[LTP] [PATCH 3/3] lib: unlimit the tmpfs size when test on small systems

[Cyril Hrubis]

Hi!
> Since commit c305a53c5 (lib: limit the size of tmpfs in LTP, Jul 9)
> Ltp set tmpfs mount size according to the tdev.size. This cause a
> new problem on small RAM system, which consume too much memory and
> finally trigger OOM.
> 
> To fix this, let's cancel the tmpfs size limitation when MemAvailable
> is less than twofold of tdev.size.
> 
> Reported-by: Ralph Siemsen <ralph.siemsen@linaro.org>
> Signed-off-by: Li Wang <liwang@redhat.com>
> ---
>  include/tst_test.h | 1 +
>  lib/tst_test.c     | 3 +++
>  2 files changed, 4 insertions(+)
> 
> diff --git a/include/tst_test.h b/include/tst_test.h
> index 5e3619698..3dcb45de0 100644
> --- a/include/tst_test.h
> +++ b/include/tst_test.h
> @@ -42,6 +42,7 @@
>  #include "tst_lockdown.h"
>  #include "tst_fips.h"
>  #include "tst_taint.h"
> +#include "tst_memutils.h"
>  
>  /*
>   * Reports testcase result.
> diff --git a/lib/tst_test.c b/lib/tst_test.c
> index 4224353da..b50856f20 100644
> --- a/lib/tst_test.c
> +++ b/lib/tst_test.c
> @@ -895,6 +895,9 @@ static const char *limit_tmpfs_mount_size(const char *mnt_data,
>  	if (strcmp(fs_type, "tmpfs"))
>  		return mnt_data;
>  
> +	if ((tst_available_mem() / 1024) < (tdev.size * 2))
> +		return mnt_data;

I'm starting to think that we should do it the other way around, i.e.

- unless the test defines .min_dev_size we should set the size for tmpfs to be really small 16MB or 32MB
- if .min_dev_size is defined and there is not enough free memory -> TCONF
- if .min_dev_size is not set and there is not even 64MB of free memory (for 32MB limit) -> TCONF

I think that this is going to work because most of the tests does not
actually consume more than a megabyte or so of the disk space for the
actuall test, the only reason why we kept bumping the loop device size
is that there are limits on minimal size imposed by filesystems.

>  	if (mnt_data)
>  		snprintf(buf, buf_size, "%s,size=%luM", mnt_data, tdev.size);
>  	else
> -- 
> 2.31.1
> 
> 
> -- 
> Mailing list info: https://lists.linux.it/listinfo/ltp

-- 
Cyril Hrubis
chrubis@suse.cz