[v4 PATCH 1/7] mm: khugepaged: check THP flag in hugepage_vma_check()

Yang Shi
2022-06-15T17:29:51Z

Currently the THP flag check in hugepage_vma_check() will fallthrough if
the flag is NEVER and VM_HUGEPAGE is set. This is not a problem for now
since all the callers have the flag checked before or can't be invoked if
the flag is NEVER.

However, the following patch will call hugepage_vma_check() in more
places, for example, page fault, so this flag must be checked in
hugepge_vma_check().

Reviewed-by: Zach O'Keefe <zokeefe@google.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Yang Shi <shy828301@gmail.com>
---
mm/khugepaged.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 476d79360101..b1dab94c0f1e 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -458,6 +458,9 @@ bool hugepage_vma_check(struct vm_area_struct *vma,
if (shmem_file(vma->vm_file))
return shmem_huge_enabled(vma);

+ if (!khugepaged_enabled())
+ return false;
+
/* THP settings require madvise. */
if (!(vm_flags & VM_HUGEPAGE) && !khugepaged_always())
return false;
--
2.26.3