mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-14 11:33:46 +00:00
46 lines
900 B
C
46 lines
900 B
C
#define _GNU_SOURCE
|
|
#include <errno.h>
|
|
#include <sched.h>
|
|
#include <syscall.h>
|
|
#include "syscall.h"
|
|
#include "atomic.h"
|
|
|
|
#ifdef VDSO_GETCPU_SYM
|
|
|
|
void *__vdsosym(const char *, const char *);
|
|
|
|
static void *volatile vdso_func;
|
|
|
|
typedef long (*getcpu_f)(unsigned *, unsigned *, void *);
|
|
|
|
static long getcpu_init(unsigned *cpu, unsigned *node, void *unused)
|
|
{
|
|
void *p = __vdsosym(VDSO_GETCPU_VER, VDSO_GETCPU_SYM);
|
|
getcpu_f f = (getcpu_f)p;
|
|
a_cas_p(&vdso_func, (void *)getcpu_init, p);
|
|
return f ? f(cpu, node, unused) : -ENOSYS;
|
|
}
|
|
|
|
static void *volatile vdso_func = (void *)getcpu_init;
|
|
|
|
#endif
|
|
|
|
int sched_getcpu(void)
|
|
{
|
|
int r;
|
|
unsigned cpu;
|
|
|
|
#ifdef VDSO_GETCPU_SYM
|
|
getcpu_f f = (getcpu_f)vdso_func;
|
|
if (f) {
|
|
r = f(&cpu, 0, 0);
|
|
if (!r) return cpu;
|
|
if (r != -ENOSYS) return __syscall_ret(r);
|
|
}
|
|
#endif
|
|
|
|
r = __syscall(SYS_getcpu, &cpu, 0, 0);
|
|
if (!r) return cpu;
|
|
return __syscall_ret(r);
|
|
}
|