From: steve.capper@arm•com (Steve Capper)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH V2 1/2] arm64: hugetlb: Fix handling of young ptes
Date: Fri, 21 Sep 2018 16:34:04 +0100 [thread overview]
Message-ID: <20180921153405.10090-2-steve.capper@arm.com> (raw)
In-Reply-To: <20180921153405.10090-1-steve.capper@arm.com>
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: d8bdcff28764 ("arm64: hugetlb: Add break-before-make logic for contiguous entries")
Signed-off-by: Steve Capper <steve.capper@arm•com>
---
arch/arm64/mm/hugetlbpage.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 192b3ba07075..f85be2f8b140 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -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));
--
2.11.0
next prev parent reply other threads:[~2018-09-21 15:34 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-21 15:34 [PATCH V2 0/2] Fixes for contiguous hugetlb Steve Capper
2018-09-21 15:34 ` Steve Capper [this message]
2018-09-21 15:34 ` [PATCH V2 2/2] arm64: hugetlb: Avoid unnecessary clearing in huge_ptep_set_access_flags Steve Capper
2018-09-24 16:25 ` [PATCH V2 0/2] Fixes for contiguous hugetlb Will Deacon
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