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taskset: move NR_CPUS determination to lib/cpuset.c 

Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
Karel Zak 2010-05-28 11:08:39 +02:00
parent d50363cd62
commit bae91ecf07
3 changed files with 45 additions and 37 deletions
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2
include/cpuset.h
View File

@ -51,6 +51,8 @@ extern int __cpuset_count_s(size_t setsize, const cpu_set_t *set);
#define cpuset_nbits(setsize) (8 * (setsize))
extern int get_max_number_of_cpus(void);
extern cpu_set_t *cpuset_alloc(int ncpus, size_t *setsize, size_t *nbits);
extern void cpuset_free(cpu_set_t *set);

41
lib/cpuset.c
View File

@ -18,6 +18,7 @@
#include <errno.h>
#include <string.h>
#include <ctype.h>
#include <sys/syscall.h>
#include "cpuset.h"
@ -53,6 +54,38 @@ static const char *nexttoken(const char *q, int sep)
return q;
}
/*
* Number of bits in a CPU bitmask on current system
*/
int get_max_number_of_cpus(void)
{
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;
}
return -1;
}
/*
* Allocates a new set for ncpus and returns size in bytes and size in bits
*/
@ -200,7 +233,13 @@ int cpumask_parse(const char *str, cpu_set_t *set, size_t setsize)
CPU_ZERO_S(setsize, set);
while (ptr >= str) {
char val = char_to_val(*ptr);
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)

39
schedutils/taskset.c
View File

@ -27,7 +27,6 @@
#include <errno.h>
#include <string.h>
#include <ctype.h>
#include <sys/syscall.h>
#include <err.h>
#include "cpuset.h"
@ -64,40 +63,6 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
}
/*
* Number of bits in a CPU bitmask on current system
*/
static int max_number_of_cpus(void)
{
int n, cpus = 2048;
size_t setsize;
cpu_set_t *set = cpuset_alloc(cpus, &setsize, NULL);
if (!set)
goto err;
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)
goto err;
continue;
}
cpuset_free(set);
return n * 8;
}
err:
errx(EXIT_FAILURE, _("cannot determine NR_CPUS; aborting"));
return 0;
}
int main(int argc, char *argv[])
{
cpu_set_t *new_set, *cur_set;
@ -143,7 +108,9 @@ int main(int argc, char *argv[])
|| (pid && (argc - optind < 1 || argc - optind > 2)))
usage(stderr);
ncpus = max_number_of_cpus();
ncpus = get_max_number_of_cpus();
if (ncpus <= 0)
errx(EXIT_FAILURE, _("cannot determine NR_CPUS; aborting"));
/*
* cur_set is always used for the sched_getaffinity call