[LTP] [PATCH 1/1] lib: Skip tst_{disable, enable}_oom_protection() for non-root

[xuyang2018.jy@fujitsu.com]

Hi Petr
> If needed to set value also for non-root, use set_oom_score_adj().
If so, why not rename set_oom_score_adj to tst_set_oom_score_adj and add 
declartion to tst_memutils.h?

ps: also have a word typo in set_oom_score_adj, adjustement => adjustment.

Best Regards
Yang Xu
>
> Fixes: 8a0827766d ("lib: add functions to adjust oom score")
>
> Signed-off-by: Petr Vorel<pvorel@suse.cz>
> ---
>   include/tst_memutils.h | 11 ++++++++++-
>   lib/tst_memutils.c     |  6 ++++++
>   2 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/include/tst_memutils.h b/include/tst_memutils.h
> index 68a6e37714..e6f946ac0c 100644
> --- a/include/tst_memutils.h
> +++ b/include/tst_memutils.h
> @@ -30,11 +30,15 @@ long long tst_available_mem(void);
>    *   echo -1000>/proc/$PID/oom_score_adj
>    * If the pid is 0 which means it will set on current(self) process.
>    *
> + * WARNING:
> + *  Do nothing for non-root, because setting value<  0 requires root.
> +    If you want to set value also for non-root, use set_oom_score_adj().
> + *
>    * Note:
>    *  This exported tst_enable_oom_protection function can be used at anywhere
>    *  you want to protect, but please remember that if you do enable protection
>    *  on a process($PID) that all the children will inherit its score and be
> - *  ignored by OOM Killer as well. So that's why tst_disable_oom_protection
> + *  ignored by OOM Killer as well. So that's why tst_disable_oom_protection()
>    *  to be used in combination.
>    */
>   void tst_enable_oom_protection(pid_t pid);
> @@ -42,6 +46,11 @@ void tst_enable_oom_protection(pid_t pid);
>   /*
>    * Disable the OOM protection for the process($PID).
>    *   echo 0>/proc/$PID/oom_score_adj
> + *
> + * WARNING:
> + *  Do nothing for non-root, because it's expected to be cleanup after
> + *  tst_enable_oom_protection(). Use set_oom_score_adj(), if you want to set
> + *  value also for non-root.
>    */
>   void tst_disable_oom_protection(pid_t pid);
>
> diff --git a/lib/tst_memutils.c b/lib/tst_memutils.c
> index 4346508d9a..f0695e026a 100644
> --- a/lib/tst_memutils.c
> +++ b/lib/tst_memutils.c
> @@ -126,10 +126,16 @@ static void set_oom_score_adj(pid_t pid, int value)
>
>   void tst_enable_oom_protection(pid_t pid)
>   {
> +	if (geteuid() != 0)
> +		return;
> +
>   	set_oom_score_adj(pid, -1000);
>   }
>
>   void tst_disable_oom_protection(pid_t pid)
>   {
> +	if (geteuid() != 0)
> +		return;
> +
>   	set_oom_score_adj(pid, 0);
>   }