This is a note to let you know that I've just added the patch titled
mm,thp,shmem: make khugepaged obey tmpfs mount flags
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-thp-shmem-make-khugepaged-obey-tmpfs-mount-flags.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit eb159c0358efea13e66925a4911bf0e44456d19d
Author: Rik van Riel <riel@xxxxxxxxxxx>
Date: Thu Feb 25 17:16:25 2021 -0800
mm,thp,shmem: make khugepaged obey tmpfs mount flags
[ Upstream commit cd89fb06509903f942a0ffe97ffa63034671ed0c ]
Currently if thp enabled=[madvise], mounting a tmpfs filesystem with
huge=always and mmapping files from that tmpfs does not result in
khugepaged collapsing those mappings, despite the mount flag indicating
that it should.
Fix that by breaking up the blocks of tests in hugepage_vma_check a little
bit, and testing things in the correct order.
Link: https://lkml.kernel.org/r/20201124194925.623931-4-riel@xxxxxxxxxxx
Fixes: c2231020ea7b ("mm: thp: register mm for khugepaged when merging vma for shmem")
Signed-off-by: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Xu Yu <xuyu@xxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/linux/khugepaged.h b/include/linux/khugepaged.h
index c941b73773216..2fcc01891b474 100644
--- a/include/linux/khugepaged.h
+++ b/include/linux/khugepaged.h
@@ -3,6 +3,7 @@
#define _LINUX_KHUGEPAGED_H
#include <linux/sched/coredump.h> /* MMF_VM_HUGEPAGE */
+#include <linux/shmem_fs.h>
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -57,6 +58,7 @@ static inline int khugepaged_enter(struct vm_area_struct *vma,
{
if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags))
if ((khugepaged_always() ||
+ (shmem_file(vma->vm_file) && shmem_huge_enabled(vma)) ||
(khugepaged_req_madv() && (vm_flags & VM_HUGEPAGE))) &&
!(vm_flags & VM_NOHUGEPAGE) &&
!test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 4e3dff13eb70c..abab394c42062 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -440,18 +440,28 @@ static inline int khugepaged_test_exit(struct mm_struct *mm)
static bool hugepage_vma_check(struct vm_area_struct *vma,
unsigned long vm_flags)
{
- if ((!(vm_flags & VM_HUGEPAGE) && !khugepaged_always()) ||
- (vm_flags & VM_NOHUGEPAGE) ||
+ /* Explicitly disabled through madvise. */
+ if ((vm_flags & VM_NOHUGEPAGE) ||
test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
return false;
- if (shmem_file(vma->vm_file) ||
- (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) &&
- vma->vm_file &&
- (vm_flags & VM_DENYWRITE))) {
+ /* Enabled via shmem mount options or sysfs settings. */
+ if (shmem_file(vma->vm_file) && shmem_huge_enabled(vma)) {
return IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) - vma->vm_pgoff,
HPAGE_PMD_NR);
}
+
+ /* THP settings require madvise. */
+ if (!(vm_flags & VM_HUGEPAGE) && !khugepaged_always())
+ return false;
+
+ /* Read-only file mappings need to be aligned for THP to work. */
+ if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && vma->vm_file &&
+ (vm_flags & VM_DENYWRITE)) {
+ return IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) - vma->vm_pgoff,
+ HPAGE_PMD_NR);
+ }
+
if (!vma->anon_vma || vma->vm_ops)
return false;
if (vma_is_temporary_stack(vma))
