From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Subject: mm/mempolicy.c:offset_il_node() document and clarify
This code was pretty obscure and was relying upon obscure side-effects of
next_node(-1, ...) and was relying upon NUMA_NO_NODE being equal to -1.
Clean that all up and document the function's intent.
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Xishi Qiu <qiuxishi@xxxxxxxxxx>
Cc: Joonsoo Kim <js1304@xxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Laura Abbott <lauraa@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mempolicy.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)
diff -puN mm/mempolicy.c~mm-mempolicyc-offset_il_node-document-and-clarify mm/mempolicy.c
--- a/mm/mempolicy.c~mm-mempolicyc-offset_il_node-document-and-clarify
+++ a/mm/mempolicy.c
@@ -1758,23 +1758,25 @@ unsigned int mempolicy_slab_node(void)
}
}
-/* Do static interleaving for a VMA with known offset. */
+/*
+ * Do static interleaving for a VMA with known offset @n. Returns the n'th
+ * node in pol->v.nodes (starting from n=0), wrapping around if n exceeds the
+ * number of present nodes.
+ */
static unsigned offset_il_node(struct mempolicy *pol,
- struct vm_area_struct *vma, unsigned long off)
+ struct vm_area_struct *vma, unsigned long n)
{
unsigned nnodes = nodes_weight(pol->v.nodes);
unsigned target;
- int c;
- int nid = NUMA_NO_NODE;
+ int i;
+ int nid;
if (!nnodes)
return numa_node_id();
- target = (unsigned int)off % nnodes;
- c = 0;
- do {
+ target = (unsigned int)n % nnodes;
+ nid = first_node(pol->v.nodes);
+ for (i = 0; i < target; i++)
nid = next_node(nid, pol->v.nodes);
- c++;
- } while (c <= target);
return nid;
}
_
--
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