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Commit b2fea988 authored by Tejun Heo's avatar Tejun Heo Committed by H. Peter Anvin
Browse files

memblock: Improve generic memblock_nid_range() using for_each_mem_pfn_range() 



Given an address range, memblock_nid_range() determines the node the
start of the range belongs to and upto where the range stays in the
same node.

It's implemented by calling get_pfn_range_for_nid(), which determines
min and max pfns for a given node, for each node and testing whether
start address falls in there.  This is not only inefficient but also
incorrect when nodes interleave as min-max ranges for nodes overlap.

This patch reimplements memblock_nid_range() using
for_each_mem_pfn_range().  It's simpler, walks the mem ranges once and
can find the exact range the start address falls in.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/1310460395-30913-5-git-send-email-tj@kernel.org


Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent c13291a5

mm/memblock.c

+3 −17
Original line number Diff line number Diff line
@@ -511,28 +511,14 @@ phys_addr_t __init memblock_alloc(phys_addr_t size, phys_addr_t align) 
phys_addr_t __weak __init memblock_nid_range(phys_addr_t start, phys_addr_t end, int *nid)

{

#ifdef CONFIG_ARCH_POPULATES_NODE_MAP

	/*

	 * This code originates from sparc which really wants use to walk by addresses

	 * and returns the nid. This is not very convenient for early_pfn_map[] users

	 * as the map isn't sorted yet, and it really wants to be walked by nid.

	 *

	 * For now, I implement the inefficient method below which walks the early

	 * map multiple times. Eventually we may want to use an ARCH config option

	 * to implement a completely different method for both case.

	 */

	unsigned long start_pfn, end_pfn;

	int i;



	for (i = 0; i < MAX_NUMNODES; i++) {

		get_pfn_range_for_nid(i, &start_pfn, &end_pfn);

		if (start < PFN_PHYS(start_pfn) || start >= PFN_PHYS(end_pfn))

			continue;

		*nid = i;

	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, nid)

		if (start >= PFN_PHYS(start_pfn) && start < PFN_PHYS(end_pfn))

			return min(end, PFN_PHYS(end_pfn));

	}

#endif

	*nid = 0;



	return end;

}