| From: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> |
| Subject: docs: update admin guide transhuge page to mention MADV_COLLAPSE everywhere |
| Date: Tue, 22 Jul 2025 06:32:18 +0100 |
| |
| We previously missed a couple places where the 'never' mode was described, |
| put the caveat regarding MADV_COLLAPSE in these locations also. |
| |
| Link: https://lkml.kernel.org/r/d54d1dfb-f06d-4979-983b-73998f05867e@lucifer.local |
| Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> |
| Cc: Baolin Wang <baolin.wang@linux.alibaba.com> |
| Cc: Barry Song <baohua@kernel.org> |
| Cc: David Hildenbrand <david@redhat.com> |
| Cc: Dev Jain <dev.jain@arm.com> |
| Cc: Jonathan Corbet <corbet@lwn.net> |
| Cc: Liam Howlett <liam.howlett@oracle.com> |
| Cc: Mariano Pache <npache@redhat.com> |
| Cc: Ryan Roberts <ryan.roberts@arm.com> |
| Cc: SeongJae Park <sj@kernel.org> |
| Cc: Zi Yan <ziy@nvidia.com> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| --- |
| |
| Documentation/admin-guide/mm/transhuge.rst | 8 ++++++-- |
| 1 file changed, 6 insertions(+), 2 deletions(-) |
| |
| --- a/Documentation/admin-guide/mm/transhuge.rst~docs-update-thp-documentation-to-clarify-sysfs-never-setting-fix |
| +++ a/Documentation/admin-guide/mm/transhuge.rst |
| @@ -385,7 +385,9 @@ always |
| Attempt to allocate huge pages every time we need a new page; |
| |
| never |
| - Do not allocate huge pages; |
| + Do not allocate huge pages. Note that ``madvise(..., MADV_COLLAPSE)`` |
| + can still cause transparent huge pages to be obtained even if this mode |
| + is specified everywhere; |
| |
| within_size |
| Only allocate huge page if it will be fully within i_size. |
| @@ -441,7 +443,9 @@ inherit |
| have enabled="inherit" and all other hugepage sizes have enabled="never"; |
| |
| never |
| - Do not allocate <size> huge pages; |
| + Do not allocate <size> huge pages. Note that ``madvise(..., |
| + MADV_COLLAPSE)`` can still cause transparent huge pages to be obtained |
| + even if this mode is specified everywhere; |
| |
| within_size |
| Only allocate <size> huge page if it will be fully within i_size. |
| _ |
