From 5ced66c901f1cf0b684feb15c2cd8b126e263d07 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Wed, 23 Jul 2008 21:27:45 -0700 Subject: [PATCH] hugetlb: abstract numa round robin selection Need this as a separate function for a future patch. No behaviour change. Acked-by: Adam Litke Acked-by: Nishanth Aravamudan Signed-off-by: Andi Kleen Signed-off-by: Nick Piggin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/hugetlb.c | 37 ++++++++++++++++++++++--------------- 1 file changed, 22 insertions(+), 15 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index bb49ce5d0067..5e620e25cf08 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -565,6 +565,27 @@ static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) 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 hstate_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; @@ -578,21 +599,7 @@ static int alloc_fresh_huge_page(struct hstate *h) 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 = hstate_next_node(h); } while (!page && h->hugetlb_next_nid != start_nid); if (ret)