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

[Hillf Danton]

>> 
> > --- 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
> 
Then in another direction, below is what I can do.

thanks
Hillf
--- a/mm/page_alloc.c	Thu Feb 25 15:43:18 2016
+++ b/mm/page_alloc.c	Fri Feb 26 18:14:59 2016
@@ -3366,8 +3366,11 @@ retry:
 		no_progress_loops++;
 
 	if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags,
-				 did_some_progress > 0, no_progress_loops))
+				 did_some_progress > 0, no_progress_loops)) {
+		/* Burn more cycles if any zone seems to satisfy our request */
+		no_progress_loops /= 2;
 		goto retry;
+	}
 
 	/* Reclaim has failed us, start killing things */
 	page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress);
--