1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * NUMA emulation
4 */
5 #include <linux/kernel.h>
6 #include <linux/errno.h>
7 #include <linux/topology.h>
8 #include <linux/memblock.h>
9 #include <asm/dma.h>
10
11 #include "numa_internal.h"
12
13 static int emu_nid_to_phys[MAX_NUMNODES];
14 static char *emu_cmdline __initdata;
15
16 int __init numa_emu_cmdline(char *str)
17 {
18 emu_cmdline = str;
19 return 0;
20 }
21
22 static int __init emu_find_memblk_by_nid(int nid, const struct numa_meminfo *mi)
23 {
24 int i;
25
26 for (i = 0; i < mi->nr_blks; i++)
27 if (mi->blk[i].nid == nid)
28 return i;
29 return -ENOENT;
30 }
31
32 static u64 __init mem_hole_size(u64 start, u64 end)
33 {
34 unsigned long start_pfn = PFN_UP(start);
35 unsigned long end_pfn = PFN_DOWN(end);
36
37 if (start_pfn < end_pfn)
38 return PFN_PHYS(absent_pages_in_range(start_pfn, end_pfn));
39 return 0;
40 }
41
42 /*
43 * Sets up nid to range from @start to @end. The return value is -errno if
44 * something went wrong, 0 otherwise.
45 */
46 static int __init emu_setup_memblk(struct numa_meminfo *ei,
47 struct numa_meminfo *pi,
48 int nid, int phys_blk, u64 size)
49 {
50 struct numa_memblk *eb = &ei->blk[ei->nr_blks];
51 struct numa_memblk *pb = &pi->blk[phys_blk];
52
53 if (ei->nr_blks >= NR_NODE_MEMBLKS) {
54 pr_err("NUMA: Too many emulated memblks, failing emulation\n");
55 return -EINVAL;
56 }
57
58 ei->nr_blks++;
59 eb->start = pb->start;
60 eb->end = pb->start + size;
61 eb->nid = nid;
62
63 if (emu_nid_to_phys[nid] == NUMA_NO_NODE)
64 emu_nid_to_phys[nid] = pb->nid;
65
66 pb->start += size;
67 if (pb->start >= pb->end) {
68 WARN_ON_ONCE(pb->start > pb->end);
69 numa_remove_memblk_from(phys_blk, pi);
70 }
71
72 printk(KERN_INFO "Faking node %d at [mem %#018Lx-%#018Lx] (%LuMB)\n",
73 nid, eb->start, eb->end - 1, (eb->end - eb->start) >> 20);
74 return 0;
75 }
76
77 /*
78 * Sets up nr_nodes fake nodes interleaved over physical nodes ranging from addr
79 * to max_addr.
80 *
81 * Returns zero on success or negative on error.
82 */
83 static int __init split_nodes_interleave(struct numa_meminfo *ei,
84 struct numa_meminfo *pi,
85 u64 addr, u64 max_addr, int nr_nodes)
86 {
87 nodemask_t physnode_mask = numa_nodes_parsed;
88 u64 size;
89 int big;
90 int nid = 0;
91 int i, ret;
92
93 if (nr_nodes <= 0)
94 return -1;
95 if (nr_nodes > MAX_NUMNODES) {
96 pr_info("numa=fake=%d too large, reducing to %d\n",
97 nr_nodes, MAX_NUMNODES);
98 nr_nodes = MAX_NUMNODES;
99 }
100
101 /*
102 * Calculate target node size. x86_32 freaks on __udivdi3() so do
103 * the division in ulong number of pages and convert back.
104 */
105 size = max_addr - addr - mem_hole_size(addr, max_addr);
106 size = PFN_PHYS((unsigned long)(size >> PAGE_SHIFT) / nr_nodes);
107
108 /*
109 * Calculate the number of big nodes that can be allocated as a result
110 * of consolidating the remainder.
111 */
112 big = ((size & ~FAKE_NODE_MIN_HASH_MASK) * nr_nodes) /
113 FAKE_NODE_MIN_SIZE;
114
115 size &= FAKE_NODE_MIN_HASH_MASK;
116 if (!size) {
117 pr_err("Not enough memory for each node. "
118 "NUMA emulation disabled.\n");
119 return -1;
120 }
121
122 /*
123 * Continue to fill physical nodes with fake nodes until there is no
124 * memory left on any of them.
125 */
126 while (!nodes_empty(physnode_mask)) {
127 for_each_node_mask(i, physnode_mask) {
128 u64 dma32_end = PFN_PHYS(MAX_DMA32_PFN);
129 u64 start, limit, end;
130 int phys_blk;
131
132 phys_blk = emu_find_memblk_by_nid(i, pi);
133 if (phys_blk < 0) {
134 node_clear(i, physnode_mask);
135 continue;
136 }
137 start = pi->blk[phys_blk].start;
138 limit = pi->blk[phys_blk].end;
139 end = start + size;
140
141 if (nid < big)
142 end += FAKE_NODE_MIN_SIZE;
143
144 /*
145 * Continue to add memory to this fake node if its
146 * non-reserved memory is less than the per-node size.
147 */
148 while (end - start - mem_hole_size(start, end) < size) {
149 end += FAKE_NODE_MIN_SIZE;
150 if (end > limit) {
151 end = limit;
152 break;
153 }
154 }
155
156 /*
157 * If there won't be at least FAKE_NODE_MIN_SIZE of
158 * non-reserved memory in ZONE_DMA32 for the next node,
159 * this one must extend to the boundary.
160 */
161 if (end < dma32_end && dma32_end - end -
162 mem_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
163 end = dma32_end;
164
165 /*
166 * If there won't be enough non-reserved memory for the
167 * next node, this one must extend to the end of the
168 * physical node.
169 */
170 if (limit - end - mem_hole_size(end, limit) < size)
171 end = limit;
172
173 ret = emu_setup_memblk(ei, pi, nid++ % nr_nodes,
174 phys_blk,
175 min(end, limit) - start);
176 if (ret < 0)
177 return ret;
178 }
179 }
180 return 0;
181 }
182
183 /*
184 * Returns the end address of a node so that there is at least `size' amount of
185 * non-reserved memory or `max_addr' is reached.
186 */
187 static u64 __init find_end_of_node(u64 start, u64 max_addr, u64 size)
188 {
189 u64 end = start + size;
190
191 while (end - start - mem_hole_size(start, end) < size) {
192 end += FAKE_NODE_MIN_SIZE;
193 if (end > max_addr) {
194 end = max_addr;
195 break;
196 }
197 }
198 return end;
199 }
200
201 static u64 uniform_size(u64 max_addr, u64 base, u64 hole, int nr_nodes)
202 {
203 unsigned long max_pfn = PHYS_PFN(max_addr);
204 unsigned long base_pfn = PHYS_PFN(base);
205 unsigned long hole_pfns = PHYS_PFN(hole);
206
207 return PFN_PHYS((max_pfn - base_pfn - hole_pfns) / nr_nodes);
208 }
209
210 /*
211 * Sets up fake nodes of `size' interleaved over physical nodes ranging from
212 * `addr' to `max_addr'.
213 *
214 * Returns zero on success or negative on error.
215 */
216 static int __init split_nodes_size_interleave_uniform(struct numa_meminfo *ei,
217 struct numa_meminfo *pi,
218 u64 addr, u64 max_addr, u64 size,
219 int nr_nodes, struct numa_memblk *pblk,
220 int nid)
221 {
222 nodemask_t physnode_mask = numa_nodes_parsed;
223 int i, ret, uniform = 0;
224 u64 min_size;
225
226 if ((!size && !nr_nodes) || (nr_nodes && !pblk))
227 return -1;
228
229 /*
230 * In the 'uniform' case split the passed in physical node by
231 * nr_nodes, in the non-uniform case, ignore the passed in
232 * physical block and try to create nodes of at least size
233 * @size.
234 *
235 * In the uniform case, split the nodes strictly by physical
236 * capacity, i.e. ignore holes. In the non-uniform case account
237 * for holes and treat @size as a minimum floor.
238 */
239 if (!nr_nodes)
240 nr_nodes = MAX_NUMNODES;
241 else {
242 nodes_clear(physnode_mask);
243 node_set(pblk->nid, physnode_mask);
244 uniform = 1;
245 }
246
247 if (uniform) {
248 min_size = uniform_size(max_addr, addr, 0, nr_nodes);
249 size = min_size;
250 } else {
251 /*
252 * The limit on emulated nodes is MAX_NUMNODES, so the
253 * size per node is increased accordingly if the
254 * requested size is too small. This creates a uniform
255 * distribution of node sizes across the entire machine
256 * (but not necessarily over physical nodes).
257 */
258 min_size = uniform_size(max_addr, addr,
259 mem_hole_size(addr, max_addr), nr_nodes);
260 }
261 min_size = ALIGN(max(min_size, FAKE_NODE_MIN_SIZE), FAKE_NODE_MIN_SIZE);
262 if (size < min_size) {
263 pr_err("Fake node size %LuMB too small, increasing to %LuMB\n",
264 size >> 20, min_size >> 20);
265 size = min_size;
266 }
267 size = ALIGN_DOWN(size, FAKE_NODE_MIN_SIZE);
268
269 /*
270 * Fill physical nodes with fake nodes of size until there is no memory
271 * left on any of them.
272 */
273 while (!nodes_empty(physnode_mask)) {
274 for_each_node_mask(i, physnode_mask) {
275 u64 dma32_end = PFN_PHYS(MAX_DMA32_PFN);
276 u64 start, limit, end;
277 int phys_blk;
278
279 phys_blk = emu_find_memblk_by_nid(i, pi);
280 if (phys_blk < 0) {
281 node_clear(i, physnode_mask);
282 continue;
283 }
284
285 start = pi->blk[phys_blk].start;
286 limit = pi->blk[phys_blk].end;
287
288 if (uniform)
289 end = start + size;
290 else
291 end = find_end_of_node(start, limit, size);
292 /*
293 * If there won't be at least FAKE_NODE_MIN_SIZE of
294 * non-reserved memory in ZONE_DMA32 for the next node,
295 * this one must extend to the boundary.
296 */
297 if (end < dma32_end && dma32_end - end -
298 mem_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
299 end = dma32_end;
300
301 /*
302 * If there won't be enough non-reserved memory for the
303 * next node, this one must extend to the end of the
304 * physical node.
305 */
306 if ((limit - end - mem_hole_size(end, limit) < size)
307 && !uniform)
308 end = limit;
309
310 ret = emu_setup_memblk(ei, pi, nid++ % MAX_NUMNODES,
311 phys_blk,
312 min(end, limit) - start);
313 if (ret < 0)
314 return ret;
315 }
316 }
317 return nid;
318 }
319
320 static int __init split_nodes_size_interleave(struct numa_meminfo *ei,
321 struct numa_meminfo *pi,
322 u64 addr, u64 max_addr, u64 size)
323 {
324 return split_nodes_size_interleave_uniform(ei, pi, addr, max_addr, size,
325 0, NULL, 0);
326 }
327
328 static int __init setup_emu2phys_nid(int *dfl_phys_nid)
329 {
330 int i, max_emu_nid = 0;
331
332 *dfl_phys_nid = NUMA_NO_NODE;
333 for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++) {
334 if (emu_nid_to_phys[i] != NUMA_NO_NODE) {
335 max_emu_nid = i;
336 if (*dfl_phys_nid == NUMA_NO_NODE)
337 *dfl_phys_nid = emu_nid_to_phys[i];
338 }
339 }
340
341 return max_emu_nid;
342 }
343
344 /**
345 * numa_emulation - Emulate NUMA nodes
346 * @numa_meminfo: NUMA configuration to massage
347 * @numa_dist_cnt: The size of the physical NUMA distance table
348 *
349 * Emulate NUMA nodes according to the numa=fake kernel parameter.
350 * @numa_meminfo contains the physical memory configuration and is modified
351 * to reflect the emulated configuration on success. @numa_dist_cnt is
352 * used to determine the size of the physical distance table.
353 *
354 * On success, the following modifications are made.
355 *
356 * - @numa_meminfo is updated to reflect the emulated nodes.
357 *
358 * - __apicid_to_node[] is updated such that APIC IDs are mapped to the
359 * emulated nodes.
360 *
361 * - NUMA distance table is rebuilt to represent distances between emulated
362 * nodes. The distances are determined considering how emulated nodes
363 * are mapped to physical nodes and match the actual distances.
364 *
365 * - emu_nid_to_phys[] reflects how emulated nodes are mapped to physical
366 * nodes. This is used by numa_add_cpu() and numa_remove_cpu().
367 *
368 * If emulation is not enabled or fails, emu_nid_to_phys[] is filled with
369 * identity mapping and no other modification is made.
370 */
371 void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
372 {
373 static struct numa_meminfo ei __initdata;
374 static struct numa_meminfo pi __initdata;
375 const u64 max_addr = PFN_PHYS(max_pfn);
376 u8 *phys_dist = NULL;
377 size_t phys_size = numa_dist_cnt * numa_dist_cnt * sizeof(phys_dist[0]);
378 int max_emu_nid, dfl_phys_nid;
379 int i, j, ret;
380
381 if (!emu_cmdline)
382 goto no_emu;
383
384 memset(&ei, 0, sizeof(ei));
385 pi = *numa_meminfo;
386
387 for (i = 0; i < MAX_NUMNODES; i++)
388 emu_nid_to_phys[i] = NUMA_NO_NODE;
389
390 /*
391 * If the numa=fake command-line contains a 'M' or 'G', it represents
392 * the fixed node size. Otherwise, if it is just a single number N,
393 * split the system RAM into N fake nodes.
394 */
395 if (strchr(emu_cmdline, 'U')) {
396 nodemask_t physnode_mask = numa_nodes_parsed;
397 unsigned long n;
398 int nid = 0;
399
400 n = simple_strtoul(emu_cmdline, &emu_cmdline, 0);
401 ret = -1;
402 for_each_node_mask(i, physnode_mask) {
403 /*
404 * The reason we pass in blk[0] is due to
405 * numa_remove_memblk_from() called by
406 * emu_setup_memblk() will delete entry 0
407 * and then move everything else up in the pi.blk
408 * array. Therefore we should always be looking
409 * at blk[0].
410 */
411 ret = split_nodes_size_interleave_uniform(&ei, &pi,
412 pi.blk[0].start, pi.blk[0].end, 0,
413 n, &pi.blk[0], nid);
414 if (ret < 0)
415 break;
416 if (ret < n) {
417 pr_info("%s: phys: %d only got %d of %ld nodes, failing\n",
418 __func__, i, ret, n);
419 ret = -1;
420 break;
421 }
422 nid = ret;
423 }
424 } else if (strchr(emu_cmdline, 'M') || strchr(emu_cmdline, 'G')) {
425 u64 size;
426
427 size = memparse(emu_cmdline, &emu_cmdline);
428 ret = split_nodes_size_interleave(&ei, &pi, 0, max_addr, size);
429 } else {
430 unsigned long n;
431
432 n = simple_strtoul(emu_cmdline, &emu_cmdline, 0);
433 ret = split_nodes_interleave(&ei, &pi, 0, max_addr, n);
434 }
435 if (*emu_cmdline == ':')
436 emu_cmdline++;
437
438 if (ret < 0)
439 goto no_emu;
440
441 if (numa_cleanup_meminfo(&ei) < 0) {
442 pr_warn("NUMA: Warning: constructed meminfo invalid, disabling emulation\n");
443 goto no_emu;
444 }
445
446 /* copy the physical distance table */
447 if (numa_dist_cnt) {
448 u64 phys;
449
450 phys = memblock_phys_alloc_range(phys_size, PAGE_SIZE, 0,
451 PFN_PHYS(max_pfn_mapped));
452 if (!phys) {
453 pr_warn("NUMA: Warning: can't allocate copy of distance table, disabling emulation\n");
454 goto no_emu;
455 }
456 phys_dist = __va(phys);
457
458 for (i = 0; i < numa_dist_cnt; i++)
459 for (j = 0; j < numa_dist_cnt; j++)
460 phys_dist[i * numa_dist_cnt + j] =
461 node_distance(i, j);
462 }
463
464 /*
465 * Determine the max emulated nid and the default phys nid to use
466 * for unmapped nodes.
467 */
468 max_emu_nid = setup_emu2phys_nid(&dfl_phys_nid);
469
470 /* commit */
471 *numa_meminfo = ei;
472
473 /* Make sure numa_nodes_parsed only contains emulated nodes */
474 nodes_clear(numa_nodes_parsed);
475 for (i = 0; i < ARRAY_SIZE(ei.blk); i++)
476 if (ei.blk[i].start != ei.blk[i].end &&
477 ei.blk[i].nid != NUMA_NO_NODE)
478 node_set(ei.blk[i].nid, numa_nodes_parsed);
479
480 /*
481 * Transform __apicid_to_node table to use emulated nids by
482 * reverse-mapping phys_nid. The maps should always exist but fall
483 * back to zero just in case.
484 */
485 for (i = 0; i < ARRAY_SIZE(__apicid_to_node); i++) {
486 if (__apicid_to_node[i] == NUMA_NO_NODE)
487 continue;
488 for (j = 0; j < ARRAY_SIZE(emu_nid_to_phys); j++)
489 if (__apicid_to_node[i] == emu_nid_to_phys[j])
490 break;
491 __apicid_to_node[i] = j < ARRAY_SIZE(emu_nid_to_phys) ? j : 0;
492 }
493
494 /* make sure all emulated nodes are mapped to a physical node */
495 for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)
496 if (emu_nid_to_phys[i] == NUMA_NO_NODE)
497 emu_nid_to_phys[i] = dfl_phys_nid;
498
499 /* transform distance table */
500 numa_reset_distance();
501 for (i = 0; i < max_emu_nid + 1; i++) {
502 for (j = 0; j < max_emu_nid + 1; j++) {
503 int physi = emu_nid_to_phys[i];
504 int physj = emu_nid_to_phys[j];
505 int dist;
506
507 if (get_option(&emu_cmdline, &dist) == 2)
508 ;
509 else if (physi >= numa_dist_cnt || physj >= numa_dist_cnt)
510 dist = physi == physj ?
511 LOCAL_DISTANCE : REMOTE_DISTANCE;
512 else
513 dist = phys_dist[physi * numa_dist_cnt + physj];
514
515 numa_set_distance(i, j, dist);
516 }
517 }
518
519 /* free the copied physical distance table */
520 memblock_free(phys_dist, phys_size);
521 return;
522
523 no_emu:
524 /* No emulation. Build identity emu_nid_to_phys[] for numa_add_cpu() */
525 for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)
526 emu_nid_to_phys[i] = i;
527 }
528
529 #ifndef CONFIG_DEBUG_PER_CPU_MAPS
530 void numa_add_cpu(int cpu)
531 {
532 int physnid, nid;
533
534 nid = early_cpu_to_node(cpu);
535 BUG_ON(nid == NUMA_NO_NODE || !node_online(nid));
536
537 physnid = emu_nid_to_phys[nid];
538
539 /*
540 * Map the cpu to each emulated node that is allocated on the physical
541 * node of the cpu's apic id.
542 */
543 for_each_online_node(nid)
544 if (emu_nid_to_phys[nid] == physnid)
545 cpumask_set_cpu(cpu, node_to_cpumask_map[nid]);
546 }
547
548 void numa_remove_cpu(int cpu)
549 {
550 int i;
551
552 for_each_online_node(i)
553 cpumask_clear_cpu(cpu, node_to_cpumask_map[i]);
554 }
555 #else /* !CONFIG_DEBUG_PER_CPU_MAPS */
556 static void numa_set_cpumask(int cpu, bool enable)
557 {
558 int nid, physnid;
559
560 nid = early_cpu_to_node(cpu);
561 if (nid == NUMA_NO_NODE) {
562 /* early_cpu_to_node() already emits a warning and trace */
563 return;
564 }
565
566 physnid = emu_nid_to_phys[nid];
567
568 for_each_online_node(nid) {
569 if (emu_nid_to_phys[nid] != physnid)
570 continue;
571
572 debug_cpumask_set_cpu(cpu, nid, enable);
573 }
574 }
575
576 void numa_add_cpu(int cpu)
577 {
578 numa_set_cpumask(cpu, true);
579 }
580
581 void numa_remove_cpu(int cpu)
582 {
583 numa_set_cpumask(cpu, false);
584 }
585 #endif /* !CONFIG_DEBUG_PER_CPU_MAPS */
586
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.