Re: [RFC][PATCH] oom_kill: avoid depends on total_vm and use realRSS/swap value for oom_score (Re: Memory overcommit

[KAMEZAWA Hiroyuki]

On Tue, 27 Oct 2009 16:45:26 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
  	/*
>  	 * After this unlock we can no longer dereference local variable `mm'
> @@ -92,8 +93,13 @@ unsigned long badness(struct task_struct
>  	 */
>  	list_for_each_entry(child, &p->children, sibling) {
>  		task_lock(child);
> -		if (child->mm != mm && child->mm)
> -			points += child->mm->total_vm/2 + 1;
> +		if (child->mm != mm && child->mm) {
> +			unsigned long cpoint;
> +			/* At considering child, we don't count swap */
> +			cpoint = get_mm_counter(child->mm, anon_rss) +
> +				 get_mm_counter(child->mm, file_rss);
> +			points += cpoint/2 + 1;
> +		}
>  		task_unlock(child);

BTW, I'd like to get rid of this code.

Can't we use other techniques for detecting fork-bomb ?

This check can't catch following type, anyway.

   fork()
     -> fork()
          -> fork()
               -> fork()
                    ....

but I have no good idea.
What is the difference with task-launcher and fork bomb()...

Thanks,
-Kame

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