memfd preservation support from the core Live Update
> > Orchestrator configuration.
> >
> > Previously, enabling CONFIG_LIVEUPDATE forced a dependency on
> > CONFIG_SHMEM and unconditionally compiled memfd_luo.o. However, Live
> > Update may be used for purposes that do not require memfd-backed memory
> > preservation.
> >
> > Introduce CONFIG_LIVEUPDATE_MEMFD to gate memfd_luo.o. This moves the
> > SHMEM and MEMFD_CREATE dependencies to the specific feature that needs
> > them, allowing the base LIVEUPDATE option to be selected independently
> > of shared memory support.
> >
> > Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
> > Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
> > ---
> > Changes v2:
> > - Updated testing config
> > - Added review-by
> >
> > kernel/liveupdate/Kconfig | 16 +++++++++++++++-
> > mm/Makefile | 2 +-
> > tools/testing/selftests/liveupdate/config | 1 +
> > 3 files changed, 17 insertions(+), 2 deletions(-)
> >
> > diff --git a/kernel/liveupdate/Kconfig b/kernel/liveupdate/Kconfig
> > index d2aeaf13c3ac..9a1a8cdcf16c 100644
> > --- a/kernel/liveupdate/Kconfig
> > +++ b/kernel/liveupdate/Kconfig
> > @@ -54,7 +54,6 @@ config KEXEC_HANDOVER_ENABLE_DEFAULT
> > config LIVEUPDATE
> > bool "Live Update Orchestrator"
> > depends on KEXEC_HANDOVER
> > - depends on SHMEM
> > help
> > Enable the Live Update Orchestrator. Live Update is a mechanism,
> > typically based on kexec, that allows the kernel to be updated
> > @@ -73,4 +72,19 @@ config LIVEUPDATE
> >
> > If unsure, say N.
> >
> > +config LIVEUPDATE_MEMFD
> > + bool "Live update support for memfd"
> > + depends on LIVEUPDATE
> > + depends on MEMFD_CREATE
> > + depends on SHMEM
>
> Maybe also
>
> default LIVEUPDATE
Yeah, I like this idea, let me make the change, and send v3.
Pasha
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2025-12-30 16:08 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2025-12-30 14:53 [PATCH v2] liveupdate: separate memfd support into LIVEUPDATE_MEMFD Pasha Tatashin
2025-12-30 15:30 ` Mike Rapoport
2025-12-30 16:07 ` Pasha Tatashin
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox