Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
 "15 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm: numa: mark huge PTEs young when clearing NUMA hinting faults
  mm: numa: slow PTE scan rate if migration failures occur
  mm: numa: preserve PTE write permissions across a NUMA hinting fault
  mm: numa: group related processes based on VMA flags instead of page table flags
  hfsplus: fix B-tree corruption after insertion at position 0
  MAINTAINERS: add Jan as DMI/SMBIOS support maintainer
  fs/affs/file.c: unlock/release page on error
  mm/page_alloc.c: call kernel_map_pages in unset_migrateype_isolate
  mm/slub: fix lockups on PREEMPT && !SMP kernels
  mm/memory hotplug: postpone the reset of obsolete pgdat
  MAINTAINERS: correct rtc armada38x pattern entry
  mm/pagewalk.c: prevent positive return value of walk_page_test() from being passed to callers
  mm: fix anon_vma->degree underflow in anon_vma endless growing prevention
  drivers/rtc/rtc-mrst: fix suspend/resume
  aoe: update aoe maintainer information

1 files changed, 12 insertions, 10 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 411144f977b1..97839f5c8c30 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3035,6 +3035,7 @@ static int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	int last_cpupid;
 	int target_nid;
 	bool migrated = false;
+	bool was_writable = pte_write(pte);
 	int flags = 0;
 
 	/* A PROT_NONE fault should not end up here */
@@ -3059,6 +3060,8 @@ static int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	/* Make it present again */
 	pte = pte_modify(pte, vma->vm_page_prot);
 	pte = pte_mkyoung(pte);
+	if (was_writable)
+		pte = pte_mkwrite(pte);
 	set_pte_at(mm, addr, ptep, pte);
 	update_mmu_cache(vma, addr, ptep);
 
@@ -3069,16 +3072,14 @@ static int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	}
 
 	/*
-	 * Avoid grouping on DSO/COW pages in specific and RO pages
-	 * in general, RO pages shouldn't hurt as much anyway since
-	 * they can be in shared cache state.
-	 *
-	 * FIXME! This checks "pmd_dirty()" as an approximation of
-	 * "is this a read-only page", since checking "pmd_write()"
-	 * is even more broken. We haven't actually turned this into
-	 * a writable page, so pmd_write() will always be false.
+	 * Avoid grouping on RO pages in general. RO pages shouldn't hurt as
+	 * much anyway since they can be in shared cache state. This misses
+	 * the case where a mapping is writable but the process never writes
+	 * to it but pte_write gets cleared during protection updates and
+	 * pte_dirty has unpredictable behaviour between PTE scan updates,
+	 * background writeback, dirty balancing and application behaviour.
 	 */
-	if (!pte_dirty(pte))
+	if (!(vma->vm_flags & VM_WRITE))
 		flags |= TNF_NO_GROUP;
 
 	/*
@@ -3102,7 +3103,8 @@ static int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	if (migrated) {
 		page_nid = target_nid;
 		flags |= TNF_MIGRATED;
-	}
+	} else
+		flags |= TNF_MIGRATE_FAIL;
 
 out:
 	if (page_nid != -1)