selftests/mm: uffd-unit-tests: add setup of HugeTLB pages

uffd-unit-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.

Replace exit() calls with _exit() to avoid restoring HugeTLB settings in
the middle of test.

Link: https://lore.kernel.org/20260511162840.375890-51-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c
index db7c26835487b95c885fb10df00d4fb5fb72705f..a6c14109e8188721ae807f3f193e1d019aab438d 100644 (file)
--- a/tools/testing/selftests/mm/uffd-unit-tests.c
+++ b/tools/testing/selftests/mm/uffd-unit-tests.c
@@ -299,7 +299,7 @@ static int pagemap_test_fork(uffd_global_test_opts_t *gopts, bool with_event, bo
                if (test_pin)
                        unpin_pages(&args);
                /* Succeed */
-               exit(0);
+               _exit(0);
        }
        waitpid(child, &result, 0);
 
@@ -767,7 +767,7 @@ static void uffd_sigbus_test_common(uffd_global_test_opts_t *gopts, bool wp)
                err("fork");
 
        if (!pid)
-               exit(faulting_process(gopts, 2, wp));
+               _exit(faulting_process(gopts, 2, wp));
 
        waitpid(pid, &err, 0);
        if (err)
@@ -821,7 +821,7 @@ static void uffd_events_test_common(uffd_global_test_opts_t *gopts, bool wp)
                err("fork");
 
        if (!pid)
-               exit(faulting_process(gopts, 0, wp));
+               _exit(faulting_process(gopts, 0, wp));
 
        waitpid(pid, &err, 0);
        if (err)
@@ -1700,11 +1700,32 @@ static int uffd_count_tests(int n_tests, int n_mems, const char *test_filter)
        return count;
 }
 
+static unsigned long uffd_setup_hugetlb(void)
+{
+       unsigned long nr_hugepages, hp_size;
+
+       hugetlb_save_settings();
+       hp_size = default_huge_page_size();
+
+       if (!hp_size)
+               return 0;
+
+       /* need twice UFFD_TEST_MEM_SIZE, one for src area and one for dst */
+       nr_hugepages = 2 * MAX(UFFD_TEST_MEM_SIZE, hp_size * 2) / hp_size;
+       hugetlb_set_nr_default_pages(nr_hugepages);
+
+       if (hugetlb_free_default_pages() < nr_hugepages)
+               return 0;
+
+       return hp_size;
+}
+
 int main(int argc, char *argv[])
 {
        int n_tests = sizeof(uffd_tests) / sizeof(uffd_test_case_t);
        int n_mems = sizeof(mem_types) / sizeof(mem_type_t);
        const char *test_filter = NULL;
+       unsigned long hugepage_size;
        bool list_only = false;
        uffd_test_case_t *test;
        mem_type_t *mem_type;
@@ -1738,6 +1759,8 @@ int main(int argc, char *argv[])
                return KSFT_PASS;
        }
 
+       hugepage_size = uffd_setup_hugetlb();
+
        ksft_print_header();
        ksft_set_plan(uffd_count_tests(n_tests, n_mems, test_filter));
 
@@ -1765,9 +1788,9 @@ int main(int argc, char *argv[])
 
                        uffd_test_start("%s on %s", test->name, mem_type->name);
                        if (mem_type->mem_flag & (MEM_HUGETLB_PRIVATE | MEM_HUGETLB)) {
-                               gopts.page_size = default_huge_page_size();
+                               gopts.page_size = hugepage_size;
                                if (gopts.page_size == 0) {
-                                       uffd_test_skip("huge page size is 0, feature missing?");
+                                       uffd_test_skip("not enough HugeTLB pages");
                                        continue;
                                }
                        } else {