[PATCH v3 34/54] selftests/mm: hmm-tests: add setup of HugeTLB pages

Mike Rapoport
2026-04-28T20:46:35Z

hmm-tests skips HugeTLB tests if there are no free huge pages prepared by a
wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Since kselftest_harness runs fixture setup and the tests in child
processes, use HUGETLB_SETUP_DEFAULT_PAGES() that defines a constructor
that runs in the main process and add verification that there are enough
free huge pages to the tests that use them.

Replace exit() calls with _exit() to avoid restoring HugeTLB settings in
the middle of test and use SIGLILL to kill a child process in
hmm_cow_in_device test to avoid interference with signal handlers in
hugepage_restore_settings().

Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
tools/testing/selftests/mm/hmm-tests.c | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/tools/testing/selftests/mm/hmm-tests.c b/tools/testing/selftests/mm/hmm-tests.c
index 409b11cad4bc..70c7ae989c01 100644
--- a/tools/testing/selftests/mm/hmm-tests.c
+++ b/tools/testing/selftests/mm/hmm-tests.c
@@ -69,6 +69,9 @@ enum {
#ifndef FOLL_LONGTERM
#define FOLL_LONGTERM 0x100 /* mapping lifetime is indefinite */
#endif
+
+HUGETLB_SETUP_DEFAULT_PAGES(1)
+
FIXTURE(hmm)
{
int fd;
@@ -632,7 +635,7 @@ TEST_F(hmm, anon_write_child)
}

close(child_fd);
- exit(0);
+ _exit(0);
}
}
}
@@ -712,7 +715,7 @@ TEST_F(hmm, anon_write_child_shared)
ASSERT_EQ(ptr[i], -i);

close(child_fd);
- exit(0);
+ _exit(0);
}

/*
@@ -784,8 +787,9 @@ TEST_F(hmm, anon_write_hugetlbfs)
int *ptr;
int ret;

- if (!default_hsize)
- SKIP(return, "Huge page size could not be determined");
+ if (!hugetlb_free_default_pages())
+ SKIP(return, "Not enough huge pages");
+ default_hsize = default_huge_page_size();

size = ALIGN(TWOMEG, default_hsize);
npages = size >> self->page_shift;
@@ -1564,9 +1568,9 @@ TEST_F(hmm, compound)
unsigned long i;

/* Skip test if we can't allocate a hugetlbfs page. */
-
- if (!default_hsize)
- SKIP(return, "Huge page size could not be determined");
+ if (!hugetlb_free_default_pages())
+ SKIP(return, "Not enough huge pages");
+ default_hsize = default_huge_page_size();

size = ALIGN(TWOMEG, default_hsize);
npages = size >> self->page_shift;
@@ -2025,10 +2029,10 @@ TEST_F(hmm, hmm_cow_in_device)
ptr[i] = i;

/* Terminate child and wait */
- EXPECT_EQ(0, kill(pid, SIGTERM));
+ EXPECT_EQ(0, kill(pid, SIGKILL));
EXPECT_EQ(pid, waitpid(pid, &status, 0));
EXPECT_NE(0, WIFSIGNALED(status));
- EXPECT_EQ(SIGTERM, WTERMSIG(status));
+ EXPECT_EQ(SIGKILL, WTERMSIG(status));

/* Take snapshot to CPU pagetables */
ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_SNAPSHOT, buffer, npages);
--
2.53.0