On Thu, 22 Jan 2026 17:02:15 +0000 Kevin Brodsky <[email protected]> wrote:
> Various improvements/fixes for the mm kselftests:
>
> - Patch 1-3 extend support for more build configurations: out-of-tree
> $KDIR, cross-compilation, etc.
>
> - Patch 4-7 fix issues related to faulting in pages, introducing a new
> helper for that purpose.
>
> - Patch 8 fixes the value returned by pagemap_ioctl (PASS was always
> returned, which explains why the issue fixed in patch 6 went
> unnoticed).
>
> - Patch 9 improves the exit code of pfnmap.
>
> Net results:
> - 1 test no longer fails (patch 7)
> - 3 tests are no longer skipped (patch 4)
> - More accurate return values for whole suites (patch 8, 9)
> - Extra tests are more likely to be built (patch 1-3)
Updated, thanks.
> ---
> v2..v3:
> - Patch 5: new patch [David Hildenbrand]
> - Patch 6: make the helper take a number of pages + pagesize, rename to
> force_read_pages() [David]
> - Patch 7: improved page count calculation (avoiding floating-point
> helper)
> - Patch 7: added Fixes tag [David]
> - Patch 9: open the file only once and save the fd [David]
> - Collected R-b/A-b
>
Below is how v3 altered mm.git:
--- a/tools/testing/selftests/mm/cow.c~b
+++ a/tools/testing/selftests/mm/cow.c
@@ -75,6 +75,18 @@ static bool range_is_swapped(void *addr,
return true;
}
+static bool populate_page_checked(char *addr)
+{
+ bool ret;
+
+ FORCE_READ(*addr);
+ ret = pagemap_is_populated(pagemap_fd, addr);
+ if (!ret)
+ ksft_print_msg("Failed to populate page\n");
+
+ return ret;
+}
+
struct comm_pipes {
int child_ready[2];
int parent_ready[2];
@@ -1549,8 +1561,10 @@ static void run_with_zeropage(non_anon_t
}
/* Read from the page to populate the shared zeropage. */
- FORCE_READ(*mem);
- FORCE_READ(*smem);
+ if (!populate_page_checked(mem) || !populate_page_checked(smem)) {
+ log_test_result(KSFT_FAIL);
+ goto munmap;
+ }
fn(mem, smem, pagesize);
munmap:
@@ -1612,8 +1626,11 @@ static void run_with_huge_zeropage(non_a
* the first sub-page and test if we get another sub-page populated
* automatically.
*/
- FORCE_READ(*mem);
- FORCE_READ(*smem);
+ if (!populate_page_checked(mem) || !populate_page_checked(smem)) {
+ log_test_result(KSFT_FAIL);
+ goto munmap;
+ }
+
if (!pagemap_is_populated(pagemap_fd, mem + pagesize) ||
!pagemap_is_populated(pagemap_fd, smem + pagesize)) {
ksft_test_result_skip("Did not get THPs populated\n");
@@ -1663,8 +1680,10 @@ static void run_with_memfd(non_anon_test
}
/* Fault the page in. */
- FORCE_READ(*mem);
- FORCE_READ(*smem);
+ if (!populate_page_checked(mem) || !populate_page_checked(smem)) {
+ log_test_result(KSFT_FAIL);
+ goto munmap;
+ }
fn(mem, smem, pagesize);
munmap:
@@ -1719,8 +1738,10 @@ static void run_with_tmpfile(non_anon_te
}
/* Fault the page in. */
- FORCE_READ(*mem);
- FORCE_READ(*smem);
+ if (!populate_page_checked(mem) || !populate_page_checked(smem)) {
+ log_test_result(KSFT_FAIL);
+ goto munmap;
+ }
fn(mem, smem, pagesize);
munmap:
@@ -1773,8 +1794,10 @@ static void run_with_memfd_hugetlb(non_a
}
/* Fault the page in. */
- FORCE_READ(*mem);
- FORCE_READ(*smem);
+ if (!populate_page_checked(mem) || !populate_page_checked(smem)) {
+ log_test_result(KSFT_FAIL);
+ goto munmap;
+ }
fn(mem, smem, hugetlbsize);
munmap:
--- a/tools/testing/selftests/mm/hugetlb-madvise.c~b
+++ a/tools/testing/selftests/mm/hugetlb-madvise.c
@@ -47,7 +47,7 @@ void write_fault_pages(void *addr, unsig
void read_fault_pages(void *addr, unsigned long nr_pages)
{
- force_read_pages_in_range(addr, nr_pages * huge_page_size);
+ force_read_pages(addr, nr_pages, huge_page_size);
}
int main(int argc, char **argv)
--- a/tools/testing/selftests/mm/pagemap_ioctl.c~b
+++ a/tools/testing/selftests/mm/pagemap_ioctl.c
@@ -1052,7 +1052,7 @@ static void test_simple(void)
int sanity_tests(void)
{
unsigned long long mem_size, vec_size;
- long ret, fd, i, buf_size;
+ long ret, fd, i, buf_size, nr_pages;
struct page_region *vec;
char *mem, *fmem;
struct stat sbuf;
@@ -1166,13 +1166,14 @@ int sanity_tests(void)
if (fmem == MAP_FAILED)
ksft_exit_fail_msg("error nomem %d %s\n", errno,
strerror(errno));
- force_read_pages_in_range(fmem, sbuf.st_size);
+ nr_pages = (sbuf.st_size + page_size - 1) / page_size;
+ force_read_pages(fmem, nr_pages, page_size);
ret = pagemap_ioctl(fmem, sbuf.st_size, vec, vec_size, 0, 0,
0, PAGEMAP_NON_WRITTEN_BITS, 0,
PAGEMAP_NON_WRITTEN_BITS);
ksft_test_result(ret >= 0 && vec[0].start == (uintptr_t)fmem &&
- LEN(vec[0]) == ceilf((float)sbuf.st_size/page_size) &&
+ LEN(vec[0]) == nr_pages &&
(vec[0].categories & PAGE_IS_FILE),
"%s Memory mapped file\n", __func__);
--- a/tools/testing/selftests/mm/pfnmap.c~b
+++ a/tools/testing/selftests/mm/pfnmap.c
@@ -30,13 +30,14 @@
static sigjmp_buf sigjmp_buf_env;
static char *file = "/dev/mem";
static off_t file_offset;
+static int fd;
static void signal_handler(int sig)
{
siglongjmp(sigjmp_buf_env, -EFAULT);
}
-static int test_read_access(char *addr, size_t size)
+static int test_read_access(char *addr, size_t size, size_t pagesize)
{
int ret;
@@ -45,7 +46,7 @@ static int test_read_access(char *addr,
ret = sigsetjmp(sigjmp_buf_env, 1);
if (!ret)
- force_read_pages_in_range(addr, size);
+ force_read_pages(addr, size/pagesize, pagesize);
if (signal(SIGSEGV, SIG_DFL) == SIG_ERR)
return -EINVAL;
@@ -104,7 +105,6 @@ static void pfnmap_init(void)
{
size_t pagesize = getpagesize();
size_t size = DEV_MEM_NPAGES * pagesize;
- int fd;
void *addr;
if (strncmp(file, "/dev/mem", strlen("/dev/mem")) == 0) {
@@ -117,16 +117,16 @@ static void pfnmap_init(void)
file_offset = 0;
}
- /*
- * Make sure we can open and map the file, and perform some basic
- * checks; skip the whole suite if anything goes wrong.
- * A fresh mapping is then created for every test case by
- * FIXTURE_SETUP(pfnmap).
- */
fd = open(file, O_RDONLY);
if (fd < 0)
ksft_exit_skip("Cannot open '%s': %s\n", file, strerror(errno));
+ /*
+ * Make sure we can map the file, and perform some basic checks; skip
+ * the whole suite if anything goes wrong.
+ * A fresh mapping is then created for every test case by
+ * FIXTURE_SETUP(pfnmap).
+ */
addr = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, file_offset);
if (addr == MAP_FAILED)
ksft_exit_skip("Cannot mmap '%s': %s\n", file, strerror(errno));
@@ -134,17 +134,15 @@ static void pfnmap_init(void)
if (!check_vmflag_pfnmap(addr))
ksft_exit_skip("Invalid file: '%s'. Not pfnmap'ed\n", file);
- if (test_read_access(addr, size))
+ if (test_read_access(addr, size, pagesize))
ksft_exit_skip("Cannot read-access mmap'ed '%s'\n", file);
munmap(addr, size);
- close(fd);
}
FIXTURE(pfnmap)
{
size_t pagesize;
- int dev_mem_fd;
char *addr1;
size_t size1;
char *addr2;
@@ -155,12 +153,9 @@ FIXTURE_SETUP(pfnmap)
{
self->pagesize = getpagesize();
- self->dev_mem_fd = open(file, O_RDONLY);
- ASSERT_GE(self->dev_mem_fd, 0);
-
self->size1 = DEV_MEM_NPAGES * self->pagesize;
self->addr1 = mmap(NULL, self->size1, PROT_READ, MAP_SHARED,
- self->dev_mem_fd, file_offset);
+ fd, file_offset);
ASSERT_NE(self->addr1, MAP_FAILED);
self->size2 = 0;
@@ -173,8 +168,6 @@ FIXTURE_TEARDOWN(pfnmap)
munmap(self->addr2, self->size2);
if (self->addr1 != MAP_FAILED)
munmap(self->addr1, self->size1);
- if (self->dev_mem_fd >= 0)
- close(self->dev_mem_fd);
}
TEST_F(pfnmap, madvise_disallowed)
@@ -214,7 +207,7 @@ TEST_F(pfnmap, munmap_split)
*/
self->size2 = self->pagesize;
self->addr2 = mmap(NULL, self->pagesize, PROT_READ, MAP_SHARED,
- self->dev_mem_fd, file_offset);
+ fd, file_offset);
ASSERT_NE(self->addr2, MAP_FAILED);
}
@@ -265,7 +258,8 @@ TEST_F(pfnmap, fork)
ASSERT_GE(pid, 0);
if (!pid) {
- EXPECT_EQ(test_read_access(self->addr1, self->size1), 0);
+ EXPECT_EQ(test_read_access(self->addr1, self->size1,
+ self->pagesize), 0);
exit(0);
}
--- a/tools/testing/selftests/mm/split_huge_page_test.c~b
+++ a/tools/testing/selftests/mm/split_huge_page_test.c
@@ -652,7 +652,7 @@ static int create_pagecache_thp_and_fd(c
}
madvise(*addr, fd_size, MADV_HUGEPAGE);
- force_read_pages_in_range(*addr, fd_size);
+ force_read_pages(*addr, fd_size / pmd_pagesize, pmd_pagesize);
if (!check_huge_file(*addr, fd_size / pmd_pagesize, pmd_pagesize)) {
ksft_print_msg("No large pagecache folio generated, please
provide a filesystem supporting large folio\n");
--- a/tools/testing/selftests/mm/vm_util.h~b
+++ a/tools/testing/selftests/mm/vm_util.h
@@ -54,10 +54,11 @@ static inline unsigned int pshift(void)
return __page_shift;
}
-static inline void force_read_pages_in_range(char *addr, size_t len)
+static inline void force_read_pages(char *addr, unsigned int nr_pages,
+ size_t pagesize)
{
- for (size_t i = 0; i < len; i += psize())
- FORCE_READ(addr[i]);
+ for (unsigned int i = 0; i < nr_pages; i++)
+ FORCE_READ(addr[i * pagesize]);
}
bool detect_huge_zeropage(void);
_
