Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
 "11 fixes"

MM fixes and one xz decompressor fix.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm/debug.c: PageAnon() is true for PageKsm() pages
  mm/debug.c: __dump_page() prints an extra line
  mm/page_io.c: do not free shared swap slots
  mm/memory_hotplug: fix try_offline_node()
  mm,thp: recheck each page before collapsing file THP
  mm: slub: really fix slab walking for init_on_free
  mm: hugetlb: switch to css_tryget() in hugetlb_cgroup_charge_cgroup()
  mm: memcg: switch to css_tryget() in get_mem_cgroup_from_mm()
  lib/xz: fix XZ_DYNALLOC to avoid useless memory reallocations
  mm: fix trying to reclaim unevictable lru page when calling madvise_pageout
  mm: mempolicy: fix the wrong return value and potential pages leak of mbind

1 files changed, 27 insertions, 16 deletions

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 07e5c67f48a8..3b62a9ff8ea0 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1646,6 +1646,18 @@ static int check_cpu_on_node(pg_data_t *pgdat)
 	return 0;
 }
 
+static int check_no_memblock_for_node_cb(struct memory_block *mem, void *arg)
+{
+	int nid = *(int *)arg;
+
+	/*
+	 * If a memory block belongs to multiple nodes, the stored nid is not
+	 * reliable. However, such blocks are always online (e.g., cannot get
+	 * offlined) and, therefore, are still spanned by the node.
+	 */
+	return mem->nid == nid ? -EEXIST : 0;
+}
+
 /**
  * try_offline_node
  * @nid: the node ID
@@ -1658,25 +1670,24 @@ static int check_cpu_on_node(pg_data_t *pgdat)
 void try_offline_node(int nid)
 {
 	pg_data_t *pgdat = NODE_DATA(nid);
-	unsigned long start_pfn = pgdat->node_start_pfn;
-	unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
-	unsigned long pfn;
-
-	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
-		unsigned long section_nr = pfn_to_section_nr(pfn);
-
-		if (!present_section_nr(section_nr))
-			continue;
+	int rc;
 
-		if (pfn_to_nid(pfn) != nid)
-			continue;
+	/*
+	 * If the node still spans pages (especially ZONE_DEVICE), don't
+	 * offline it. A node spans memory after move_pfn_range_to_zone(),
+	 * e.g., after the memory block was onlined.
+	 */
+	if (pgdat->node_spanned_pages)
+		return;
 
-		/*
-		 * some memory sections of this node are not removed, and we
-		 * can't offline node now.
-		 */
+	/*
+	 * Especially offline memory blocks might not be spanned by the
+	 * node. They will get spanned by the node once they get onlined.
+	 * However, they link to the node in sysfs and can get onlined later.
+	 */
+	rc = for_each_memory_block(&nid, check_no_memblock_for_node_cb);
+	if (rc)
 		return;
-	}
 
 	if (check_cpu_on_node(pgdat))
 		return;