mm/vmalloc: fix numa spreading for large hash tables

Eric Dumazet reported a strange numa spreading info in [1], and found
commit 121e6f32 ("mm/vmalloc: hugepage vmalloc mappings") introduced
this issue [2].

Dig into the difference before and after this patch, page allocation has
some difference:

before:
  alloc_large_system_hash
    __vmalloc
      __vmalloc_node(..., NUMA_NO_NODE, ...)
        __vmalloc_node_range
          __vmalloc_area_node
            alloc_page /* because NUMA_NO_NODE, so choose alloc_page branch */
              alloc_pages_current
                alloc_page_interleave /* can be proved by print policy mode */

after:
  alloc_large_system_hash
    __vmalloc
      __vmalloc_node(..., NUMA_NO_NODE, ...)
        __vmalloc_node_range
          __vmalloc_area_node
            alloc_pages_node /* choose nid by nuam_mem_id() */
              __alloc_pages_node(nid, ....)

So after commit 121e6f32 ("mm/vmalloc: hugepage vmalloc mappings"),
it will allocate memory in current node instead of interleaving allocate
memory.

Link: https://lore.kernel.org/linux-mm/CANn89iL6AAyWhfxdHO+jaT075iOa3XcYn9k6JJc7JR2XYn6k_Q@mail.gmail.com/ [1]
Link: https://lore.kernel.org/linux-mm/CANn89iLofTR=AK-QOZY87RdUZENCZUT4O6a0hvhu3_EwRMerOg@mail.gmail.com/ [2]
Link: https://lkml.kernel.org/r/20211021080744.874701-2-chenwandun@huawei.com
Fixes: 121e6f32 ("mm/vmalloc: hugepage vmalloc mappings")
Signed-off-by: Chen Wandun <chenwandun@huawei.com>
Reported-by: Eric Dumazet <edumazet@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Uladzislau Rezki <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmalloc.c

@@ -2816,6 +2816,8 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
 		unsigned int order, unsigned int nr_pages, struct page **pages)
 {
 	unsigned int nr_allocated = 0;
+	struct page *page;
+	int i;
 
 	/*
 	 * For order-0 pages we make use of bulk allocator, if
@@ -2823,7 +2825,7 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
 	 * to fails, fallback to a single page allocator that is
 	 * more permissive.
 	 */
-	if (!order) {
+	if (!order && nid != NUMA_NO_NODE) {
 		while (nr_allocated < nr_pages) {
 			unsigned int nr, nr_pages_request;
 
@@ -2848,7 +2850,7 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
 			if (nr != nr_pages_request)
 				break;
 		}
-	} else
+	} else if (order)
 		/*
 		 * Compound pages required for remap_vmalloc_page if
 		 * high-order pages.
@@ -2856,10 +2858,11 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
 		gfp |= __GFP_COMP;
 
 	/* High-order pages or fallback path if "bulk" fails. */
-	while (nr_allocated < nr_pages) {
-		struct page *page;
-		int i;
 
+	while (nr_allocated < nr_pages) {
+		if (nid == NUMA_NO_NODE)
+			page = alloc_pages(gfp, order);
+		else
 			page = alloc_pages_node(nid, gfp, order);
 		if (unlikely(!page))
 			break;