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authorLee Schermerhorn <Lee.Schermerhorn@hp.com>2009-09-21 17:01:04 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2009-10-05 08:28:03 -0700
commitc7be4a49273fc339f6eb3cf785ef454b723b3d00 (patch)
tree0b0506a0360cabf1c351456ca5202284d52e0003
parentec49bc1bdc7c6e92873373ff61206c366d63a50a (diff)
downloadlwn-c7be4a49273fc339f6eb3cf785ef454b723b3d00.tar.gz
lwn-c7be4a49273fc339f6eb3cf785ef454b723b3d00.zip
hugetlb: restore interleaving of bootmem huge pages (2.6.31)
Not upstream as it is fixed differently in .32 I noticed that alloc_bootmem_huge_page() will only advance to the next node on failure to allocate a huge page. 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. Andy Whitcroft countered that the existing behavior looked like Andi Kleen's original implementation and suggested that we ask him. We did and Andy replied that his intention was to interleave the allocations. So, ... This patch moves the advance of the hstate next node from which to allocate up before the test for success of the attempted allocation. This will unconditionally advance the next node from which to alloc, interleaving successful allocations over the nodes with sufficient contiguous memory, and skipping over nodes that fail the huge page allocation attempt. Note that alloc_bootmem_huge_page() will only be called for huge pages of order > MAX_ORDER. Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: David Rientjes <rientjes@google.com> Cc: Adam Litke <agl@us.ibm.com> Cc: Andy Whitcroft <apw@canonical.com> Cc: Eric Whitney <eric.whitney@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--mm/hugetlb.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 2403eb9a03f0..42f7e1a3fcbf 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1017,6 +1017,7 @@ int __weak alloc_bootmem_huge_page(struct hstate *h)
NODE_DATA(h->hugetlb_next_nid),
huge_page_size(h), huge_page_size(h), 0);
+ hstate_next_node(h);
if (addr) {
/*
* Use the beginning of the huge page to store the
@@ -1026,7 +1027,6 @@ int __weak alloc_bootmem_huge_page(struct hstate *h)
m = addr;
goto found;
}
- hstate_next_node(h);
nr_nodes--;
}
return 0;