mm/mempolicy.c:offset_il_node() document and clarify (fee83b3a) · Commits · 戴 / test

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@suse.cz> Cc: Xishi Qiu <qiuxishi@huawei.com> Cc: Joonsoo Kim <js1304@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Laura Abbott <lauraa@codeaurora.org> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/mempolicy.c

+11 −9

Original line number	Diff line number	Diff line
		@@ -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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