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Subject[PATCH] [7/18] Abstract out the NUMA node round robin code into a separate function
Date

Need this as a separate function for a future patch.

No behaviour change.

Signed-off-by: Andi Kleen <ak@suse.de>

---
mm/hugetlb.c | 37 ++++++++++++++++++++++---------------
1 file changed, 22 insertions(+), 15 deletions(-)
Index: linux/mm/hugetlb.c
===================================================================
--- linux.orig/mm/hugetlb.c
+++ linux/mm/hugetlb.c
@@ -219,6 +219,27 @@ static struct page *alloc_fresh_huge_pag
return page;
}

+/*
+ * Use a helper variable to find the next node and then
+ * copy it back to hugetlb_next_nid afterwards:
+ * otherwise there's a window in which a racer might
+ * pass invalid nid MAX_NUMNODES to alloc_pages_node.
+ * But we don't need to use a spin_lock here: it really
+ * doesn't matter if occasionally a racer chooses the
+ * same nid as we do. Move nid forward in the mask even
+ * if we just successfully allocated a hugepage so that
+ * the next caller gets hugepages on the next node.
+ */
+static int huge_next_node(struct hstate *h)
+{
+ int next_nid;
+ next_nid = next_node(h->hugetlb_next_nid, node_online_map);
+ if (next_nid == MAX_NUMNODES)
+ next_nid = first_node(node_online_map);
+ h->hugetlb_next_nid = next_nid;
+ return next_nid;
+}
+
static int alloc_fresh_huge_page(struct hstate *h)
{
struct page *page;
@@ -232,21 +253,7 @@ static int alloc_fresh_huge_page(struct
page = alloc_fresh_huge_page_node(h, h->hugetlb_next_nid);
if (page)
ret = 1;
- /*
- * Use a helper variable to find the next node and then
- * copy it back to hugetlb_next_nid afterwards:
- * otherwise there's a window in which a racer might
- * pass invalid nid MAX_NUMNODES to alloc_pages_node.
- * But we don't need to use a spin_lock here: it really
- * doesn't matter if occasionally a racer chooses the
- * same nid as we do. Move nid forward in the mask even
- * if we just successfully allocated a hugepage so that
- * the next caller gets hugepages on the next node.
- */
- next_nid = next_node(h->hugetlb_next_nid, node_online_map);
- if (next_nid == MAX_NUMNODES)
- next_nid = first_node(node_online_map);
- h->hugetlb_next_nid = next_nid;
+ next_nid = huge_next_node(h);
} while (!page && h->hugetlb_next_nid != start_nid);

return ret;

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