diff options
Diffstat (limited to 'mm/huge_memory.c')
| -rw-r--r-- | mm/huge_memory.c | 50 |
1 files changed, 24 insertions, 26 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index cb7be110cad3..fc00c8cb5a82 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); |