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

[Mike Rapoport <rppt@kernel.org>]

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.