[PATCH 6/8][for -mm] mem_notify v6: (optional) fixed incorrect shrink_zone
DORMANTno replies
From: KOSAKI Motohiro <hidden>
Date: 2008-02-09 15:26:10
Also in:
linux-fsdevel, lkml
Subsystem:
memory management, memory management - mglru (multi-gen lru), memory management - reclaim, the rest · Maintainers:
Andrew Morton, Johannes Weiner, Linus Torvalds
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 <redacted>
---
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 --
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