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Commit a6af2bc3 authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
Browse files

[PATCH] Avoid excessive sorting of early_node_map[] 



find_min_pfn_for_node() and find_min_pfn_with_active_regions() sort
early_node_map[] on every call.  This is an excessive amount of sorting and
that can be avoided.  This patch always searches the whole early_node_map[]
in find_min_pfn_for_node() instead of returning the first value found.  The
map is then only sorted once when required.  Successfully boot tested on a
number of machines.

[akpm@osdl.org: cleanup]
Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e10a4437

mm/page_alloc.c

+13 −7
Original line number Diff line number Diff line
@@ -2877,22 +2877,25 @@ static void __init sort_node_map(void) 
			cmp_node_active_region, NULL);

}



/* Find the lowest pfn for a node. This depends on a sorted early_node_map */

/* Find the lowest pfn for a node */

unsigned long __init find_min_pfn_for_node(unsigned long nid)

{

	int i;



	/* Regions in the early_node_map can be in any order */

	sort_node_map();

	unsigned long min_pfn = ULONG_MAX;



	/* Assuming a sorted map, the first range found has the starting pfn */

	for_each_active_range_index_in_nid(i, nid)

		return early_node_map[i].start_pfn;

		min_pfn = min(min_pfn, early_node_map[i].start_pfn);



	printk(KERN_WARNING "Could not find start_pfn for node %lu\n", nid);

	if (min_pfn == ULONG_MAX) {

		printk(KERN_WARNING

			"Could not find start_pfn for node %lu\n", nid);

		return 0;

	}



	return min_pfn;

}



/**

 * find_min_pfn_with_active_regions - Find the minimum PFN registered

 *
@@ -2939,6 +2942,9 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn) 
	unsigned long nid;

	enum zone_type i;



	/* Sort early_node_map as initialisation assumes it is sorted */

	sort_node_map();



	/* Record where the zone boundaries are */

	memset(arch_zone_lowest_possible_pfn, 0,

				sizeof(arch_zone_lowest_possible_pfn));