cpumap.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2#include <errno.h>
  3#include <perf/cpumap.h>
  4#include <stdlib.h>
  5#include <linux/refcount.h>
  6#include <internal/cpumap.h>
  7#include <asm/bug.h>
  8#include <stdio.h>
  9#include <string.h>
 10#include <unistd.h>
 11#include <ctype.h>
 12#include <limits.h>
 13#include "internal.h"
 14#include <api/fs/fs.h>
 15
 16#define MAX_NR_CPUS 4096
 17
 18void perf_cpu_map__set_nr(struct perf_cpu_map *map, int nr_cpus)
 19{
 20	RC_CHK_ACCESS(map)->nr = nr_cpus;
 21}
 22
 23struct perf_cpu_map *perf_cpu_map__alloc(int nr_cpus)
 24{
 25	RC_STRUCT(perf_cpu_map) *cpus;
 26	struct perf_cpu_map *result;
 27
 28	if (nr_cpus == 0)
 29		return NULL;
 30
 31	cpus = malloc(sizeof(*cpus) + sizeof(struct perf_cpu) * nr_cpus);
 32	if (ADD_RC_CHK(result, cpus)) {
 33		cpus->nr = nr_cpus;
 34		refcount_set(&cpus->refcnt, 1);
 35	}
 36	return result;
 37}
 38
 39struct perf_cpu_map *perf_cpu_map__new_any_cpu(void)
 40{
 41	struct perf_cpu_map *cpus = perf_cpu_map__alloc(1);
 42
 43	if (cpus)
 44		RC_CHK_ACCESS(cpus)->map[0].cpu = -1;
 45
 46	return cpus;
 47}
 48
 49static void cpu_map__delete(struct perf_cpu_map *map)
 50{
 51	if (map) {
 52		WARN_ONCE(refcount_read(perf_cpu_map__refcnt(map)) != 0,
 53			  "cpu_map refcnt unbalanced\n");
 54		RC_CHK_FREE(map);
 55	}
 56}
 57
 58struct perf_cpu_map *perf_cpu_map__get(struct perf_cpu_map *map)
 59{
 60	struct perf_cpu_map *result;
 61
 62	if (RC_CHK_GET(result, map))
 63		refcount_inc(perf_cpu_map__refcnt(map));
 64
 65	return result;
 66}
 67
 68void perf_cpu_map__put(struct perf_cpu_map *map)
 69{
 70	if (map) {
 71		if (refcount_dec_and_test(perf_cpu_map__refcnt(map)))
 72			cpu_map__delete(map);
 73		else
 74			RC_CHK_PUT(map);
 75	}
 76}
 77
 78static struct perf_cpu_map *cpu_map__new_sysconf(void)
 79{
 80	struct perf_cpu_map *cpus;
 81	int nr_cpus, nr_cpus_conf;
 82
 83	nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
 84	if (nr_cpus < 0)
 85		return NULL;
 86
 87	nr_cpus_conf = sysconf(_SC_NPROCESSORS_CONF);
 88	if (nr_cpus != nr_cpus_conf) {
 89		pr_warning("Number of online CPUs (%d) differs from the number configured (%d) the CPU map will only cover the first %d CPUs.",
 90			nr_cpus, nr_cpus_conf, nr_cpus);
 91	}
 92
 93	cpus = perf_cpu_map__alloc(nr_cpus);
 94	if (cpus != NULL) {
 95		int i;
 96
 97		for (i = 0; i < nr_cpus; ++i)
 98			RC_CHK_ACCESS(cpus)->map[i].cpu = i;
 99	}
100
101	return cpus;
102}
103
104static struct perf_cpu_map *cpu_map__new_sysfs_online(void)
105{
106	struct perf_cpu_map *cpus = NULL;
107	char *buf = NULL;
108	size_t buf_len;
109
110	if (sysfs__read_str("devices/system/cpu/online", &buf, &buf_len) >= 0) {
111		cpus = perf_cpu_map__new(buf);
112		free(buf);
113	}
114	return cpus;
115}
116
117struct perf_cpu_map *perf_cpu_map__new_online_cpus(void)
118{
119	struct perf_cpu_map *cpus = cpu_map__new_sysfs_online();
120
121	if (cpus)
122		return cpus;
123
124	return cpu_map__new_sysconf();
125}
126
127
128static int cmp_cpu(const void *a, const void *b)
129{
130	const struct perf_cpu *cpu_a = a, *cpu_b = b;
131
132	return cpu_a->cpu - cpu_b->cpu;
133}
134
135static struct perf_cpu __perf_cpu_map__cpu(const struct perf_cpu_map *cpus, int idx)
136{
137	return RC_CHK_ACCESS(cpus)->map[idx];
138}
139
140static struct perf_cpu_map *cpu_map__trim_new(int nr_cpus, const struct perf_cpu *tmp_cpus)
141{
142	size_t payload_size = nr_cpus * sizeof(struct perf_cpu);
143	struct perf_cpu_map *cpus = perf_cpu_map__alloc(nr_cpus);
144	int i, j;
145
146	if (cpus != NULL) {
147		memcpy(RC_CHK_ACCESS(cpus)->map, tmp_cpus, payload_size);
148		qsort(RC_CHK_ACCESS(cpus)->map, nr_cpus, sizeof(struct perf_cpu), cmp_cpu);
149		/* Remove dups */
150		j = 0;
151		for (i = 0; i < nr_cpus; i++) {
152			if (i == 0 ||
153			    __perf_cpu_map__cpu(cpus, i).cpu !=
154			    __perf_cpu_map__cpu(cpus, i - 1).cpu) {
155				RC_CHK_ACCESS(cpus)->map[j++].cpu =
156					__perf_cpu_map__cpu(cpus, i).cpu;
157			}
158		}
159		perf_cpu_map__set_nr(cpus, j);
160		assert(j <= nr_cpus);
161	}
162	return cpus;
163}
164
165struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list)
166{
167	struct perf_cpu_map *cpus = NULL;
168	unsigned long start_cpu, end_cpu = 0;
169	char *p = NULL;
170	int i, nr_cpus = 0;
171	struct perf_cpu *tmp_cpus = NULL, *tmp;
172	int max_entries = 0;
173
174	if (!cpu_list)
175		return perf_cpu_map__new_online_cpus();
176
177	/*
178	 * must handle the case of empty cpumap to cover
179	 * TOPOLOGY header for NUMA nodes with no CPU
180	 * ( e.g., because of CPU hotplug)
181	 */
182	if (!isdigit(*cpu_list) && *cpu_list != '\0')
183		goto out;
184
185	while (isdigit(*cpu_list)) {
186		p = NULL;
187		start_cpu = strtoul(cpu_list, &p, 0);
188		if (start_cpu >= INT16_MAX
189		    || (*p != '\0' && *p != ',' && *p != '-' && *p != '\n'))
190			goto invalid;
191
192		if (*p == '-') {
193			cpu_list = ++p;
194			p = NULL;
195			end_cpu = strtoul(cpu_list, &p, 0);
196
197			if (end_cpu >= INT16_MAX || (*p != '\0' && *p != ',' && *p != '\n'))
198				goto invalid;
199
200			if (end_cpu < start_cpu)
201				goto invalid;
202		} else {
203			end_cpu = start_cpu;
204		}
205
206		WARN_ONCE(end_cpu >= MAX_NR_CPUS, "Perf can support %d CPUs. "
207						  "Consider raising MAX_NR_CPUS\n", MAX_NR_CPUS);
208
209		for (; start_cpu <= end_cpu; start_cpu++) {
210			/* check for duplicates */
211			for (i = 0; i < nr_cpus; i++)
212				if (tmp_cpus[i].cpu == (int16_t)start_cpu)
213					goto invalid;
214
215			if (nr_cpus == max_entries) {
216				max_entries += max(end_cpu - start_cpu + 1, 16UL);
217				tmp = realloc(tmp_cpus, max_entries * sizeof(struct perf_cpu));
218				if (tmp == NULL)
219					goto invalid;
220				tmp_cpus = tmp;
221			}
222			tmp_cpus[nr_cpus++].cpu = (int16_t)start_cpu;
223		}
224		if (*p)
225			++p;
226
227		cpu_list = p;
228	}
229
230	if (nr_cpus > 0) {
231		cpus = cpu_map__trim_new(nr_cpus, tmp_cpus);
232	} else if (*cpu_list != '\0') {
233		pr_warning("Unexpected characters at end of cpu list ('%s'), using online CPUs.",
234			   cpu_list);
235		cpus = perf_cpu_map__new_online_cpus();
236	} else {
237		cpus = perf_cpu_map__new_any_cpu();
238	}
239invalid:
240	free(tmp_cpus);
241out:
242	return cpus;
243}
244
245struct perf_cpu_map *perf_cpu_map__new_int(int cpu)
246{
247	struct perf_cpu_map *cpus = perf_cpu_map__alloc(1);
248
249	if (cpus)
250		RC_CHK_ACCESS(cpus)->map[0].cpu = cpu;
251
252	return cpus;
253}
254
255static int __perf_cpu_map__nr(const struct perf_cpu_map *cpus)
256{
257	return RC_CHK_ACCESS(cpus)->nr;
258}
259
260struct perf_cpu perf_cpu_map__cpu(const struct perf_cpu_map *cpus, int idx)
261{
262	struct perf_cpu result = {
263		.cpu = -1
264	};
265
266	if (cpus && idx < __perf_cpu_map__nr(cpus))
267		return __perf_cpu_map__cpu(cpus, idx);
268
269	return result;
270}
271
272int perf_cpu_map__nr(const struct perf_cpu_map *cpus)
273{
274	return cpus ? __perf_cpu_map__nr(cpus) : 1;
275}
276
277bool perf_cpu_map__has_any_cpu_or_is_empty(const struct perf_cpu_map *map)
278{
279	return map ? __perf_cpu_map__cpu(map, 0).cpu == -1 : true;
280}
281
282bool perf_cpu_map__is_any_cpu_or_is_empty(const struct perf_cpu_map *map)
283{
284	if (!map)
285		return true;
286
287	return __perf_cpu_map__nr(map) == 1 && __perf_cpu_map__cpu(map, 0).cpu == -1;
288}
289
290bool perf_cpu_map__is_empty(const struct perf_cpu_map *map)
291{
292	return map == NULL;
293}
294
295int perf_cpu_map__idx(const struct perf_cpu_map *cpus, struct perf_cpu cpu)
296{
297	int low, high;
298
299	if (!cpus)
300		return -1;
301
302	low = 0;
303	high = __perf_cpu_map__nr(cpus);
304	while (low < high) {
305		int idx = (low + high) / 2;
306		struct perf_cpu cpu_at_idx = __perf_cpu_map__cpu(cpus, idx);
307
308		if (cpu_at_idx.cpu == cpu.cpu)
309			return idx;
310
311		if (cpu_at_idx.cpu > cpu.cpu)
312			high = idx;
313		else
314			low = idx + 1;
315	}
316
317	return -1;
318}
319
320bool perf_cpu_map__has(const struct perf_cpu_map *cpus, struct perf_cpu cpu)
321{
322	return perf_cpu_map__idx(cpus, cpu) != -1;
323}
324
325bool perf_cpu_map__equal(const struct perf_cpu_map *lhs, const struct perf_cpu_map *rhs)
326{
327	int nr;
328
329	if (lhs == rhs)
330		return true;
331
332	if (!lhs || !rhs)
333		return false;
334
335	nr = __perf_cpu_map__nr(lhs);
336	if (nr != __perf_cpu_map__nr(rhs))
337		return false;
338
339	for (int idx = 0; idx < nr; idx++) {
340		if (__perf_cpu_map__cpu(lhs, idx).cpu != __perf_cpu_map__cpu(rhs, idx).cpu)
341			return false;
342	}
343	return true;
344}
345
346bool perf_cpu_map__has_any_cpu(const struct perf_cpu_map *map)
347{
348	return map && __perf_cpu_map__cpu(map, 0).cpu == -1;
349}
350
351struct perf_cpu perf_cpu_map__min(const struct perf_cpu_map *map)
352{
353	struct perf_cpu cpu, result = {
354		.cpu = -1
355	};
356	int idx;
357
358	perf_cpu_map__for_each_cpu_skip_any(cpu, idx, map) {
359		result = cpu;
360		break;
361	}
362	return result;
363}
364
365struct perf_cpu perf_cpu_map__max(const struct perf_cpu_map *map)
366{
367	struct perf_cpu result = {
368		.cpu = -1
369	};
370
371	if (!map)
372		return result;
373
374	// The CPUs are always sorted and nr is always > 0 as 0 length map is
375	// encoded as NULL.
376	return __perf_cpu_map__cpu(map, __perf_cpu_map__nr(map) - 1);
377}
378
379/** Is 'b' a subset of 'a'. */
380bool perf_cpu_map__is_subset(const struct perf_cpu_map *a, const struct perf_cpu_map *b)
381{
382	if (a == b || !b)
383		return true;
384	if (!a || __perf_cpu_map__nr(b) > __perf_cpu_map__nr(a))
385		return false;
386
387	for (int i = 0, j = 0; i < __perf_cpu_map__nr(a); i++) {
388		if (__perf_cpu_map__cpu(a, i).cpu > __perf_cpu_map__cpu(b, j).cpu)
389			return false;
390		if (__perf_cpu_map__cpu(a, i).cpu == __perf_cpu_map__cpu(b, j).cpu) {
391			j++;
392			if (j == __perf_cpu_map__nr(b))
393				return true;
394		}
395	}
396	return false;
397}
398
399/*
400 * Merge two cpumaps.
401 *
402 * If 'other' is subset of '*orig', '*orig' keeps itself with no reference count
403 * change (similar to "realloc").
404 *
405 * If '*orig' is subset of 'other', '*orig' reuses 'other' with its reference
406 * count increased.
407 *
408 * Otherwise, '*orig' gets freed and replaced with a new map.
409 */
410int perf_cpu_map__merge(struct perf_cpu_map **orig, struct perf_cpu_map *other)
411{
412	struct perf_cpu *tmp_cpus;
413	int tmp_len;
414	int i, j, k;
415	struct perf_cpu_map *merged;
416
417	if (perf_cpu_map__is_subset(*orig, other))
418		return 0;
419	if (perf_cpu_map__is_subset(other, *orig)) {
420		perf_cpu_map__put(*orig);
421		*orig = perf_cpu_map__get(other);
422		return 0;
423	}
424
425	tmp_len = __perf_cpu_map__nr(*orig) + __perf_cpu_map__nr(other);
426	tmp_cpus = malloc(tmp_len * sizeof(struct perf_cpu));
427	if (!tmp_cpus)
428		return -ENOMEM;
429
430	/* Standard merge algorithm from wikipedia */
431	i = j = k = 0;
432	while (i < __perf_cpu_map__nr(*orig) && j < __perf_cpu_map__nr(other)) {
433		if (__perf_cpu_map__cpu(*orig, i).cpu <= __perf_cpu_map__cpu(other, j).cpu) {
434			if (__perf_cpu_map__cpu(*orig, i).cpu == __perf_cpu_map__cpu(other, j).cpu)
435				j++;
436			tmp_cpus[k++] = __perf_cpu_map__cpu(*orig, i++);
437		} else
438			tmp_cpus[k++] = __perf_cpu_map__cpu(other, j++);
439	}
440
441	while (i < __perf_cpu_map__nr(*orig))
442		tmp_cpus[k++] = __perf_cpu_map__cpu(*orig, i++);
443
444	while (j < __perf_cpu_map__nr(other))
445		tmp_cpus[k++] = __perf_cpu_map__cpu(other, j++);
446	assert(k <= tmp_len);
447
448	merged = cpu_map__trim_new(k, tmp_cpus);
449	free(tmp_cpus);
450	perf_cpu_map__put(*orig);
451	*orig = merged;
452	return 0;
453}
454
455struct perf_cpu_map *perf_cpu_map__intersect(struct perf_cpu_map *orig,
456					     struct perf_cpu_map *other)
457{
458	int i, j, k;
459	struct perf_cpu_map *merged;
460
461	if (perf_cpu_map__is_subset(other, orig))
462		return perf_cpu_map__get(orig);
463	if (perf_cpu_map__is_subset(orig, other))
464		return perf_cpu_map__get(other);
465
466	i = j = k = 0;
467	while (i < __perf_cpu_map__nr(orig) && j < __perf_cpu_map__nr(other)) {
468		if (__perf_cpu_map__cpu(orig, i).cpu < __perf_cpu_map__cpu(other, j).cpu)
469			i++;
470		else if (__perf_cpu_map__cpu(orig, i).cpu > __perf_cpu_map__cpu(other, j).cpu)
471			j++;
472		else { /* CPUs match. */
473			i++;
474			j++;
475			k++;
476		}
477	}
478	if (k == 0) /* Maps are completely disjoint. */
479		return NULL;
480
481	merged = perf_cpu_map__alloc(k);
482	if (!merged)
483		return NULL;
484	/* Entries are added to merged in sorted order, so no need to sort again. */
485	i = j = k = 0;
486	while (i < __perf_cpu_map__nr(orig) && j < __perf_cpu_map__nr(other)) {
487		if (__perf_cpu_map__cpu(orig, i).cpu < __perf_cpu_map__cpu(other, j).cpu)
488			i++;
489		else if (__perf_cpu_map__cpu(orig, i).cpu > __perf_cpu_map__cpu(other, j).cpu)
490			j++;
491		else {
492			j++;
493			RC_CHK_ACCESS(merged)->map[k++] = __perf_cpu_map__cpu(orig, i++);
494		}
495	}
496	return merged;
497}