Re: [PATCH v2] mm/memory-failure: Support disabling soft offline for HugeTLB pages

On Mon, 15 Sep 2025 19:27:41 -0500 Kyle Meyer kyle.meyer@hpe.com wrote:

Soft offlining a HugeTLB page reduces the HugeTLB page pool.

Commit 56374430c5dfc ("mm/memory-failure: userspace controls soft-offlining pages") introduced the following sysctl interface to control soft offline:

/proc/sys/vm/enable_soft_offline

The interface does not distinguish between page types:

0 - Soft offline is disabled
1 - Soft offline is enabled

Convert enable_soft_offline to a bitmask and support disabling soft offline for HugeTLB pages:

Bits:

0 - Enable soft offline
1 - Disable soft offline for HugeTLB pages

Supported values:

0 - Soft offline is disabled
1 - Soft offline is enabled
3 - Soft offline is enabled (disabled for HugeTLB pages)

Existing behavior is preserved.

um, why? What benefit does this patch provide to our users? Use-cases, before-and-after scenarios, etc?

Update documentation and HugeTLB soft offline self tests.

Reported-by: Shawn Fan shawn.fan@intel.com

Interesting. What did Shawn report? (Closes:!).

Suggested-by: Tony Luck tony.luck@intel.com Signed-off-by: Kyle Meyer kyle.meyer@hpe.com

...

.../ABI/testing/sysfs-memory-page-offline | 3 ++ Documentation/admin-guide/sysctl/vm.rst | 28 ++++++++++++++++--- mm/memory-failure.c | 17 +++++++++-- .../selftests/mm/hugetlb-soft-offline.c | 19 ++++++++++--- 4 files changed, 56 insertions(+), 11 deletions(-)

I'll add it because testing, but please do explain why I added it?