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Diffstat (limited to 'mm/huge_memory.c')
-rw-r--r--mm/huge_memory.c50
1 files changed, 24 insertions, 26 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index cb7be11..fc00c8c 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1211,7 +1211,7 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
return ERR_PTR(-EFAULT);
/* Full NUMA hinting faults to serialise migration in fault paths */
- if ((flags & FOLL_NUMA) && pmd_numa(*pmd))
+ if ((flags & FOLL_NUMA) && pmd_protnone(*pmd))
goto out;
page = pmd_page(*pmd);
@@ -1262,6 +1262,9 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
bool migrated = false;
int flags = 0;
+ /* A PROT_NONE fault should not end up here */
+ BUG_ON(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)));
+
ptl = pmd_lock(mm, pmdp);
if (unlikely(!pmd_same(pmd, *pmdp)))
goto out_unlock;
@@ -1272,8 +1275,9 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
* check_same as the page may no longer be mapped.
*/
if (unlikely(pmd_trans_migrating(*pmdp))) {
+ page = pmd_page(*pmdp);
spin_unlock(ptl);
- wait_migrate_huge_page(vma->anon_vma, pmdp);
+ wait_on_page_locked(page);
goto out;
}
@@ -1341,7 +1345,7 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
/*
* Migrate the THP to the requested node, returns with page unlocked
- * and pmd_numa cleared.
+ * and access rights restored.
*/
spin_unlock(ptl);
migrated = migrate_misplaced_transhuge_page(mm, vma,
@@ -1354,9 +1358,8 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
goto out;
clear_pmdnuma:
BUG_ON(!PageLocked(page));
- pmd = pmd_mknonnuma(pmd);
+ pmd = pmd_modify(pmd, vma->vm_page_prot);
set_pmd_at(mm, haddr, pmdp, pmd);
- VM_BUG_ON(pmd_numa(*pmdp));
update_mmu_cache_pmd(vma, addr, pmdp);
unlock_page(page);
out_unlock:
@@ -1479,29 +1482,24 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
pmd_t entry;
- ret = 1;
- if (!prot_numa) {
+
+ /*
+ * Avoid trapping faults against the zero page. The read-only
+ * data is likely to be read-cached on the local CPU and
+ * local/remote hits to the zero page are not interesting.
+ */
+ if (prot_numa && is_huge_zero_pmd(*pmd)) {
+ spin_unlock(ptl);
+ return 0;
+ }
+
+ if (!prot_numa || !pmd_protnone(*pmd)) {
+ ret = 1;
entry = pmdp_get_and_clear_notify(mm, addr, pmd);
- if (pmd_numa(entry))
- entry = pmd_mknonnuma(entry);
entry = pmd_modify(entry, newprot);
ret = HPAGE_PMD_NR;
set_pmd_at(mm, addr, pmd, entry);
BUG_ON(pmd_write(entry));
- } else {
- struct page *page = pmd_page(*pmd);
-
- /*
- * Do not trap faults against the zero page. The
- * read-only data is likely to be read-cached on the
- * local CPU cache and it is less useful to know about
- * local vs remote hits on the zero page.
- */
- if (!is_huge_zero_page(page) &&
- !pmd_numa(*pmd)) {
- pmdp_set_numa(mm, addr, pmd);
- ret = HPAGE_PMD_NR;
- }
}
spin_unlock(ptl);
}
@@ -1766,9 +1764,9 @@ static int __split_huge_page_map(struct page *page,
pte_t *pte, entry;
BUG_ON(PageCompound(page+i));
/*
- * Note that pmd_numa is not transferred deliberately
- * to avoid any possibility that pte_numa leaks to
- * a PROT_NONE VMA by accident.
+ * Note that NUMA hinting access restrictions are not
+ * transferred to avoid any possibility of altering
+ * permissions across VMAs.
*/
entry = mk_pte(page + i, vma->vm_page_prot);
entry = maybe_mkwrite(pte_mkdirty(entry), vma);

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