static int stress_mremap_child(
const args_t *args,
const size_t sz,
size_t new_sz,
const size_t page_size,
const size_t mremap_bytes,
int *flags)
{
do {
uint8_t *buf = NULL;
size_t old_sz;
if (!g_keep_stressing_flag)
break;
buf = mmap(NULL, new_sz, PROT_READ | PROT_WRITE, *flags, -1, 0);
if (buf == MAP_FAILED) {
/* Force MAP_POPULATE off, just in case */
#if defined(MAP_POPULATE)
*flags &= ~MAP_POPULATE;
#endif
continue; /* Try again */
}
(void)madvise_random(buf, new_sz);
(void)mincore_touch_pages(buf, mremap_bytes);
/* Ensure we can write to the mapped pages */
if (g_opt_flags & OPT_FLAGS_VERIFY) {
mmap_set(buf, new_sz, page_size);
if (mmap_check(buf, sz, page_size) < 0) {
pr_fail("%s: mmap'd region of %zu "
"bytes does not contain expected data\n",
args->name, sz);
(void)munmap(buf, new_sz);
return EXIT_FAILURE;
}
}
old_sz = new_sz;
new_sz >>= 1;
while (new_sz > page_size) {
if (try_remap(args, &buf, old_sz, new_sz) < 0) {
(void)munmap(buf, old_sz);
return EXIT_FAILURE;
}
(void)madvise_random(buf, new_sz);
if (g_opt_flags & OPT_FLAGS_VERIFY) {
if (mmap_check(buf, new_sz, page_size) < 0) {
pr_fail("%s: mremap'd region "
"of %zu bytes does "
"not contain expected data\n",
args->name, sz);
(void)munmap(buf, new_sz);
return EXIT_FAILURE;
}
}
old_sz = new_sz;
new_sz >>= 1;
}
new_sz <<= 1;
while (new_sz < mremap_bytes) {
if (try_remap(args, &buf, old_sz, new_sz) < 0) {
(void)munmap(buf, old_sz);
return EXIT_FAILURE;
}
(void)madvise_random(buf, new_sz);
old_sz = new_sz;
new_sz <<= 1;
}
(void)munmap(buf, old_sz);
inc_counter(args);
} while (keep_stressing());
return EXIT_SUCCESS;
}
/*
* stress_mremap()
* stress mmap
*/
int stress_mremap(
uint64_t *const counter,
const uint32_t instance,
const uint64_t max_ops,
const char *name)
{
uint8_t *buf = NULL;
const size_t page_size = stress_get_pagesize();
size_t sz, new_sz, old_sz;
int flags = MAP_PRIVATE | MAP_ANONYMOUS;
(void)instance;
#ifdef MAP_POPULATE
flags |= MAP_POPULATE;
#endif
if (!set_mremap_bytes) {
if (opt_flags & OPT_FLAGS_MAXIMIZE)
opt_mremap_bytes = MAX_MREMAP_BYTES;
if (opt_flags & OPT_FLAGS_MINIMIZE)
opt_mremap_bytes = MIN_MREMAP_BYTES;
}
new_sz = sz = opt_mremap_bytes & ~(page_size - 1);
/* Make sure this is killable by OOM killer */
set_oom_adjustment(name, true);
do {
if (!opt_do_run)
break;
buf = mmap(NULL, new_sz, PROT_READ | PROT_WRITE, flags, -1, 0);
if (buf == MAP_FAILED) {
/* Force MAP_POPULATE off, just in case */
#ifdef MAP_POPULATE
flags &= ~MAP_POPULATE;
#endif
continue; /* Try again */
}
(void)madvise_random(buf, new_sz);
(void)mincore_touch_pages(buf, opt_mremap_bytes);
/* Ensure we can write to the mapped pages */
if (opt_flags & OPT_FLAGS_VERIFY) {
stress_mremap_set(buf, new_sz, page_size);
if (stress_mremap_check(buf, sz, page_size) < 0) {
pr_fail(stderr, "%s: mmap'd region of %zu "
"bytes does not contain expected data\n",
name, sz);
munmap(buf, new_sz);
return EXIT_FAILURE;
}
}
old_sz = new_sz;
new_sz >>= 1;
while (new_sz > page_size) {
if (try_remap(name, &buf, old_sz, new_sz) < 0) {
munmap(buf, old_sz);
return EXIT_FAILURE;
}
(void)madvise_random(buf, new_sz);
if (opt_flags & OPT_FLAGS_VERIFY) {
if (stress_mremap_check(buf, new_sz, page_size) < 0) {
pr_fail(stderr, "%s: mremap'd region "
"of %zu bytes does "
"not contain expected data\n",
name, sz);
munmap(buf, new_sz);
return EXIT_FAILURE;
}
}
old_sz = new_sz;
new_sz >>= 1;
}
new_sz <<= 1;
while (new_sz < opt_mremap_bytes) {
if (try_remap(name, &buf, old_sz, new_sz) < 0) {
munmap(buf, old_sz);
return EXIT_FAILURE;
}
(void)madvise_random(buf, new_sz);
old_sz = new_sz;
new_sz <<= 1;
}
(void)munmap(buf, old_sz);
(*counter)++;
} while (opt_do_run && (!max_ops || *counter < max_ops));
return EXIT_SUCCESS;
}