Date: Tue, 15 Jan 2008 11:37:48 +0900
From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Subject: Re: [RFC][PATCH 4/5] memory_pressure_notify() caller
Cc: kosaki.motohiro@jp.fujitsu.com, linux-mm@kvack.org,
       linux-kernel@vger.kernel.org, Marcelo Tosatti <marcelo@kvack.org>,
       Daniel Spang <daniel.spang@gmail.com>, Rik van Riel <riel@redhat.com>,
       Andrew Morton <akpm@linux-foundation.org>
In-Reply-To: <20080115110631.4cab1e65.kamezawa.hiroyu@jp.fujitsu.com>
References: <20080115100124.117B.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20080115110631.4cab1e65.kamezawa.hiroyu@jp.fujitsu.com>
Message-Id: <20080115112114.118E.KOSAKI.MOTOHIRO@jp.fujitsu.com>
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Hi KAME, 

> > +	notify_threshold = (zone->pages_high +
> > +			    zone->lowmem_reserve[MAX_NR_ZONES-1]) * 2;
> > +
> Why MAX_NR_ZONES-1 ?

this is intent to max lowmem_reserve.

in normal case, 
shrink_active_list isn't called when free_pages > pages_high.
but just after memory freed, it happened rarely.

I don't want incorrect notify at system enough free memory.

related discussion
  http://marc.info/?l=linux-mm&m=119878630211348&w=2


> > +	if (unlikely((prev_free <= notify_threshold) &&
> > +		     (zone_page_state(zone, NR_FREE_PAGES) > notify_threshold)))
> > +		memory_pressure_notify(zone, 0);
> >  }
> 
> How about this
> ==
> if (unlikely(zone->mem_notify_status && ...) 

Nice idea.
I will applied it at next post.

thank you!


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