From 353dc187840100fabeb946bb9573bc5ca5e04fcb Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Wed, 6 Mar 2024 18:13:28 +0800 Subject: [PATCH] docs: hugetlbpage.rst: add hugetlb migration description Add some description of the hugetlb migration strategy. Link: https://lkml.kernel.org/r/63fb16e7a4ebc5cb69ce655af86e29b2d8e9ba34.1709719720.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Reviewed-by: Oscar Salvador Cc: David Hildenbrand Cc: Miaohe Lin Cc: Michal Hocko Cc: Muchun Song Cc: Naoya Horiguchi Signed-off-by: Andrew Morton --- Documentation/admin-guide/mm/hugetlbpage.rst | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Documentation/admin-guide/mm/hugetlbpage.rst b/Documentation/admin-guide/mm/hugetlbpage.rst index e4d4b4a8dc97..f34a0d798d5b 100644 --- a/Documentation/admin-guide/mm/hugetlbpage.rst +++ b/Documentation/admin-guide/mm/hugetlbpage.rst @@ -376,6 +376,13 @@ Note that the number of overcommit and reserve pages remain global quantities, as we don't know until fault time, when the faulting task's mempolicy is applied, from which node the huge page allocation will be attempted. +The hugetlb may be migrated between the per-node hugepages pool in the following +scenarios: memory offline, memory failure, longterm pinning, syscalls(mbind, +migrate_pages and move_pages), alloc_contig_range() and alloc_contig_pages(). +Now only memory offline, memory failure and syscalls allow fallbacking to allocate +a new hugetlb on a different node if the current node is unable to allocate during +hugetlb migration, that means these 3 cases can break the per-node hugepages pool. + .. _using_huge_pages: Using Huge Pages