Thread (65 messages) 65 messages, 4 authors, 2011-09-29

Re: [patch 08/11] mm: vmscan: convert global reclaim to per-memcg LRU lists

From: Michal Hocko <hidden>
Date: 2011-09-21 13:10:49
Also in: lkml

On Mon 12-09-11 12:57:25, Johannes Weiner wrote:
The global per-zone LRU lists are about to go away on memcg-enabled
kernels, global reclaim must be able to find its pages on the
per-memcg LRU lists.

Since the LRU pages of a zone are distributed over all existing memory
cgroups, a scan target for a zone is complete when all memory cgroups
are scanned for their proportional share of a zone's memory.

The forced scanning of small scan targets from kswapd is limited to
zones marked unreclaimable, otherwise kswapd can quickly overreclaim
by force-scanning the LRU lists of multiple memory cgroups.

Signed-off-by: Johannes Weiner <redacted>
Reviewed-by: Michal Hocko <redacted>

Minor nit bellow
quoted hunk ↗ jump to hunk
---
 mm/vmscan.c |   39 ++++++++++++++++++++++-----------------
 1 files changed, 22 insertions(+), 17 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index bb4d8b8..053609e 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2451,13 +2445,24 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
 static void age_active_anon(struct zone *zone, struct scan_control *sc,
 			    int priority)
 {
-	struct mem_cgroup_zone mz = {
-		.mem_cgroup = NULL,
-		.zone = zone,
-	};
+	struct mem_cgroup *mem;
+
+	if (!total_swap_pages)
+		return;
+
+	mem = mem_cgroup_iter(NULL, NULL, NULL);
Wouldn't be for_each_mem_cgroup more appropriate? Macro is not exported
but probably worth exporting? The same applies for
scan_zone_unevictable_pages from the previous patch.
+	do {
+		struct mem_cgroup_zone mz = {
+			.mem_cgroup = mem,
+			.zone = zone,
+		};
 
-	if (inactive_anon_is_low(&mz))
-		shrink_active_list(SWAP_CLUSTER_MAX, &mz, sc, priority, 0);
+		if (inactive_anon_is_low(&mz))
+			shrink_active_list(SWAP_CLUSTER_MAX, &mz,
+					   sc, priority, 0);
+
+		mem = mem_cgroup_iter(NULL, mem, NULL);
+	} while (mem);
 }
-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic

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