mm: clarify why we want kmalloc before falling backto vmallock

[karo-tx-linux.git] / mm / util.c

diff --git a/mm/util.c b/mm/util.c
index 464df34899031d46058b7cbadc1c3be24ae8dc89..26be6407abd7efe452a585d341a8d7e5b53d2b32 100644 (file)
--- a/mm/util.c
+++ b/mm/util.c
@@ -357,8 +357,11 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node)
        WARN_ON_ONCE((flags & GFP_KERNEL) != GFP_KERNEL);
 
        /*
-        * Make sure that larger requests are not too disruptive - no OOM
-        * killer and no allocation failure warnings as we have a fallback
+        * We want to attempt a large physically contiguous block first because
+        * it is less likely to fragment multiple larger blocks and therefore
+        * contribute to a long term fragmentation less than vmalloc fallback.
+        * However make sure that larger requests are not too disruptive - no
+        * OOM killer and no allocation failure warnings as we have a fallback.
         */
        if (size > PAGE_SIZE) {
                kmalloc_flags |= __GFP_NOWARN;