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| author | Andrew Morton <akpm@osdl.org> | 2006-01-06 00:11:14 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-01-06 08:33:27 -0800 |
| commit | 210fe530305ee50cd889fe9250168228b2994f32 (patch) | |
| tree | 4d22a28cf28abded5f77daef5b025c04d1ffea56 /mm | |
| parent | 41e9b63b35b52cf918a4ffdb8d77862ab824aa8b (diff) | |
| download | lwn-210fe530305ee50cd889fe9250168228b2994f32.tar.gz lwn-210fe530305ee50cd889fe9250168228b2994f32.zip | |
[PATCH] vmscan: balancing fix
Revert a patch which went into 2.6.8-rc1. The changelog for that patch was:
The shrink_zone() logic can, under some circumstances, cause far too many
pages to be reclaimed. Say, we're scanning at high priority and suddenly
hit a large number of reclaimable pages on the LRU.
Change things so we bale out when SWAP_CLUSTER_MAX pages have been
reclaimed.
Problem is, this change caused significant imbalance in inter-zone scan
balancing by truncating scans of larger zones.
Suppose, for example, ZONE_HIGHMEM is 10x the size of ZONE_NORMAL. The zone
balancing algorithm would require that if we're scanning 100 pages of
ZONE_HIGHMEM, we should scan 10 pages of ZONE_NORMAL. But this logic will
cause the scanning of ZONE_HIGHMEM to bale out after only 32 pages are
reclaimed. Thus effectively causing smaller zones to be scanned relatively
harder than large ones.
Now I need to remember what the workload was which caused me to write this
patch originally, then fix it up in a different way...
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/vmscan.c | 8 |
1 files changed, 0 insertions, 8 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index b2baca7645d7..5c8a412b43f4 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -63,9 +63,6 @@ struct scan_control { unsigned long nr_mapped; /* From page_state */ - /* How many pages shrink_cache() should reclaim */ - int nr_to_reclaim; - /* Ask shrink_caches, or shrink_zone to scan at this priority */ unsigned int priority; @@ -656,7 +653,6 @@ static void shrink_cache(struct zone *zone, struct scan_control *sc) if (current_is_kswapd()) mod_page_state(kswapd_steal, nr_freed); mod_page_state_zone(zone, pgsteal, nr_freed); - sc->nr_to_reclaim -= nr_freed; spin_lock_irq(&zone->lru_lock); /* @@ -856,8 +852,6 @@ shrink_zone(struct zone *zone, struct scan_control *sc) else nr_inactive = 0; - sc->nr_to_reclaim = sc->swap_cluster_max; - while (nr_active || nr_inactive) { if (nr_active) { sc->nr_to_scan = min(nr_active, @@ -871,8 +865,6 @@ shrink_zone(struct zone *zone, struct scan_control *sc) (unsigned long)sc->swap_cluster_max); nr_inactive -= sc->nr_to_scan; shrink_cache(zone, sc); - if (sc->nr_to_reclaim <= 0) - break; } } |