linux-kernel - Re: [PATCH 04/31] mm, vmscan: begin reclaiming pages on a per-node basis

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Date:	Mon, 4 Jul 2016 11:33:25 +0100
From:	Mel Gorman <mgorman@...hsingularity.net>
To:	Hillf Danton <hillf.zj@...baba-inc.com>
Cc:	linux-kernel <linux-kernel@...r.kernel.org>, linux-mm@...ck.org
Subject: Re: [PATCH 04/31] mm, vmscan: begin reclaiming pages on a per-node
 basis

On Mon, Jul 04, 2016 at 06:08:27PM +0800, Hillf Danton wrote:
> > @@ -2561,17 +2580,23 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
> >  	 * highmem pages could be pinning lowmem pages storing buffer_heads
> >  	 */
> >  	orig_mask = sc->gfp_mask;
> > -	if (buffer_heads_over_limit)
> > +	if (buffer_heads_over_limit) {
> >  		sc->gfp_mask |= __GFP_HIGHMEM;
> > +		sc->reclaim_idx = classzone_idx = gfp_zone(sc->gfp_mask);
> > +	}
> > 
> We need to push/pop ->reclaim_idx as ->gfp_mask handled?
> 

I saw no harm in having one full reclaim attempt reclaiming from all
zones if buffer_heads_over_limit was triggered. If it fails, the page
allocator will loop again and reset the reclaim_idx.

-- 
Mel Gorman
SUSE Labs