Re: [PATCH 07/34] mm, vmscan: make kswapd reclaim in terms of nodes

From	Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 07/34] mm, vmscan: make kswapd reclaim in terms of nodes
Date	2016-08-31 08:20 +0200
Message-ID	<sc72p-7cd-3@gated-at.bofh.it> (permalink)
References	(1 earlier) <rSAA1-2Xn-1@gated-at.bofh.it> <sbrmx-5BR-5@gated-at.bofh.it> <sbQ1A-4A6-21@gated-at.bofh.it> <sbSd4-64E-31@gated-at.bofh.it> <sbSPM-6x2-31@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

> > The trigger is memblock_reserve() for the complete node memory.  And
> > this is exactly what FA_DUMP does.  Here again the node has memory but
> > its all reserved so there is no free memory in the node.
> > 
> > Did you mean populated_zone() when you said zone_populated or have I
> > mistaken? populated_zone() does return 1 since it checks for
> > zone->present_pages.
> > 
> 
> Yes, I meant populated_zone(). Using present pages may have hidden
> a long-lived corner case as it was unexpected that an entire node
> would be reserved. The old code happened to survive *probably* because
> pgdat_reclaimable would look false and kswapd checks for pgdat being
> balanced would happen to do the right thing in this case.
> 
> Can you check if something like this works?
> 
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index d572b78b65e1..cf64a5456cf6 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -830,7 +830,7 @@ unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long);
> 
>  static inline int populated_zone(struct zone *zone)
>  {
> -	return (!!zone->present_pages);
> +	return (!!zone->managed_pages);
>  }
> 
>  extern int movable_zone;
> 

This indeed fixes the problem.
Please add my 
Tested-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

Thread

Re: [PATCH 07/34] mm, vmscan: make kswapd reclaim in terms of nodes Srikar Dronamraju <srikar@linux.vnet.ibm.com> - 2016-08-29 11:50 +0200
  Re: [PATCH 07/34] mm, vmscan: make kswapd reclaim in terms of nodes Mel Gorman <mgorman@techsingularity.net> - 2016-08-30 14:10 +0200
    Re: [PATCH 07/34] mm, vmscan: make kswapd reclaim in terms of nodes Srikar Dronamraju <srikar@linux.vnet.ibm.com> - 2016-08-30 16:30 +0200
      Re: [PATCH 07/34] mm, vmscan: make kswapd reclaim in terms of nodes Mel Gorman <mgorman@techsingularity.net> - 2016-08-30 17:10 +0200
        Re: [PATCH 07/34] mm, vmscan: make kswapd reclaim in terms of nodes Srikar Dronamraju <srikar@linux.vnet.ibm.com> - 2016-08-31 08:20 +0200
          Re: [PATCH 07/34] mm, vmscan: make kswapd reclaim in terms of nodes Mel Gorman <mgorman@techsingularity.net> - 2016-08-31 11:00 +0200
            Re: [PATCH 07/34] mm, vmscan: make kswapd reclaim in terms of nodes Michal Hocko <mhocko@kernel.org> - 2016-08-31 13:10 +0200
              Re: [PATCH 07/34] mm, vmscan: make kswapd reclaim in terms of nodes Mel Gorman <mgorman@techsingularity.net> - 2016-08-31 14:50 +0200
            Re: [PATCH 07/34] mm, vmscan: make kswapd reclaim in terms of nodes Srikar Dronamraju <srikar@linux.vnet.ibm.com> - 2016-08-31 19:40 +0200

csiph-web