From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754107Ab2GWNrB (ORCPT ); Mon, 23 Jul 2012 09:47:01 -0400 Received: from cantor2.suse.de ([195.135.220.15]:58569 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753264Ab2GWNiv (ORCPT ); Mon, 23 Jul 2012 09:38:51 -0400 From: Mel Gorman To: Stable Cc: Linux-MM , LKML , Mel Gorman Subject: [PATCH 04/34] mm: vmscan: fix force-scanning small targets without swap Date: Mon, 23 Jul 2012 14:38:17 +0100 Message-Id: <1343050727-3045-5-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 1.7.9.2 In-Reply-To: <1343050727-3045-1-git-send-email-mgorman@suse.de> References: <1343050727-3045-1-git-send-email-mgorman@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Johannes Weiner commit a4d3e9e76337059406fcf3ead288c0df22a790e9 upstream. Stable note: Not tracked in Bugzilla. This patch augments an earlier commit that avoids scanning priority being artificially raised. The older fix was particularly important for small memcgs to avoid calling wait_iff_congested() unnecessarily. Without swap, anonymous pages are not scanned. As such, they should not count when considering force-scanning a small target if there is no swap. Otherwise, targets are not force-scanned even when their effective scan number is zero and the other conditions--kswapd/memcg--apply. This fixes 246e87a93934 ("memcg: fix get_scan_count() for small targets"). [akpm@linux-foundation.org: fix comment] Signed-off-by: Johannes Weiner Acked-by: KAMEZAWA Hiroyuki Reviewed-by: Michal Hocko Cc: Ying Han Cc: Balbir Singh Cc: KOSAKI Motohiro Cc: Daisuke Nishimura Acked-by: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Mel Gorman --- mm/vmscan.c | 27 ++++++++++++--------------- 1 file changed, 12 insertions(+), 15 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 769935d..bdfdec3 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1747,23 +1747,15 @@ static void get_scan_count(struct zone *zone, struct scan_control *sc, u64 fraction[2], denominator; enum lru_list l; int noswap = 0; - int force_scan = 0; + bool force_scan = false; unsigned long nr_force_scan[2]; - - 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) + - zone_nr_lru_pages(zone, sc, LRU_INACTIVE_FILE); - - if (((anon + file) >> priority) < SWAP_CLUSTER_MAX) { - /* kswapd does zone balancing and need to scan this zone */ - if (scanning_global_lru(sc) && current_is_kswapd()) - force_scan = 1; - /* memcg may have small limit and need to avoid priority drop */ - if (!scanning_global_lru(sc)) - force_scan = 1; - } + /* kswapd does zone balancing and needs to scan this zone */ + if (scanning_global_lru(sc) && current_is_kswapd()) + force_scan = true; + /* memcg may have small limit and need to avoid priority drop */ + if (!scanning_global_lru(sc)) + force_scan = true; /* If we have no swap space, do not bother scanning anon pages. */ if (!sc->may_swap || (nr_swap_pages <= 0)) { @@ -1776,6 +1768,11 @@ static void get_scan_count(struct zone *zone, struct scan_control *sc, goto out; } + 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) + + zone_nr_lru_pages(zone, sc, LRU_INACTIVE_FILE); + if (scanning_global_lru(sc)) { free = zone_page_state(zone, NR_FREE_PAGES); /* If we have very few page cache pages, -- 1.7.9.2