arm64: hugetlb: Fix handling of young ptes

In the contiguous bit hugetlb break-before-make code we assume that all
hugetlb pages are young.

In fact, remove_migration_pte is able to place an old hugetlb pte so
this assumption is not valid.

This patch fixes the contiguous hugetlb scanning code to preserve young
ptes.

Fixes: d8bdcff287 ("arm64: hugetlb: Add break-before-make logic for contiguous entries")
Signed-off-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Steve Capper 2018-09-21 16:34:04 +01:00 committed by Will Deacon
parent 6bf4ca7fbc
commit 469ed9d823
1 changed files with 9 additions and 3 deletions

View File

@ -117,11 +117,14 @@ static pte_t get_clear_flush(struct mm_struct *mm,
/*
* If HW_AFDBM is enabled, then the HW could turn on
* the dirty bit for any page in the set, so check
* them all. All hugetlb entries are already young.
* the dirty or accessed bit for any page in the set,
* so check them all.
*/
if (pte_dirty(pte))
orig_pte = pte_mkdirty(orig_pte);
if (pte_young(pte))
orig_pte = pte_mkyoung(orig_pte);
}
if (valid) {
@ -340,10 +343,13 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma,
if (!pte_same(orig_pte, pte))
changed = 1;
/* Make sure we don't lose the dirty state */
/* Make sure we don't lose the dirty or young state */
if (pte_dirty(orig_pte))
pte = pte_mkdirty(pte);
if (pte_young(orig_pte))
pte = pte_mkyoung(pte);
hugeprot = pte_pgprot(pte);
for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn)
set_pte_at(vma->vm_mm, addr, ptep, pfn_pte(pfn, hugeprot));