[PATCH v8 10/10] selftests/mm/cow: Add tests for anonymous multi-size THP

Ryan Roberts
2023-12-04T10:22:03Z

Add tests similar to the existing PMD-sized THP tests, but which operate
on memory backed by (PTE-mapped) multi-size THP. This reuses all the
existing infrastructure. If the test suite detects that multi-size THP
is not supported by the kernel, the new tests are skipped.

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---
tools/testing/selftests/mm/cow.c | 84 +++++++++++++++++++++++++++-----
1 file changed, 72 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/mm/cow.c b/tools/testing/selftests/mm/cow.c
index 4d0b5a125d3c..37b4d7d28ae9 100644
--- a/tools/testing/selftests/mm/cow.c
+++ b/tools/testing/selftests/mm/cow.c
@@ -29,15 +29,49 @@
#include "../../../../mm/gup_test.h"
#include "../kselftest.h"
#include "vm_util.h"
+#include "thp_settings.h"

static size_t pagesize;
static int pagemap_fd;
static size_t pmdsize;
+static int nr_thpsizes;
+static size_t thpsizes[20];
static int nr_hugetlbsizes;
static size_t hugetlbsizes[10];
static int gup_fd;
static bool has_huge_zeropage;

+static int sz2ord(size_t size)
+{
+ return __builtin_ctzll(size / pagesize);
+}
+
+static int detect_thp_sizes(size_t sizes[], int max)
+{
+ int count = 0;
+ unsigned long orders;
+ size_t kb;
+ int i;
+
+ /* thp not supported at all. */
+ if (!pmdsize)
+ return 0;
+
+ orders = 1UL << sz2ord(pmdsize);
+ orders |= thp_supported_orders();
+
+ for (i = 0; orders && count < max; i++) {
+ if (!(orders & (1UL << i)))
+ continue;
+ orders &= ~(1UL << i);
+ kb = (pagesize >> 10) << i;
+ sizes[count++] = kb * 1024;
+ ksft_print_msg("[INFO] detected THP size: %zu KiB\n", kb);
+ }
+
+ return count;
+}
+
static void detect_huge_zeropage(void)
{
int fd = open("/sys/kernel/mm/transparent_hugepage/use_zero_page",
@@ -1101,15 +1135,27 @@ static void run_anon_test_case(struct test_case const *test_case)

run_with_base_page(test_case->fn, test_case->desc);
run_with_base_page_swap(test_case->fn, test_case->desc);
- if (pmdsize) {
- run_with_thp(test_case->fn, test_case->desc, pmdsize);
- run_with_thp_swap(test_case->fn, test_case->desc, pmdsize);
- run_with_pte_mapped_thp(test_case->fn, test_case->desc, pmdsize);
- run_with_pte_mapped_thp_swap(test_case->fn, test_case->desc, pmdsize);
- run_with_single_pte_of_thp(test_case->fn, test_case->desc, pmdsize);
- run_with_single_pte_of_thp_swap(test_case->fn, test_case->desc, pmdsize);
- run_with_partial_mremap_thp(test_case->fn, test_case->desc, pmdsize);
- run_with_partial_shared_thp(test_case->fn, test_case->desc, pmdsize);
+ for (i = 0; i < nr_thpsizes; i++) {
+ size_t size = thpsizes[i];
+ struct thp_settings settings = *thp_current_settings();
+
+ settings.hugepages[sz2ord(pmdsize)].enabled = THP_NEVER;
+ settings.hugepages[sz2ord(size)].enabled = THP_ALWAYS;
+ thp_push_settings(&settings);
+
+ if (size == pmdsize) {
+ run_with_thp(test_case->fn, test_case->desc, size);
+ run_with_thp_swap(test_case->fn, test_case->desc, size);
+ }
+
+ run_with_pte_mapped_thp(test_case->fn, test_case->desc, size);
+ run_with_pte_mapped_thp_swap(test_case->fn, test_case->desc, size);
+ run_with_single_pte_of_thp(test_case->fn, test_case->desc, size);
+ run_with_single_pte_of_thp_swap(test_case->fn, test_case->desc, size);
+ run_with_partial_mremap_thp(test_case->fn, test_case->desc, size);
+ run_with_partial_shared_thp(test_case->fn, test_case->desc, size);
+
+ thp_pop_settings();
}
for (i = 0; i < nr_hugetlbsizes; i++)
run_with_hugetlb(test_case->fn, test_case->desc,
@@ -1130,8 +1176,9 @@ static int tests_per_anon_test_case(void)
{
int tests = 2 + nr_hugetlbsizes;

+ tests += 6 * nr_thpsizes;
if (pmdsize)
- tests += 8;
+ tests += 2;
return tests;
}

@@ -1689,15 +1736,23 @@ static int tests_per_non_anon_test_case(void)
int main(int argc, char **argv)
{
int err;
+ struct thp_settings default_settings;

pagesize = getpagesize();
pmdsize = read_pmd_pagesize();
if (pmdsize) {
+ /* Only if THP is supported. */
+ thp_read_settings(&default_settings);
+ default_settings.hugepages[sz2ord(pmdsize)].enabled = THP_INHERIT;
+ thp_save_settings();
+ thp_push_settings(&default_settings);
+
ksft_print_msg("[INFO] detected PMD size: %zu KiB\n",
pmdsize / 1024);
- ksft_print_msg("[INFO] detected THP size: %zu KiB\n",
- pmdsize / 1024);
+
+ nr_thpsizes = detect_thp_sizes(thpsizes, ARRAY_SIZE(thpsizes));
}
+
nr_hugetlbsizes = detect_hugetlb_page_sizes(hugetlbsizes,
ARRAY_SIZE(hugetlbsizes));
detect_huge_zeropage();
@@ -1716,6 +1771,11 @@ int main(int argc, char **argv)
run_anon_thp_test_cases();
run_non_anon_test_cases();

+ if (pmdsize) {
+ /* Only if THP is supported. */
+ thp_restore_settings();
+ }
+
err = ksft_get_fail_cnt();
if (err)
ksft_exit_fail_msg("%d out of %d tests failed\n",
--
2.25.1