mmzone: note that node_size_lock should be manipulated via pgdat_resize_lock()

Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 9ec7cffcae2188fe65873ea0d976ca955aabef8b..e511f9429f1e3813a15864256c5813c27524a107 100644 (file)
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -733,6 +733,9 @@ typedef struct pglist_data {
         * or node_spanned_pages stay constant.  Holding this will also
         * guarantee that any pfn_valid() stays that way.
         *
+        * pgdat_resize_lock() and pgdat_resize_unlock() are provided to
+        * manipulate node_size_lock without checking for CONFIG_MEMORY_HOTPLUG.
+        *
         * Nests above zone->lock and zone->span_seqlock
         */
        spinlock_t node_size_lock;