[patch 1/3] x86: fix numa emulation calculation of big nodes

From: David Rientjes
Date: Mon Feb 15 2010 - 16:43:37 EST


numa=fake=N uses split_nodes_interleave() to partition the system into N
fake nodes. Each node size must have be a multiple of
FAKE_NODE_MIN_SIZE, otherwise it is possible to get strange alignments.
Because of this, the remaining memory from each node when rounded to
FAKE_NODE_MIN_SIZE is consolidated into a number of "big nodes" that are
bigger than the rest.

The calculation of the number of big nodes is incorrect since it is using
a logical AND operator when it should be multiplying the rounded-off
portion of each node with N.

Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
---
arch/x86/mm/numa_64.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/mm/numa_64.c b/arch/x86/mm/numa_64.c
--- a/arch/x86/mm/numa_64.c
+++ b/arch/x86/mm/numa_64.c
@@ -427,7 +427,7 @@ static int __init split_nodes_interleave(u64 addr, u64 max_addr,
* Calculate the number of big nodes that can be allocated as a result
* of consolidating the remainder.
*/
- big = ((size & ~FAKE_NODE_MIN_HASH_MASK) & nr_nodes) /
+ big = ((size & ~FAKE_NODE_MIN_HASH_MASK) * nr_nodes) /
FAKE_NODE_MIN_SIZE;

size &= FAKE_NODE_MIN_HASH_MASK;
--
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