[PATCH] mm: hugetlb_vmemmap: use bulk allocator in alloc_vmemmap_page_list()

[Kefeng Wang <wangkefeng.wang@huawei.com>]

It is needed 4095 pages(1G) or 7 pages(2M) to be allocated once in
alloc_vmemmap_page_list(), so let's add a bulk allocator varietas
alloc_pages_bulk_list_node() and switch alloc_vmemmap_page_list()
to use it to accelerate page allocation.

Simple test on arm64's qemu with 1G Hugetlb, 870,842ns vs 3,845,252ns
despite the fluctuations, it is still a nice improvement.

Tested-by: Yuan Can <yuancan@huawei.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 include/linux/gfp.h  | 9 +++++++++
 mm/hugetlb_vmemmap.c | 7 ++++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 665f06675c83..d6e82f15b61f 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -195,6 +195,15 @@ alloc_pages_bulk_list(gfp_t gfp, unsigned long nr_pages, struct list_head *list)
 	return __alloc_pages_bulk(gfp, numa_mem_id(), NULL, nr_pages, list, NULL);
 }
 
+static inline unsigned long
+alloc_pages_bulk_list_node(gfp_t gfp, int nid, unsigned long nr_pages, struct list_head *list)
+{
+	if (nid == NUMA_NO_NODE)
+		nid = numa_mem_id();
+
+	return __alloc_pages_bulk(gfp, nid, NULL, nr_pages, list, NULL);
+}
+
 static inline unsigned long
 alloc_pages_bulk_array(gfp_t gfp, unsigned long nr_pages, struct page **page_array)
 {
diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index 4b9734777f69..699c4fea6b9f 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -384,8 +384,13 @@ static int alloc_vmemmap_page_list(unsigned long start, unsigned long end,
 	unsigned long nr_pages = (end - start) >> PAGE_SHIFT;
 	int nid = page_to_nid((struct page *)start);
 	struct page *page, *next;
+	unsigned long nr_alloced;
 
-	while (nr_pages--) {
+	nr_alloced = alloc_pages_bulk_list_node(gfp_mask, nid, nr_pages, list);
+	if (!nr_alloced)
+		return -ENOMEM;
+
+	while (nr_alloced < nr_pages) {
 		page = alloc_pages_node(nid, gfp_mask, 0);
 		if (!page)
 			goto out;
-- 
2.27.0