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Date: Wed, 15 Sep 2010 11:31:00 +0800
From: Wu Fengguang <fengguang.wu@intel.com>
To: "Li, Shaohua" <shaohua.li@intel.com>
Cc: Neil Brown <neilb@suse.de>, Rik van Riel <riel@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: Deadlock possibly caused by too_many_isolated.
Message-ID: <20100915033059.GA12542@localhost>
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On Wed, Sep 15, 2010 at 11:18:32AM +0800, Li, Shaohua wrote:

> > +	if (!(sc->gfp_mask & __GFP_WAIT))
> > +		return 0;
> > +
> it appears __GFP_WAIT allocation doesn't go to direct reclaim.

Good point! So we are returning to its very first version ;)

--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1135,6 +1135,7 @@ static int too_many_isolated(struct zone *zone, int file,
 		struct scan_control *sc)
 {
 	unsigned long inactive, isolated;
+	int ratio;
 
 	if (current_is_kswapd())
 		return 0;
@@ -1150,7 +1151,9 @@ static int too_many_isolated(struct zone *zone, int file,
 		isolated = zone_page_state(zone, NR_ISOLATED_ANON);
 	}
 
-	return isolated > inactive;
+	ratio = sc->gfp_mask & (__GFP_IO | __GFP_FS) ? 1 : 8;
+
+	return isolated > inactive * ratio;
 }
 
 /*