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-rw-r--r--mm/memory_hotplug.c51
1 files changed, 35 insertions, 16 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index df570e5c71cc..3b62a9ff8ea0 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -447,6 +447,14 @@ static void update_pgdat_span(struct pglist_data *pgdat)
zone->spanned_pages;
/* No need to lock the zones, they can't change. */
+ if (!zone->spanned_pages)
+ continue;
+ if (!node_end_pfn) {
+ node_start_pfn = zone->zone_start_pfn;
+ node_end_pfn = zone_end_pfn;
+ continue;
+ }
+
if (zone_end_pfn > node_end_pfn)
node_end_pfn = zone_end_pfn;
if (zone->zone_start_pfn < node_start_pfn)
@@ -1638,6 +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
@@ -1650,25 +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;