On 6/10/26 4:29 AM, Baolin Wang wrote:
> Added a new command 'mthp_khugepaged' for mTHP collapse, along with the '-c'
> parameter to specify the collapse order. Additionally, added mTHP collapse
> test cases for 'collapse_full', 'collapse_empty', and 'collapse_single_mthp'
> for both anonymous pages and shmem. All khugepaged test cases passed.
>
> Signed-off-by: Baolin Wang <[email protected]>
Will rip out the Shmem stuff and test these selftests on top of my mTHP stuff
soon :)
Ill provide the diff so its easier for you and if I come up with more cases ill
add those too.
Thanks for doing this!!!
-- Nico
> ---
> tools/testing/selftests/mm/khugepaged.c | 135 +++++++++++++++++++---
> tools/testing/selftests/mm/run_vmtests.sh | 4 +
> 2 files changed, 120 insertions(+), 19 deletions(-)
>
> diff --git a/tools/testing/selftests/mm/khugepaged.c
> b/tools/testing/selftests/mm/khugepaged.c
> index f69be6be0ecd..8975be5b7b2f 100644
> --- a/tools/testing/selftests/mm/khugepaged.c
> +++ b/tools/testing/selftests/mm/khugepaged.c
> @@ -26,9 +26,11 @@
>
> #define BASE_ADDR ((void *)(1UL << 30))
> static unsigned long hpage_pmd_size;
> +static int hpage_pmd_order;
> static unsigned long page_size;
> static int hpage_pmd_nr;
> static int anon_order;
> +static int collapse_order;
>
> #define PID_SMAPS "/proc/self/smaps"
> #define TEST_FILE "collapse_test_file"
> @@ -69,6 +71,7 @@ struct collapse_context {
> };
>
> static struct collapse_context *khugepaged_context;
> +static struct collapse_context *mthp_khugepaged_context;
> static struct collapse_context *madvise_context;
>
> struct file_info {
> @@ -554,25 +557,25 @@ static void madvise_collapse(const char *msg, char *p,
> int nr_hpages,
> }
>
> #define TICK 500000
> -static bool wait_for_scan(const char *msg, char *p, int nr_hpages,
> - struct mem_ops *ops)
> +static bool wait_for_scan(const char *msg, char *p, unsigned long size,
> + int nr_hpages, int collap_order, struct mem_ops *ops)
> {
> - unsigned long size = nr_hpages * hpage_pmd_size;
> + unsigned long hpage_size = page_size << collap_order;
> int full_scans;
> int timeout = 6; /* 3 seconds */
>
> /* Sanity check */
> - if (!ops->check_huge(p, size, 0, hpage_pmd_size))
> + if (!ops->check_huge(p, size, 0, hpage_size))
> ksft_exit_fail_msg("Unexpected huge page\n");
>
> - madvise(p, nr_hpages * hpage_pmd_size, MADV_HUGEPAGE);
> + madvise(p, size, MADV_HUGEPAGE);
>
> /* Wait until the second full_scan completed */
> full_scans = thp_read_num("khugepaged/full_scans") + 2;
>
> ksft_print_msg("%s...", msg);
> while (timeout--) {
> - if (ops->check_huge(p, size, nr_hpages, hpage_pmd_size))
> + if (ops->check_huge(p, size, nr_hpages, hpage_size))
> break;
> if (thp_read_num("khugepaged/full_scans") >= full_scans)
> break;
> @@ -595,7 +598,7 @@ static void khugepaged_collapse(const char *msg, char *p,
> int nr_hpages,
> if (!is_tmpfs(ops) && ops == &__read_write_file_write_ops)
> expect = false;
>
> - if (wait_for_scan(msg, p, nr_hpages, ops)) {
> + if (wait_for_scan(msg, p, size, nr_hpages, hpage_pmd_order, ops)) {
> if (expect)
> fail("Timeout");
> else
> @@ -617,12 +620,65 @@ static void khugepaged_collapse(const char *msg, char
> *p, int nr_hpages,
> fail("Fail");
> }
>
> +static void mthp_khugepaged_collapse(const char *msg, char *p, int nr_hpages,
> + struct mem_ops *ops, bool expect)
> +{
> + unsigned long hpage_size = page_size << collapse_order;
> + struct thp_settings settings = *thp_current_settings();
> + /* mTHP collpase only allocates PMD sized memory */
> + unsigned long size = hpage_pmd_size;
> +
> + /* Set mTHP setting for mTHP collapse */
> + if (ops == &__anon_ops) {
> + settings.thp_enabled = THP_NEVER;
> + settings.hugepages[collapse_order].enabled = THP_ALWAYS;
> + } else if (ops == &__shmem_ops) {
> + settings.shmem_enabled = SHMEM_NEVER;
> + settings.shmem_hugepages[collapse_order].enabled = SHMEM_ALWAYS;
> + }
> +
> + thp_push_settings(&settings);
> +
> + if (wait_for_scan(msg, p, size, nr_hpages, collapse_order, ops)) {
> + if (expect)
> + fail("Timeout");
> + else
> + success("OK");
> +
> + /* Restore THP settings for mTHP collapse. */
> + thp_pop_settings();
> + return;
> + }
> +
> + /*
> + * For file and shmem memory, khugepaged only retracts pte entries after
> + * putting the new hugepage in the page cache. The hugepage must be
> + * subsequently refaulted to install the pmd mapping for the mm.
> + */
> + if (ops != &__anon_ops)
> + ops->fault(p, 0, nr_hpages * hpage_size);
> +
> + if (ops->check_huge(p, size, expect ? nr_hpages : 0, hpage_size))
> + success("OK");
> + else
> + fail("Fail");
> +
> + /* Restore THP settings for mTHP collapse. */
> + thp_pop_settings();
> +}
> +
> static struct collapse_context __khugepaged_context = {
> .collapse = &khugepaged_collapse,
> .enforce_pte_scan_limits = true,
> .name = "khugepaged",
> };
>
> +static struct collapse_context __mthp_khugepaged_context = {
> + .collapse = &mthp_khugepaged_collapse,
> + .enforce_pte_scan_limits = true,
> + .name = "mthp_khugepaged",
> +};
> +
> static struct collapse_context __madvise_context = {
> .collapse = &madvise_collapse,
> .enforce_pte_scan_limits = false,
> @@ -661,10 +717,17 @@ static void alloc_at_fault(void)
> static void collapse_full(struct collapse_context *c, struct mem_ops *ops)
> {
> void *p;
> - int nr_hpages = 4;
> + int nr_pmds = 4, nr_hpages = 4;
> unsigned long size = nr_hpages * hpage_pmd_size;
>
> - p = ops->setup_area(nr_hpages);
> + /* Only try 1 PMD sized range for mTHP collapse. */
> + if (c == &__mthp_khugepaged_context) {
> + nr_pmds = 1;
> + nr_hpages = 1 << (hpage_pmd_order - collapse_order);
> + size = hpage_pmd_size;
> + }
> +
> + p = ops->setup_area(nr_pmds);
> ops->fault(p, 0, size);
> c->collapse("Collapse multiple fully populated PTE table", p, nr_hpages,
> ops, true);
> @@ -676,10 +739,31 @@ static void collapse_full(struct collapse_context *c,
> struct mem_ops *ops)
>
> static void collapse_empty(struct collapse_context *c, struct mem_ops *ops)
> {
> + int nr_hpages = 1;
> + void *p;
> +
> + if (c == &__mthp_khugepaged_context)
> + nr_hpages = 1 << (hpage_pmd_order - collapse_order);
> +
> + p = ops->setup_area(1);
> + c->collapse("Do not collapse empty PTE table", p, nr_hpages, ops,
> false);
> + ops->cleanup_area(p, hpage_pmd_size);
> + ksft_test_result_report(exit_status, "%s\n", __func__);
> +}
> +
> +static void collapse_single_mthp(struct collapse_context *c, struct mem_ops
> *ops)
> +{
> + unsigned long hpage_size = page_size << collapse_order;
> void *p;
>
> p = ops->setup_area(1);
> - c->collapse("Do not collapse empty PTE table", p, 1, ops, false);
> + /*
> + * Only fault collapse_order sized ranges, and only check 1
> + * collapse_order sized huge page.
> + */
> + ops->fault(p, 0, hpage_size);
> + c->collapse("Collapse PTE table with half PTE entries present",
> + p, 1, ops, true);
> ops->cleanup_area(p, hpage_pmd_size);
> ksft_test_result_report(exit_status, "%s\n", __func__);
> }
> @@ -1081,8 +1165,8 @@ static void madvise_retracted_page_tables(struct
> collapse_context *c,
> ops->fault(p, 0, size);
>
> /* Let khugepaged collapse and leave pmd cleared */
> - if (wait_for_scan("Collapse and leave PMD cleared", p, nr_hpages,
> - ops)) {
> + if (wait_for_scan("Collapse and leave PMD cleared", p, size, nr_hpages,
> + hpage_pmd_order, ops)) {
> fail("Timeout");
> return;
> }
> @@ -1098,7 +1182,7 @@ static void usage(void)
> {
> fprintf(stderr, "\nUsage: ./khugepaged [OPTIONS] <test type>
> [dir]\n\n");
> fprintf(stderr, "\t<test type>\t: <context>:<mem_type>\n");
> - fprintf(stderr, "\t<context>\t: [all|khugepaged|madvise]\n");
> + fprintf(stderr, "\t<context>\t:
> [all|khugepaged|mthp_khugepaged|madvise]\n");
> fprintf(stderr, "\t<mem_type>\t: [all|anon|file|shmem]\n");
> fprintf(stderr, "\n\t\"file,all\" mem_type requires [dir] argument\n");
> fprintf(stderr, "\n\t\"file,all\" mem_type requires a file system\n");
> @@ -1109,6 +1193,7 @@ static void usage(void)
> fprintf(stderr, "\t\t-h: This help message.\n");
> fprintf(stderr, "\t\t-s: mTHP size, expressed as page order.\n");
> fprintf(stderr, "\t\t Defaults to 0. Use this size for anon or shmem
> allocations.\n");
> + fprintf(stderr, "\t\t-c: collapse order for mTHP collapse, expressed as
> page order.\n");
> exit(1);
> }
>
> @@ -1118,11 +1203,14 @@ static void parse_test_type(int argc, char **argv)
> char *buf;
> const char *token;
>
> - while ((opt = getopt(argc, argv, "s:h")) != -1) {
> + while ((opt = getopt(argc, argv, "s:c:h")) != -1) {
> switch (opt) {
> case 's':
> anon_order = atoi(optarg);
> break;
> + case 'c':
> + collapse_order = atoi(optarg);
> + break;
> case 'h':
> default:
> usage();
> @@ -1148,6 +1236,10 @@ static void parse_test_type(int argc, char **argv)
> madvise_context = &__madvise_context;
> } else if (!strcmp(token, "khugepaged")) {
> khugepaged_context = &__khugepaged_context;
> + } else if (!strcmp(token, "mthp_khugepaged")) {
> + mthp_khugepaged_context = &__mthp_khugepaged_context;
> + if (collapse_order == 0 || collapse_order >= hpage_pmd_order)
> + usage();
> } else if (!strcmp(token, "madvise")) {
> madvise_context = &__madvise_context;
> } else {
> @@ -1213,7 +1305,6 @@ static int nr_test_cases;
>
> int main(int argc, char **argv)
> {
> - int hpage_pmd_order;
> struct thp_settings default_settings = {
> .thp_enabled = THP_MADVISE,
> .thp_defrag = THP_DEFRAG_ALWAYS,
> @@ -1239,10 +1330,6 @@ int main(int argc, char **argv)
> if (!thp_is_enabled())
> ksft_exit_skip("Transparent Hugepages not available\n");
>
> - parse_test_type(argc, argv);
> -
> - setbuf(stdout, NULL);
> -
> page_size = getpagesize();
> hpage_pmd_size = read_pmd_pagesize();
> if (!hpage_pmd_size)
> @@ -1250,6 +1337,10 @@ int main(int argc, char **argv)
> hpage_pmd_nr = hpage_pmd_size / page_size;
> hpage_pmd_order = __builtin_ctz(hpage_pmd_nr);
>
> + parse_test_type(argc, argv);
> +
> + setbuf(stdout, NULL);
> +
> default_settings.khugepaged.max_ptes_none = hpage_pmd_nr - 1;
> default_settings.khugepaged.max_ptes_swap = hpage_pmd_nr / 8;
> default_settings.khugepaged.max_ptes_shared = hpage_pmd_nr / 2;
> @@ -1267,6 +1358,8 @@ int main(int argc, char **argv)
> TEST(collapse_full, khugepaged_context, read_write_file_read_ops);
> TEST(collapse_full, khugepaged_context, read_write_file_write_ops);
> TEST(collapse_full, khugepaged_context, shmem_ops);
> + TEST(collapse_full, mthp_khugepaged_context, anon_ops);
> + TEST(collapse_full, mthp_khugepaged_context, shmem_ops);
> TEST(collapse_full, madvise_context, anon_ops);
> TEST(collapse_full, madvise_context, read_only_file_ops);
> TEST(collapse_full, madvise_context, read_write_file_read_ops);
> @@ -1274,8 +1367,12 @@ int main(int argc, char **argv)
> TEST(collapse_full, madvise_context, shmem_ops);
>
> TEST(collapse_empty, khugepaged_context, anon_ops);
> + TEST(collapse_empty, mthp_khugepaged_context, anon_ops);
> TEST(collapse_empty, madvise_context, anon_ops);
>
> + TEST(collapse_single_mthp, mthp_khugepaged_context, anon_ops);
> + TEST(collapse_single_mthp, mthp_khugepaged_context, shmem_ops);
> +
> TEST(collapse_single_pte_entry, khugepaged_context, anon_ops);
> TEST(collapse_single_pte_entry, khugepaged_context, read_only_file_ops);
> TEST(collapse_single_pte_entry, khugepaged_context,
> read_write_file_read_ops);
> diff --git a/tools/testing/selftests/mm/run_vmtests.sh
> b/tools/testing/selftests/mm/run_vmtests.sh
> index 8c296dedf047..c0f4f3e5f1f1 100755
> --- a/tools/testing/selftests/mm/run_vmtests.sh
> +++ b/tools/testing/selftests/mm/run_vmtests.sh
> @@ -411,6 +411,10 @@ CATEGORY="thp" run_test ./khugepaged all:shmem
>
> CATEGORY="thp" run_test ./khugepaged -s 4 all:shmem
>
> +CATEGORY="thp" run_test ./khugepaged -c 4 mthp_khugepaged:anon
> +
> +CATEGORY="thp" run_test ./khugepaged -c 4 mthp_khugepaged:shmem
> +
> # Try to create XFS if not provided
> if [ -z "${SPLIT_HUGE_PAGE_TEST_XFS_PATH}" ]; then
> if test_selected "thp"; then
