The patch titled
Subject: mm/huge_memory: check folio_test_anon() before mapping_large_folio_support()
has been added to the -mm mm-unstable branch. Its filename is
mm-huge_memory-add-buddy-allocator-like-non-uniform-folio_split-fix.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-huge_memory-add-buddy-allocator-like-non-uniform-folio_split-fix.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: Zi Yan <ziy@xxxxxxxxxx>
Subject: mm/huge_memory: check folio_test_anon() before mapping_large_folio_support()
Date: Sun, 16 Feb 2025 09:01:29 -0500
Otherwise mapping_large_folio_support() complains.
Link: https://lkml.kernel.org/r/4483B46A-FEAF-46D9-AFF4-F0DF34864633@xxxxxxxxxx
Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
Reported-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Cc: Kirill A. Shuemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Yang Shi <yang@xxxxxxxxxxxxxxxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 48 ++++++++++++++++++++++-----------------------
1 file changed, 24 insertions(+), 24 deletions(-)
--- a/mm/huge_memory.c~mm-huge_memory-add-buddy-allocator-like-non-uniform-folio_split-fix
+++ a/mm/huge_memory.c
@@ -3723,20 +3723,19 @@ after_split:
static bool non_uniform_split_supported(struct folio *folio, unsigned int new_order,
bool warns)
{
- /* order-1 is not supported for anonymous THP. */
- if (folio_test_anon(folio) && new_order == 1) {
- VM_WARN_ONCE(warns, "Cannot split to order-1 folio");
- return false;
- }
-
- /*
- * No split if the file system does not support large folio.
- * Note that we might still have THPs in such mappings due to
- * CONFIG_READ_ONLY_THP_FOR_FS. But in that case, the mapping
- * does not actually support large folios properly.
- */
- if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) &&
+ if (folio_test_anon(folio)) {
+ /* order-1 is not supported for anonymous THP. */
+ VM_WARN_ONCE(warns && new_order == 1,
+ "Cannot split to order-1 folio");
+ return new_order != 1;
+ } else if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) &&
!mapping_large_folio_support(folio->mapping)) {
+ /*
+ * No split if the file system does not support large folio.
+ * Note that we might still have THPs in such mappings due to
+ * CONFIG_READ_ONLY_THP_FOR_FS. But in that case, the mapping
+ * does not actually support large folios properly.
+ */
VM_WARN_ONCE(warns,
"Cannot split file folio to non-0 order");
return false;
@@ -3756,24 +3755,25 @@ static bool non_uniform_split_supported(
static bool uniform_split_supported(struct folio *folio, unsigned int new_order,
bool warns)
{
- if (folio_test_anon(folio) && new_order == 1) {
- VM_WARN_ONCE(warns, "Cannot split to order-1 folio");
- return false;
- }
-
- if (new_order) {
+ if (folio_test_anon(folio)) {
+ VM_WARN_ONCE(warns && new_order == 1,
+ "Cannot split to order-1 folio");
+ return new_order != 1;
+ } else if (new_order) {
if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) &&
!mapping_large_folio_support(folio->mapping)) {
VM_WARN_ONCE(warns,
"Cannot split file folio to non-0 order");
return false;
}
- if (folio_test_swapcache(folio)) {
- VM_WARN_ONCE(warns,
- "Cannot split swapcache folio to non-0 order");
- return false;
- }
}
+
+ if (new_order && folio_test_swapcache(folio)) {
+ VM_WARN_ONCE(warns,
+ "Cannot split swapcache folio to non-0 order");
+ return false;
+ }
+
return true;
}
_
Patches currently in -mm which might be from ziy@xxxxxxxxxx are
selftests-mm-make-file-backed-thp-split-work-by-writing-pmd-size-data.patch
mm-huge_memory-allow-split-shmem-large-folio-to-any-lower-order.patch
selftests-mm-test-splitting-file-backed-thp-to-any-lower-order.patch
xarray-add-xas_try_split-to-split-a-multi-index-entry.patch
xarray-add-xas_try_split-to-split-a-multi-index-entry-fix.patch
mm-huge_memory-add-two-new-not-yet-used-functions-for-folio_split.patch
mm-huge_memory-add-two-new-not-yet-used-functions-for-folio_split-fix.patch
mm-huge_memory-move-folio-split-common-code-to-__folio_split.patch
mm-huge_memory-add-buddy-allocator-like-non-uniform-folio_split.patch
mm-huge_memory-add-buddy-allocator-like-non-uniform-folio_split-fix.patch
mm-huge_memory-remove-the-old-unused-__split_huge_page.patch
mm-huge_memory-add-folio_split-to-debugfs-testing-interface.patch
mm-truncate-use-buddy-allocator-like-folio-split-for-truncate-operation.patch
selftests-mm-add-tests-for-folio_split-buddy-allocator-like-split.patch
mm-filemap-use-xas_try_split-in-__filemap_add_folio.patch
mm-shmem-use-xas_try_split-in-shmem_split_large_entry.patch
