[16/19] mm/hugetlb: try preferred node first when alloc gigantic page from cma

Commit Message

Andrew Morton Sept. 4, 2020, 11:36 p.m. UTC

From: Li Xinhai <[e-mail]>
Subject: mm/hugetlb: try preferred node first when alloc gigantic page from cma

Since commit cf11e85fc08cc6a4 ("mm: hugetlb: optionally allocate gigantic
hugepages using cma"), the gigantic page would be allocated from node
which is not the preferred node, although there are pages available from
that node.  The reason is that the nid parameter has been ignored in
alloc_gigantic_page().

Besides, the __GFP_THISNODE also need be checked if user required to alloc
only from the preferred node.

After this patch, the preferred node is tried first before other allowed
nodes, and don't try to allocate from other nodes if __GFP_THISNODE is
specified.  If user don't specify the preferred node, the current node
will be used as preferred node, which makes sure consistent behavior of
allocating gigantic and non-gigantic hugetlb page.

Link: https://lkml.kernel.org/r/[e-mail]
Fixes: cf11e85fc08cc6a4 ("mm: hugetlb: optionally allocate gigantic hugepages using cma")
Signed-off-by: Li Xinhai <[e-mail]>
Acked-by: Michal Hocko <[e-mail]>
Reviewed-by: Mike Kravetz <[e-mail]>
Cc: Roman Gushchin <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/hugetlb.c |   23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

Patch

--- a/mm/hugetlb.c~mm-hugetlb-try-preferred-node-first-when-alloc-gigantic-page-from-cma
+++ a/mm/hugetlb.c
@@ -1250,21 +1250,32 @@  static struct page *alloc_gigantic_page(
 		int nid, nodemask_t *nodemask)
 {
 	unsigned long nr_pages = 1UL << huge_page_order(h);
+	if (nid == NUMA_NO_NODE)
+		nid = numa_mem_id();
 
 #ifdef CONFIG_CMA
 	{
 		struct page *page;
 		int node;
 
-		for_each_node_mask(node, *nodemask) {
-			if (!hugetlb_cma[node])
-				continue;
-
-			page = cma_alloc(hugetlb_cma[node], nr_pages,
-					 huge_page_order(h), true);
+		if (hugetlb_cma[nid]) {
+			page = cma_alloc(hugetlb_cma[nid], nr_pages,
+					huge_page_order(h), true);
 			if (page)
 				return page;
 		}
+
+		if (!(gfp_mask & __GFP_THISNODE)) {
+			for_each_node_mask(node, *nodemask) {
+				if (node == nid || !hugetlb_cma[node])
+					continue;
+
+				page = cma_alloc(hugetlb_cma[node], nr_pages,
+						huge_page_order(h), true);
+				if (page)
+					return page;
+			}
+		}
 	}
 #endif