Messages in this thread | | | Date | Mon, 18 May 2009 11:15:36 +0800 | From | Wu Fengguang <> | Subject | Re: [PATCH 1/4] vmscan: change the number of the unmapped files in zone reclaim |
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On Wed, May 13, 2009 at 12:06:28PM +0900, KOSAKI Motohiro wrote: > Subject: [PATCH] vmscan: change the number of the unmapped files in zone reclaim > > Documentation/sysctl/vm.txt says > > A percentage of the total pages in each zone. Zone reclaim will only > occur if more than this percentage of pages are file backed and unmapped. > This is to insure that a minimal amount of local pages is still available for > file I/O even if the node is overallocated. > > However, zone_page_state(zone, NR_FILE_PAGES) contain some non file backed pages > (e.g. swapcache, buffer-head) > > The right calculation is to use NR_{IN}ACTIVE_FILE. > > > Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> > Cc: Christoph Lameter <cl@linux-foundation.org> > Cc: Rik van Riel <riel@redhat.com> > --- > mm/vmscan.c | 21 ++++++++++++++------- > 1 file changed, 14 insertions(+), 7 deletions(-) > > Index: b/mm/vmscan.c > =================================================================== > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -2397,6 +2397,7 @@ 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(); > @@ -2409,9 +2410,11 @@ static int __zone_reclaim(struct zone *z > reclaim_state.reclaimed_slab = 0; > p->reclaim_state = &reclaim_state; > > - if (zone_page_state(zone, NR_FILE_PAGES) - > - zone_page_state(zone, NR_FILE_MAPPED) > > - zone->min_unmapped_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);
This can possibly go negative.
> + if (nr_unmapped_file_pages > zone->min_unmapped_pages) { > /* > * Free memory by calling shrink zone with increasing > * priorities until we have enough memory freed. > @@ -2458,6 +2461,8 @@ int zone_reclaim(struct zone *zone, gfp_ > { > int node_id; > int ret; > + long nr_unmapped_file_pages; > + long nr_slab_reclaimable; > > /* > * Zone reclaim reclaims unmapped file backed pages and > @@ -2469,10 +2474,12 @@ int zone_reclaim(struct zone *zone, gfp_ > * if less than a specified percentage of the zone is used by > * unmapped file backed pages. > */ > - if (zone_page_state(zone, NR_FILE_PAGES) - > - zone_page_state(zone, NR_FILE_MAPPED) <= zone->min_unmapped_pages > - && zone_page_state(zone, NR_SLAB_RECLAIMABLE) > - <= zone->min_slab_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);
Ditto.
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
> + nr_slab_reclaimable = zone_page_state(zone, NR_SLAB_RECLAIMABLE); > + if (nr_unmapped_file_pages <= zone->min_unmapped_pages && > + nr_slab_reclaimable <= zone->min_slab_pages) > return 0; > > if (zone_is_all_unreclaimable(zone)) > > > -- > 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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
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