https://github.com/torvalds/linux
Tip revision: f40ddce88593482919761f74910f42f4b84c004b authored by Linus Torvalds on 14 February 2021, 22:32:24 UTC
Linux 5.11
Linux 5.11
Tip revision: f40ddce
cpumap.c
// SPDX-License-Identifier: GPL-2.0-only
#include <perf/cpumap.h>
#include <stdlib.h>
#include <linux/refcount.h>
#include <internal/cpumap.h>
#include <asm/bug.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <ctype.h>
#include <limits.h>
struct perf_cpu_map *perf_cpu_map__dummy_new(void)
{
struct perf_cpu_map *cpus = malloc(sizeof(*cpus) + sizeof(int));
if (cpus != NULL) {
cpus->nr = 1;
cpus->map[0] = -1;
refcount_set(&cpus->refcnt, 1);
}
return cpus;
}
static void cpu_map__delete(struct perf_cpu_map *map)
{
if (map) {
WARN_ONCE(refcount_read(&map->refcnt) != 0,
"cpu_map refcnt unbalanced\n");
free(map);
}
}
struct perf_cpu_map *perf_cpu_map__get(struct perf_cpu_map *map)
{
if (map)
refcount_inc(&map->refcnt);
return map;
}
void perf_cpu_map__put(struct perf_cpu_map *map)
{
if (map && refcount_dec_and_test(&map->refcnt))
cpu_map__delete(map);
}
static struct perf_cpu_map *cpu_map__default_new(void)
{
struct perf_cpu_map *cpus;
int nr_cpus;
nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
if (nr_cpus < 0)
return NULL;
cpus = malloc(sizeof(*cpus) + nr_cpus * sizeof(int));
if (cpus != NULL) {
int i;
for (i = 0; i < nr_cpus; ++i)
cpus->map[i] = i;
cpus->nr = nr_cpus;
refcount_set(&cpus->refcnt, 1);
}
return cpus;
}
static int cmp_int(const void *a, const void *b)
{
return *(const int *)a - *(const int*)b;
}
static struct perf_cpu_map *cpu_map__trim_new(int nr_cpus, int *tmp_cpus)
{
size_t payload_size = nr_cpus * sizeof(int);
struct perf_cpu_map *cpus = malloc(sizeof(*cpus) + payload_size);
int i, j;
if (cpus != NULL) {
memcpy(cpus->map, tmp_cpus, payload_size);
qsort(cpus->map, nr_cpus, sizeof(int), cmp_int);
/* Remove dups */
j = 0;
for (i = 0; i < nr_cpus; i++) {
if (i == 0 || cpus->map[i] != cpus->map[i - 1])
cpus->map[j++] = cpus->map[i];
}
cpus->nr = j;
assert(j <= nr_cpus);
refcount_set(&cpus->refcnt, 1);
}
return cpus;
}
struct perf_cpu_map *perf_cpu_map__read(FILE *file)
{
struct perf_cpu_map *cpus = NULL;
int nr_cpus = 0;
int *tmp_cpus = NULL, *tmp;
int max_entries = 0;
int n, cpu, prev;
char sep;
sep = 0;
prev = -1;
for (;;) {
n = fscanf(file, "%u%c", &cpu, &sep);
if (n <= 0)
break;
if (prev >= 0) {
int new_max = nr_cpus + cpu - prev - 1;
WARN_ONCE(new_max >= MAX_NR_CPUS, "Perf can support %d CPUs. "
"Consider raising MAX_NR_CPUS\n", MAX_NR_CPUS);
if (new_max >= max_entries) {
max_entries = new_max + MAX_NR_CPUS / 2;
tmp = realloc(tmp_cpus, max_entries * sizeof(int));
if (tmp == NULL)
goto out_free_tmp;
tmp_cpus = tmp;
}
while (++prev < cpu)
tmp_cpus[nr_cpus++] = prev;
}
if (nr_cpus == max_entries) {
max_entries += MAX_NR_CPUS;
tmp = realloc(tmp_cpus, max_entries * sizeof(int));
if (tmp == NULL)
goto out_free_tmp;
tmp_cpus = tmp;
}
tmp_cpus[nr_cpus++] = cpu;
if (n == 2 && sep == '-')
prev = cpu;
else
prev = -1;
if (n == 1 || sep == '\n')
break;
}
if (nr_cpus > 0)
cpus = cpu_map__trim_new(nr_cpus, tmp_cpus);
else
cpus = cpu_map__default_new();
out_free_tmp:
free(tmp_cpus);
return cpus;
}
static struct perf_cpu_map *cpu_map__read_all_cpu_map(void)
{
struct perf_cpu_map *cpus = NULL;
FILE *onlnf;
onlnf = fopen("/sys/devices/system/cpu/online", "r");
if (!onlnf)
return cpu_map__default_new();
cpus = perf_cpu_map__read(onlnf);
fclose(onlnf);
return cpus;
}
struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list)
{
struct perf_cpu_map *cpus = NULL;
unsigned long start_cpu, end_cpu = 0;
char *p = NULL;
int i, nr_cpus = 0;
int *tmp_cpus = NULL, *tmp;
int max_entries = 0;
if (!cpu_list)
return cpu_map__read_all_cpu_map();
/*
* must handle the case of empty cpumap to cover
* TOPOLOGY header for NUMA nodes with no CPU
* ( e.g., because of CPU hotplug)
*/
if (!isdigit(*cpu_list) && *cpu_list != '\0')
goto out;
while (isdigit(*cpu_list)) {
p = NULL;
start_cpu = strtoul(cpu_list, &p, 0);
if (start_cpu >= INT_MAX
|| (*p != '\0' && *p != ',' && *p != '-'))
goto invalid;
if (*p == '-') {
cpu_list = ++p;
p = NULL;
end_cpu = strtoul(cpu_list, &p, 0);
if (end_cpu >= INT_MAX || (*p != '\0' && *p != ','))
goto invalid;
if (end_cpu < start_cpu)
goto invalid;
} else {
end_cpu = start_cpu;
}
WARN_ONCE(end_cpu >= MAX_NR_CPUS, "Perf can support %d CPUs. "
"Consider raising MAX_NR_CPUS\n", MAX_NR_CPUS);
for (; start_cpu <= end_cpu; start_cpu++) {
/* check for duplicates */
for (i = 0; i < nr_cpus; i++)
if (tmp_cpus[i] == (int)start_cpu)
goto invalid;
if (nr_cpus == max_entries) {
max_entries += MAX_NR_CPUS;
tmp = realloc(tmp_cpus, max_entries * sizeof(int));
if (tmp == NULL)
goto invalid;
tmp_cpus = tmp;
}
tmp_cpus[nr_cpus++] = (int)start_cpu;
}
if (*p)
++p;
cpu_list = p;
}
if (nr_cpus > 0)
cpus = cpu_map__trim_new(nr_cpus, tmp_cpus);
else if (*cpu_list != '\0')
cpus = cpu_map__default_new();
else
cpus = perf_cpu_map__dummy_new();
invalid:
free(tmp_cpus);
out:
return cpus;
}
int perf_cpu_map__cpu(const struct perf_cpu_map *cpus, int idx)
{
if (cpus && idx < cpus->nr)
return cpus->map[idx];
return -1;
}
int perf_cpu_map__nr(const struct perf_cpu_map *cpus)
{
return cpus ? cpus->nr : 1;
}
bool perf_cpu_map__empty(const struct perf_cpu_map *map)
{
return map ? map->map[0] == -1 : true;
}
int perf_cpu_map__idx(struct perf_cpu_map *cpus, int cpu)
{
int i;
for (i = 0; i < cpus->nr; ++i) {
if (cpus->map[i] == cpu)
return i;
}
return -1;
}
int perf_cpu_map__max(struct perf_cpu_map *map)
{
int i, max = -1;
for (i = 0; i < map->nr; i++) {
if (map->map[i] > max)
max = map->map[i];
}
return max;
}
/*
* Merge two cpumaps
*
* orig either gets freed and replaced with a new map, or reused
* with no reference count change (similar to "realloc")
* other has its reference count increased.
*/
struct perf_cpu_map *perf_cpu_map__merge(struct perf_cpu_map *orig,
struct perf_cpu_map *other)
{
int *tmp_cpus;
int tmp_len;
int i, j, k;
struct perf_cpu_map *merged;
if (!orig && !other)
return NULL;
if (!orig) {
perf_cpu_map__get(other);
return other;
}
if (!other)
return orig;
if (orig->nr == other->nr &&
!memcmp(orig->map, other->map, orig->nr * sizeof(int)))
return orig;
tmp_len = orig->nr + other->nr;
tmp_cpus = malloc(tmp_len * sizeof(int));
if (!tmp_cpus)
return NULL;
/* Standard merge algorithm from wikipedia */
i = j = k = 0;
while (i < orig->nr && j < other->nr) {
if (orig->map[i] <= other->map[j]) {
if (orig->map[i] == other->map[j])
j++;
tmp_cpus[k++] = orig->map[i++];
} else
tmp_cpus[k++] = other->map[j++];
}
while (i < orig->nr)
tmp_cpus[k++] = orig->map[i++];
while (j < other->nr)
tmp_cpus[k++] = other->map[j++];
assert(k <= tmp_len);
merged = cpu_map__trim_new(k, tmp_cpus);
free(tmp_cpus);
perf_cpu_map__put(orig);
return merged;
}