From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id 85DE160021B for ; Wed, 30 Dec 2009 08:07:13 -0500 (EST) Date: Wed, 30 Dec 2009 22:06:46 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [PATCH 2/4] vmscan: get_scan_ratio cleanup In-Reply-To: <20091229073412.GN3601@balbir.in.ibm.com> References: <20091228164733.A68A.A69D9226@jp.fujitsu.com> <20091229073412.GN3601@balbir.in.ibm.com> Message-Id: <20091230214955.1A10.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: balbir@linux.vnet.ibm.com Cc: kosaki.motohiro@jp.fujitsu.com, LKML , linux-mm , Andrew Morton , Mel Gorman , KAMEZAWA Hiroyuki List-ID: > * KOSAKI Motohiro [2009-12-28 16:48:06]: > > > The get_scan_ratio() should have all scan-ratio related calculations. > > Thus, this patch move some calculation into get_scan_ratio. > > > > Signed-off-by: KOSAKI Motohiro > > --- > > mm/vmscan.c | 23 ++++++++++++++--------- > > 1 files changed, 14 insertions(+), 9 deletions(-) > > > > diff --git a/mm/vmscan.c b/mm/vmscan.c > > index 2bbee91..640486b 100644 > > --- a/mm/vmscan.c > > +++ b/mm/vmscan.c > > @@ -1501,6 +1501,13 @@ static void get_scan_ratio(struct zone *zone, struct scan_control *sc, > > unsigned long ap, fp; > > struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); > > > > + /* If we have no swap space, do not bother scanning anon pages. */ > > + if (!sc->may_swap || (nr_swap_pages <= 0)) { > > + percent[0] = 0; > > + percent[1] = 100; > > + return; > > + } > > + > > > > anon = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_ANON) + > > zone_nr_lru_pages(zone, sc, LRU_INACTIVE_ANON); > > file = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_FILE) + > > @@ -1598,22 +1605,20 @@ static void shrink_zone(int priority, struct zone *zone, > > unsigned long nr_reclaimed = sc->nr_reclaimed; > > unsigned long nr_to_reclaim = sc->nr_to_reclaim; > > struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); > > - int noswap = 0; > > > > - /* If we have no swap space, do not bother scanning anon pages. */ > > - if (!sc->may_swap || (nr_swap_pages <= 0)) { > > - noswap = 1; > > - percent[0] = 0; > > - percent[1] = 100; > > - } else > > - get_scan_ratio(zone, sc, percent); > > + get_scan_ratio(zone, sc, percent); > > Where do we set noswap? Is percent[0] == 0 used to indicate noswap = > 1? Yes, I intended so. I guess your question can convert next sentence. following case makes different result, is it intentional? - there are free swap - sc->may_swap == 1 - priority == 0 - percent[0] == 0 My answer is, it isn't happen on practical workload. if priority reach to 0, vmscan always scan and reclaim some anon (please recall, now vmscan automatically enable lumpy_reclaim if priority < 10), then recent_rotated_anon isn't 0 always.. practically. Do you think this is wrong assumption? > > for_each_evictable_lru(l) { > > int file = is_file_lru(l); > > unsigned long scan; > > > > + if (percent[file] == 0) { > > + nr[l] = 0; > > + continue; > > + } > > + > > Is this really needed? Won't nr_scan_try_batch handle it correctly? this two if branch is nicer than "priority || noswap", I think. it clearly explain what do it. > > > scan = zone_nr_lru_pages(zone, sc, l); > > - if (priority || noswap) { > > + if (priority) { > > scan >>= priority; > > scan = (scan * percent[file]) / 100; > > } > > -- > Balbir -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org