Messages in this thread Patch in this message | | | From | KOSAKI Motohiro <> | Subject | [PATCH 1/4] vmscan: change the number of the unmapped files in zone reclaim | Date | Wed, 13 May 2009 12:06:28 +0900 (JST) |
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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); + + 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); + 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))
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