Add configuration options for the multigenerational lru.
Signed-off-by: Yu Zhao <yuzhao@xxxxxxxxxx>
Tested-by: Konstantin Kharlamov <Hi-Angel@xxxxxxxxx>
---
mm/Kconfig | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 59 insertions(+)
diff --git a/mm/Kconfig b/mm/Kconfig
index d16ba9249bc5..48e7babb22e5 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -896,4 +896,63 @@ config SECRETMEM
source "mm/damon/Kconfig"
+# the multigenerational lru {
+config LRU_GEN
+ bool "Multigenerational LRU"
+ depends on MMU
+ # the following options may leave not enough spare bits in page->flags
+ depends on !MAXSMP && (64BIT || !SPARSEMEM || SPARSEMEM_VMEMMAP)
+ help
+ A high performance LRU implementation to heavily overcommit workloads
+ that are not IO bound. See Documentation/vm/multigen_lru.rst for
+ details.
+
+ Warning: do not enable this option unless you plan to use it because
+ it introduces a small per-process and per-memcg and per-node memory
+ overhead.
+
+config LRU_GEN_ENABLED
+ bool "Turn on by default"
+ depends on LRU_GEN
+ help
+ The default value of /sys/kernel/mm/lru_gen/enabled is 0. This option
+ changes it to 1.
+
+ Warning: the default value is the fast path. See
+ Documentation/static-keys.txt for details.
+
+config LRU_GEN_STATS
+ bool "Full stats for debugging"
+ depends on LRU_GEN
+ help
+ This option keeps full stats for each generation, which can be read
+ from /sys/kernel/debug/lru_gen_full.
+
+ Warning: do not enable this option unless you plan to use it because
+ it introduces an additional small per-process and per-memcg and
+ per-node memory overhead.
+
+config NR_LRU_GENS
+ int "Max number of generations"
+ depends on LRU_GEN
+ range 4 31
+ default 7
+ help
+ This will use order_base_2(N+1) spare bits from page flags.
+
+ Warning: do not use numbers larger than necessary because each
+ generation introduces a small per-node and per-memcg memory overhead.
+
+config TIERS_PER_GEN
+ int "Number of tiers per generation"
+ depends on LRU_GEN
+ range 2 5
+ default 4
+ help
+ This will use N-2 spare bits from page flags.
+
+ Larger values generally offer better protection to active pages under
+ heavy buffered I/O workloads.
+# }
+
endmenu
--
2.34.0.rc0.344.g81b53c2807-goog
