From 1e7e5a9048b30c57ba1ddaa6cdf59b21b65cde99 Mon Sep 17 00:00:00 2001 From: Martin Hicks Date: Tue, 21 Jun 2005 17:14:43 -0700 Subject: [PATCH] [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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mmzone.h | 2 ++ mm/page_alloc.c | 1 + mm/vmscan.c | 10 ++++++++++ 3 files changed, 13 insertions(+) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index dfc2452ccb..18fed8b679 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 a9da20bc2e..2019c1b192 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 7da846960d..24da725a30 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; } -- 2.39.5