Re: [PATCH 12/53] selftests/mm: khugepaged: group tests in an array

Mike Rapoport
2026-04-14T15:59:39Z

Hi Donet,

On Tue, Apr 14, 2026 at 12:32:48PM +0530, Donet Tom wrote:
> Hi Mike
>
> On 4/6/26 7:46 PM, Mike Rapoport wrote:
> get_finfo(argv[1]);
> }
>
> +typedef void (*test_fn)(struct collapse_context *c, struct mem_ops *ops);
> +
> +struct test_case {
> + struct collapse_context *ctx;
> + struct mem_ops *ops;
> + const char *desc;
> + test_fn fn;
> +};
> +
> +#define MAX_TEST_CASES 45
>
> I see 48 tests in khugepaged.c, and running khugepaged all:all results in the
> error below. Should MAX_TEST_CASES be updated to 48 instead?

I'm going to bump it to 64 to accommodate potential future tests.

> ./khugepaged all:all .
> TAP version 13
> # Save THP and khugepaged settings... OK
> Bail out! MAX_ADD_CASES is too small
> # Totals: pass:0 fail:0 xfail:0 xpass:0 skip:0 error:0
> # Restore THP and khugepaged settings... OK
> # Totals: pass:0 fail:0 xfail:0 xpass:0 skip:0 error:0
>
>
> +static struct test_case test_cases[MAX_TEST_CASES];
> +static int nr_test_cases;
> +
> +#define TEST(t, c, o) do { \
> + if (c && o) { \
> + if (nr_test_cases >= MAX_TEST_CASES) { \
>
>
> I had a small question—since the number of tests is fixed, would this check
> still be necessary?

If we add too much tests without updating the maximum we get a nice "Bail
out" rather than SIGSEGV :)

> + printf("MAX_ADD_CASES is too small\n"); \
> + exit(EXIT_FAILURE); \
> + } \
> + test_cases[nr_test_cases++] = (struct test_case){ \
> + .ctx = c, \
> + .ops = o, \
> + .desc = #t, \
> + .fn = t, \
> + }; \
> + } \
> + } while (0)
> +
> int main(int argc, char **argv)
> {
> int hpage_pmd_order;
> @@ -1216,13 +1244,6 @@ int main(int argc, char **argv)
>
> alloc_at_fault();
>
> -#define TEST(t, c, o) do { \
> - if (c && o) { \
> - printf("\nRun test: " #t " (%s:%s)\n", c->name, o->name); \
> - t(c, o); \
> - } \
> - } while (0)
> -
> TEST(collapse_full, khugepaged_context, anon_ops);
> TEST(collapse_full, khugepaged_context, file_ops);
> TEST(collapse_full, khugepaged_context, shmem_ops);
> @@ -1284,5 +1305,13 @@ int main(int argc, char **argv)
> TEST(madvise_retracted_page_tables, madvise_context, file_ops);
> TEST(madvise_retracted_page_tables, madvise_context, shmem_ops);
>
> + for (int i = 0; i < nr_test_cases; i++) {
> + struct test_case *t = &test_cases[i];
> +
> + exit_status = KSFT_PASS;
> + printf("\nRun test: %s: (%s:%s)\n", t->desc, t->ctx->name, t->ops->name);
> + t->fn(t->ctx, t->ops);
> + }
> +
> restore_settings(0);
> }
>
>
> -Donet
>

--
Sincerely yours,
Mike.