hugetlb: restore interleaving of bootmem huge pages

I noticed that alloc_bootmem_huge_page() will only advance to the next
node on failure to allocate a huge page, potentially filling nodes with
huge-pages.  I asked about this on linux-mm and linux-numa, cc'ing the
usual huge page suspects.

Mel Gorman responded:

	I strongly suspect that the same node being used until allocation
	failure instead of round-robin is an oversight and not deliberate
	at all. It appears to be a side-effect of a fix made way back in
	commit 63b4613c3f0d4b724ba259dc6c201bb68b884e1a ["hugetlb: fix
	hugepage allocation with memoryless nodes"]. Prior to that patch
	it looked like allocations would always round-robin even when
	allocation was successful.

This patch--factored out of my "hugetlb mempolicy" series--moves the
advance of the hstate next node from which to allocate up before the test
for success of the attempted allocation.

Note that alloc_bootmem_huge_page() is only used for order > MAX_ORDER
huge pages.

I'll post a separate patch for mainline/stable, as the above mentioned
"balance freeing" series renamed the next node to alloc function.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Reviewed-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Andy Whitcroft <apw@canonical.com>
Reviewed-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index f10cc274a7d90b32287800ebcd614787ab9c5692..c001f846f17d1ee1baa6b9036d66ca00490a97a2 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1031,6 +1031,7 @@ int __weak alloc_bootmem_huge_page(struct hstate *h)
                                NODE_DATA(h->next_nid_to_alloc),
                                huge_page_size(h), huge_page_size(h), 0);
 
+               hstate_next_node_to_alloc(h);
                if (addr) {
                        /*
                         * Use the beginning of the huge page to store the
@@ -1040,7 +1041,6 @@ int __weak alloc_bootmem_huge_page(struct hstate *h)
                        m = addr;
                        goto found;
                }
-               hstate_next_node_to_alloc(h);
                nr_nodes--;
        }
        return 0;