Commit 953f064a authored Sep 04, 2020 by Li Xinhai Committed by Linus Torvalds Sep 05, 2020

mm/hugetlb: try preferred node first when alloc gigantic page from cma



Since commit cf11e85f ("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.

Fixes: cf11e85f ("mm: hugetlb: optionally allocate gigantic hugepages using cma")
Signed-off-by: Li Xinhai <lixinhai.lxh@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Link: https://lkml.kernel.org/r/20200902025016.697260-1-lixinhai.lxh@gmail.com


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 3d321bf8

mm/hugetlb.c

+17 −6

Original line number	Diff line number	Diff line
		@@ -1250,14 +1250,24 @@ static struct page alloc_gigantic_page(struct hstate h, gfp_t gfp_mask,
		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;

		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 (!hugetlb_cma[node])
		if (node == nid \|\| !hugetlb_cma[node])
		continue;

		page = cma_alloc(hugetlb_cma[node], nr_pages,
		@@ -1266,6 +1276,7 @@ static struct page alloc_gigantic_page(struct hstate h, gfp_t gfp_mask,
		return page;
		}
		}
		}
		#endif

		return alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask);

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