On 15/11/25 04:55, Andrew Morton wrote:
On Fri, 14 Nov 2025 10:44:59 +0530 Sourabh Jain <[email protected]>
wrote:
All existing kexec and kdump sysfs entries are moved to a new location,
/sys/kernel/kexec, to keep /sys/kernel/ clean and better organized.
Symlinks are created at the old locations for backward compatibility and
can be removed in the future [02/05].
While doing this cleanup, missing ABI documentation for the old sysfs
interfaces is added, and those entries are marked as deprecated
[01/05 and 03/05]. New ABI documentation is also added for the
reorganized interfaces. [04/05]
Along with this reorganization, a new sysfs file,
/sys/kernel/kexec/crash_cma_ranges, is introduced to export crashkernel
CMA reservation details to user space [05/05]. This helps tools
determine the total crashkernel reserved memory and warn users that
capturing user pages while CMA is reserved may cause incomplete or
unreliable dumps.
Patchset does three unrelated things in remarkably random order.
1: Document existing stuff
Great, thanks, in it goes.
2: export crashkernel CMA reservation to userspace
Well, OK, probably reasonable, didn't look closely.
3: Alter longstanding userspace ABI with deprecation plan
Whoa, tricky, needs careful consideration.
So can we please prepare and consider this material in three separate
patchsets? In the above order, I suggest.
Yeah sure.
The question here is where to add the new CMA reservation sysfs.
Should I place it under /sys/kernel/ or create /sys/kernel/kexec and
add it there?
Since I am proposing that all kexec sysfs entries move to the new
location /sys/kernel/kexec, I am going to add the CMA reservation
sysfs under /sys/kernel/kexec to avoid creating a symlink for this
entry later in my third patch series.
- Sourabh
