The patch titled
Subject: docs: hugetlbpage.rst: add hugetlb migration description
has been added to the -mm mm-unstable branch. Its filename is
docs-hugetlbpagerst-add-hugetlb-migration-description.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/docs-hugetlbpagerst-add-hugetlb-migration-description.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Subject: docs: hugetlbpage.rst: add hugetlb migration description
Date: Wed, 6 Mar 2024 18:13:28 +0800
Add some description of the hugetlb migration strategy.
Link: https://lkml.kernel.org/r/63fb16e7a4ebc5cb69ce655af86e29b2d8e9ba34.1709719720.git.baolin.wang@xxxxxxxxxxxxxxxxx
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/admin-guide/mm/hugetlbpage.rst | 7 +++++++
1 file changed, 7 insertions(+)
--- a/Documentation/admin-guide/mm/hugetlbpage.rst~docs-hugetlbpagerst-add-hugetlb-migration-description
+++ a/Documentation/admin-guide/mm/hugetlbpage.rst
@@ -376,6 +376,13 @@ Note that the number of overcommit and r
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
_
Patches currently in -mm which might be from baolin.wang@xxxxxxxxxxxxxxxxx are
mm-record-the-migration-reason-for-struct-migration_target_control.patch
mm-hugetlb-make-the-hugetlb-migration-strategy-consistent.patch
docs-hugetlbpagerst-add-hugetlb-migration-description.patch
