Add configuration options for the multigenerational lru. Signed-off-by: Yu Zhao <yuzhao@xxxxxxxxxx> --- mm/Kconfig | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) diff --git a/mm/Kconfig b/mm/Kconfig index 24c045b24b95..0be1c6c90cc0 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -872,4 +872,59 @@ config MAPPING_DIRTY_HELPERS config KMAP_LOCAL bool +config LRU_GEN + bool "Multigenerational LRU" + depends on MMU + 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 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. + + Higher values generally offer better protection to active pages under + heavy buffered I/O workloads. + +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. + endmenu -- 2.31.1.295.g9ea45b61b8-goog
