summaryrefslogtreecommitdiff
path: root/arch/x86/mm/numa_emulation.c
blob: 1a02b791d273cb1e9981663d67131f01c211753e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
// SPDX-License-Identifier: GPL-2.0
/*
 * NUMA emulation
 */
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/topology.h>
#include <linux/memblock.h>
#include <asm/dma.h>

#include "numa_internal.h"

static int emu_nid_to_phys[MAX_NUMNODES];
static char *emu_cmdline __initdata;

int __init numa_emu_cmdline(char *str)
{
	emu_cmdline = str;
	return 0;
}

static int __init emu_find_memblk_by_nid(int nid, const struct numa_meminfo *mi)
{
	int i;

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

static u64 __init mem_hole_size(u64 start, u64 end)
{
	unsigned long start_pfn = PFN_UP(start);
	unsigned long end_pfn = PFN_DOWN(end);

	if (start_pfn < end_pfn)
		return PFN_PHYS(absent_pages_in_range(start_pfn, end_pfn));
	return 0;
}

/*
 * Sets up nid to range from @start to @end.  The return value is -errno if
 * something went wrong, 0 otherwise.
 */
static int __init emu_setup_memblk(struct numa_meminfo *ei,
				   struct numa_meminfo *pi,
				   int nid, int phys_blk, u64 size)
{
	struct numa_memblk *eb = &ei->blk[ei->nr_blks];
	struct numa_memblk *pb = &pi->blk[phys_blk];

	if (ei->nr_blks >= NR_NODE_MEMBLKS) {
		pr_err("NUMA: Too many emulated memblks, failing emulation\n");
		return -EINVAL;
	}

	ei->nr_blks++;
	eb->start = pb->start;
	eb->end = pb->start + size;
	eb->nid = nid;

	if (emu_nid_to_phys[nid] == NUMA_NO_NODE)
		emu_nid_to_phys[nid] = pb->nid;

	pb->start += size;
	if (pb->start >= pb->end) {
		WARN_ON_ONCE(pb->start > pb->end);
		numa_remove_memblk_from(phys_blk, pi);
	}

	printk(KERN_INFO "Faking node %d at [mem %#018Lx-%#018Lx] (%LuMB)\n",
	       nid, eb->start, eb->end - 1, (eb->end - eb->start) >> 20);
	return 0;
}

/*
 * Sets up nr_nodes fake nodes interleaved over physical nodes ranging from addr
 * to max_addr.
 *
 * Returns zero on success or negative on error.
 */
static int __init split_nodes_interleave(struct numa_meminfo *ei,
					 struct numa_meminfo *pi,
					 u64 addr, u64 max_addr, int nr_nodes)
{
	nodemask_t physnode_mask = numa_nodes_parsed;
	u64 size;
	int big;
	int nid = 0;
	int i, ret;

	if (nr_nodes <= 0)
		return -1;
	if (nr_nodes > MAX_NUMNODES) {
		pr_info("numa=fake=%d too large, reducing to %d\n",
			nr_nodes, MAX_NUMNODES);
		nr_nodes = MAX_NUMNODES;
	}

	/*
	 * Calculate target node size.  x86_32 freaks on __udivdi3() so do
	 * the division in ulong number of pages and convert back.
	 */
	size = max_addr - addr - mem_hole_size(addr, max_addr);
	size = PFN_PHYS((unsigned long)(size >> PAGE_SHIFT) / nr_nodes);

	/*
	 * Calculate the number of big nodes that can be allocated as a result
	 * of consolidating the remainder.
	 */
	big = ((size & ~FAKE_NODE_MIN_HASH_MASK) * nr_nodes) /
		FAKE_NODE_MIN_SIZE;

	size &= FAKE_NODE_MIN_HASH_MASK;
	if (!size) {
		pr_err("Not enough memory for each node.  "
			"NUMA emulation disabled.\n");
		return -1;
	}

	/*
	 * Continue to fill physical nodes with fake nodes until there is no
	 * memory left on any of them.
	 */
	while (nodes_weight(physnode_mask)) {
		for_each_node_mask(i, physnode_mask) {
			u64 dma32_end = PFN_PHYS(MAX_DMA32_PFN);
			u64 start, limit, end;
			int phys_blk;

			phys_blk = emu_find_memblk_by_nid(i, pi);
			if (phys_blk < 0) {
				node_clear(i, physnode_mask);
				continue;
			}
			start = pi->blk[phys_blk].start;
			limit = pi->blk[phys_blk].end;
			end = start + size;

			if (nid < big)
				end += FAKE_NODE_MIN_SIZE;

			/*
			 * Continue to add memory to this fake node if its
			 * non-reserved memory is less than the per-node size.
			 */
			while (end - start - mem_hole_size(start, end) < size) {
				end += FAKE_NODE_MIN_SIZE;
				if (end > limit) {
					end = limit;
					break;
				}
			}

			/*
			 * If there won't be at least FAKE_NODE_MIN_SIZE of
			 * non-reserved memory in ZONE_DMA32 for the next node,
			 * this one must extend to the boundary.
			 */
			if (end < dma32_end && dma32_end - end -
			    mem_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
				end = dma32_end;

			/*
			 * If there won't be enough non-reserved memory for the
			 * next node, this one must extend to the end of the
			 * physical node.
			 */
			if (limit - end - mem_hole_size(end, limit) < size)
				end = limit;

			ret = emu_setup_memblk(ei, pi, nid++ % nr_nodes,
					       phys_blk,
					       min(end, limit) - start);
			if (ret < 0)
				return ret;
		}
	}
	return 0;
}

/*
 * Returns the end address of a node so that there is at least `size' amount of
 * non-reserved memory or `max_addr' is reached.
 */
static u64 __init find_end_of_node(u64 start, u64 max_addr, u64 size)
{
	u64 end = start + size;

	while (end - start - mem_hole_size(start, end) < size) {
		end += FAKE_NODE_MIN_SIZE;
		if (end > max_addr) {
			end = max_addr;
			break;
		}
	}
	return end;
}

static u64 uniform_size(u64 max_addr, u64 base, u64 hole, int nr_nodes)
{
	unsigned long max_pfn = PHYS_PFN(max_addr);
	unsigned long base_pfn = PHYS_PFN(base);
	unsigned long hole_pfns = PHYS_PFN(hole);

	return PFN_PHYS((max_pfn - base_pfn - hole_pfns) / nr_nodes);
}

/*
 * Sets up fake nodes of `size' interleaved over physical nodes ranging from
 * `addr' to `max_addr'.
 *
 * Returns zero on success or negative on error.
 */
static int __init split_nodes_size_interleave_uniform(struct numa_meminfo *ei,
					      struct numa_meminfo *pi,
					      u64 addr, u64 max_addr, u64 size,
					      int nr_nodes, struct numa_memblk *pblk,
					      int nid)
{
	nodemask_t physnode_mask = numa_nodes_parsed;
	int i, ret, uniform = 0;
	u64 min_size;

	if ((!size && !nr_nodes) || (nr_nodes && !pblk))
		return -1;

	/*
	 * In the 'uniform' case split the passed in physical node by
	 * nr_nodes, in the non-uniform case, ignore the passed in
	 * physical block and try to create nodes of at least size
	 * @size.
	 *
	 * In the uniform case, split the nodes strictly by physical
	 * capacity, i.e. ignore holes. In the non-uniform case account
	 * for holes and treat @size as a minimum floor.
	 */
	if (!nr_nodes)
		nr_nodes = MAX_NUMNODES;
	else {
		nodes_clear(physnode_mask);
		node_set(pblk->nid, physnode_mask);
		uniform = 1;
	}

	if (uniform) {
		min_size = uniform_size(max_addr, addr, 0, nr_nodes);
		size = min_size;
	} else {
		/*
		 * The limit on emulated nodes is MAX_NUMNODES, so the
		 * size per node is increased accordingly if the
		 * requested size is too small.  This creates a uniform
		 * distribution of node sizes across the entire machine
		 * (but not necessarily over physical nodes).
		 */
		min_size = uniform_size(max_addr, addr,
				mem_hole_size(addr, max_addr), nr_nodes);
	}
	min_size = ALIGN(max(min_size, FAKE_NODE_MIN_SIZE), FAKE_NODE_MIN_SIZE);
	if (size < min_size) {
		pr_err("Fake node size %LuMB too small, increasing to %LuMB\n",
			size >> 20, min_size >> 20);
		size = min_size;
	}
	size = ALIGN_DOWN(size, FAKE_NODE_MIN_SIZE);

	/*
	 * Fill physical nodes with fake nodes of size until there is no memory
	 * left on any of them.
	 */
	while (nodes_weight(physnode_mask)) {
		for_each_node_mask(i, physnode_mask) {
			u64 dma32_end = PFN_PHYS(MAX_DMA32_PFN);
			u64 start, limit, end;
			int phys_blk;

			phys_blk = emu_find_memblk_by_nid(i, pi);
			if (phys_blk < 0) {
				node_clear(i, physnode_mask);
				continue;
			}

			start = pi->blk[phys_blk].start;
			limit = pi->blk[phys_blk].end;

			if (uniform)
				end = start + size;
			else
				end = find_end_of_node(start, limit, size);
			/*
			 * If there won't be at least FAKE_NODE_MIN_SIZE of
			 * non-reserved memory in ZONE_DMA32 for the next node,
			 * this one must extend to the boundary.
			 */
			if (end < dma32_end && dma32_end - end -
			    mem_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
				end = dma32_end;

			/*
			 * If there won't be enough non-reserved memory for the
			 * next node, this one must extend to the end of the
			 * physical node.
			 */
			if ((limit - end - mem_hole_size(end, limit) < size)
					&& !uniform)
				end = limit;

			ret = emu_setup_memblk(ei, pi, nid++ % MAX_NUMNODES,
					       phys_blk,
					       min(end, limit) - start);
			if (ret < 0)
				return ret;
		}
	}
	return nid;
}

static int __init split_nodes_size_interleave(struct numa_meminfo *ei,
					      struct numa_meminfo *pi,
					      u64 addr, u64 max_addr, u64 size)
{
	return split_nodes_size_interleave_uniform(ei, pi, addr, max_addr, size,
			0, NULL, 0);
}

static int __init setup_emu2phys_nid(int *dfl_phys_nid)
{
	int i, max_emu_nid = 0;

	*dfl_phys_nid = NUMA_NO_NODE;
	for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++) {
		if (emu_nid_to_phys[i] != NUMA_NO_NODE) {
			max_emu_nid = i;
			if (*dfl_phys_nid == NUMA_NO_NODE)
				*dfl_phys_nid = emu_nid_to_phys[i];
		}
	}

	return max_emu_nid;
}

/**
 * numa_emulation - Emulate NUMA nodes
 * @numa_meminfo: NUMA configuration to massage
 * @numa_dist_cnt: The size of the physical NUMA distance table
 *
 * Emulate NUMA nodes according to the numa=fake kernel parameter.
 * @numa_meminfo contains the physical memory configuration and is modified
 * to reflect the emulated configuration on success.  @numa_dist_cnt is
 * used to determine the size of the physical distance table.
 *
 * On success, the following modifications are made.
 *
 * - @numa_meminfo is updated to reflect the emulated nodes.
 *
 * - __apicid_to_node[] is updated such that APIC IDs are mapped to the
 *   emulated nodes.
 *
 * - NUMA distance table is rebuilt to represent distances between emulated
 *   nodes.  The distances are determined considering how emulated nodes
 *   are mapped to physical nodes and match the actual distances.
 *
 * - emu_nid_to_phys[] reflects how emulated nodes are mapped to physical
 *   nodes.  This is used by numa_add_cpu() and numa_remove_cpu().
 *
 * If emulation is not enabled or fails, emu_nid_to_phys[] is filled with
 * identity mapping and no other modification is made.
 */
void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
{
	static struct numa_meminfo ei __initdata;
	static struct numa_meminfo pi __initdata;
	const u64 max_addr = PFN_PHYS(max_pfn);
	u8 *phys_dist = NULL;
	size_t phys_size = numa_dist_cnt * numa_dist_cnt * sizeof(phys_dist[0]);
	int max_emu_nid, dfl_phys_nid;
	int i, j, ret;

	if (!emu_cmdline)
		goto no_emu;

	memset(&ei, 0, sizeof(ei));
	pi = *numa_meminfo;

	for (i = 0; i < MAX_NUMNODES; i++)
		emu_nid_to_phys[i] = NUMA_NO_NODE;

	/*
	 * If the numa=fake command-line contains a 'M' or 'G', it represents
	 * the fixed node size.  Otherwise, if it is just a single number N,
	 * split the system RAM into N fake nodes.
	 */
	if (strchr(emu_cmdline, 'U')) {
		nodemask_t physnode_mask = numa_nodes_parsed;
		unsigned long n;
		int nid = 0;

		n = simple_strtoul(emu_cmdline, &emu_cmdline, 0);
		ret = -1;
		for_each_node_mask(i, physnode_mask) {
			/*
			 * The reason we pass in blk[0] is due to
			 * numa_remove_memblk_from() called by
			 * emu_setup_memblk() will delete entry 0
			 * and then move everything else up in the pi.blk
			 * array. Therefore we should always be looking
			 * at blk[0].
			 */
			ret = split_nodes_size_interleave_uniform(&ei, &pi,
					pi.blk[0].start, pi.blk[0].end, 0,
					n, &pi.blk[0], nid);
			if (ret < 0)
				break;
			if (ret < n) {
				pr_info("%s: phys: %d only got %d of %ld nodes, failing\n",
						__func__, i, ret, n);
				ret = -1;
				break;
			}
			nid = ret;
		}
	} else if (strchr(emu_cmdline, 'M') || strchr(emu_cmdline, 'G')) {
		u64 size;

		size = memparse(emu_cmdline, &emu_cmdline);
		ret = split_nodes_size_interleave(&ei, &pi, 0, max_addr, size);
	} else {
		unsigned long n;

		n = simple_strtoul(emu_cmdline, &emu_cmdline, 0);
		ret = split_nodes_interleave(&ei, &pi, 0, max_addr, n);
	}
	if (*emu_cmdline == ':')
		emu_cmdline++;

	if (ret < 0)
		goto no_emu;

	if (numa_cleanup_meminfo(&ei) < 0) {
		pr_warn("NUMA: Warning: constructed meminfo invalid, disabling emulation\n");
		goto no_emu;
	}

	/* copy the physical distance table */
	if (numa_dist_cnt) {
		u64 phys;

		phys = memblock_phys_alloc_range(phys_size, PAGE_SIZE, 0,
						 PFN_PHYS(max_pfn_mapped));
		if (!phys) {
			pr_warn("NUMA: Warning: can't allocate copy of distance table, disabling emulation\n");
			goto no_emu;
		}
		phys_dist = __va(phys);

		for (i = 0; i < numa_dist_cnt; i++)
			for (j = 0; j < numa_dist_cnt; j++)
				phys_dist[i * numa_dist_cnt + j] =
					node_distance(i, j);
	}

	/*
	 * Determine the max emulated nid and the default phys nid to use
	 * for unmapped nodes.
	 */
	max_emu_nid = setup_emu2phys_nid(&dfl_phys_nid);

	/* commit */
	*numa_meminfo = ei;

	/* Make sure numa_nodes_parsed only contains emulated nodes */
	nodes_clear(numa_nodes_parsed);
	for (i = 0; i < ARRAY_SIZE(ei.blk); i++)
		if (ei.blk[i].start != ei.blk[i].end &&
		    ei.blk[i].nid != NUMA_NO_NODE)
			node_set(ei.blk[i].nid, numa_nodes_parsed);

	/*
	 * Transform __apicid_to_node table to use emulated nids by
	 * reverse-mapping phys_nid.  The maps should always exist but fall
	 * back to zero just in case.
	 */
	for (i = 0; i < ARRAY_SIZE(__apicid_to_node); i++) {
		if (__apicid_to_node[i] == NUMA_NO_NODE)
			continue;
		for (j = 0; j < ARRAY_SIZE(emu_nid_to_phys); j++)
			if (__apicid_to_node[i] == emu_nid_to_phys[j])
				break;
		__apicid_to_node[i] = j < ARRAY_SIZE(emu_nid_to_phys) ? j : 0;
	}

	/* make sure all emulated nodes are mapped to a physical node */
	for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)
		if (emu_nid_to_phys[i] == NUMA_NO_NODE)
			emu_nid_to_phys[i] = dfl_phys_nid;

	/* transform distance table */
	numa_reset_distance();
	for (i = 0; i < max_emu_nid + 1; i++) {
		for (j = 0; j < max_emu_nid + 1; j++) {
			int physi = emu_nid_to_phys[i];
			int physj = emu_nid_to_phys[j];
			int dist;

			if (get_option(&emu_cmdline, &dist) == 2)
				;
			else if (physi >= numa_dist_cnt || physj >= numa_dist_cnt)
				dist = physi == physj ?
					LOCAL_DISTANCE : REMOTE_DISTANCE;
			else
				dist = phys_dist[physi * numa_dist_cnt + physj];

			numa_set_distance(i, j, dist);
		}
	}

	/* free the copied physical distance table */
	memblock_free(phys_dist, phys_size);
	return;

no_emu:
	/* No emulation.  Build identity emu_nid_to_phys[] for numa_add_cpu() */
	for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)
		emu_nid_to_phys[i] = i;
}

#ifndef CONFIG_DEBUG_PER_CPU_MAPS
void numa_add_cpu(int cpu)
{
	int physnid, nid;

	nid = early_cpu_to_node(cpu);
	BUG_ON(nid == NUMA_NO_NODE || !node_online(nid));

	physnid = emu_nid_to_phys[nid];

	/*
	 * Map the cpu to each emulated node that is allocated on the physical
	 * node of the cpu's apic id.
	 */
	for_each_online_node(nid)
		if (emu_nid_to_phys[nid] == physnid)
			cpumask_set_cpu(cpu, node_to_cpumask_map[nid]);
}

void numa_remove_cpu(int cpu)
{
	int i;

	for_each_online_node(i)
		cpumask_clear_cpu(cpu, node_to_cpumask_map[i]);
}
#else	/* !CONFIG_DEBUG_PER_CPU_MAPS */
static void numa_set_cpumask(int cpu, bool enable)
{
	int nid, physnid;

	nid = early_cpu_to_node(cpu);
	if (nid == NUMA_NO_NODE) {
		/* early_cpu_to_node() already emits a warning and trace */
		return;
	}

	physnid = emu_nid_to_phys[nid];

	for_each_online_node(nid) {
		if (emu_nid_to_phys[nid] != physnid)
			continue;

		debug_cpumask_set_cpu(cpu, nid, enable);
	}
}

void numa_add_cpu(int cpu)
{
	numa_set_cpumask(cpu, true);
}

void numa_remove_cpu(int cpu)
{
	numa_set_cpumask(cpu, false);
}
#endif	/* !CONFIG_DEBUG_PER_CPU_MAPS */