Date: Fri, 2 Apr 2010 17:24:41 +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: <20100402092441.GA21100@sli10-desk.sh.intel.com>
References: <20100331145030.03A1.A69D9226@jp.fujitsu.com>
 <20100402065052.GA28027@sli10-desk.sh.intel.com>
 <20100402181307.6470.A69D9226@jp.fujitsu.com>
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On Fri, Apr 02, 2010 at 05:14:38PM +0800, KOSAKI Motohiro wrote:
> > > > This patch makes a lot of sense than previous. however I think <1% anon ratio
> > > > shouldn't happen anyway because file lru doesn't have reclaimable pages.
> > > > <1% seems no good reclaim rate.
> > > 
> > > Oops, the above mention is wrong. sorry. only 1 page is still too big.
> > > because under streaming io workload, the number of scanning anon pages should
> > > be zero. this is very strong requirement. if not, backup operation will makes
> > > a lot of swapping out.
> > Sounds there is no big impact for the workload which you mentioned with the patch.
> > please see below descriptions.
> > I updated the description of the patch as fengguang suggested.
> 
> Umm.. sorry, no.
> 
> "one fix but introduce another one bug" is not good deal. instead, 
> I'll revert the guilty commit at first as akpm mentioned.
Even we revert the commit, the patch still has its benefit, as it increases
calculation precision, right?

Thanks,
Shaohua
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