Commit 68fd111e authored Feb 15, 2010 by David Rientjes Committed by H. Peter Anvin Feb 15, 2010

x86, numa: Fix numa emulation calculation of big nodes



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@google.com>
LKML-Reference: <alpine.DEB.2.00.1002151342230.26927@chino.kir.corp.google.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

parent 0271f910

arch/x86/mm/numa_64.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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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