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util-linux/lib/cpuset.c

415 lines
8.4 KiB

/*
* Terminology:
*
* cpuset - (libc) cpu_set_t data structure represents set of CPUs
* cpumask - string with hex mask (e.g. "0x00000001")
* cpulist - string with CPU ranges (e.g. "0-3,5,7,8")
*
* Based on code from taskset.c and Linux kernel.
*
* This file may be redistributed under the terms of the
* GNU Lesser General Public License.
*
* Copyright (C) 2010 Karel Zak <kzak@redhat.com>
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sched.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>
#ifdef HAVE_SYS_SYSCALL_H
#include <sys/syscall.h>
#endif
#include "cpuset.h"
#include "c.h"
static inline int val_to_char(int v)
{
if (v >= 0 && v < 10)
return '0' + v;
if (v >= 10 && v < 16)
return ('a' - 10) + v;
return -1;
}
static inline int char_to_val(int c)
{
int cl;
if (c >= '0' && c <= '9')
return c - '0';
cl = tolower(c);
if (cl >= 'a' && cl <= 'f')
return cl + (10 - 'a');
return -1;
}
static const char *nexttoken(const char *q, int sep)
{
if (q)
q = strchr(q, sep);
if (q)
q++;
return q;
}
/*
* Number of bits in a CPU bitmask on current system
*/
int get_max_number_of_cpus(void)
{
#ifdef SYS_sched_getaffinity
int n, cpus = 2048;
size_t setsize;
cpu_set_t *set = cpuset_alloc(cpus, &setsize, NULL);
if (!set)
return -1; /* error */
for (;;) {
CPU_ZERO_S(setsize, set);
/* the library version does not return size of cpumask_t */
n = syscall(SYS_sched_getaffinity, 0, setsize, set);
if (n < 0 && errno == EINVAL && cpus < 1024 * 1024) {
cpuset_free(set);
cpus *= 2;
set = cpuset_alloc(cpus, &setsize, NULL);
if (!set)
return -1; /* error */
continue;
}
cpuset_free(set);
return n * 8;
}
#endif
return -1;
}
/*
* Allocates a new set for ncpus and returns size in bytes and size in bits
*/
cpu_set_t *cpuset_alloc(int ncpus, size_t *setsize, size_t *nbits)
{
cpu_set_t *set = CPU_ALLOC(ncpus);
if (!set)
return NULL;
if (setsize)
*setsize = CPU_ALLOC_SIZE(ncpus);
if (nbits)
*nbits = cpuset_nbits(CPU_ALLOC_SIZE(ncpus));
return set;
}
void cpuset_free(cpu_set_t *set)
{
CPU_FREE(set);
}
#if !HAVE_DECL_CPU_ALLOC
/* Please, use CPU_COUNT_S() macro. This is fallback */
int __cpuset_count_s(size_t setsize, const cpu_set_t *set)
{
int s = 0;
const __cpu_mask *p = set->__bits;
const __cpu_mask *end = &set->__bits[setsize / sizeof (__cpu_mask)];
while (p < end) {
__cpu_mask l = *p++;
if (l == 0)
continue;
# if LONG_BIT > 32
l = (l & 0x5555555555555555ul) + ((l >> 1) & 0x5555555555555555ul);
l = (l & 0x3333333333333333ul) + ((l >> 2) & 0x3333333333333333ul);
l = (l & 0x0f0f0f0f0f0f0f0ful) + ((l >> 4) & 0x0f0f0f0f0f0f0f0ful);
l = (l & 0x00ff00ff00ff00fful) + ((l >> 8) & 0x00ff00ff00ff00fful);
l = (l & 0x0000ffff0000fffful) + ((l >> 16) & 0x0000ffff0000fffful);
l = (l & 0x00000000fffffffful) + ((l >> 32) & 0x00000000fffffffful);
# else
l = (l & 0x55555555ul) + ((l >> 1) & 0x55555555ul);
l = (l & 0x33333333ul) + ((l >> 2) & 0x33333333ul);
l = (l & 0x0f0f0f0ful) + ((l >> 4) & 0x0f0f0f0ful);
l = (l & 0x00ff00fful) + ((l >> 8) & 0x00ff00fful);
l = (l & 0x0000fffful) + ((l >> 16) & 0x0000fffful);
# endif
s += l;
}
return s;
}
#endif
/*
* Returns human readable representation of the cpuset. The output format is
* a list of CPUs with ranges (for example, "0,1,3-9").
*/
char *cpulist_create(char *str, size_t len,
cpu_set_t *set, size_t setsize)
{
size_t i;
char *ptr = str;
int entry_made = 0;
size_t max = cpuset_nbits(setsize);
for (i = 0; i < max; i++) {
if (CPU_ISSET_S(i, setsize, set)) {
int rlen;
size_t j, run = 0;
entry_made = 1;
for (j = i + 1; j < max; j++) {
if (CPU_ISSET_S(j, setsize, set))
run++;
else
break;
}
if (!run)
rlen = snprintf(ptr, len, "%zu,", i);
else if (run == 1) {
rlen = snprintf(ptr, len, "%zu,%zu,", i, i + 1);
i++;
} else {
rlen = snprintf(ptr, len, "%zu-%zu,", i, i + run);
i += run;
}
if (rlen < 0 || (size_t) rlen >= len)
return NULL;
ptr += rlen;
len -= rlen;
}
}
ptr -= entry_made;
*ptr = '\0';
return str;
}
/*
* Returns string with CPU mask.
*/
char *cpumask_create(char *str, size_t len,
cpu_set_t *set, size_t setsize)
{
char *ptr = str;
char *ret = NULL;
int cpu;
for (cpu = cpuset_nbits(setsize) - 4; cpu >= 0; cpu -= 4) {
char val = 0;
if (len == (size_t) (ptr - str))
break;
if (CPU_ISSET_S(cpu, setsize, set))
val |= 1;
if (CPU_ISSET_S(cpu + 1, setsize, set))
val |= 2;
if (CPU_ISSET_S(cpu + 2, setsize, set))
val |= 4;
if (CPU_ISSET_S(cpu + 3, setsize, set))
val |= 8;
if (!ret && val)
ret = ptr;
*ptr++ = val_to_char(val);
}
*ptr = '\0';
return ret ? ret : ptr - 1;
}
/*
* Parses string with CPUs mask.
*/
int cpumask_parse(const char *str, cpu_set_t *set, size_t setsize)
{
int len = strlen(str);
const char *ptr = str + len - 1;
int cpu = 0;
/* skip 0x, it's all hex anyway */
if (len > 1 && !memcmp(str, "0x", 2L))
str += 2;
CPU_ZERO_S(setsize, set);
while (ptr >= str) {
char val;
/* cpu masks in /sys uses comma as a separator */
if (*ptr == ',')
ptr--;
val = char_to_val(*ptr);
if (val == (char) -1)
return -1;
if (val & 1)
CPU_SET_S(cpu, setsize, set);
if (val & 2)
CPU_SET_S(cpu + 1, setsize, set);
if (val & 4)
CPU_SET_S(cpu + 2, setsize, set);
if (val & 8)
CPU_SET_S(cpu + 3, setsize, set);
ptr--;
cpu += 4;
}
return 0;
}
static int nextnumber(const char *str, char **end, unsigned int *result)
{
errno = 0;
if (str == NULL || *str == '\0' || !isdigit(*str))
return -EINVAL;
*result = (unsigned int) strtoul(str, end, 10);
if (errno)
return -errno;
if (str == *end)
return -EINVAL;
return 0;
}
/*
* Parses string with list of CPU ranges.
* Returns 0 on success.
* Returns 1 on error.
* Returns 2 if fail is set and a cpu number passed in the list doesn't fit
* into the cpu_set. If fail is not set cpu numbers that do not fit are
* ignored and 0 is returned instead.
*/
int cpulist_parse(const char *str, cpu_set_t *set, size_t setsize, int fail)
{
size_t max = cpuset_nbits(setsize);
const char *p, *q;
char *end = NULL;
q = str;
CPU_ZERO_S(setsize, set);
while (p = q, q = nexttoken(q, ','), p) {
unsigned int a; /* beginning of range */
unsigned int b; /* end of range */
unsigned int s; /* stride */
const char *c1, *c2;
if (nextnumber(p, &end, &a) != 0)
return 1;
b = a;
s = 1;
p = end;
c1 = nexttoken(p, '-');
c2 = nexttoken(p, ',');
if (c1 != NULL && (c2 == NULL || c1 < c2)) {
if (nextnumber(c1, &end, &b) != 0)
return 1;
c1 = end && *end ? nexttoken(end, ':') : NULL;
if (c1 != NULL && (c2 == NULL || c1 < c2)) {
if (nextnumber(c1, &end, &s) != 0)
return 1;
if (s == 0)
return 1;
}
}
if (!(a <= b))
return 1;
while (a <= b) {
if (fail && (a >= max))
return 2;
CPU_SET_S(a, setsize, set);
a += s;
}
}
if (end && *end)
return 1;
return 0;
}
#ifdef TEST_PROGRAM_CPUSET
#include <getopt.h>
int main(int argc, char *argv[])
{
cpu_set_t *set;
size_t setsize, buflen, nbits;
char *buf, *mask = NULL, *range = NULL;
int ncpus = 2048, rc, c;
static const struct option longopts[] = {
{ "ncpus", 1, NULL, 'n' },
{ "mask", 1, NULL, 'm' },
{ "range", 1, NULL, 'r' },
{ NULL, 0, NULL, 0 }
};
while ((c = getopt_long(argc, argv, "n:m:r:", longopts, NULL)) != -1) {
switch(c) {
case 'n':
ncpus = atoi(optarg);
break;
case 'm':
mask = strdup(optarg);
break;
case 'r':
range = strdup(optarg);
break;
default:
goto usage_err;
}
}
if (!mask && !range)
goto usage_err;
set = cpuset_alloc(ncpus, &setsize, &nbits);
if (!set)
err(EXIT_FAILURE, "failed to allocate cpu set");
/*
fprintf(stderr, "ncpus: %d, cpuset bits: %zd, cpuset bytes: %zd\n",
ncpus, nbits, setsize);
*/
buflen = 7 * nbits;
buf = malloc(buflen);
if (!buf)
err(EXIT_FAILURE, "failed to allocate cpu set buffer");
if (mask)
rc = cpumask_parse(mask, set, setsize);
else
rc = cpulist_parse(range, set, setsize, 0);
if (rc)
errx(EXIT_FAILURE, "failed to parse string: %s", mask ? : range);
printf("%-15s = %15s ", mask ? : range,
cpumask_create(buf, buflen, set, setsize));
printf("[%s]\n", cpulist_create(buf, buflen, set, setsize));
free(buf);
free(mask);
free(range);
cpuset_free(set);
return EXIT_SUCCESS;
usage_err:
fprintf(stderr,
"usage: %s [--ncpus <num>] --mask <mask> | --range <list>\n",
program_invocation_short_name);
exit(EXIT_FAILURE);
}
#endif