Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758064AbZFIHUt (ORCPT ); Tue, 9 Jun 2009 03:20:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754155AbZFIHUl (ORCPT ); Tue, 9 Jun 2009 03:20:41 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:60631 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750810AbZFIHUl (ORCPT ); Tue, 9 Jun 2009 03:20:41 -0400 From: KOSAKI Motohiro To: Daisuke Nishimura Subject: Re: [PATCH mmotm] vmscan: handle may_swap more strictly (Re: [PATCH mmotm] vmscan: fix may_swap handling for memcg) Cc: kosaki.motohiro@jp.fujitsu.com, LKML , linux-mm , Andrew Morton , Johannes Weiner , Balbir Singh , KAMEZAWA Hiroyuki In-Reply-To: <20090609161330.fcd5facb.nishimura@mxp.nes.nec.co.jp> References: <20090608165457.fa8d17e6.nishimura@mxp.nes.nec.co.jp> <20090609161330.fcd5facb.nishimura@mxp.nes.nec.co.jp> Message-Id: <20090609161925.DD70.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Date: Tue, 9 Jun 2009 16:20:40 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2816 Lines: 87 > > > and, too many recliaming pages is not only memcg issue. I don't think this > > > patch provide generic solution. > > > > > Ah, you're right. It's not only memcg issue. > > > How about this one ? > > === > From: Daisuke Nishimura > > Commit 2e2e425989080cc534fc0fca154cae515f971cf5 ("vmscan,memcg: reintroduce > sc->may_swap) add may_swap flag and handle it at get_scan_ratio(). > > But the result of get_scan_ratio() is ignored when priority == 0, > so anon lru is scanned even if may_swap == 0 or nr_swap_pages == 0. > IMHO, this is not an expected behavior. > > As for memcg especially, because of this behavior many and many pages are > swapped-out just in vain when oom is invoked by mem+swap limit. > > This patch is for handling may_swap flag more strictly. > > Signed-off-by: Daisuke Nishimura Looks great. your patch doesn't only improve memcg, bug also improve noswap system. Thanks. Reviewed-by: KOSAKI Motohiro > --- > mm/vmscan.c | 18 +++++++++--------- > 1 files changed, 9 insertions(+), 9 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 2ddcfc8..bacb092 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -1407,13 +1407,6 @@ 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_pages(zone, sc, LRU_ACTIVE_ANON) + > zone_nr_pages(zone, sc, LRU_INACTIVE_ANON); > file = zone_nr_pages(zone, sc, LRU_ACTIVE_FILE) + > @@ -1511,15 +1504,22 @@ static void shrink_zone(int priority, struct zone *zone, > enum lru_list l; > unsigned long nr_reclaimed = sc->nr_reclaimed; > unsigned long swap_cluster_max = sc->swap_cluster_max; > + int noswap = 0; > > - get_scan_ratio(zone, sc, percent); > + /* 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); > > for_each_evictable_lru(l) { > int file = is_file_lru(l); > unsigned long scan; > > scan = zone_nr_pages(zone, sc, l); > - if (priority) { > + if (priority || noswap) { > scan >>= priority; > scan = (scan * percent[file]) / 100; > } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/