Subject: [RFC PATCH 2/5] mm: large system hash avoid vmap for non-NUMA machines when hashdist

From: Nicholas Piggin <[email-masked]>
Date: Wed, 15 May 2019 23:19:41 +1000

hashdist currently always uses vmalloc when hashdist is true. When
there is only 1 online node and size <= MAX_ORDER, vmalloc can be
avoided.

Signed-off-by: Nicholas Piggin <[email-masked]>
---
 mm/page_alloc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 1683d54d6405..1312d4db5602 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -7978,7 +7978,8 @@ void *__init alloc_large_system_hash(const char *tablename,
 			else
 				table = memblock_alloc_raw(size,
 							   SMP_CACHE_BYTES);
-		} else if (get_order(size) >= MAX_ORDER || hashdist) {
+		} else if (get_order(size) >= MAX_ORDER ||
+				(hashdist && num_online_nodes() > 1)) {
 			table = __vmalloc(size, gfp_flags, PAGE_KERNEL);
 		} else {
 			/*
-- 
2.20.1