mm: vmscan: convert global reclaim to per-memcg LRU lists
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 <jweiner@redhat.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Ying Han <yinghan@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 136c7eb..024168c 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1886,7 +1886,7 @@
* latencies, so it's better to scan a minimum amount there as
* well.
*/
- if (current_is_kswapd())
+ if (current_is_kswapd() && mz->zone->all_unreclaimable)
force_scan = true;
if (!global_reclaim(sc))
force_scan = true;
@@ -2111,16 +2111,6 @@
};
struct mem_cgroup *memcg;
- if (global_reclaim(sc)) {
- struct mem_cgroup_zone mz = {
- .mem_cgroup = NULL,
- .zone = zone,
- };
-
- shrink_mem_cgroup_zone(priority, &mz, sc);
- return;
- }
-
memcg = mem_cgroup_iter(root, NULL, &reclaim);
do {
struct mem_cgroup_zone mz = {
@@ -2134,6 +2124,10 @@
* scanned it with decreasing priority levels until
* nr_to_reclaim had been reclaimed. This priority
* cycle is thus over after a single memcg.
+ *
+ * Direct reclaim and kswapd, on the other hand, have
+ * to scan all memory cgroups to fulfill the overall
+ * scan target for the zone.
*/
if (!global_reclaim(sc)) {
mem_cgroup_iter_break(root, memcg);
@@ -2478,13 +2472,24 @@
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 *memcg;
- if (inactive_anon_is_low(&mz))
- shrink_active_list(SWAP_CLUSTER_MAX, &mz, sc, priority, 0);
+ if (!total_swap_pages)
+ return;
+
+ memcg = mem_cgroup_iter(NULL, NULL, NULL);
+ do {
+ struct mem_cgroup_zone mz = {
+ .mem_cgroup = memcg,
+ .zone = zone,
+ };
+
+ if (inactive_anon_is_low(&mz))
+ shrink_active_list(SWAP_CLUSTER_MAX, &mz,
+ sc, priority, 0);
+
+ memcg = mem_cgroup_iter(NULL, memcg, NULL);
+ } while (memcg);
}
/*