void mem_map()
{
static char *p;
if (flag_allocated) {
if (munmap(p, memsize) == -1)
err(5, "munmap failed");
} else {
p = mmap(NULL, memsize, PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_ANONYMOUS, 0, 0);
if (p == MAP_FAILED)
err(4, "mmap failed");
touch_memory(p);
}
flag_allocated = !flag_allocated;
}
/*
* segment_touch() - "touch" [read or write] each page of specified range
* -- from offset to offset+length -- to fault in or to
* test protection.
* NOTE: offset is relative to start of mapping, not start of file!
*/
int
segment_touch(char *name, range_t *range, int rw)
{
glctx_t *gcp = &glctx;
segment_t *segp;
off_t offset;
size_t length, maxlength;
unsigned long *memp;
struct timeval t_start, t_end;
segp = segment_get(name);
if (segp == NULL) {
fprintf(stderr, "%s: no such segment: %s\n",
gcp->program_name, name);
return SEG_ERR;
}
offset = round_down_to_pagesize(range->offset);
if (offset >= segp->seg_length) {
fprintf(stderr, "%s: offset %ld is past end of segment %s\n",
gcp->program_name, offset, name);
return SEG_ERR;
}
memp = (unsigned long*)(segp->seg_start + offset);
maxlength = segp->seg_length - offset;
length = range->length;
if (length)
length = round_up_to_pagesize(length);
/*
* note: we silently truncate to max length [end of segment]
*/
if (length == 0 || length > maxlength)
length = maxlength;
gettimeofday(&t_start, NULL);
touch_memory(rw, memp, length);
gettimeofday(&t_end, NULL);
printf("%s: touched %d pages in %6.3f secs\n",
gcp->program_name, length/gcp->pagesize,
(float)(tv_diff_usec(&t_start, &t_end))/1000000.0);
return SEG_OK;
}
