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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
       LKML <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
       Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH 06/11] memcg: make inactive_anon_is_low()
Cc: kosaki.motohiro@jp.fujitsu.com
In-Reply-To: <20081203135249.GE17701@balbir.in.ibm.com>
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Date: Thu,  4 Dec 2008 15:14:20 +0900 (JST)
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> > +/*
> > + * The inactive anon list should be small enough that the VM never has to
> > + * do too much work, but large enough that each inactive page has a chance
> > + * to be referenced again before it is swapped out.
> > + *
> > + * this calculation is straightforward porting from
> > + * page_alloc.c::setup_per_zone_inactive_ratio().
> > + * it describe more detail.
> > + */
> > +static void mem_cgroup_set_inactive_ratio(struct mem_cgroup *memcg)
> > +{
> > +	unsigned int gb, ratio;
> > +
> > +	gb = res_counter_read_u64(&memcg->res, RES_LIMIT) >> 30;
> > +	if (gb)
> > +		ratio = int_sqrt(10 * gb);
> 
> I don't understand where the magic number 10 comes from?

the function comment write to

  this calculation is straightforward porting from
  page_alloc.c::setup_per_zone_inactive_ratio().
  it describe more detail.





> > @@ -1400,7 +1412,7 @@ static unsigned long shrink_list(enum lr
> >  	}
> > 
> >  	if (lru == LRU_ACTIVE_ANON &&
> > -	    (!scan_global_lru(sc) || inactive_anon_is_low(zone))) {
> > +	    inactive_anon_is_low(zone, sc)) {
> 
> Can't we merge the line with the "if" statement

Will fix.

thanks.