On 02.07.25 16:20, Muhammad Usama Anjum wrote:
Add test cases to test the correctness of PFN ZERO flag of pagemap_scan ioctl. Test with normal pages backed memory and huge pages backed memory.
Cc: David Hildenbrand david@redhat.com Signed-off-by: Muhammad Usama Anjum usama.anjum@collabora.com
The bug has been fixed [1].
[1] https://lore.kernel.org/all/20250617143532.2375383-1-david@redhat.com Changes since v1:
- Skip if madvise() fails
- Skip test if use_zero_page isn't set to 1
- Keep on using memalign()+free() to allocate huge pages
tools/testing/selftests/mm/pagemap_ioctl.c | 86 +++++++++++++++++++++- 1 file changed, 85 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/mm/pagemap_ioctl.c b/tools/testing/selftests/mm/pagemap_ioctl.c index 57b4bba2b45f3..976ab357f4651 100644 --- a/tools/testing/selftests/mm/pagemap_ioctl.c +++ b/tools/testing/selftests/mm/pagemap_ioctl.c @@ -1,4 +1,5 @@ // SPDX-License-Identifier: GPL-2.0
- #define _GNU_SOURCE #include <stdio.h> #include <fcntl.h>
@@ -1480,6 +1481,86 @@ static void transact_test(int page_size) extra_thread_faults); } +bool is_use_zero_page_set(void) +{
- ssize_t bytes_read;
- char buffer[2];
- int fd;
- fd = open("/sys/kernel/mm/transparent_hugepage/use_zero_page", O_RDONLY);
- if (fd < 0)
return 0;- bytes_read = read(fd, buffer, sizeof(buffer) - 1);
- if (bytes_read <= 0) {
close(fd);return 0;- }
- close(fd);
- if (atoi(buffer) != 1)
return 0;- return 1;
+}
You should probably factor out detect_huge_zeropage() from cow.c into vm_utils.c, and let it return the result.
+void zeropfn_tests(void) +{
- unsigned long long mem_size;
- struct page_region vec;
- int i, ret;
- char *mem;
- /* Test with normal memory */
- mem_size = 10 * page_size;
- mem = mmap(NULL, mem_size, PROT_READ, MAP_PRIVATE | MAP_ANON, -1, 0);
- if (mem == MAP_FAILED)
ksft_exit_fail_msg("error nomem\n");- /* Touch each page to ensure it's mapped */
- for (i = 0; i < mem_size; i += page_size)
(void)((volatile char *)mem)[i];- ret = pagemap_ioctl(mem, mem_size, &vec, 1, 0,
(mem_size / page_size), PAGE_IS_PFNZERO, 0, 0, PAGE_IS_PFNZERO);- if (ret < 0)
ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno));- ksft_test_result(ret == 1 && LEN(vec) == (mem_size / page_size),
"%s all pages must have PFNZERO set\n", __func__);- munmap(mem, mem_size);
- /* Test with huge page if user_zero_page is set to 1 */
- if (!is_use_zero_page_set()) {
ksft_test_result_skip("%s use_zero_page not supported or set to 1\n", __func__);return;- }
- mem_size = 10 * hpage_size;
- mem = memalign(hpage_size, mem_size);
- if (!mem)
ksft_exit_fail_msg("error nomem\n");
Didn't we discuss using mmap() instead?
See run_with_huge_zeropage() in cow.c on how to do the alignemnt yourself easily.