[LTP] [PATCH v1] mmapstress06: TCONF on systems without swap space

[Petr Vorel]

Hi all,

> mmapstress06 is designed to stress the mfile_swap kernel primitive, which
> manages shared anonymous memory. On architectures with large pages (like
> 64KB on ppc64le), the test's hardcoded request for 32769 pages results
> in a ~2GB mapping. So in suse test system configured with 2GB of RAM and
> no swap space, the test will fails with following information:

> mmapstress06: errno = 12; large mmap failed
> for this test to run, it needs a mmap space of
> 32769 pages

> The failure occurs because the 2GB request cannot be fulfilled within
> the 2GB RAM limit without swap backing. Since the test specifically
> intends to exercise swap-related logic (mfile_swap), it should be skipped
> with TCONF when the system lacks swap space.

> Signed-off-by: Wei Gao <wegao@suse.com>
> ---
>  testcases/kernel/mem/mmapstress/mmapstress06.c | 8 ++++++++
>  1 file changed, 8 insertions(+)

> diff --git a/testcases/kernel/mem/mmapstress/mmapstress06.c b/testcases/kernel/mem/mmapstress/mmapstress06.c
> index 37b7edc84..54b5febbf 100644
> --- a/testcases/kernel/mem/mmapstress/mmapstress06.c
> +++ b/testcases/kernel/mem/mmapstress/mmapstress06.c
> @@ -51,6 +51,8 @@ void ok_exit();

>  #define ANON_GRAN_PAGES_MAX	(32U)

> +#include "tst_memutils.h"
> +
>  extern time_t time(time_t *);
>  extern char *ctime(const time_t *);
>  extern int atoi(const char *);
> @@ -74,6 +76,12 @@ int main(int argc, char *argv[])
>  		(void)fprintf(stderr, "usage: %s sleep_time\n", argv[0]);
>  		anyfail();
>  	}
> +
> +	if (tst_available_swap() <= 0) {
> +		tst_resm(TCONF, "Test requires swap space to exercise mfile_swap logic");
Why to require swap for the test instead of checking for ENOMEM later?

> +		tst_exit();
nit: I'd use tst_brkm() although it has ugly "Remaining cases broken" message as
it will be more obvious when doing rewrite.

> +	}

How about this? (with cleanup of ugly printf).

Kind regards,
Petr

+++ testcases/kernel/mem/mmapstress/mmapstress06.c
@@ -89,10 +89,12 @@ int main(int argc, char *argv[])
 	    (mmapaddr, (ANON_GRAN_PAGES_MAX * NMFPTEPG + 1) * pagesize,
 	     PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, 0,
 	     0) == (caddr_t) - 1) {
-		ERROR("large mmap failed");
-		printf("for this test to run, it needs a mmap space of\n");
-		printf("%d pages\n", (ANON_GRAN_PAGES_MAX * NMFPTEPG + 1));
-		return 1;
+		if (errno == ENOMEM) {
+			tst_brkm(TCONF, NULL, "not enough memory or swap for mmap() %d pages",
+					 ANON_GRAN_PAGES_MAX * NMFPTEPG + 1);
+		}
+
+		tst_brkm(TBROK | TERRNO, NULL, "mmap() failed");
 	}
 	(void)sleep(sleep_time);
 	(void)time(&t);