From: Asier Gutierrez MADV_HUGEPAGE and MADV_NOHUGEPAGE are guarded and they are not available when compiling the kernel without TRANSPARENT_HUGEPAGE option. The DAMON behaviour is to silently fail [1] in when DAMOS_HUGEPAGE or DAMOS_NOHUGEPAGE are used, but TRANSPARENT_HUGEPAGE is disabled. Update the DAMON documentation to reflect this behaviour. [1]: https://lore.kernel.org/66131775-180b-4b9f-b7ce-61a3e077b6e6@huawei-partners.com/ Signed-off-by: Asier Gutierrez Reviewed-by: SeongJae Park Signed-off-by: SeongJae Park --- Changes from v1 (https://lore.kernel.org/20260316140822.2033181-1-gutierrez.asier@huawei-partners.com) - Wordsmith description. - Rebase to latest mm-new. Documentation/mm/damon/design.rst | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst index dc37402c0fee9..838b14d225193 100644 --- a/Documentation/mm/damon/design.rst +++ b/Documentation/mm/damon/design.rst @@ -460,9 +460,13 @@ that supports each action are as below. - ``pageout``: Reclaim the region. Supported by ``vaddr``, ``fvaddr`` and ``paddr`` operations set. - ``hugepage``: Call ``madvise()`` for the region with ``MADV_HUGEPAGE``. - Supported by ``vaddr`` and ``fvaddr`` operations set. + Supported by ``vaddr`` and ``fvaddr`` operations set. When + TRANSPARENT_HUGEPAGE is disabled, the application of the action will just + fail. - ``nohugepage``: Call ``madvise()`` for the region with ``MADV_NOHUGEPAGE``. - Supported by ``vaddr`` and ``fvaddr`` operations set. + Supported by ``vaddr`` and ``fvaddr`` operations set. When + TRANSPARENT_HUGEPAGE is disabled, the application of the action will just + fail. - ``lru_prio``: Prioritize the region on its LRU lists. Supported by ``paddr`` operations set. - ``lru_deprio``: Deprioritize the region on its LRU lists. base-commit: 809b8b9fc1374abb1b1b50fbd0260085b0832b2e -- 2.47.3