[PATCH v8 09/10] selftests/mm/cow: Generalize do_run_with_thp() helper

Ryan Roberts
2023-12-04T10:22:07Z

do_run_with_thp() prepares (PMD-sized) THP memory into different states
before running tests. With the introduction of multi-size THP, we would
like to reuse this logic to also test those smaller THP sizes. So let's
add a thpsize parameter which tells the function what size THP it should
operate on.

A separate commit will utilize this change to add new tests for
multi-size THP, where available.

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---
tools/testing/selftests/mm/cow.c | 121 +++++++++++++++++--------------
1 file changed, 67 insertions(+), 54 deletions(-)

diff --git a/tools/testing/selftests/mm/cow.c b/tools/testing/selftests/mm/cow.c
index 7324ce5363c0..4d0b5a125d3c 100644
--- a/tools/testing/selftests/mm/cow.c
+++ b/tools/testing/selftests/mm/cow.c
@@ -32,7 +32,7 @@

static size_t pagesize;
static int pagemap_fd;
-static size_t thpsize;
+static size_t pmdsize;
static int nr_hugetlbsizes;
static size_t hugetlbsizes[10];
static int gup_fd;
@@ -734,7 +734,7 @@ enum thp_run {
THP_RUN_PARTIAL_SHARED,
};

-static void do_run_with_thp(test_fn fn, enum thp_run thp_run)
+static void do_run_with_thp(test_fn fn, enum thp_run thp_run, size_t thpsize)
{
char *mem, *mmap_mem, *tmp, *mremap_mem = MAP_FAILED;
size_t size, mmap_size, mremap_size;
@@ -759,11 +759,11 @@ static void do_run_with_thp(test_fn fn, enum thp_run thp_run)
}

/*
- * Try to populate a THP. Touch the first sub-page and test if we get
- * another sub-page populated automatically.
+ * Try to populate a THP. Touch the first sub-page and test if
+ * we get the last sub-page populated automatically.
*/
mem[0] = 0;
- if (!pagemap_is_populated(pagemap_fd, mem + pagesize)) {
+ if (!pagemap_is_populated(pagemap_fd, mem + thpsize - pagesize)) {
ksft_test_result_skip("Did not get a THP populated\n");
goto munmap;
}
@@ -773,12 +773,14 @@ static void do_run_with_thp(test_fn fn, enum thp_run thp_run)
switch (thp_run) {
case THP_RUN_PMD:
case THP_RUN_PMD_SWAPOUT:
+ assert(thpsize == pmdsize);
break;
case THP_RUN_PTE:
case THP_RUN_PTE_SWAPOUT:
/*
* Trigger PTE-mapping the THP by temporarily mapping a single
- * subpage R/O.
+ * subpage R/O. This is a noop if the THP is not pmdsize (and
+ * therefore already PTE-mapped).
*/
ret = mprotect(mem + pagesize, pagesize, PROT_READ);
if (ret) {
@@ -875,52 +877,60 @@ static void do_run_with_thp(test_fn fn, enum thp_run thp_run)
munmap(mremap_mem, mremap_size);
}

-static void run_with_thp(test_fn fn, const char *desc)
+static void run_with_thp(test_fn fn, const char *desc, size_t size)
{
- ksft_print_msg("[RUN] %s ... with THP\n", desc);
- do_run_with_thp(fn, THP_RUN_PMD);
+ ksft_print_msg("[RUN] %s ... with THP (%zu kB)\n",
+ desc, size / 1024);
+ do_run_with_thp(fn, THP_RUN_PMD, size);
}

-static void run_with_thp_swap(test_fn fn, const char *desc)
+static void run_with_thp_swap(test_fn fn, const char *desc, size_t size)
{
- ksft_print_msg("[RUN] %s ... with swapped-out THP\n", desc);
- do_run_with_thp(fn, THP_RUN_PMD_SWAPOUT);
+ ksft_print_msg("[RUN] %s ... with swapped-out THP (%zu kB)\n",
+ desc, size / 1024);
+ do_run_with_thp(fn, THP_RUN_PMD_SWAPOUT, size);
}

-static void run_with_pte_mapped_thp(test_fn fn, const char *desc)
+static void run_with_pte_mapped_thp(test_fn fn, const char *desc, size_t size)
{
- ksft_print_msg("[RUN] %s ... with PTE-mapped THP\n", desc);
- do_run_with_thp(fn, THP_RUN_PTE);
+ ksft_print_msg("[RUN] %s ... with PTE-mapped THP (%zu kB)\n",
+ desc, size / 1024);
+ do_run_with_thp(fn, THP_RUN_PTE, size);
}

-static void run_with_pte_mapped_thp_swap(test_fn fn, const char *desc)
+static void run_with_pte_mapped_thp_swap(test_fn fn, const char *desc, size_t size)
{
- ksft_print_msg("[RUN] %s ... with swapped-out, PTE-mapped THP\n", desc);
- do_run_with_thp(fn, THP_RUN_PTE_SWAPOUT);
+ ksft_print_msg("[RUN] %s ... with swapped-out, PTE-mapped THP (%zu kB)\n",
+ desc, size / 1024);
+ do_run_with_thp(fn, THP_RUN_PTE_SWAPOUT, size);
}

-static void run_with_single_pte_of_thp(test_fn fn, const char *desc)
+static void run_with_single_pte_of_thp(test_fn fn, const char *desc, size_t size)
{
- ksft_print_msg("[RUN] %s ... with single PTE of THP\n", desc);
- do_run_with_thp(fn, THP_RUN_SINGLE_PTE);
+ ksft_print_msg("[RUN] %s ... with single PTE of THP (%zu kB)\n",
+ desc, size / 1024);
+ do_run_with_thp(fn, THP_RUN_SINGLE_PTE, size);
}

-static void run_with_single_pte_of_thp_swap(test_fn fn, const char *desc)
+static void run_with_single_pte_of_thp_swap(test_fn fn, const char *desc, size_t size)
{
- ksft_print_msg("[RUN] %s ... with single PTE of swapped-out THP\n", desc);
- do_run_with_thp(fn, THP_RUN_SINGLE_PTE_SWAPOUT);
+ ksft_print_msg("[RUN] %s ... with single PTE of swapped-out THP (%zu kB)\n",
+ desc, size / 1024);
+ do_run_with_thp(fn, THP_RUN_SINGLE_PTE_SWAPOUT, size);
}

-static void run_with_partial_mremap_thp(test_fn fn, const char *desc)
+static void run_with_partial_mremap_thp(test_fn fn, const char *desc, size_t size)
{
- ksft_print_msg("[RUN] %s ... with partially mremap()'ed THP\n", desc);
- do_run_with_thp(fn, THP_RUN_PARTIAL_MREMAP);
+ ksft_print_msg("[RUN] %s ... with partially mremap()'ed THP (%zu kB)\n",
+ desc, size / 1024);
+ do_run_with_thp(fn, THP_RUN_PARTIAL_MREMAP, size);
}

-static void run_with_partial_shared_thp(test_fn fn, const char *desc)
+static void run_with_partial_shared_thp(test_fn fn, const char *desc, size_t size)
{
- ksft_print_msg("[RUN] %s ... with partially shared THP\n", desc);
- do_run_with_thp(fn, THP_RUN_PARTIAL_SHARED);
+ ksft_print_msg("[RUN] %s ... with partially shared THP (%zu kB)\n",
+ desc, size / 1024);
+ do_run_with_thp(fn, THP_RUN_PARTIAL_SHARED, size);
}

static void run_with_hugetlb(test_fn fn, const char *desc, size_t hugetlbsize)
@@ -1091,15 +1101,15 @@ 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 (thpsize) {
- run_with_thp(test_case->fn, test_case->desc);
- run_with_thp_swap(test_case->fn, test_case->desc);
- run_with_pte_mapped_thp(test_case->fn, test_case->desc);
- run_with_pte_mapped_thp_swap(test_case->fn, test_case->desc);
- run_with_single_pte_of_thp(test_case->fn, test_case->desc);
- run_with_single_pte_of_thp_swap(test_case->fn, test_case->desc);
- run_with_partial_mremap_thp(test_case->fn, test_case->desc);
- run_with_partial_shared_thp(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_hugetlbsizes; i++)
run_with_hugetlb(test_case->fn, test_case->desc,
@@ -1120,7 +1130,7 @@ static int tests_per_anon_test_case(void)
{
int tests = 2 + nr_hugetlbsizes;

- if (thpsize)
+ if (pmdsize)
tests += 8;
return tests;
}
@@ -1329,7 +1339,7 @@ static void run_anon_thp_test_cases(void)
{
int i;

- if (!thpsize)
+ if (!pmdsize)
return;

ksft_print_msg("[INFO] Anonymous THP tests\n");
@@ -1338,13 +1348,13 @@ static void run_anon_thp_test_cases(void)
struct test_case const *test_case = &anon_thp_test_cases[i];

ksft_print_msg("[RUN] %s\n", test_case->desc);
- do_run_with_thp(test_case->fn, THP_RUN_PMD);
+ do_run_with_thp(test_case->fn, THP_RUN_PMD, pmdsize);
}
}

static int tests_per_anon_thp_test_case(void)
{
- return thpsize ? 1 : 0;
+ return pmdsize ? 1 : 0;
}

typedef void (*non_anon_test_fn)(char *mem, const char *smem, size_t size);
@@ -1419,7 +1429,7 @@ static void run_with_huge_zeropage(non_anon_test_fn fn, const char *desc)
}

/* For alignment purposes, we need twice the thp size. */
- mmap_size = 2 * thpsize;
+ mmap_size = 2 * pmdsize;
mmap_mem = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (mmap_mem == MAP_FAILED) {
@@ -1434,11 +1444,11 @@ static void run_with_huge_zeropage(non_anon_test_fn fn, const char *desc)
}

/* We need a THP-aligned memory area. */
- mem = (char *)(((uintptr_t)mmap_mem + thpsize) & ~(thpsize - 1));
- smem = (char *)(((uintptr_t)mmap_smem + thpsize) & ~(thpsize - 1));
+ mem = (char *)(((uintptr_t)mmap_mem + pmdsize) & ~(pmdsize - 1));
+ smem = (char *)(((uintptr_t)mmap_smem + pmdsize) & ~(pmdsize - 1));

- ret = madvise(mem, thpsize, MADV_HUGEPAGE);
- ret |= madvise(smem, thpsize, MADV_HUGEPAGE);
+ ret = madvise(mem, pmdsize, MADV_HUGEPAGE);
+ ret |= madvise(smem, pmdsize, MADV_HUGEPAGE);
if (ret) {
ksft_test_result_fail("MADV_HUGEPAGE failed\n");
goto munmap;
@@ -1457,7 +1467,7 @@ static void run_with_huge_zeropage(non_anon_test_fn fn, const char *desc)
goto munmap;
}

- fn(mem, smem, thpsize);
+ fn(mem, smem, pmdsize);
munmap:
munmap(mmap_mem, mmap_size);
if (mmap_smem != MAP_FAILED)
@@ -1650,7 +1660,7 @@ static void run_non_anon_test_case(struct non_anon_test_case const *test_case)
run_with_zeropage(test_case->fn, test_case->desc);
run_with_memfd(test_case->fn, test_case->desc);
run_with_tmpfile(test_case->fn, test_case->desc);
- if (thpsize)
+ if (pmdsize)
run_with_huge_zeropage(test_case->fn, test_case->desc);
for (i = 0; i < nr_hugetlbsizes; i++)
run_with_memfd_hugetlb(test_case->fn, test_case->desc,
@@ -1671,7 +1681,7 @@ static int tests_per_non_anon_test_case(void)
{
int tests = 3 + nr_hugetlbsizes;

- if (thpsize)
+ if (pmdsize)
tests += 1;
return tests;
}
@@ -1681,10 +1691,13 @@ int main(int argc, char **argv)
int err;

pagesize = getpagesize();
- thpsize = read_pmd_pagesize();
- if (thpsize)
+ pmdsize = read_pmd_pagesize();
+ if (pmdsize) {
+ ksft_print_msg("[INFO] detected PMD size: %zu KiB\n",
+ pmdsize / 1024);
ksft_print_msg("[INFO] detected THP size: %zu KiB\n",
- thpsize / 1024);
+ pmdsize / 1024);
+ }
nr_hugetlbsizes = detect_hugetlb_page_sizes(hugetlbsizes,
ARRAY_SIZE(hugetlbsizes));
detect_huge_zeropage();
--
2.25.1