Re: [PATCH 0/3] OOM detection rework v4

[Michal Hocko]

On Fri 26-02-16 15:54:19, Hillf Danton wrote:
> > 
> > It didn't really help, I'm afraid: it reduces the actual number of OOM
> > kills which occur before the job is terminated, but doesn't stop the
> > job from being terminated very soon.
> > 
> > I also tried Hillf's patch (separately) too, but as you expected,
> > it didn't seem to make any difference.
> > 
> Perhaps non-costly means NOFAIL as shown by folding the two

nofail only means that the page allocator doesn't return with NULL.
OOM killer is still not put aside...

> patches into one. Can it make any sense?
> 
> thanks
> Hillf
> --- a/mm/page_alloc.c	Thu Feb 25 15:43:18 2016
> +++ b/mm/page_alloc.c	Fri Feb 26 15:18:55 2016
> @@ -3113,6 +3113,8 @@ should_reclaim_retry(gfp_t gfp_mask, uns
>  	struct zone *zone;
>  	struct zoneref *z;
>  
> +	if (order <= PAGE_ALLOC_COSTLY_ORDER)
> +		return true;

This is defeating the whole purpose of the rework - to behave
deterministically. You have just disabled the oom killer completely.
This is not the way to go

-- 
Michal Hocko
SUSE Labs