Re: [PATCH 4/9] oom: oom_kill_process() need to check p is unkillable

[Minchan Kim <minchan.kim@gmail.com>]

On Wed, Jun 16, 2010 at 08:32:45PM +0900, KOSAKI Motohiro wrote:
> When oom_kill_allocating_task is enabled, an argument of
> oom_kill_process is not selected by select_bad_process(), but
> just out_of_memory() caller task. It mean the task can be
> unkillable. check it first.
> 
> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
> ---
>  mm/oom_kill.c |   11 +++++++++++
>  1 files changed, 11 insertions(+), 0 deletions(-)
> 
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> index 6ca6cb8..3e48023 100644
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -436,6 +436,17 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
>  	unsigned long victim_points = 0;
>  	struct timespec uptime;
>  
> +	/*
> +	 * When oom_kill_allocating_task is enabled, p can be
> +	 * unkillable. check it first.
> +	 */
> +	if (is_global_init(p) || (p->flags & PF_KTHREAD))
> +		return 1;
> +	if (mem && !task_in_mem_cgroup(p, mem))
> +		return 1;
> +	if (!has_intersects_mems_allowed(p, nodemask))
> +		return 1;
> +

I think this check could be done before oom_kill_proces in case of
sysctl_oom_kill_allocating_task, too. 

-- 
Kind regards,
Minchan Kim