ZEN: Tune mgLRU to protect cache used in the last second

damentz · Kaz205 · commit caaada1a6e89 · 2023-06-08T14:11:58.000+09:00
Although not identical to the le9 patches that protect a byte-amount of cache through tunables, multigenerational LRU now supports protecting cache accessed in the last X milliseconds. In torvalds#218, Yu recommends starting with 1000ms and tuning as needed. This looks like a safe default and turning on this feature should help users that don't know they need it.
diff --git a/mm/vmscan.c b/mm/vmscan.c
@@ -4604,7 +4604,11 @@ static bool lruvec_is_reclaimable(struct lruvec *lruvec, struct scan_control *sc
 }
 
 /* to protect the working set of the last N jiffies */
+#ifdef CONFIG_ZEN_INTERACTIVE
+static unsigned long lru_gen_min_ttl __read_mostly = HZ;
+#else
 static unsigned long lru_gen_min_ttl __read_mostly;
+#endif
 
 static void lru_gen_age_node(struct pglist_data *pgdat, struct scan_control *sc)
 {

Original file line number	Diff line number	Diff line change
`@@ -4604,7 +4604,11 @@ static bool lruvec_is_reclaimable(struct lruvec lruvec, struct scan_control sc`
`4604`	`4604`	`}`
`4605`	`4605`
`4606`	`4606`	`/* to protect the working set of the last N jiffies */`
	`4607`	`+#ifdef CONFIG_ZEN_INTERACTIVE`
	`4608`	`+static unsigned long lru_gen_min_ttl __read_mostly = HZ;`
	`4609`	`+#else`
`4607`	`4610`	`static unsigned long lru_gen_min_ttl __read_mostly;`
	`4611`	`+#endif`
`4608`	`4612`
`4609`	`4613`	`static void lru_gen_age_node(struct pglist_data pgdat, struct scan_control sc)`
`4610`	`4614`	`{`