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Date: Tue, 30 Mar 2010 16:13:40 +0800
From: Shaohua Li <shaohua.li@intel.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
       "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
       "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
       "Wu, Fengguang" <fengguang.wu@intel.com>
Subject: Re: [PATCH]vmscan: handle underflow for get_scan_ratio
Message-ID: <20100330081340.GA23691@sli10-desk.sh.intel.com>
References: <20100330153750.8EA2.A69D9226@jp.fujitsu.com>
 <20100330065358.GA24828@sli10-desk.sh.intel.com>
 <20100330160820.8EA8.A69D9226@jp.fujitsu.com>
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On Tue, Mar 30, 2010 at 03:31:40PM +0800, KOSAKI Motohiro wrote:
> > > > > Very unfortunately, this patch isn't acceptable. In past time, vmscan 
> > > > > had similar logic, but 1% swap-out made lots bug reports. 
> > > > can you elaborate this?
> > > > Completely restore previous behavior (do full scan with priority 0) is
> > > > ok too.
> > > 
> > > This is a option. but we need to know the root cause anyway.
> > I thought I mentioned the root cause in first mail. My debug shows
> > recent_rotated[0] is big, but recent_rotated[1] is almost zero, which makes
> > percent[0] 0. But you can double check too.
> 
> To revert can save percent[0]==0 && priority==0 case. but it shouldn't
> happen, I think. It mean to happen big latency issue.
> 
> Can you please try following patch? Also, I'll prepare reproduce environment soon.
still oom with the patch.