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

[Donet Tom]

On 4/14/26 9:29 PM, Mike Rapoport wrote:
> 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 :)


Thanks for the clarification. It’s good to include this change.


>   
> >      +                       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