Messages in this thread Patch in this message | | | Date | Thu, 24 Jan 2008 13:23:53 +0900 | From | KOSAKI Motohiro <> | Subject | [RFC][PATCH 6/8] mem_notify v5: (optional) fixed incorrect shrink_zone |
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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 ;-)
ChangeLog v5: new
--- mm/vmscan.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-)
Index: b/mm/vmscan.c =================================================================== --- a/mm/vmscan.c 2008-01-18 14:18:27.000000000 +0900 +++ b/mm/vmscan.c 2008-01-18 14:49:06.000000000 +0900 @@ -948,7 +948,7 @@ 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; } @@ -1214,18 +1214,29 @@ 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
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