target/linux/generic/backport-5.15/020-v6.1-09-mm-multigenerational-lru-Kconfig.patch

   1 From 3008095eb835d207dd7e5b60899aad17f32aa9f7 Mon Sep 17 00:00:00 2001
   2 From: Yu Zhao <yuzhao@google.com>
   3 Date: Mon, 25 Jan 2021 21:47:24 -0700
   4 Subject: [PATCH 09/10] mm: multigenerational lru: Kconfig
   5
   6 Add configuration options for the multigenerational lru.
   7
   8 Signed-off-by: Yu Zhao <yuzhao@google.com>
   9 Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
  10 Change-Id: Ic74ea07f8fb5f56e6904a1b80c3c286bc2911635
  11 ---
  12  mm/Kconfig | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
  13  1 file changed, 59 insertions(+)
  14
  15 --- a/mm/Kconfig
  16 +++ b/mm/Kconfig
  17 @@ -899,4 +899,63 @@ config SECRETMEM
  18
  19  source "mm/damon/Kconfig"
  20
  21 +# the multigenerational lru {
  22 +config LRU_GEN
  23 +       bool "Multigenerational LRU"
  24 +       depends on MMU
  25 +       # the following options may leave not enough spare bits in page->flags
  26 +       depends on !MAXSMP && (64BIT || !SPARSEMEM || SPARSEMEM_VMEMMAP)
  27 +       help
  28 +         A high performance LRU implementation to heavily overcommit workloads
  29 +         that are not IO bound. See Documentation/vm/multigen_lru.rst for
  30 +         details.
  31 +
  32 +         Warning: do not enable this option unless you plan to use it because
  33 +         it introduces a small per-process and per-memcg and per-node memory
  34 +         overhead.
  35 +
  36 +config LRU_GEN_ENABLED
  37 +       bool "Turn on by default"
  38 +       depends on LRU_GEN
  39 +       help
  40 +         The default value of /sys/kernel/mm/lru_gen/enabled is 0. This option
  41 +         changes it to 1.
  42 +
  43 +         Warning: the default value is the fast path. See
  44 +         Documentation/static-keys.txt for details.
  45 +
  46 +config LRU_GEN_STATS
  47 +       bool "Full stats for debugging"
  48 +       depends on LRU_GEN
  49 +       help
  50 +         This option keeps full stats for each generation, which can be read
  51 +         from /sys/kernel/debug/lru_gen_full.
  52 +
  53 +         Warning: do not enable this option unless you plan to use it because
  54 +         it introduces an additional small per-process and per-memcg and
  55 +         per-node memory overhead.
  56 +
  57 +config NR_LRU_GENS
  58 +       int "Max number of generations"
  59 +       depends on LRU_GEN
  60 +       range 4 31
  61 +       default 7
  62 +       help
  63 +         This will use order_base_2(N+1) spare bits from page flags.
  64 +
  65 +         Warning: do not use numbers larger than necessary because each
  66 +         generation introduces a small per-node and per-memcg memory overhead.
  67 +
  68 +config TIERS_PER_GEN
  69 +       int "Number of tiers per generation"
  70 +       depends on LRU_GEN
  71 +       range 2 5
  72 +       default 4
  73 +       help
  74 +         This will use N-2 spare bits from page flags.
  75 +
  76 +         Larger values generally offer better protection to active pages under
  77 +         heavy buffered I/O workloads.
  78 +# }
  79 +
  80  endmenu