Re: 4.8.8 kernel trigger OOM killer repeatedly when I have lots of RAM that should be free

[Hillf Danton]

On Wednesday, November 23, 2016 2:34 PM Michal Hocko wrote:
> @@ -3161,6 +3161,16 @@ should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_fla
>  	if (!order || order > PAGE_ALLOC_COSTLY_ORDER)
>  		return false;
> 
> +#ifdef CONFIG_COMPACTION
> +	/*
> +	 * This is a gross workaround to compensate a lack of reliable compaction
> +	 * operation. We cannot simply go OOM with the current state of the compaction
> +	 * code because this can lead to pre mature OOM declaration.
> +	 */
> +	if (order <= PAGE_ALLOC_COSTLY_ORDER)

No need to check order once more.
Plus can we retry without CONFIG_COMPACTION enabled?

> +		return true;
> +#endif
> +
>  	/*
>  	 * There are setups with compaction disabled which would prefer to loop
>  	 * inside the allocator rather than hit the oom killer prematurely.
> --
> Michal Hocko
> SUSE Labs
>