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selftests/vm: anon_cow: THP tests

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Let's add various THP variants that we'll run with our existing test
cases.

Link: https://lkml.kernel.org/r/20220927110120.106906-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph von Recklinghausen <crecklin@redhat.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
David Hildenbrand 2022-09-27 13:01:16 +02:00 committed by Andrew Morton
parent a905e82ae4
commit f4b5fd6946
1 changed files with 258 additions and 1 deletions
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259
tools/testing/selftests/vm/anon_cow.c
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@ -24,6 +24,43 @@
static size_t pagesize;
static int pagemap_fd;
static size_t thpsize;
static void detect_thpsize(void)
{
int fd = open("/sys/kernel/mm/transparent_hugepage/hpage_pmd_size",
O_RDONLY);
size_t size = 0;
char buf[15];
int ret;
if (fd < 0)
return;
ret = pread(fd, buf, sizeof(buf), 0);
if (ret > 0 && ret < sizeof(buf)) {
buf[ret] = 0;
size = strtoul(buf, NULL, 10);
if (size < pagesize)
size = 0;
if (size > 0) {
thpsize = size;
ksft_print_msg("[INFO] detected THP size: %zu KiB\n",
thpsize / 1024);
}
}
close(fd);
}
static bool range_is_swapped(void *addr, size_t size)
{
for (; size; addr += pagesize, size -= pagesize)
if (!pagemap_is_swapped(pagemap_fd, addr))
return false;
return true;
}
struct comm_pipes {
int child_ready[2];
@ -319,6 +356,206 @@ static void run_with_base_page_swap(test_fn fn, const char *desc)
do_run_with_base_page(fn, true);
}
enum thp_run {
THP_RUN_PMD,
THP_RUN_PMD_SWAPOUT,
THP_RUN_PTE,
THP_RUN_PTE_SWAPOUT,
THP_RUN_SINGLE_PTE,
THP_RUN_SINGLE_PTE_SWAPOUT,
THP_RUN_PARTIAL_MREMAP,
THP_RUN_PARTIAL_SHARED,
};
static void do_run_with_thp(test_fn fn, enum thp_run thp_run)
{
char *mem, *mmap_mem, *tmp, *mremap_mem = MAP_FAILED;
size_t size, mmap_size, mremap_size;
int ret;
/* For alignment purposes, we need twice the thp size. */
mmap_size = 2 * thpsize;
mmap_mem = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (mmap_mem == MAP_FAILED) {
ksft_test_result_fail("mmap() failed\n");
return;
}
/* We need a THP-aligned memory area. */
mem = (char *)(((uintptr_t)mmap_mem + thpsize) & ~(thpsize - 1));
ret = madvise(mem, thpsize, MADV_HUGEPAGE);
if (ret) {
ksft_test_result_fail("MADV_HUGEPAGE failed\n");
goto munmap;
}
/*
* Try to populate a THP. Touch the first sub-page and test if we get
* another sub-page populated automatically.
*/
mem[0] = 0;
if (!pagemap_is_populated(pagemap_fd, mem + pagesize)) {
ksft_test_result_skip("Did not get a THP populated\n");
goto munmap;
}
memset(mem, 0, thpsize);
size = thpsize;
switch (thp_run) {
case THP_RUN_PMD:
case THP_RUN_PMD_SWAPOUT:
break;
case THP_RUN_PTE:
case THP_RUN_PTE_SWAPOUT:
/*
* Trigger PTE-mapping the THP by temporarily mapping a single
* subpage R/O.
*/
ret = mprotect(mem + pagesize, pagesize, PROT_READ);
if (ret) {
ksft_test_result_fail("mprotect() failed\n");
goto munmap;
}
ret = mprotect(mem + pagesize, pagesize, PROT_READ | PROT_WRITE);
if (ret) {
ksft_test_result_fail("mprotect() failed\n");
goto munmap;
}
break;
case THP_RUN_SINGLE_PTE:
case THP_RUN_SINGLE_PTE_SWAPOUT:
/*
* Discard all but a single subpage of that PTE-mapped THP. What
* remains is a single PTE mapping a single subpage.
*/
ret = madvise(mem + pagesize, thpsize - pagesize, MADV_DONTNEED);
if (ret) {
ksft_test_result_fail("MADV_DONTNEED failed\n");
goto munmap;
}
size = pagesize;
break;
case THP_RUN_PARTIAL_MREMAP:
/*
* Remap half of the THP. We need some new memory location
* for that.
*/
mremap_size = thpsize / 2;
mremap_mem = mmap(NULL, mremap_size, PROT_NONE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (mem == MAP_FAILED) {
ksft_test_result_fail("mmap() failed\n");
goto munmap;
}
tmp = mremap(mem + mremap_size, mremap_size, mremap_size,
MREMAP_MAYMOVE | MREMAP_FIXED, mremap_mem);
if (tmp != mremap_mem) {
ksft_test_result_fail("mremap() failed\n");
goto munmap;
}
size = mremap_size;
break;
case THP_RUN_PARTIAL_SHARED:
/*
* Share the first page of the THP with a child and quit the
* child. This will result in some parts of the THP never
* have been shared.
*/
ret = madvise(mem + pagesize, thpsize - pagesize, MADV_DONTFORK);
if (ret) {
ksft_test_result_fail("MADV_DONTFORK failed\n");
goto munmap;
}
ret = fork();
if (ret < 0) {
ksft_test_result_fail("fork() failed\n");
goto munmap;
} else if (!ret) {
exit(0);
}
wait(&ret);
/* Allow for sharing all pages again. */
ret = madvise(mem + pagesize, thpsize - pagesize, MADV_DOFORK);
if (ret) {
ksft_test_result_fail("MADV_DOFORK failed\n");
goto munmap;
}
break;
default:
assert(false);
}
switch (thp_run) {
case THP_RUN_PMD_SWAPOUT:
case THP_RUN_PTE_SWAPOUT:
case THP_RUN_SINGLE_PTE_SWAPOUT:
madvise(mem, size, MADV_PAGEOUT);
if (!range_is_swapped(mem, size)) {
ksft_test_result_skip("MADV_PAGEOUT did not work, is swap enabled?\n");
goto munmap;
}
break;
default:
break;
}
fn(mem, size);
munmap:
munmap(mmap_mem, mmap_size);
if (mremap_mem != MAP_FAILED)
munmap(mremap_mem, mremap_size);
}
static void run_with_thp(test_fn fn, const char *desc)
{
ksft_print_msg("[RUN] %s ... with THP\n", desc);
do_run_with_thp(fn, THP_RUN_PMD);
}
static void run_with_thp_swap(test_fn fn, const char *desc)
{
ksft_print_msg("[RUN] %s ... with swapped-out THP\n", desc);
do_run_with_thp(fn, THP_RUN_PMD_SWAPOUT);
}
static void run_with_pte_mapped_thp(test_fn fn, const char *desc)
{
ksft_print_msg("[RUN] %s ... with PTE-mapped THP\n", desc);
do_run_with_thp(fn, THP_RUN_PTE);
}
static void run_with_pte_mapped_thp_swap(test_fn fn, const char *desc)
{
ksft_print_msg("[RUN] %s ... with swapped-out, PTE-mapped THP\n", desc);
do_run_with_thp(fn, THP_RUN_PTE_SWAPOUT);
}
static void run_with_single_pte_of_thp(test_fn fn, const char *desc)
{
ksft_print_msg("[RUN] %s ... with single PTE of THP\n", desc);
do_run_with_thp(fn, THP_RUN_SINGLE_PTE);
}
static void run_with_single_pte_of_thp_swap(test_fn fn, const char *desc)
{
ksft_print_msg("[RUN] %s ... with single PTE of swapped-out THP\n", desc);
do_run_with_thp(fn, THP_RUN_SINGLE_PTE_SWAPOUT);
}
static void run_with_partial_mremap_thp(test_fn fn, const char *desc)
{
ksft_print_msg("[RUN] %s ... with partially mremap()'ed THP\n", desc);
do_run_with_thp(fn, THP_RUN_PARTIAL_MREMAP);
}
static void run_with_partial_shared_thp(test_fn fn, const char *desc)
{
ksft_print_msg("[RUN] %s ... with partially shared THP\n", desc);
do_run_with_thp(fn, THP_RUN_PARTIAL_SHARED);
}
struct test_case {
const char *desc;
test_fn fn;
@ -367,6 +604,16 @@ static void run_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);
}
}
static void run_test_cases(void)
@ -377,15 +624,25 @@ static void run_test_cases(void)
run_test_case(&test_cases[i]);
}
static int tests_per_test_case(void)
{
int tests = 2;
if (thpsize)
tests += 8;
return tests;
}
int main(int argc, char **argv)
{
int nr_test_cases = ARRAY_SIZE(test_cases);
int err;
pagesize = getpagesize();
detect_thpsize();
ksft_print_header();
ksft_set_plan(nr_test_cases * 2);
ksft_set_plan(nr_test_cases * tests_per_test_case());
pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
if (pagemap_fd < 0)