From mboxrd@z Thu Jan 1 00:00:00 1970 From: "KOSAKI Motohiro" Subject: [PATCH 6/8][for -mm] mem_notify v6: (optional) fixed incorrect shrink_zone Date: Sun, 10 Feb 2008 00:26:10 +0900 Message-ID: <2f11576a0802090726u167095ads88a9726108f1296a@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: kosaki.motohiro@jp.fujitsu.com, "Marcelo Tosatti" , "Daniel Spang" , "Rik van Riel" , "Andrew Morton" , "Alan Cox" , linux-fsdevel@vger.kernel.org, "Pavel Machek" , "Al Boldi" , "Jon Masters" , "Zan Lynx" To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org on X86, ZONE_DMA is very very small. It is often no used at all. Unfortunately, when NR_ACTIVE==0, NR_INACTIVE==0, shrink_zone() try to reclaim 1 page. because zone->nr_scan_active += (zone_page_state(zone, NR_ACTIVE) >> priority) + 1; ^^^^^ it cause unnecessary low memory notify ;-) I fixed it. ChangeLog v5: new Signed-off-by: KOSAKI Motohiro --- mm/vmscan.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) Index: b/mm/vmscan.c =================================================================== --- a/mm/vmscan.c 2008-02-03 20:27:53.000000000 +0900 +++ b/mm/vmscan.c 2008-02-03 20:33:13.000000000 +0900 @@ -947,7 +947,7 @@ static inline void note_zone_scanning_pr static inline int zone_is_near_oom(struct zone *zone) { - return zone->pages_scanned >= (zone_page_state(zone, NR_ACTIVE) + return zone->pages_scanned > (zone_page_state(zone, NR_ACTIVE) + zone_page_state(zone, NR_INACTIVE))*3; } @@ -1196,18 +1196,29 @@ static unsigned long shrink_zone(int pri unsigned long nr_inactive; unsigned long nr_to_scan; unsigned long nr_reclaimed = 0; + unsigned long tmp; + unsigned long zone_active; + unsigned long zone_inactive; if (scan_global_lru(sc)) { /* * Add one to nr_to_scan just to make sure that the kernel * will slowly sift through the active list. */ - zone->nr_scan_active += - (zone_page_state(zone, NR_ACTIVE) >> priority) + 1; + zone_active = zone_page_state(zone, NR_ACTIVE); + tmp = (zone_active >> priority) + 1; + if (unlikely(tmp > zone_active)) + tmp = zone_active; + zone->nr_scan_active += tmp; nr_active = zone->nr_scan_active; - zone->nr_scan_inactive += - (zone_page_state(zone, NR_INACTIVE) >> priority) + 1; + + zone_inactive = zone_page_state(zone, NR_INACTIVE); + tmp = (zone_inactive >> priority) + 1; + if (unlikely(tmp > zone_inactive)) + tmp = zone_inactive; + zone->nr_scan_inactive += tmp; nr_inactive = zone->nr_scan_inactive; + if (nr_inactive >= sc->swap_cluster_max) zone->nr_scan_inactive = 0; else