Answer by user11509478 for How to keep executable code in memory even under memory pressure ? in Linux

To answer the question, here's a simple/preliminary patch to not evict Active(file)(as seen in /proc/meminfo) if it's less than 256 MiB, that seems to work ok (no disk thrashing) with linux-stable 5.2.4:

diff --git a/mm/vmscan.c b/mm/vmscan.cindex dbdc46a84f63..7a0b7e32ff45 100644--- a/mm/vmscan.c+++ b/mm/vmscan.c@@ -2445,6 +2445,13 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg,            BUG();        }+    if (NR_ACTIVE_FILE == lru) {+      long long kib_active_file_now=global_node_page_state(NR_ACTIVE_FILE) * MAX_NR_ZONES;+      if (kib_active_file_now <= 256*1024) {+        nr[lru] = 0; //don't reclaim any Active(file) (see /proc/meminfo) if they are under 256MiB+        continue;+      }+    }        *lru_pages += size;        nr[lru] = scan;    }

Note that some yet-to-be-foundregression on kernel 5.3.0-rc4-gd45331b00ddb will cause a system freeze(without disk thrashing, and sysrq will still work) even without this patch.

(any new developments related to this should be happening here.)