From 230e5b585403cc427f4625b6a78739aabd599e3c Mon Sep 17 00:00:00 2001
From: Johannes Weiner <hannes@cmpxchg.org>
Date: Sat, 30 Nov 2019 17:55:37 -0800
Subject: [PATCH] mm: vmscan: move inactive_list_is_low() swap check to the
caller
References: bnc#1155780 (VM/FS functional and performance backports)
Patch-mainline: v5.5-rc1
Git-commit: a108629149cc63cfb6fd446184e3e578e04bcfd1
inactive_list_is_low() should be about one thing: checking the ratio
between inactive and active list. Kitchensink checks like the one for
swap space makes the function hard to use and modify its callsites.
Luckly, most callers already have an understanding of the swap situation,
so it's easy to clean up.
get_scan_count() has its own, memcg-aware swap check, and doesn't even get
to the inactive_list_is_low() check on the anon list when there is no swap
space available.
shrink_list() is called on the results of get_scan_count(), so that check
is redundant too.
age_active_anon() has its own totalswap_pages check right before it checks
the list proportions.
The shrink_node_memcg() site is the only one that doesn't do its own swap
check. Add it there.
Then delete the swap check from inactive_list_is_low().
Link: http://lkml.kernel.org/r/20191022144803.302233-4-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
mm/vmscan.c | 9 +--------
1 file changed, 1 insertion(+), 8 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 89a9e7ed192c..1d4ad7c1449e 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2173,13 +2173,6 @@ static bool inactive_list_is_low(struct lruvec *lruvec, bool file,
unsigned long refaults;
unsigned long gb;
- /*
- * If we don't have swap space, anonymous page deactivation
- * is pointless.
- */
- if (!file && !total_swap_pages)
- return false;
-
inactive = lruvec_lru_size(lruvec, inactive_lru, sc->reclaim_idx);
active = lruvec_lru_size(lruvec, active_lru, sc->reclaim_idx);
@@ -2600,7 +2593,7 @@ static void shrink_node_memcg(struct pglist_data *pgdat, struct mem_cgroup *memc
* Even if we did not try to evict anon pages at all, we want to
* rebalance the anon lru active/inactive ratio.
*/
- if (inactive_list_is_low(lruvec, false, sc, true))
+ if (total_swap_pages && inactive_list_is_low(lruvec, false, sc, true))
shrink_active_list(SWAP_CLUSTER_MAX, lruvec,
sc, LRU_ACTIVE_ANON);
}