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authorMel Gorman <mgorman@techsingularity.net>2021-06-28 19:42:21 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-06-29 10:53:54 -0700
commitc49c2c47dab6b8d45022b3fabf0642a0e62e3109 (patch)
tree4a5929d0291298c04a6b8af7958ce77bbca64bb9 /mm/vmscan.c
parent3b12e7e97938424de2bb1b95ba0bd6a49bad39f9 (diff)
mm/page_alloc: limit the number of pages on PCP lists when reclaim is active
When kswapd is active then direct reclaim is potentially active. In either case, it is possible that a zone would be balanced if pages were not trapped on PCP lists. Instead of draining remote pages, simply limit the size of the PCP lists while kswapd is active. Link: https://lkml.kernel.org/r/20210525080119.5455-6-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmscan.c')
-rw-r--r--mm/vmscan.c35
1 files changed, 35 insertions, 0 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index f96d62159720..d7c3cb8688dd 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3722,6 +3722,38 @@ static bool kswapd_shrink_node(pg_data_t *pgdat,
return sc->nr_scanned >= sc->nr_to_reclaim;
}
+/* Page allocator PCP high watermark is lowered if reclaim is active. */
+static inline void
+update_reclaim_active(pg_data_t *pgdat, int highest_zoneidx, bool active)
+{
+ int i;
+ struct zone *zone;
+
+ for (i = 0; i <= highest_zoneidx; i++) {
+ zone = pgdat->node_zones + i;
+
+ if (!managed_zone(zone))
+ continue;
+
+ if (active)
+ set_bit(ZONE_RECLAIM_ACTIVE, &zone->flags);
+ else
+ clear_bit(ZONE_RECLAIM_ACTIVE, &zone->flags);
+ }
+}
+
+static inline void
+set_reclaim_active(pg_data_t *pgdat, int highest_zoneidx)
+{
+ update_reclaim_active(pgdat, highest_zoneidx, true);
+}
+
+static inline void
+clear_reclaim_active(pg_data_t *pgdat, int highest_zoneidx)
+{
+ update_reclaim_active(pgdat, highest_zoneidx, false);
+}
+
/*
* For kswapd, balance_pgdat() will reclaim pages across a node from zones
* that are eligible for use by the caller until at least one zone is
@@ -3774,6 +3806,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int highest_zoneidx)
boosted = nr_boost_reclaim;
restart:
+ set_reclaim_active(pgdat, highest_zoneidx);
sc.priority = DEF_PRIORITY;
do {
unsigned long nr_reclaimed = sc.nr_reclaimed;
@@ -3907,6 +3940,8 @@ restart:
pgdat->kswapd_failures++;
out:
+ clear_reclaim_active(pgdat, highest_zoneidx);
+
/* If reclaim was boosted, account for the reclaim done in this pass */
if (boosted) {
unsigned long flags;