mm/damon: use set_huge_pte_at() to make huge pte old

The huge_ptep_set_access_flags() can not make the huge pte old according
to the discussion [1], that means we will always mornitor the young state
of the hugetlb though we stopped accessing the hugetlb, as a result DAMON
will get inaccurate accessing statistics.

So changing to use set_huge_pte_at() to make the huge pte old to fix this
issue.

[1] https://lore.kernel.org/all/Yqy97gXI4Nqb7dYo@arm.com/

Link: https://lkml.kernel.org/r/1655692482-28797-1-git-send-email-baolin.wang@linux.alibaba.com
Fixes: 49f4203aae06 ("mm/damon: add access checking for hugetlb pages")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index 59e1653..3c7b9d6 100644 (file)
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -336,8 +336,7 @@ static void damon_hugetlb_mkold(pte_t *pte, struct mm_struct *mm,
        if (pte_young(entry)) {
                referenced = true;
                entry = pte_mkold(entry);
-               huge_ptep_set_access_flags(vma, addr, pte, entry,
-                                          vma->vm_flags & VM_WRITE);
+               set_huge_pte_at(mm, addr, pte, entry);
        }
 
 #ifdef CONFIG_MMU_NOTIFIER