From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id 04E3E6B005D for ; Thu, 11 Jun 2009 07:15:27 -0400 (EDT) Date: Thu, 11 Jun 2009 12:15:51 +0100 From: Mel Gorman Subject: Re: [PATCH for mmotm 5/5] fix vmscan-change-the-number-of-the-unmapped-files-in-zone-reclaim.patch Message-ID: <20090611111550.GF7302@csn.ul.ie> References: <20090611192114.6D4A.A69D9226@jp.fujitsu.com> <20090611192757.6D59.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20090611192757.6D59.A69D9226@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: linux-mm , LKML , Wu Fengguang , Andrew Morton List-ID: On Thu, Jun 11, 2009 at 07:28:30PM +0900, KOSAKI Motohiro wrote: > Subject: [PATCH] fix vmscan-change-the-number-of-the-unmapped-files-in-zone-reclaim.patch > > > + nr_unmapped_file_pages = zone_page_state(zone, NR_INACTIVE_FILE) + > + zone_page_state(zone, NR_ACTIVE_FILE) - > + zone_page_state(zone, NR_FILE_MAPPED); > > is wrong. it can be underflow because tmpfs pages are not counted NR_*_FILE, > but they are counted NR_FILE_MAPPED. > > fixing here. > > > Signed-off-by: KOSAKI Motohiro > Cc: Mel Gorman > Cc: Wu Fengguang > --- > mm/vmscan.c | 32 ++++++++++++++++++++------------ > 1 file changed, 20 insertions(+), 12 deletions(-) > > Index: b/mm/vmscan.c > =================================================================== > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -2333,6 +2333,23 @@ int sysctl_min_unmapped_ratio = 1; > */ > int sysctl_min_slab_ratio = 5; > > +static unsigned long zone_unmapped_file_pages(struct zone *zone) > +{ > + long nr_file_pages; > + long nr_file_mapped; > + long nr_unmapped_file_pages; > + > + nr_file_pages = zone_page_state(zone, NR_INACTIVE_FILE) + > + zone_page_state(zone, NR_ACTIVE_FILE); > + nr_file_mapped = zone_page_state(zone, NR_FILE_MAPPED) - > + zone_page_state(zone, > + NR_SWAP_BACKED_FILE_MAPPED); > + nr_unmapped_file_pages = nr_file_pages - nr_file_mapped; > + > + return nr_unmapped_file_pages > 0 ? nr_unmapped_file_pages : 0; > +} This is a more accurate calculation for sure. The question is - is it necessary? > + > + > /* > * Try to free up some pages from this zone through reclaim. > */ > @@ -2355,7 +2372,6 @@ static int __zone_reclaim(struct zone *z > .isolate_pages = isolate_pages_global, > }; > unsigned long slab_reclaimable; > - long nr_unmapped_file_pages; > > disable_swap_token(); > cond_resched(); > @@ -2368,11 +2384,7 @@ static int __zone_reclaim(struct zone *z > reclaim_state.reclaimed_slab = 0; > p->reclaim_state = &reclaim_state; > > - nr_unmapped_file_pages = zone_page_state(zone, NR_INACTIVE_FILE) + > - zone_page_state(zone, NR_ACTIVE_FILE) - > - zone_page_state(zone, NR_FILE_MAPPED); > - > - if (nr_unmapped_file_pages > zone->min_unmapped_pages) { > + if (zone_unmapped_file_pages(zone) > zone->min_unmapped_pages) { > /* > * Free memory by calling shrink zone with increasing > * priorities until we have enough memory freed. > @@ -2419,8 +2431,7 @@ int zone_reclaim(struct zone *zone, gfp_ > { > int node_id; > int ret; > - long nr_unmapped_file_pages; > - long nr_slab_reclaimable; > + unsigned long nr_slab_reclaimable; > > /* > * Zone reclaim reclaims unmapped file backed pages and > @@ -2432,11 +2443,8 @@ int zone_reclaim(struct zone *zone, gfp_ > * if less than a specified percentage of the zone is used by > * unmapped file backed pages. > */ > - nr_unmapped_file_pages = zone_page_state(zone, NR_INACTIVE_FILE) + > - zone_page_state(zone, NR_ACTIVE_FILE) - > - zone_page_state(zone, NR_FILE_MAPPED); > nr_slab_reclaimable = zone_page_state(zone, NR_SLAB_RECLAIMABLE); > - if (nr_unmapped_file_pages <= zone->min_unmapped_pages && > + if (zone_unmapped_file_pages(zone) <= zone->min_unmapped_pages && > nr_slab_reclaimable <= zone->min_slab_pages) > return 0; > > > -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- 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