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authorMartin Hicks <mort@sgi.com>2005-06-22 04:14:43 +0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-22 05:46:14 +0400
commit1e7e5a9048b30c57ba1ddaa6cdf59b21b65cde99 (patch)
tree26eb9c483718ca1a0fad23597c0dfd3a69e9f080
parent0c35bbadc59f5ed105c34471143eceb4c0dd9c95 (diff)
downloadlinux-1e7e5a9048b30c57ba1ddaa6cdf59b21b65cde99.tar.xz
[PATCH] VM: rate limit early reclaim
When early zone reclaim is turned on the LRU is scanned more frequently when a zone is low on memory. This limits when the zone reclaim can be called by skipping the scan if another thread (either via kswapd or sync reclaim) is already reclaiming from the zone. Signed-off-by: Martin Hicks <mort@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--include/linux/mmzone.h2
-rw-r--r--mm/page_alloc.c1
-rw-r--r--mm/vmscan.c10
3 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index dfc2452ccb10..18fed8b67943 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -149,6 +149,8 @@ struct zone {
* as it fails a watermark_ok() in __alloc_pages?
*/
int reclaim_pages;
+ /* A count of how many reclaimers are scanning this zone */
+ atomic_t reclaim_in_progress;
/*
* prev_priority holds the scanning priority for this zone. It is
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a9da20bc2ed0..2019c1b19254 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1738,6 +1738,7 @@ static void __init free_area_init_core(struct pglist_data *pgdat,
zone->nr_scan_inactive = 0;
zone->nr_active = 0;
zone->nr_inactive = 0;
+ atomic_set(&zone->reclaim_in_progress, -1);
if (!size)
continue;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 7da846960d8a..24da725a30f0 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -900,7 +900,9 @@ shrink_caches(struct zone **zones, struct scan_control *sc)
if (zone->all_unreclaimable && sc->priority != DEF_PRIORITY)
continue; /* Let kswapd poll it */
+ atomic_inc(&zone->reclaim_in_progress);
shrink_zone(zone, sc);
+ atomic_dec(&zone->reclaim_in_progress);
}
}
@@ -1111,7 +1113,9 @@ scan:
sc.nr_reclaimed = 0;
sc.priority = priority;
sc.swap_cluster_max = nr_pages? nr_pages : SWAP_CLUSTER_MAX;
+ atomic_inc(&zone->reclaim_in_progress);
shrink_zone(zone, &sc);
+ atomic_dec(&zone->reclaim_in_progress);
reclaim_state->reclaimed_slab = 0;
nr_slab = shrink_slab(sc.nr_scanned, GFP_KERNEL,
lru_pages);
@@ -1354,9 +1358,15 @@ int zone_reclaim(struct zone *zone, unsigned int gfp_mask, unsigned int order)
else
sc.swap_cluster_max = SWAP_CLUSTER_MAX;
+ /* Don't reclaim the zone if there are other reclaimers active */
+ if (!atomic_inc_and_test(&zone->reclaim_in_progress))
+ goto out;
+
shrink_zone(zone, &sc);
total_reclaimed = sc.nr_reclaimed;
+ out:
+ atomic_dec(&zone->reclaim_in_progress);
return total_reclaimed;
}