The patch titled
Subject: mm/huge_memory: allow split shmem large folio to any lower order
has been added to the -mm mm-unstable branch. Its filename is
mm-huge_memory-allow-split-shmem-large-folio-to-any-lower-order.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-allow-split-shmem-large-folio-to-any-lower-order.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: allow split shmem large folio to any lower order
Date: Wed, 22 Jan 2025 11:19:27 -0500
Commit 4d684b5f92ba ("mm: shmem: add large folio support for tmpfs") has
added large folio support to shmem. Remove the restriction in
split_huge_page*().
Link: https://lkml.kernel.org/r/20250122161928.1240637-2-ziy@xxxxxxxxxx
Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Reviewed-by: Yang Shi <yang@xxxxxxxxxxxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Hugh Dickens <hughd@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Cc: Kirill A. Shuemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: linmiaohe <linmiaohe@xxxxxxxxxx>
Cc: Mattew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
--- a/mm/huge_memory.c~mm-huge_memory-allow-split-shmem-large-folio-to-any-lower-order
+++ a/mm/huge_memory.c
@@ -3299,7 +3299,7 @@ static void __split_huge_page(struct pag
/* Some pages can be beyond EOF: drop them from page cache */
if (tail->index >= end) {
if (shmem_mapping(folio->mapping))
- nr_dropped++;
+ nr_dropped += new_nr;
else if (folio_test_clear_dirty(tail))
folio_account_cleaned(tail,
inode_to_wb(folio->mapping->host));
@@ -3465,12 +3465,6 @@ int split_huge_page_to_list_to_order(str
return -EINVAL;
}
} else if (new_order) {
- /* Split shmem folio to non-zero order not supported */
- if (shmem_mapping(folio->mapping)) {
- VM_WARN_ONCE(1,
- "Cannot split shmem folio to non-0 order");
- return -EINVAL;
- }
/*
* No split if the file system does not support large folio.
* Note that we might still have THPs in such mappings due to
_
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
