static void *perf_event_mmap(int fd)
{
int mmap_size = perf_mmap_size();
void *base;
base = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (base == MAP_FAILED) {
p_err("event mmap failed: %s\n", strerror(errno));
return NULL;
}
return base;
}
/* Open a perf event with ring buffer for the current thread */
int perf_fd_open(struct perf_fd *p, struct perf_event_attr *attr, int buf_size_shift)
{
p->pfd = syscall(__NR_perf_event_open, attr, 0, -1, -1, 0);
if (p->pfd < 0)
return -1;
struct perf_event_mmap_page *mpage;
mpage = mmap(NULL, perf_mmap_size(buf_size_shift),
PROT_READ|PROT_WRITE, MAP_SHARED,
p->pfd, 0);
if (mpage == (struct perf_event_mmap_page *)-1L) {
close(p->pfd);
return -1;
}
p->mpage = mpage;
p->buf_size_shift = buf_size_shift;
return 0;
}
static void perf_event_unmap(void *mem)
{
if (munmap(mem, perf_mmap_size()))
fprintf(stderr, "Can't unmap ring memory!\n");
}
void perf_fd_close(struct perf_fd *p)
{
munmap(p->mpage, perf_mmap_size(p->buf_size_shift));
close(p->pfd);
p->mpage = NULL;
}
