mm/numa_memblks.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later

 #include <linux/array_size.h>
 #include <linux/sort.h>
 #include <linux/printk.h>
 #include <linux/memblock.h>
 #include <linux/numa.h>
 #include <linux/numa_memblks.h>

 int numa_distance_cnt;
 static u8 *numa_distance;

 nodemask_t numa_nodes_parsed __initdata;

 static struct numa_meminfo numa_meminfo __initdata_or_meminfo;
 static struct numa_meminfo numa_reserved_meminfo __initdata_or_meminfo;

 /*
  * Set nodes, which have memory in @mi, in *@nodemask.
  */
 static void __init numa_nodemask_from_meminfo(nodemask_t *nodemask,
 					      const struct numa_meminfo *mi)
 {
 	int i;

 	for (i = 0; i < ARRAY_SIZE(mi->blk); i++)
 		if (mi->blk[i].start != mi->blk[i].end &&
 		    mi->blk[i].nid != NUMA_NO_NODE)
 			node_set(mi->blk[i].nid, *nodemask);
 }

 /**
  * numa_reset_distance - Reset NUMA distance table
  *
  * The current table is freed.  The next numa_set_distance() call will
  * create a new one.
  */
 void __init numa_reset_distance(void)
 {
 	size_t size = numa_distance_cnt * numa_distance_cnt * sizeof(numa_distance[0]);

 	/* numa_distance could be 1LU marking allocation failure, test cnt */
 	if (numa_distance_cnt)
 		memblock_free(numa_distance, size);
 	numa_distance_cnt = 0;
 	numa_distance = NULL;	/* enable table creation */
 }

 static int __init numa_alloc_distance(void)
 {
 	nodemask_t nodes_parsed;
 	size_t size;
 	int i, j, cnt = 0;

 	/* size the new table and allocate it */
 	nodes_parsed = numa_nodes_parsed;
 	numa_nodemask_from_meminfo(&nodes_parsed, &numa_meminfo);

 	for_each_node_mask(i, nodes_parsed)
 		cnt = i;
 	cnt++;
 	size = cnt * cnt * sizeof(numa_distance[0]);

 	numa_distance = memblock_alloc(size, PAGE_SIZE);
 	if (!numa_distance) {
 		pr_warn("Warning: can't allocate distance table!\n");
 		/* don't retry until explicitly reset */
 		numa_distance = (void *)1LU;
 		return -ENOMEM;
 	}

 	numa_distance_cnt = cnt;

 	/* fill with the default distances */
 	for (i = 0; i < cnt; i++)
 		for (j = 0; j < cnt; j++)
 			numa_distance[i * cnt + j] = i == j ?
 				LOCAL_DISTANCE : REMOTE_DISTANCE;
 	printk(KERN_DEBUG "NUMA: Initialized distance table, cnt=%d\n", cnt);

 	return 0;
 }

 /**
  * numa_set_distance - Set NUMA distance from one NUMA to another
  * @from: the 'from' node to set distance
  * @to: the 'to'  node to set distance
  * @distance: NUMA distance
  *
  * Set the distance from node @from to @to to @distance.  If distance table
  * doesn't exist, one which is large enough to accommodate all the currently
  * known nodes will be created.
  *
  * If such table cannot be allocated, a warning is printed and further
  * calls are ignored until the distance table is reset with
  * numa_reset_distance().
  *
  * If @from or @to is higher than the highest known node or lower than zero
  * at the time of table creation or @distance doesn't make sense, the call
  * is ignored.
  * This is to allow simplification of specific NUMA config implementations.
  */
 void __init numa_set_distance(int from, int to, int distance)
 {
 	if (!numa_distance && numa_alloc_distance() < 0)
 		return;

 	if (from >= numa_distance_cnt || to >= numa_distance_cnt ||
 			from < 0 || to < 0) {
 		pr_warn_once("Warning: node ids are out of bound, from=%d to=%d distance=%d\n",
 			     from, to, distance);
 		return;
 	}

 	if ((u8)distance != distance ||
 	    (from == to && distance != LOCAL_DISTANCE)) {
 		pr_warn_once("Warning: invalid distance parameter, from=%d to=%d distance=%d\n",
 			     from, to, distance);
 		return;
 	}

 	numa_distance[from * numa_distance_cnt + to] = distance;
 }

 int __node_distance(int from, int to)
 {
 	if (from >= numa_distance_cnt || to >= numa_distance_cnt)
 		return from == to ? LOCAL_DISTANCE : REMOTE_DISTANCE;
 	return numa_distance[from * numa_distance_cnt + to];
 }
 EXPORT_SYMBOL(__node_distance);

 static int __init numa_add_memblk_to(int nid, u64 start, u64 end,
 				     struct numa_meminfo *mi)
 {
 	/* ignore zero length blks */
 	if (start == end)
 		return 0;

 	/* whine about and ignore invalid blks */
 	if (start > end || nid < 0 || nid >= MAX_NUMNODES) {
 		pr_warn("Warning: invalid memblk node %d [mem %#010Lx-%#010Lx]\n",
 			nid, start, end - 1);
 		return 0;
 	}

 	if (mi->nr_blks >= NR_NODE_MEMBLKS) {
 		pr_err("too many memblk ranges\n");
 		return -EINVAL;
 	}

 	mi->blk[mi->nr_blks].start = start;
 	mi->blk[mi->nr_blks].end = end;
 	mi->blk[mi->nr_blks].nid = nid;
 	mi->nr_blks++;
 	return 0;
 }

 /**
  * numa_remove_memblk_from - Remove one numa_memblk from a numa_meminfo
  * @idx: Index of memblk to remove
  * @mi: numa_meminfo to remove memblk from
  *
  * Remove @idx'th numa_memblk from @mi by shifting @mi->blk[] and
  * decrementing @mi->nr_blks.
  */
 void __init numa_remove_memblk_from(int idx, struct numa_meminfo *mi)
 {
 	mi->nr_blks--;
 	memmove(&mi->blk[idx], &mi->blk[idx + 1],
 		(mi->nr_blks - idx) * sizeof(mi->blk[0]));
 }

 /**
  * numa_move_tail_memblk - Move a numa_memblk from one numa_meminfo to another
  * @dst: numa_meminfo to append block to
  * @idx: Index of memblk to remove
  * @src: numa_meminfo to remove memblk from
  */
 static void __init numa_move_tail_memblk(struct numa_meminfo *dst, int idx,
 					 struct numa_meminfo *src)
 {
 	dst->blk[dst->nr_blks++] = src->blk[idx];
 	numa_remove_memblk_from(idx, src);
 }

 /**
  * numa_add_memblk - Add one numa_memblk to numa_meminfo
  * @nid: NUMA node ID of the new memblk
  * @start: Start address of the new memblk
  * @end: End address of the new memblk
  *
  * Add a new memblk to the default numa_meminfo.
  *
  * RETURNS:
  * 0 on success, -errno on failure.
  */
 int __init numa_add_memblk(int nid, u64 start, u64 end)
 {
 	return numa_add_memblk_to(nid, start, end, &numa_meminfo);
 }

 /**
  * numa_add_reserved_memblk - Add one numa_memblk to numa_reserved_meminfo
  * @nid: NUMA node ID of the new memblk
  * @start: Start address of the new memblk
  * @end: End address of the new memblk
  *
  * Add a new memblk to the numa_reserved_meminfo.
  *
  * Usage Case: numa_cleanup_meminfo() reconciles all numa_memblk instances
  * against memblock_type information and moves any that intersect reserved
  * ranges to numa_reserved_meminfo. However, when that information is known
  * ahead of time, we use numa_add_reserved_memblk() to add the numa_memblk
  * to numa_reserved_meminfo directly.
  *
  * RETURNS:
  * 0 on success, -errno on failure.
  */
 int __init numa_add_reserved_memblk(int nid, u64 start, u64 end)
 {
 	return numa_add_memblk_to(nid, start, end, &numa_reserved_meminfo);
 }

 /**
  * numa_cleanup_meminfo - Cleanup a numa_meminfo
  * @mi: numa_meminfo to clean up
  *
  * Sanitize @mi by merging and removing unnecessary memblks.  Also check for
  * conflicts and clear unused memblks.
  *
  * RETURNS:
  * 0 on success, -errno on failure.
  */
 int __init numa_cleanup_meminfo(struct numa_meminfo *mi)
 {
 	const u64 low = memblock_start_of_DRAM();
 	const u64 high = memblock_end_of_DRAM();
 	int i, j, k;

 	/* first, trim all entries */
 	for (i = 0; i < mi->nr_blks; i++) {
 		struct numa_memblk *bi = &mi->blk[i];

 		/* move / save reserved memory ranges */
 		if (!memblock_overlaps_region(&memblock.memory,
 					bi->start, bi->end - bi->start)) {
 			numa_move_tail_memblk(&numa_reserved_meminfo, i--, mi);
 			continue;
 		}

 		/* make sure all non-reserved blocks are inside the limits */
 		bi->start = max(bi->start, low);

 		/* preserve info for non-RAM areas above 'max_pfn': */
 		if (bi->end > high) {
 			numa_add_memblk_to(bi->nid, high, bi->end,
 					   &numa_reserved_meminfo);
 			bi->end = high;
 		}

 		/* and there's no empty block */
 		if (bi->start >= bi->end)
 			numa_remove_memblk_from(i--, mi);
 	}

 	/* merge neighboring / overlapping entries */
 	for (i = 0; i < mi->nr_blks; i++) {
 		struct numa_memblk *bi = &mi->blk[i];

 		for (j = i + 1; j < mi->nr_blks; j++) {
 			struct numa_memblk *bj = &mi->blk[j];
 			u64 start, end;

 			/*
 			 * See whether there are overlapping blocks.  Whine
 			 * about but allow overlaps of the same nid.  They
 			 * will be merged below.
 			 */
 			if (bi->end > bj->start && bi->start < bj->end) {
 				if (bi->nid != bj->nid) {
 					pr_err("node %d [mem %#010Lx-%#010Lx] overlaps with node %d [mem %#010Lx-%#010Lx]\n",
 					       bi->nid, bi->start, bi->end - 1,
 					       bj->nid, bj->start, bj->end - 1);
 					return -EINVAL;
 				}
 				pr_warn("Warning: node %d [mem %#010Lx-%#010Lx] overlaps with itself [mem %#010Lx-%#010Lx]\n",
 					bi->nid, bi->start, bi->end - 1,
 					bj->start, bj->end - 1);
 			}

 			/*
 			 * Join together blocks on the same node, holes
 			 * between which don't overlap with memory on other
 			 * nodes.
 			 */
 			if (bi->nid != bj->nid)
 				continue;
 			start = min(bi->start, bj->start);
 			end = max(bi->end, bj->end);
 			for (k = 0; k < mi->nr_blks; k++) {
 				struct numa_memblk *bk = &mi->blk[k];

 				if (bi->nid == bk->nid)
 					continue;
 				if (start < bk->end && end > bk->start)
 					break;
 			}
 			if (k < mi->nr_blks)
 				continue;
 			pr_info("NUMA: Node %d [mem %#010Lx-%#010Lx] + [mem %#010Lx-%#010Lx] -> [mem %#010Lx-%#010Lx]\n",
 			       bi->nid, bi->start, bi->end - 1, bj->start,
 			       bj->end - 1, start, end - 1);
 			bi->start = start;
 			bi->end = end;
 			numa_remove_memblk_from(j--, mi);
 		}
 	}

 	/* clear unused ones */
 	for (i = mi->nr_blks; i < ARRAY_SIZE(mi->blk); i++) {
 		mi->blk[i].start = mi->blk[i].end = 0;
 		mi->blk[i].nid = NUMA_NO_NODE;
 	}

 	return 0;
 }

 /*
  * Mark all currently memblock-reserved physical memory (which covers the
  * kernel's own memory ranges) as hot-unswappable.
  */
 static void __init numa_clear_kernel_node_hotplug(void)
 {
 	nodemask_t reserved_nodemask = NODE_MASK_NONE;
 	struct memblock_region *mb_region;
 	int i;

 	/*
 	 * We have to do some preprocessing of memblock regions, to
 	 * make them suitable for reservation.
 	 *
 	 * At this time, all memory regions reserved by memblock are
 	 * used by the kernel, but those regions are not split up
 	 * along node boundaries yet, and don't necessarily have their
 	 * node ID set yet either.
 	 *
 	 * So iterate over all parsed memory blocks and use those ranges to
 	 * set the nid in memblock.reserved.  This will split up the
 	 * memblock regions along node boundaries and will set the node IDs
 	 * as well.
 	 */
 	for (i = 0; i < numa_meminfo.nr_blks; i++) {
 		struct numa_memblk *mb = numa_meminfo.blk + i;
 		int ret;

 		ret = memblock_set_node(mb->start, mb->end - mb->start,
 					&memblock.reserved, mb->nid);
 		WARN_ON_ONCE(ret);
 	}

 	/*
 	 * Now go over all reserved memblock regions, to construct a
 	 * node mask of all kernel reserved memory areas.
 	 *
 	 * [ Note, when booting with mem=nn[kMG] or in a kdump kernel,
 	 *   numa_meminfo might not include all memblock.reserved
 	 *   memory ranges, because quirks such as trim_snb_memory()
 	 *   reserve specific pages for Sandy Bridge graphics. ]
 	 */
 	for_each_reserved_mem_region(mb_region) {
 		int nid = memblock_get_region_node(mb_region);

 		if (numa_valid_node(nid))
 			node_set(nid, reserved_nodemask);
 	}

 	/*
 	 * Finally, clear the MEMBLOCK_HOTPLUG flag for all memory
 	 * belonging to the reserved node mask.
 	 *
 	 * Note that this will include memory regions that reside
 	 * on nodes that contain kernel memory - entire nodes
 	 * become hot-unpluggable:
 	 */
 	for (i = 0; i < numa_meminfo.nr_blks; i++) {
 		struct numa_memblk *mb = numa_meminfo.blk + i;

 		if (!node_isset(mb->nid, reserved_nodemask))
 			continue;

 		memblock_clear_hotplug(mb->start, mb->end - mb->start);
 	}
 }

 static int __init numa_register_meminfo(struct numa_meminfo *mi)
 {
 	int i;

 	/* Account for nodes with cpus and no memory */
 	node_possible_map = numa_nodes_parsed;
 	numa_nodemask_from_meminfo(&node_possible_map, mi);
 	if (WARN_ON(nodes_empty(node_possible_map)))
 		return -EINVAL;

 	for (i = 0; i < mi->nr_blks; i++) {
 		struct numa_memblk *mb = &mi->blk[i];

 		memblock_set_node(mb->start, mb->end - mb->start,
 				  &memblock.memory, mb->nid);
 	}

 	/*
 	 * At very early time, the kernel have to use some memory such as
 	 * loading the kernel image. We cannot prevent this anyway. So any
 	 * node the kernel resides in should be un-hotpluggable.
 	 *
 	 * And when we come here, alloc node data won't fail.
 	 */
 	numa_clear_kernel_node_hotplug();

 	/*
 	 * If sections array is gonna be used for pfn -> nid mapping, check
 	 * whether its granularity is fine enough.
 	 */
 	if (IS_ENABLED(NODE_NOT_IN_PAGE_FLAGS)) {
 		unsigned long pfn_align = node_map_pfn_alignment();

 		if (pfn_align && pfn_align < PAGES_PER_SECTION) {
 			unsigned long node_align_mb = PFN_PHYS(pfn_align) >> 20;

 			unsigned long sect_align_mb = PFN_PHYS(PAGES_PER_SECTION) >> 20;

 			pr_warn("Node alignment %luMB < min %luMB, rejecting NUMA config\n",
 				node_align_mb, sect_align_mb);
 			return -EINVAL;
 		}
 	}

 	return 0;
 }

 int __init numa_memblks_init(int (*init_func)(void),
 			     bool memblock_force_top_down)
 {
 	phys_addr_t max_addr = (phys_addr_t)ULLONG_MAX;
 	int ret;

 	nodes_clear(numa_nodes_parsed);
 	nodes_clear(node_possible_map);
 	nodes_clear(node_online_map);
 	memset(&numa_meminfo, 0, sizeof(numa_meminfo));
 	WARN_ON(memblock_set_node(0, max_addr, &memblock.memory, NUMA_NO_NODE));
 	WARN_ON(memblock_set_node(0, max_addr, &memblock.reserved,
 				  NUMA_NO_NODE));
 	/* In case that parsing SRAT failed. */
 	WARN_ON(memblock_clear_hotplug(0, max_addr));
 	numa_reset_distance();

 	ret = init_func();
 	if (ret < 0)
 		return ret;

 	/*
 	 * We reset memblock back to the top-down direction
 	 * here because if we configured ACPI_NUMA, we have
 	 * parsed SRAT in init_func(). It is ok to have the
 	 * reset here even if we did't configure ACPI_NUMA
 	 * or acpi numa init fails and fallbacks to dummy
 	 * numa init.
 	 */
 	if (memblock_force_top_down)
 		memblock_set_bottom_up(false);

 	ret = numa_cleanup_meminfo(&numa_meminfo);
 	if (ret < 0)
 		return ret;

 	numa_emulation(&numa_meminfo, numa_distance_cnt);

 	return numa_register_meminfo(&numa_meminfo);
 }

 static int __init cmp_memblk(const void *a, const void *b)
 {
 	const struct numa_memblk *ma = *(const struct numa_memblk **)a;
 	const struct numa_memblk *mb = *(const struct numa_memblk **)b;

 	return (ma->start > mb->start) - (ma->start < mb->start);
 }

 static struct numa_memblk *numa_memblk_list[NR_NODE_MEMBLKS] __initdata;

 /**
  * numa_fill_memblks - Fill gaps in numa_meminfo memblks
  * @start: address to begin fill
  * @end: address to end fill
  *
  * Find and extend numa_meminfo memblks to cover the physical
  * address range @start-@end
  *
  * RETURNS:
  * 0		  : Success
  * NUMA_NO_MEMBLK : No memblks exist in address range @start-@end
  */

 int __init numa_fill_memblks(u64 start, u64 end)
 {
 	struct numa_memblk **blk = &numa_memblk_list[0];
 	struct numa_meminfo *mi = &numa_meminfo;
 	int count = 0;
 	u64 prev_end;

 	/*
 	 * Create a list of pointers to numa_meminfo memblks that
 	 * overlap start, end. The list is used to make in-place
 	 * changes that fill out the numa_meminfo memblks.
 	 */
 	for (int i = 0; i < mi->nr_blks; i++) {
 		struct numa_memblk *bi = &mi->blk[i];

 		if (memblock_addrs_overlap(start, end - start, bi->start,
 					   bi->end - bi->start)) {
 			blk[count] = &mi->blk[i];
 			count++;
 		}
 	}
 	if (!count)
 		return NUMA_NO_MEMBLK;

 	/* Sort the list of pointers in memblk->start order */
 	sort(&blk[0], count, sizeof(blk[0]), cmp_memblk, NULL);

 	/* Make sure the first/last memblks include start/end */
 	blk[0]->start = min(blk[0]->start, start);
 	blk[count - 1]->end = max(blk[count - 1]->end, end);

 	/*
 	 * Fill any gaps by tracking the previous memblks
 	 * end address and backfilling to it if needed.
 	 */
 	prev_end = blk[0]->end;
 	for (int i = 1; i < count; i++) {
 		struct numa_memblk *curr = blk[i];

 		if (prev_end >= curr->start) {
 			if (prev_end < curr->end)
 				prev_end = curr->end;
 		} else {
 			curr->start = prev_end;
 			prev_end = curr->end;
 		}
 	}
 	return 0;
 }

 #ifdef CONFIG_NUMA_KEEP_MEMINFO
 static int meminfo_to_nid(struct numa_meminfo *mi, u64 start)
 {
 	int i;

 	for (i = 0; i < mi->nr_blks; i++)
 		if (mi->blk[i].start <= start && mi->blk[i].end > start)
 			return mi->blk[i].nid;
 	return NUMA_NO_NODE;
 }

 int phys_to_target_node(u64 start)
 {
 	int nid = meminfo_to_nid(&numa_meminfo, start);

 	/*
 	 * Prefer online nodes, but if reserved memory might be
 	 * hot-added continue the search with reserved ranges.
 	 */
 	if (nid != NUMA_NO_NODE)
 		return nid;

 	return meminfo_to_nid(&numa_reserved_meminfo, start);
 }
 EXPORT_SYMBOL_GPL(phys_to_target_node);

 int memory_add_physaddr_to_nid(u64 start)
 {
 	int nid = meminfo_to_nid(&numa_meminfo, start);

 	if (nid == NUMA_NO_NODE)
 		nid = numa_meminfo.blk[0].nid;
 	return nid;
 }
 EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);

 #endif /* CONFIG_NUMA_KEEP_MEMINFO */
	// SPDX-License-Identifier: GPL-2.0-or-later

	#include <linux/array_size.h>
	#include <linux/sort.h>
	#include <linux/printk.h>
	#include <linux/memblock.h>
	#include <linux/numa.h>
	#include <linux/numa_memblks.h>

	int numa_distance_cnt;
	static u8 *numa_distance;

	nodemask_t numa_nodes_parsed __initdata;

	static struct numa_meminfo numa_meminfo __initdata_or_meminfo;
	static struct numa_meminfo numa_reserved_meminfo __initdata_or_meminfo;

	/*
	* Set nodes, which have memory in @mi, in *@nodemask.
	*/
	static void __init numa_nodemask_from_meminfo(nodemask_t *nodemask,
	const struct numa_meminfo *mi)
	{
	int i;

	for (i = 0; i < ARRAY_SIZE(mi->blk); i++)
	if (mi->blk[i].start != mi->blk[i].end &&
	mi->blk[i].nid != NUMA_NO_NODE)
	node_set(mi->blk[i].nid, *nodemask);
	}

	/**
	* numa_reset_distance - Reset NUMA distance table
	*
	* The current table is freed. The next numa_set_distance() call will
	* create a new one.
	*/
	void __init numa_reset_distance(void)
	{
	size_t size = numa_distance_cnt * numa_distance_cnt * sizeof(numa_distance[0]);

	/* numa_distance could be 1LU marking allocation failure, test cnt */
	if (numa_distance_cnt)
	memblock_free(numa_distance, size);
	numa_distance_cnt = 0;
	numa_distance = NULL; /* enable table creation */
	}

	static int __init numa_alloc_distance(void)
	{
	nodemask_t nodes_parsed;
	size_t size;
	int i, j, cnt = 0;

	/* size the new table and allocate it */
	nodes_parsed = numa_nodes_parsed;
	numa_nodemask_from_meminfo(&nodes_parsed, &numa_meminfo);

	for_each_node_mask(i, nodes_parsed)
	cnt = i;
	cnt++;
	size = cnt * cnt * sizeof(numa_distance[0]);

	numa_distance = memblock_alloc(size, PAGE_SIZE);
	if (!numa_distance) {
	pr_warn("Warning: can't allocate distance table!\n");
	/* don't retry until explicitly reset */
	numa_distance = (void *)1LU;
	return -ENOMEM;
	}

	numa_distance_cnt = cnt;

	/* fill with the default distances */
	for (i = 0; i < cnt; i++)
	for (j = 0; j < cnt; j++)
	numa_distance[i * cnt + j] = i == j ?
	LOCAL_DISTANCE : REMOTE_DISTANCE;
	printk(KERN_DEBUG "NUMA: Initialized distance table, cnt=%d\n", cnt);

	return 0;
	}

	/**
	* numa_set_distance - Set NUMA distance from one NUMA to another
	* @from: the 'from' node to set distance
	* @to: the 'to' node to set distance
	* @distance: NUMA distance
	*
	* Set the distance from node @from to @to to @distance. If distance table
	* doesn't exist, one which is large enough to accommodate all the currently
	* known nodes will be created.
	*
	* If such table cannot be allocated, a warning is printed and further
	* calls are ignored until the distance table is reset with
	* numa_reset_distance().
	*
	* If @from or @to is higher than the highest known node or lower than zero
	* at the time of table creation or @distance doesn't make sense, the call
	* is ignored.
	* This is to allow simplification of specific NUMA config implementations.
	*/
	void __init numa_set_distance(int from, int to, int distance)
	{
	if (!numa_distance && numa_alloc_distance() < 0)
	return;

	if (from >= numa_distance_cnt \|\| to >= numa_distance_cnt \|\|
	from < 0 \|\| to < 0) {
	pr_warn_once("Warning: node ids are out of bound, from=%d to=%d distance=%d\n",
	from, to, distance);
	return;
	}

	if ((u8)distance != distance \|\|
	(from == to && distance != LOCAL_DISTANCE)) {
	pr_warn_once("Warning: invalid distance parameter, from=%d to=%d distance=%d\n",
	from, to, distance);
	return;
	}

	numa_distance[from * numa_distance_cnt + to] = distance;
	}

	int __node_distance(int from, int to)
	{
	if (from >= numa_distance_cnt \|\| to >= numa_distance_cnt)
	return from == to ? LOCAL_DISTANCE : REMOTE_DISTANCE;
	return numa_distance[from * numa_distance_cnt + to];
	}
	EXPORT_SYMBOL(__node_distance);

	static int __init numa_add_memblk_to(int nid, u64 start, u64 end,
	struct numa_meminfo *mi)
	{
	/* ignore zero length blks */
	if (start == end)
	return 0;

	/* whine about and ignore invalid blks */
	if (start > end \|\| nid < 0 \|\| nid >= MAX_NUMNODES) {
	pr_warn("Warning: invalid memblk node %d [mem %#010Lx-%#010Lx]\n",
	nid, start, end - 1);
	return 0;
	}

	if (mi->nr_blks >= NR_NODE_MEMBLKS) {
	pr_err("too many memblk ranges\n");
	return -EINVAL;
	}

	mi->blk[mi->nr_blks].start = start;
	mi->blk[mi->nr_blks].end = end;
	mi->blk[mi->nr_blks].nid = nid;
	mi->nr_blks++;
	return 0;
	}

	/**
	* numa_remove_memblk_from - Remove one numa_memblk from a numa_meminfo
	* @idx: Index of memblk to remove
	* @mi: numa_meminfo to remove memblk from
	*
	* Remove @idx'th numa_memblk from @mi by shifting @mi->blk[] and
	* decrementing @mi->nr_blks.
	*/
	void __init numa_remove_memblk_from(int idx, struct numa_meminfo *mi)
	{
	mi->nr_blks--;
	memmove(&mi->blk[idx], &mi->blk[idx + 1],
	(mi->nr_blks - idx) * sizeof(mi->blk[0]));
	}

	/**
	* numa_move_tail_memblk - Move a numa_memblk from one numa_meminfo to another
	* @dst: numa_meminfo to append block to
	* @idx: Index of memblk to remove
	* @src: numa_meminfo to remove memblk from
	*/
	static void __init numa_move_tail_memblk(struct numa_meminfo *dst, int idx,
	struct numa_meminfo *src)
	{
	dst->blk[dst->nr_blks++] = src->blk[idx];
	numa_remove_memblk_from(idx, src);
	}

	/**
	* numa_add_memblk - Add one numa_memblk to numa_meminfo
	* @nid: NUMA node ID of the new memblk
	* @start: Start address of the new memblk
	* @end: End address of the new memblk
	*
	* Add a new memblk to the default numa_meminfo.
	*
	* RETURNS:
	* 0 on success, -errno on failure.
	*/
	int __init numa_add_memblk(int nid, u64 start, u64 end)
	{
	return numa_add_memblk_to(nid, start, end, &numa_meminfo);
	}

	/**
	* numa_add_reserved_memblk - Add one numa_memblk to numa_reserved_meminfo
	* @nid: NUMA node ID of the new memblk
	* @start: Start address of the new memblk
	* @end: End address of the new memblk
	*
	* Add a new memblk to the numa_reserved_meminfo.
	*
	* Usage Case: numa_cleanup_meminfo() reconciles all numa_memblk instances
	* against memblock_type information and moves any that intersect reserved
	* ranges to numa_reserved_meminfo. However, when that information is known
	* ahead of time, we use numa_add_reserved_memblk() to add the numa_memblk
	* to numa_reserved_meminfo directly.
	*
	* RETURNS:
	* 0 on success, -errno on failure.
	*/
	int __init numa_add_reserved_memblk(int nid, u64 start, u64 end)
	{
	return numa_add_memblk_to(nid, start, end, &numa_reserved_meminfo);
	}

	/**
	* numa_cleanup_meminfo - Cleanup a numa_meminfo
	* @mi: numa_meminfo to clean up
	*
	* Sanitize @mi by merging and removing unnecessary memblks. Also check for
	* conflicts and clear unused memblks.
	*
	* RETURNS:
	* 0 on success, -errno on failure.
	*/
	int __init numa_cleanup_meminfo(struct numa_meminfo *mi)
	{
	const u64 low = memblock_start_of_DRAM();
	const u64 high = memblock_end_of_DRAM();
	int i, j, k;

	/* first, trim all entries */
	for (i = 0; i < mi->nr_blks; i++) {
	struct numa_memblk *bi = &mi->blk[i];

	/* move / save reserved memory ranges */
	if (!memblock_overlaps_region(&memblock.memory,
	bi->start, bi->end - bi->start)) {
	numa_move_tail_memblk(&numa_reserved_meminfo, i--, mi);
	continue;
	}

	/* make sure all non-reserved blocks are inside the limits */
	bi->start = max(bi->start, low);

	/* preserve info for non-RAM areas above 'max_pfn': */
	if (bi->end > high) {
	numa_add_memblk_to(bi->nid, high, bi->end,
	&numa_reserved_meminfo);
	bi->end = high;
	}

	/* and there's no empty block */
	if (bi->start >= bi->end)
	numa_remove_memblk_from(i--, mi);
	}

	/* merge neighboring / overlapping entries */
	for (i = 0; i < mi->nr_blks; i++) {
	struct numa_memblk *bi = &mi->blk[i];

	for (j = i + 1; j < mi->nr_blks; j++) {
	struct numa_memblk *bj = &mi->blk[j];
	u64 start, end;

	/*
	* See whether there are overlapping blocks. Whine
	* about but allow overlaps of the same nid. They
	* will be merged below.
	*/
	if (bi->end > bj->start && bi->start < bj->end) {
	if (bi->nid != bj->nid) {
	pr_err("node %d [mem %#010Lx-%#010Lx] overlaps with node %d [mem %#010Lx-%#010Lx]\n",
	bi->nid, bi->start, bi->end - 1,
	bj->nid, bj->start, bj->end - 1);
	return -EINVAL;
	}
	pr_warn("Warning: node %d [mem %#010Lx-%#010Lx] overlaps with itself [mem %#010Lx-%#010Lx]\n",
	bi->nid, bi->start, bi->end - 1,
	bj->start, bj->end - 1);
	}

	/*
	* Join together blocks on the same node, holes
	* between which don't overlap with memory on other
	* nodes.
	*/
	if (bi->nid != bj->nid)
	continue;
	start = min(bi->start, bj->start);
	end = max(bi->end, bj->end);
	for (k = 0; k < mi->nr_blks; k++) {
	struct numa_memblk *bk = &mi->blk[k];

	if (bi->nid == bk->nid)
	continue;
	if (start < bk->end && end > bk->start)
	break;
	}
	if (k < mi->nr_blks)
	continue;
	pr_info("NUMA: Node %d [mem %#010Lx-%#010Lx] + [mem %#010Lx-%#010Lx] -> [mem %#010Lx-%#010Lx]\n",
	bi->nid, bi->start, bi->end - 1, bj->start,
	bj->end - 1, start, end - 1);
	bi->start = start;
	bi->end = end;
	numa_remove_memblk_from(j--, mi);
	}
	}

	/* clear unused ones */
	for (i = mi->nr_blks; i < ARRAY_SIZE(mi->blk); i++) {
	mi->blk[i].start = mi->blk[i].end = 0;
	mi->blk[i].nid = NUMA_NO_NODE;
	}

	return 0;
	}

	/*
	* Mark all currently memblock-reserved physical memory (which covers the
	* kernel's own memory ranges) as hot-unswappable.
	*/
	static void __init numa_clear_kernel_node_hotplug(void)
	{
	nodemask_t reserved_nodemask = NODE_MASK_NONE;
	struct memblock_region *mb_region;
	int i;

	/*
	* We have to do some preprocessing of memblock regions, to
	* make them suitable for reservation.
	*
	* At this time, all memory regions reserved by memblock are
	* used by the kernel, but those regions are not split up
	* along node boundaries yet, and don't necessarily have their
	* node ID set yet either.
	*
	* So iterate over all parsed memory blocks and use those ranges to
	* set the nid in memblock.reserved. This will split up the
	* memblock regions along node boundaries and will set the node IDs
	* as well.
	*/
	for (i = 0; i < numa_meminfo.nr_blks; i++) {
	struct numa_memblk *mb = numa_meminfo.blk + i;
	int ret;

	ret = memblock_set_node(mb->start, mb->end - mb->start,
	&memblock.reserved, mb->nid);
	WARN_ON_ONCE(ret);
	}

	/*
	* Now go over all reserved memblock regions, to construct a
	* node mask of all kernel reserved memory areas.
	*
	* [ Note, when booting with mem=nn[kMG] or in a kdump kernel,
	* numa_meminfo might not include all memblock.reserved
	* memory ranges, because quirks such as trim_snb_memory()
	* reserve specific pages for Sandy Bridge graphics. ]
	*/
	for_each_reserved_mem_region(mb_region) {
	int nid = memblock_get_region_node(mb_region);

	if (numa_valid_node(nid))
	node_set(nid, reserved_nodemask);
	}

	/*
	* Finally, clear the MEMBLOCK_HOTPLUG flag for all memory
	* belonging to the reserved node mask.
	*
	* Note that this will include memory regions that reside
	* on nodes that contain kernel memory - entire nodes
	* become hot-unpluggable:
	*/
	for (i = 0; i < numa_meminfo.nr_blks; i++) {
	struct numa_memblk *mb = numa_meminfo.blk + i;

	if (!node_isset(mb->nid, reserved_nodemask))
	continue;

	memblock_clear_hotplug(mb->start, mb->end - mb->start);
	}
	}

	static int __init numa_register_meminfo(struct numa_meminfo *mi)
	{
	int i;

	/* Account for nodes with cpus and no memory */
	node_possible_map = numa_nodes_parsed;
	numa_nodemask_from_meminfo(&node_possible_map, mi);
	if (WARN_ON(nodes_empty(node_possible_map)))
	return -EINVAL;

	for (i = 0; i < mi->nr_blks; i++) {
	struct numa_memblk *mb = &mi->blk[i];

	memblock_set_node(mb->start, mb->end - mb->start,
	&memblock.memory, mb->nid);
	}

	/*
	* At very early time, the kernel have to use some memory such as
	* loading the kernel image. We cannot prevent this anyway. So any
	* node the kernel resides in should be un-hotpluggable.
	*
	* And when we come here, alloc node data won't fail.
	*/
	numa_clear_kernel_node_hotplug();

	/*
	* If sections array is gonna be used for pfn -> nid mapping, check
	* whether its granularity is fine enough.
	*/
	if (IS_ENABLED(NODE_NOT_IN_PAGE_FLAGS)) {
	unsigned long pfn_align = node_map_pfn_alignment();

	if (pfn_align && pfn_align < PAGES_PER_SECTION) {
	unsigned long node_align_mb = PFN_PHYS(pfn_align) >> 20;

	unsigned long sect_align_mb = PFN_PHYS(PAGES_PER_SECTION) >> 20;

	pr_warn("Node alignment %luMB < min %luMB, rejecting NUMA config\n",
	node_align_mb, sect_align_mb);
	return -EINVAL;
	}
	}

	return 0;
	}

	int __init numa_memblks_init(int (*init_func)(void),
	bool memblock_force_top_down)
	{
	phys_addr_t max_addr = (phys_addr_t)ULLONG_MAX;
	int ret;

	nodes_clear(numa_nodes_parsed);
	nodes_clear(node_possible_map);
	nodes_clear(node_online_map);
	memset(&numa_meminfo, 0, sizeof(numa_meminfo));
	WARN_ON(memblock_set_node(0, max_addr, &memblock.memory, NUMA_NO_NODE));
	WARN_ON(memblock_set_node(0, max_addr, &memblock.reserved,
	NUMA_NO_NODE));
	/* In case that parsing SRAT failed. */
	WARN_ON(memblock_clear_hotplug(0, max_addr));
	numa_reset_distance();

	ret = init_func();
	if (ret < 0)
	return ret;

	/*
	* We reset memblock back to the top-down direction
	* here because if we configured ACPI_NUMA, we have
	* parsed SRAT in init_func(). It is ok to have the
	* reset here even if we did't configure ACPI_NUMA
	* or acpi numa init fails and fallbacks to dummy
	* numa init.
	*/
	if (memblock_force_top_down)
	memblock_set_bottom_up(false);

	ret = numa_cleanup_meminfo(&numa_meminfo);
	if (ret < 0)
	return ret;

	numa_emulation(&numa_meminfo, numa_distance_cnt);

	return numa_register_meminfo(&numa_meminfo);
	}

	static int __init cmp_memblk(const void a, const void b)
	{
	const struct numa_memblk ma = (const struct numa_memblk **)a;
	const struct numa_memblk mb = (const struct numa_memblk **)b;

	return (ma->start > mb->start) - (ma->start < mb->start);
	}

	static struct numa_memblk *numa_memblk_list[NR_NODE_MEMBLKS] __initdata;

	/**
	* numa_fill_memblks - Fill gaps in numa_meminfo memblks
	* @start: address to begin fill
	* @end: address to end fill
	*
	* Find and extend numa_meminfo memblks to cover the physical
	* address range @start-@end
	*
	* RETURNS:
	* 0 : Success
	* NUMA_NO_MEMBLK : No memblks exist in address range @start-@end
	*/

	int __init numa_fill_memblks(u64 start, u64 end)
	{
	struct numa_memblk **blk = &numa_memblk_list[0];
	struct numa_meminfo *mi = &numa_meminfo;
	int count = 0;
	u64 prev_end;

	/*
	* Create a list of pointers to numa_meminfo memblks that
	* overlap start, end. The list is used to make in-place
	* changes that fill out the numa_meminfo memblks.
	*/
	for (int i = 0; i < mi->nr_blks; i++) {
	struct numa_memblk *bi = &mi->blk[i];

	if (memblock_addrs_overlap(start, end - start, bi->start,
	bi->end - bi->start)) {
	blk[count] = &mi->blk[i];
	count++;
	}
	}
	if (!count)
	return NUMA_NO_MEMBLK;

	/* Sort the list of pointers in memblk->start order */
	sort(&blk[0], count, sizeof(blk[0]), cmp_memblk, NULL);

	/* Make sure the first/last memblks include start/end */
	blk[0]->start = min(blk[0]->start, start);
	blk[count - 1]->end = max(blk[count - 1]->end, end);

	/*
	* Fill any gaps by tracking the previous memblks
	* end address and backfilling to it if needed.
	*/
	prev_end = blk[0]->end;
	for (int i = 1; i < count; i++) {
	struct numa_memblk *curr = blk[i];

	if (prev_end >= curr->start) {
	if (prev_end < curr->end)
	prev_end = curr->end;
	} else {
	curr->start = prev_end;
	prev_end = curr->end;
	}
	}
	return 0;
	}

	#ifdef CONFIG_NUMA_KEEP_MEMINFO
	static int meminfo_to_nid(struct numa_meminfo *mi, u64 start)
	{
	int i;

	for (i = 0; i < mi->nr_blks; i++)
	if (mi->blk[i].start <= start && mi->blk[i].end > start)
	return mi->blk[i].nid;
	return NUMA_NO_NODE;
	}

	int phys_to_target_node(u64 start)
	{
	int nid = meminfo_to_nid(&numa_meminfo, start);

	/*
	* Prefer online nodes, but if reserved memory might be
	* hot-added continue the search with reserved ranges.
	*/
	if (nid != NUMA_NO_NODE)
	return nid;

	return meminfo_to_nid(&numa_reserved_meminfo, start);
	}
	EXPORT_SYMBOL_GPL(phys_to_target_node);

	int memory_add_physaddr_to_nid(u64 start)
	{
	int nid = meminfo_to_nid(&numa_meminfo, start);

	if (nid == NUMA_NO_NODE)
	nid = numa_meminfo.blk[0].nid;
	return nid;
	}
	EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);

	#endif /* CONFIG_NUMA_KEEP_MEMINFO */