[LTP] [PATCH] hugemmap32: guarantee enough memory for gigantic hugepage

[Martin Doucha]

Hi,

On 08. 05. 23 15:49, Li Wang wrote:
>    To get rid of warning on ppc64le:
> 
>      hugemmap32.c:34: TWARN: Failed to close FILE
>           '/sys/kernel/mm/hugepages/hugepages-16777216kB/nr_hugepages'
>      hugemmap32.c:35: TCONF: Can't update the gigantic hugepages.
>      hugemmap32.c:69: TWARN: Failed to close FILE
>           '/sys/kernel/mm/hugepages/hugepages-16777216kB/nr_hugepages': EINVAL (22)
> 
>    # ll /sys/kernel/mm/hugepages/
>    total 0
>    drwxr-xr-x. 2 root root 0 May  4 02:02 hugepages-16384kB
>    drwxr-xr-x. 2 root root 0 May  4 02:02 hugepages-16777216kB
> 
>    # cat /proc/meminfo | grep -i Hugepagesize
>    Hugepagesize:      16384 kB
> 
>    # free -h
>                   total        used        free      shared  buff/cache   available
>    Mem:           7.4Gi       1.1Gi       992Mi        13Mi       5.9Gi       6.3Gi
>    Swap:          4.0Gi          0B       4.0Gi
> 
> Signed-off-by: Li Wang <liwang@redhat.com>
> ---
>   testcases/kernel/mem/hugetlb/hugemmap/hugemmap32.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/testcases/kernel/mem/hugetlb/hugemmap/hugemmap32.c b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap32.c
> index 34b322bfa..7ff23b236 100644
> --- a/testcases/kernel/mem/hugetlb/hugemmap/hugemmap32.c
> +++ b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap32.c
> @@ -60,6 +60,12 @@ static void setup(void)
>   		tst_brk(TCONF, "Gigantic hugepages not supported");
>   
>   	SAFE_CLOSEDIR(dir);
> +
> +	if (tst_available_mem() < (long long)hpage_size) {
> +		g_hpage_path[0] = '\0';
> +		tst_brk(TCONF, "No enough memory for gigantic hugepage reserving");
> +	}
> +
>   	SAFE_FILE_LINES_SCANF(g_hpage_path, "%d", &org_g_hpages);
>   }

I also recommend calling
SAFE_FILE_PRINTF("/proc/sys/vm/drop_caches", "3");

It doesn't whether you do it before or after tst_available_mem() since 
caches count as available.

-- 
Martin Doucha   mdoucha@suse.cz
QA Engineer for Software Maintenance
SUSE LINUX, s.r.o.
CORSO IIa
Krizikova 148/34
186 00 Prague 8
Czech Republic