The patch titled
Subject: mm: don't try THP alignment for FS without get_unmapped_area
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-dont-try-thp-align-for-fs-without-get_unmapped_area.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-dont-try-thp-align-for-fs-without-get_unmapped_area.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Subject: mm: don't try THP alignment for FS without get_unmapped_area
Date: Fri, 6 Dec 2024 15:03:45 +0800
Commit ed48e87c7df3 ("thp: add thp_get_unmapped_area_vmflags()") changes
thp_get_unmapped_area() to thp_get_unmapped_area_vmflags() in
__get_unmapped_area(), which doesn't initialize local get_area for
anonymous mappings. This leads to us always trying THP alignment even for
file_operations which have a NULL ->get_unmapped_area() callback.
Since commit efa7df3e3bb5 ("mm: align larger anonymous mappings on THP
boundaries") we only want to enable THP alignment for anonymous mappings,
so add a !file check to avoid attempting THP alignment for file mappings.
Link: https://lkml.kernel.org/r/20241206070345.2526501-1-wangkefeng.wang@xxxxxxxxxx
Fixes: ed48e87c7df3 ("thp: add thp_get_unmapped_area_vmflags()")
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>
Reviewed-by: Yang Shi <shy828301@xxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Cc: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/mmap.c~mm-dont-try-thp-align-for-fs-without-get_unmapped_area
+++ a/mm/mmap.c
@@ -892,7 +892,7 @@ __get_unmapped_area(struct file *file, u
if (get_area) {
addr = get_area(file, addr, len, pgoff, flags);
- } else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)
+ } else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && !file
&& !addr /* no hint */
&& IS_ALIGNED(len, PMD_SIZE)) {
/* Ensures that larger anonymous mappings are THP aligned. */
_
Patches currently in -mm which might be from wangkefeng.wang@xxxxxxxxxx are
mm-use-aligned-address-in-clear_gigantic_page.patch
mm-use-aligned-address-in-copy_user_gigantic_page.patch
mm-dont-try-thp-align-for-fs-without-get_unmapped_area.patch
