#define THP_SYSFS "/sys/kernel/mm/transparent_hugepage/"
#define PID_SMAPS "/proc/self/smaps"
+struct mem_ops {
+ void *(*setup_area)(int nr_hpages);
+ void (*cleanup_area)(void *p, unsigned long size);
+ void (*fault)(void *p, unsigned long start, unsigned long end);
+ bool (*check_huge)(void *addr, int nr_hpages);
+};
+
struct collapse_context {
- void (*collapse)(const char *msg, char *p, int nr_hpages, bool expect);
+ void (*collapse)(const char *msg, char *p, int nr_hpages,
+ struct mem_ops *ops, bool expect);
bool enforce_pte_scan_limits;
};
signal(SIGQUIT, restore_settings);
}
-static bool check_huge(void *addr, int nr_hpages)
-{
- return check_huge_anon(addr, nr_hpages, hpage_pmd_size);
-}
-
#define MAX_LINE_LENGTH 500
static bool check_swap(void *addr, unsigned long size)
{
* Returns pmd-mapped hugepage in VMA marked VM_HUGEPAGE, filled with
* validate_memory()'able contents.
*/
-static void *alloc_hpage(void)
+static void *alloc_hpage(struct mem_ops *ops)
{
- void *p;
+ void *p = ops->setup_area(1);
- p = alloc_mapping(1);
+ ops->fault(p, 0, hpage_pmd_size);
+
+ /*
+ * VMA should be neither VM_HUGEPAGE nor VM_NOHUGEPAGE.
+ * The latter is ineligible for collapse by MADV_COLLAPSE
+ * while the former might cause MADV_COLLAPSE to race with
+ * khugepaged on low-load system (like a test machine), which
+ * would cause MADV_COLLAPSE to fail with EAGAIN.
+ */
printf("Allocate huge page...");
- madvise(p, hpage_pmd_size, MADV_HUGEPAGE);
- fill_memory(p, 0, hpage_pmd_size);
- if (check_huge(p, 1))
- success("OK");
- else
- fail("Fail");
+ if (madvise_collapse_retry(p, hpage_pmd_size)) {
+ perror("madvise(MADV_COLLAPSE)");
+ exit(EXIT_FAILURE);
+ }
+ if (!ops->check_huge(p, 1)) {
+ perror("madvise(MADV_COLLAPSE)");
+ exit(EXIT_FAILURE);
+ }
+ if (madvise(p, hpage_pmd_size, MADV_HUGEPAGE)) {
+ perror("madvise(MADV_HUGEPAGE)");
+ exit(EXIT_FAILURE);
+ }
+ success("OK");
return p;
}
}
}
-static void madvise_collapse(const char *msg, char *p, int nr_hpages,
- bool expect)
+static void *anon_setup_area(int nr_hpages)
+{
+ return alloc_mapping(nr_hpages);
+}
+
+static void anon_cleanup_area(void *p, unsigned long size)
+{
+ munmap(p, size);
+}
+
+static void anon_fault(void *p, unsigned long start, unsigned long end)
+{
+ fill_memory(p, start, end);
+}
+
+static bool anon_check_huge(void *addr, int nr_hpages)
+{
+ return check_huge_anon(addr, nr_hpages, hpage_pmd_size);
+}
+
+static struct mem_ops anon_ops = {
+ .setup_area = &anon_setup_area,
+ .cleanup_area = &anon_cleanup_area,
+ .fault = &anon_fault,
+ .check_huge = &anon_check_huge,
+};
+
+static void __madvise_collapse(const char *msg, char *p, int nr_hpages,
+ struct mem_ops *ops, bool expect)
{
int ret;
struct settings settings = *current_settings();
printf("%s...", msg);
- /* Sanity check */
- if (!check_huge(p, 0)) {
- printf("Unexpected huge page\n");
- exit(EXIT_FAILURE);
- }
/*
* Prevent khugepaged interference and tests that MADV_COLLAPSE
ret = madvise_collapse_retry(p, nr_hpages * hpage_pmd_size);
if (((bool)ret) == expect)
fail("Fail: Bad return value");
- else if (check_huge(p, nr_hpages) != expect)
+ else if (!ops->check_huge(p, expect ? nr_hpages : 0))
fail("Fail: check_huge()");
else
success("OK");
pop_settings();
}
+static void madvise_collapse(const char *msg, char *p, int nr_hpages,
+ struct mem_ops *ops, bool expect)
+{
+ /* Sanity check */
+ if (!ops->check_huge(p, 0)) {
+ printf("Unexpected huge page\n");
+ exit(EXIT_FAILURE);
+ }
+ __madvise_collapse(msg, p, nr_hpages, ops, expect);
+}
+
#define TICK 500000
-static bool wait_for_scan(const char *msg, char *p, int nr_hpages)
+static bool wait_for_scan(const char *msg, char *p, int nr_hpages,
+ struct mem_ops *ops)
{
int full_scans;
int timeout = 6; /* 3 seconds */
/* Sanity check */
- if (!check_huge(p, 0)) {
+ if (!ops->check_huge(p, 0)) {
printf("Unexpected huge page\n");
exit(EXIT_FAILURE);
}
printf("%s...", msg);
while (timeout--) {
- if (check_huge(p, nr_hpages))
+ if (ops->check_huge(p, nr_hpages))
break;
if (read_num("khugepaged/full_scans") >= full_scans)
break;
}
static void khugepaged_collapse(const char *msg, char *p, int nr_hpages,
- bool expect)
+ struct mem_ops *ops, bool expect)
{
- if (wait_for_scan(msg, p, nr_hpages)) {
+ if (wait_for_scan(msg, p, nr_hpages, ops)) {
if (expect)
fail("Timeout");
else
success("OK");
return;
- } else if (check_huge(p, nr_hpages) == expect) {
+ }
+
+ if (ops->check_huge(p, expect ? nr_hpages : 0))
success("OK");
- } else {
+ else
fail("Fail");
- }
}
static void alloc_at_fault(void)
p = alloc_mapping(1);
*p = 1;
printf("Allocate huge page on fault...");
- if (check_huge(p, 1))
+ if (check_huge_anon(p, 1, hpage_pmd_size))
success("OK");
else
fail("Fail");
madvise(p, page_size, MADV_DONTNEED);
printf("Split huge PMD on MADV_DONTNEED...");
- if (check_huge(p, 0))
+ if (check_huge_anon(p, 0, hpage_pmd_size))
success("OK");
else
fail("Fail");
munmap(p, hpage_pmd_size);
}
-static void collapse_full(struct collapse_context *c)
+static void collapse_full(struct collapse_context *c, struct mem_ops *ops)
{
void *p;
int nr_hpages = 4;
unsigned long size = nr_hpages * hpage_pmd_size;
- p = alloc_mapping(nr_hpages);
- fill_memory(p, 0, size);
+ p = ops->setup_area(nr_hpages);
+ ops->fault(p, 0, size);
c->collapse("Collapse multiple fully populated PTE table", p, nr_hpages,
- true);
+ ops, true);
validate_memory(p, 0, size);
- munmap(p, size);
+ ops->cleanup_area(p, size);
}
-static void collapse_empty(struct collapse_context *c)
+static void collapse_empty(struct collapse_context *c, struct mem_ops *ops)
{
void *p;
- p = alloc_mapping(1);
- c->collapse("Do not collapse empty PTE table", p, 1, false);
- munmap(p, hpage_pmd_size);
+ p = ops->setup_area(1);
+ c->collapse("Do not collapse empty PTE table", p, 1, ops, false);
+ ops->cleanup_area(p, hpage_pmd_size);
}
-static void collapse_single_pte_entry(struct collapse_context *c)
+static void collapse_single_pte_entry(struct collapse_context *c, struct mem_ops *ops)
{
void *p;
- p = alloc_mapping(1);
- fill_memory(p, 0, page_size);
+ p = ops->setup_area(1);
+ ops->fault(p, 0, page_size);
c->collapse("Collapse PTE table with single PTE entry present", p,
- 1, true);
- validate_memory(p, 0, page_size);
- munmap(p, hpage_pmd_size);
+ 1, ops, true);
+ ops->cleanup_area(p, hpage_pmd_size);
}
-static void collapse_max_ptes_none(struct collapse_context *c)
+static void collapse_max_ptes_none(struct collapse_context *c, struct mem_ops *ops)
{
int max_ptes_none = hpage_pmd_nr / 2;
struct settings settings = *current_settings();
settings.khugepaged.max_ptes_none = max_ptes_none;
push_settings(&settings);
- p = alloc_mapping(1);
+ p = ops->setup_area(1);
- fill_memory(p, 0, (hpage_pmd_nr - max_ptes_none - 1) * page_size);
+ ops->fault(p, 0, (hpage_pmd_nr - max_ptes_none - 1) * page_size);
c->collapse("Maybe collapse with max_ptes_none exceeded", p, 1,
- !c->enforce_pte_scan_limits);
+ ops, !c->enforce_pte_scan_limits);
validate_memory(p, 0, (hpage_pmd_nr - max_ptes_none - 1) * page_size);
if (c->enforce_pte_scan_limits) {
- fill_memory(p, 0, (hpage_pmd_nr - max_ptes_none) * page_size);
- c->collapse("Collapse with max_ptes_none PTEs empty", p, 1,
+ ops->fault(p, 0, (hpage_pmd_nr - max_ptes_none) * page_size);
+ c->collapse("Collapse with max_ptes_none PTEs empty", p, 1, ops,
true);
validate_memory(p, 0,
(hpage_pmd_nr - max_ptes_none) * page_size);
}
-
- munmap(p, hpage_pmd_size);
+ ops->cleanup_area(p, hpage_pmd_size);
pop_settings();
}
-static void collapse_swapin_single_pte(struct collapse_context *c)
+static void collapse_swapin_single_pte(struct collapse_context *c, struct mem_ops *ops)
{
void *p;
- p = alloc_mapping(1);
- fill_memory(p, 0, hpage_pmd_size);
+
+ p = ops->setup_area(1);
+ ops->fault(p, 0, hpage_pmd_size);
printf("Swapout one page...");
if (madvise(p, page_size, MADV_PAGEOUT)) {
goto out;
}
- c->collapse("Collapse with swapping in single PTE entry", p, 1, true);
+ c->collapse("Collapse with swapping in single PTE entry", p, 1, ops,
+ true);
validate_memory(p, 0, hpage_pmd_size);
out:
- munmap(p, hpage_pmd_size);
+ ops->cleanup_area(p, hpage_pmd_size);
}
-static void collapse_max_ptes_swap(struct collapse_context *c)
+static void collapse_max_ptes_swap(struct collapse_context *c, struct mem_ops *ops)
{
int max_ptes_swap = read_num("khugepaged/max_ptes_swap");
void *p;
- p = alloc_mapping(1);
+ p = ops->setup_area(1);
+ ops->fault(p, 0, hpage_pmd_size);
- fill_memory(p, 0, hpage_pmd_size);
printf("Swapout %d of %d pages...", max_ptes_swap + 1, hpage_pmd_nr);
if (madvise(p, (max_ptes_swap + 1) * page_size, MADV_PAGEOUT)) {
perror("madvise(MADV_PAGEOUT)");
goto out;
}
- c->collapse("Maybe collapse with max_ptes_swap exceeded", p, 1,
+ c->collapse("Maybe collapse with max_ptes_swap exceeded", p, 1, ops,
!c->enforce_pte_scan_limits);
validate_memory(p, 0, hpage_pmd_size);
if (c->enforce_pte_scan_limits) {
- fill_memory(p, 0, hpage_pmd_size);
+ ops->fault(p, 0, hpage_pmd_size);
printf("Swapout %d of %d pages...", max_ptes_swap,
hpage_pmd_nr);
if (madvise(p, max_ptes_swap * page_size, MADV_PAGEOUT)) {
}
c->collapse("Collapse with max_ptes_swap pages swapped out", p,
- 1, true);
+ 1, ops, true);
validate_memory(p, 0, hpage_pmd_size);
}
out:
- munmap(p, hpage_pmd_size);
+ ops->cleanup_area(p, hpage_pmd_size);
}
-static void collapse_single_pte_entry_compound(struct collapse_context *c)
+static void collapse_single_pte_entry_compound(struct collapse_context *c, struct mem_ops *ops)
{
void *p;
- p = alloc_hpage();
+ p = alloc_hpage(ops);
+
madvise(p, hpage_pmd_size, MADV_NOHUGEPAGE);
printf("Split huge page leaving single PTE mapping compound page...");
madvise(p + page_size, hpage_pmd_size - page_size, MADV_DONTNEED);
- if (check_huge(p, 0))
+ if (ops->check_huge(p, 0))
success("OK");
else
fail("Fail");
c->collapse("Collapse PTE table with single PTE mapping compound page",
- p, 1, true);
+ p, 1, ops, true);
validate_memory(p, 0, page_size);
- munmap(p, hpage_pmd_size);
+ ops->cleanup_area(p, hpage_pmd_size);
}
-static void collapse_full_of_compound(struct collapse_context *c)
+static void collapse_full_of_compound(struct collapse_context *c, struct mem_ops *ops)
{
void *p;
- p = alloc_hpage();
+ p = alloc_hpage(ops);
printf("Split huge page leaving single PTE page table full of compound pages...");
madvise(p, page_size, MADV_NOHUGEPAGE);
madvise(p, hpage_pmd_size, MADV_NOHUGEPAGE);
- if (check_huge(p, 0))
+ if (ops->check_huge(p, 0))
success("OK");
else
fail("Fail");
- c->collapse("Collapse PTE table full of compound pages", p, 1, true);
+ c->collapse("Collapse PTE table full of compound pages", p, 1, ops,
+ true);
validate_memory(p, 0, hpage_pmd_size);
- munmap(p, hpage_pmd_size);
+ ops->cleanup_area(p, hpage_pmd_size);
}
-static void collapse_compound_extreme(struct collapse_context *c)
+static void collapse_compound_extreme(struct collapse_context *c, struct mem_ops *ops)
{
void *p;
int i;
- p = alloc_mapping(1);
+ p = ops->setup_area(1);
for (i = 0; i < hpage_pmd_nr; i++) {
printf("\rConstruct PTE page table full of different PTE-mapped compound pages %3d/%d...",
i + 1, hpage_pmd_nr);
madvise(BASE_ADDR, hpage_pmd_size, MADV_HUGEPAGE);
- fill_memory(BASE_ADDR, 0, hpage_pmd_size);
- if (!check_huge(BASE_ADDR, 1)) {
+ ops->fault(BASE_ADDR, 0, hpage_pmd_size);
+ if (!ops->check_huge(BASE_ADDR, 1)) {
printf("Failed to allocate huge page\n");
exit(EXIT_FAILURE);
}
}
}
- munmap(BASE_ADDR, hpage_pmd_size);
- fill_memory(p, 0, hpage_pmd_size);
- if (check_huge(p, 0))
+ ops->cleanup_area(BASE_ADDR, hpage_pmd_size);
+ ops->fault(p, 0, hpage_pmd_size);
+ if (!ops->check_huge(p, 1))
success("OK");
else
fail("Fail");
c->collapse("Collapse PTE table full of different compound pages", p, 1,
- true);
+ ops, true);
validate_memory(p, 0, hpage_pmd_size);
- munmap(p, hpage_pmd_size);
+ ops->cleanup_area(p, hpage_pmd_size);
}
-static void collapse_fork(struct collapse_context *c)
+static void collapse_fork(struct collapse_context *c, struct mem_ops *ops)
{
int wstatus;
void *p;
- p = alloc_mapping(1);
+ p = ops->setup_area(1);
printf("Allocate small page...");
- fill_memory(p, 0, page_size);
- if (check_huge(p, 0))
+ ops->fault(p, 0, page_size);
+ if (ops->check_huge(p, 0))
success("OK");
else
fail("Fail");
skip_settings_restore = true;
exit_status = 0;
- if (check_huge(p, 0))
+ if (ops->check_huge(p, 0))
success("OK");
else
fail("Fail");
- fill_memory(p, page_size, 2 * page_size);
+ ops->fault(p, page_size, 2 * page_size);
c->collapse("Collapse PTE table with single page shared with parent process",
- p, 1, true);
+ p, 1, ops, true);
validate_memory(p, 0, page_size);
- munmap(p, hpage_pmd_size);
+ ops->cleanup_area(p, hpage_pmd_size);
exit(exit_status);
}
exit_status += WEXITSTATUS(wstatus);
printf("Check if parent still has small page...");
- if (check_huge(p, 0))
+ if (ops->check_huge(p, 0))
success("OK");
else
fail("Fail");
validate_memory(p, 0, page_size);
- munmap(p, hpage_pmd_size);
+ ops->cleanup_area(p, hpage_pmd_size);
}
-static void collapse_fork_compound(struct collapse_context *c)
+static void collapse_fork_compound(struct collapse_context *c, struct mem_ops *ops)
{
int wstatus;
void *p;
- p = alloc_hpage();
+ p = alloc_hpage(ops);
printf("Share huge page over fork()...");
if (!fork()) {
/* Do not touch settings on child exit */
skip_settings_restore = true;
exit_status = 0;
- if (check_huge(p, 1))
+ if (ops->check_huge(p, 1))
success("OK");
else
fail("Fail");
printf("Split huge page PMD in child process...");
madvise(p, page_size, MADV_NOHUGEPAGE);
madvise(p, hpage_pmd_size, MADV_NOHUGEPAGE);
- if (check_huge(p, 0))
+ if (ops->check_huge(p, 0))
success("OK");
else
fail("Fail");
- fill_memory(p, 0, page_size);
+ ops->fault(p, 0, page_size);
write_num("khugepaged/max_ptes_shared", hpage_pmd_nr - 1);
c->collapse("Collapse PTE table full of compound pages in child",
- p, 1, true);
+ p, 1, ops, true);
write_num("khugepaged/max_ptes_shared",
current_settings()->khugepaged.max_ptes_shared);
validate_memory(p, 0, hpage_pmd_size);
- munmap(p, hpage_pmd_size);
+ ops->cleanup_area(p, hpage_pmd_size);
exit(exit_status);
}
exit_status += WEXITSTATUS(wstatus);
printf("Check if parent still has huge page...");
- if (check_huge(p, 1))
+ if (ops->check_huge(p, 1))
success("OK");
else
fail("Fail");
validate_memory(p, 0, hpage_pmd_size);
- munmap(p, hpage_pmd_size);
+ ops->cleanup_area(p, hpage_pmd_size);
}
-static void collapse_max_ptes_shared(struct collapse_context *c)
+static void collapse_max_ptes_shared(struct collapse_context *c, struct mem_ops *ops)
{
int max_ptes_shared = read_num("khugepaged/max_ptes_shared");
int wstatus;
void *p;
- p = alloc_hpage();
+ p = alloc_hpage(ops);
printf("Share huge page over fork()...");
if (!fork()) {
/* Do not touch settings on child exit */
skip_settings_restore = true;
exit_status = 0;
- if (check_huge(p, 1))
+ if (ops->check_huge(p, 1))
success("OK");
else
fail("Fail");
printf("Trigger CoW on page %d of %d...",
hpage_pmd_nr - max_ptes_shared - 1, hpage_pmd_nr);
- fill_memory(p, 0, (hpage_pmd_nr - max_ptes_shared - 1) * page_size);
- if (check_huge(p, 0))
+ ops->fault(p, 0, (hpage_pmd_nr - max_ptes_shared - 1) * page_size);
+ if (ops->check_huge(p, 0))
success("OK");
else
fail("Fail");
c->collapse("Maybe collapse with max_ptes_shared exceeded", p,
- 1, !c->enforce_pte_scan_limits);
+ 1, ops, !c->enforce_pte_scan_limits);
if (c->enforce_pte_scan_limits) {
printf("Trigger CoW on page %d of %d...",
hpage_pmd_nr - max_ptes_shared, hpage_pmd_nr);
- fill_memory(p, 0, (hpage_pmd_nr - max_ptes_shared) *
+ ops->fault(p, 0, (hpage_pmd_nr - max_ptes_shared) *
page_size);
- if (check_huge(p, 0))
+ if (ops->check_huge(p, 0))
success("OK");
else
fail("Fail");
c->collapse("Collapse with max_ptes_shared PTEs shared",
- p, 1, true);
+ p, 1, ops, true);
}
validate_memory(p, 0, hpage_pmd_size);
- munmap(p, hpage_pmd_size);
+ ops->cleanup_area(p, hpage_pmd_size);
exit(exit_status);
}
exit_status += WEXITSTATUS(wstatus);
printf("Check if parent still has huge page...");
- if (check_huge(p, 1))
+ if (ops->check_huge(p, 1))
success("OK");
else
fail("Fail");
validate_memory(p, 0, hpage_pmd_size);
- munmap(p, hpage_pmd_size);
+ ops->cleanup_area(p, hpage_pmd_size);
}
-static void madvise_collapse_existing_thps(void)
+static void madvise_collapse_existing_thps(struct collapse_context *c,
+ struct mem_ops *ops)
{
void *p;
- int err;
- p = alloc_mapping(1);
- fill_memory(p, 0, hpage_pmd_size);
+ p = ops->setup_area(1);
+ ops->fault(p, 0, hpage_pmd_size);
+ c->collapse("Collapse fully populated PTE table...", p, 1, ops, true);
+ validate_memory(p, 0, hpage_pmd_size);
- printf("Collapse fully populated PTE table...");
- /*
- * Note that we don't set MADV_HUGEPAGE here, which
- * also tests that VM_HUGEPAGE isn't required for
- * MADV_COLLAPSE in "madvise" mode.
- */
- err = madvise(p, hpage_pmd_size, MADV_COLLAPSE);
- if (err == 0 && check_huge(p, 1)) {
- success("OK");
- printf("Re-collapse PMD-mapped hugepage");
- err = madvise(p, hpage_pmd_size, MADV_COLLAPSE);
- if (err == 0 && check_huge(p, 1))
- success("OK");
- else
- fail("Fail");
- } else {
- fail("Fail");
- }
+ /* c->collapse() will find a hugepage and complain - call directly. */
+ __madvise_collapse("Re-collapse PMD-mapped hugepage", p, 1, ops, true);
validate_memory(p, 0, hpage_pmd_size);
- munmap(p, hpage_pmd_size);
+ ops->cleanup_area(p, hpage_pmd_size);
}
int main(int argc, const char **argv)
c.collapse = &khugepaged_collapse;
c.enforce_pte_scan_limits = true;
- collapse_full(&c);
- collapse_empty(&c);
- collapse_single_pte_entry(&c);
- collapse_max_ptes_none(&c);
- collapse_swapin_single_pte(&c);
- collapse_max_ptes_swap(&c);
- collapse_single_pte_entry_compound(&c);
- collapse_full_of_compound(&c);
- collapse_compound_extreme(&c);
- collapse_fork(&c);
- collapse_fork_compound(&c);
- collapse_max_ptes_shared(&c);
+ collapse_full(&c, &anon_ops);
+ collapse_empty(&c, &anon_ops);
+ collapse_single_pte_entry(&c, &anon_ops);
+ collapse_max_ptes_none(&c, &anon_ops);
+ collapse_swapin_single_pte(&c, &anon_ops);
+ collapse_max_ptes_swap(&c, &anon_ops);
+ collapse_single_pte_entry_compound(&c, &anon_ops);
+ collapse_full_of_compound(&c, &anon_ops);
+ collapse_compound_extreme(&c, &anon_ops);
+ collapse_fork(&c, &anon_ops);
+ collapse_fork_compound(&c, &anon_ops);
+ collapse_max_ptes_shared(&c, &anon_ops);
}
if (!strcmp(tests, "madvise") || !strcmp(tests, "all")) {
printf("\n*** Testing context: madvise ***\n");
c.collapse = &madvise_collapse;
c.enforce_pte_scan_limits = false;
- collapse_full(&c);
- collapse_empty(&c);
- collapse_single_pte_entry(&c);
- collapse_max_ptes_none(&c);
- collapse_swapin_single_pte(&c);
- collapse_max_ptes_swap(&c);
- collapse_single_pte_entry_compound(&c);
- collapse_full_of_compound(&c);
- collapse_compound_extreme(&c);
- collapse_fork(&c);
- collapse_fork_compound(&c);
- collapse_max_ptes_shared(&c);
- madvise_collapse_existing_thps();
+ collapse_full(&c, &anon_ops);
+ collapse_empty(&c, &anon_ops);
+ collapse_single_pte_entry(&c, &anon_ops);
+ collapse_max_ptes_none(&c, &anon_ops);
+ collapse_swapin_single_pte(&c, &anon_ops);
+ collapse_max_ptes_swap(&c, &anon_ops);
+ collapse_single_pte_entry_compound(&c, &anon_ops);
+ collapse_full_of_compound(&c, &anon_ops);
+ collapse_compound_extreme(&c, &anon_ops);
+ collapse_fork(&c, &anon_ops);
+ collapse_fork_compound(&c, &anon_ops);
+ collapse_max_ptes_shared(&c, &anon_ops);
+ madvise_collapse_existing_thps(&c, &anon_ops);
}
restore_settings(0);