patch: drop lru_gen v5, included in xanmod

3 files changed, 3 insertions, 4999 deletions

diff --git a/.SRCINFO b/.SRCINFO
index 30f4f7e01bb3..67a32b2ea275 100644
--- a/.SRCINFO
+++ b/.SRCINFO
@@ -24,7 +24,6 @@ pkgbase = linux-xanmod-rog
 	source = https://cdn.kernel.org/pub/linux/kernel/v5.x/incr/patch-5.15.2-3.xz
 	source = revert-amd-pstate-v3.patch
 	source = squashed-amd-pstate-v4-for-5.15.patch
-	source = squashed-mm-multigenerational-lru-v5-for-5.15.y.patch
 	source = x86-ACPI-State-Optimize-C3-entry-on-AMD-CPUs.patch
 	source = acpi-battery-Always-read-fresh-battery-state-on-update.patch
 	source = x86-change-default-to-spec_store_bypass_disable-prct.patch
@@ -54,7 +53,6 @@ pkgbase = linux-xanmod-rog
 	sha256sums = 074f5dd036079f81fcc4a239b6d159528fa22a57e06d5658f8b5c4970de65c26
 	sha256sums = 12d78853f582ccf8027dbd2cbc27b0fcde106202958c6be31054815bae7752ae
 	sha256sums = 8592fc434cc7d52b0fefe478de19d0af3d7e06406d8d09bd1bc85e6805738e68
-	sha256sums = 7675116fc7da55cfb9c6ceaaf120c5ebd285a13b1f1641ca810dd05516c88e0b
 	sha256sums = 923230ed8367e28adfdeed75d3cdba9eec6b781818c37f6f3d3eb64101d2e716
 	sha256sums = f7a4bf6293912bfc4a20743e58a5a266be8c4dbe3c1862d196d3a3b45f2f7c90
 	sha256sums = cc401107f1bf7b7d8e8a78ee594f9db4b6fa252b7239b6aa88f678aef84d935c
diff --git a/PKGBUILD b/PKGBUILD
index 7d32f6299e86..f4fface3291d 100644
--- a/PKGBUILD
+++ b/PKGBUILD
@@ -127,8 +127,9 @@ source=("https://cdn.kernel.org/pub/linux/kernel/v${_branch}/linux-${_major}.tar
         "revert-amd-pstate-v3.patch"
         "squashed-amd-pstate-v4-for-5.15.patch"
 
-        # multigenerational lru v5
-        "squashed-mm-multigenerational-lru-v5-for-5.15.y.patch"
+        # multigenerational lru v5 included in Xanmod
+
+        # 5.15: k10temp support for Zen3 APUs
 
         # 5.16: don't drop shared caches on C3 state transitions
         "x86-ACPI-State-Optimize-C3-entry-on-AMD-CPUs.patch"
@@ -136,8 +137,6 @@ source=("https://cdn.kernel.org/pub/linux/kernel/v${_branch}/linux-${_major}.tar
         # -- patch from Chromium developers; more accurately report battery state changes
         "acpi-battery-Always-read-fresh-battery-state-on-update.patch"
 
-        # 5.15: k10temp support for Zen3 APUs
-
         # 5.16 spectre defaults
         "x86-change-default-to-spec_store_bypass_disable-prct.patch"
 
@@ -184,7 +183,6 @@ sha256sums=('57b2cf6991910e3b67a1b3490022e8a0674b6965c74c12da1e99d138d1991ee8'
             '074f5dd036079f81fcc4a239b6d159528fa22a57e06d5658f8b5c4970de65c26'
             '12d78853f582ccf8027dbd2cbc27b0fcde106202958c6be31054815bae7752ae'
             '8592fc434cc7d52b0fefe478de19d0af3d7e06406d8d09bd1bc85e6805738e68'
-            '7675116fc7da55cfb9c6ceaaf120c5ebd285a13b1f1641ca810dd05516c88e0b'
             '923230ed8367e28adfdeed75d3cdba9eec6b781818c37f6f3d3eb64101d2e716'
             'f7a4bf6293912bfc4a20743e58a5a266be8c4dbe3c1862d196d3a3b45f2f7c90'
             'cc401107f1bf7b7d8e8a78ee594f9db4b6fa252b7239b6aa88f678aef84d935c'
diff --git a/squashed-mm-multigenerational-lru-v5-for-5.15.y.patch b/squashed-mm-multigenerational-lru-v5-for-5.15.y.patch
deleted file mode 100644
index ac999b039a6b..000000000000
--- a/squashed-mm-multigenerational-lru-v5-for-5.15.y.patch
+++ /dev/null
@@ -1,4992 +0,0 @@
-From 7a36e5837e0242a27b8f8b27b2ed46617678d62b Mon Sep 17 00:00:00 2001
-From: Scott B <arglebargle@arglebargle.dev>
-Date: Sun, 14 Nov 2021 04:20:28 -0800
-Subject: [PATCH] squashed mm multigenerational lru v5 for 5.15.y
-
-Squashed commit of the following:
-
-commit 19e8961fca725ce8ee2643cb2ff4a818c864ee30
-Author: Yu Zhao <yuzhao@google.com>
-Date:   Wed Nov 10 21:15:10 2021 -0700
-
-    mm: multigenerational lru: documentation
-
-    Add Documentation/vm/multigen_lru.rst.
-
-    Signed-off-by: Yu Zhao <yuzhao@google.com>
-    Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
-
-commit 4326538c0c4edf38c30156b2ff956bc7df448249
-Author: Yu Zhao <yuzhao@google.com>
-Date:   Wed Nov 10 21:15:09 2021 -0700
-
-    mm: multigenerational lru: Kconfig
-
-    Add configuration options for the multigenerational lru.
-
-    Signed-off-by: Yu Zhao <yuzhao@google.com>
-    Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
-
-commit 1fbf643cde24bf5b7925a6dc2b6f04832519213a
-Author: Yu Zhao <yuzhao@google.com>
-Date:   Wed Nov 10 21:15:08 2021 -0700
-
-    mm: multigenerational lru: user interface
-
-    Add /sys/kernel/mm/lru_gen/enabled to enable and disable the
-    multigenerational lru at runtime.
-
-    Add /sys/kernel/mm/lru_gen/min_ttl_ms to protect the working set of a
-    given number of milliseconds. The OOM killer is invoked if this
-    working set cannot be kept in memory.
-
-    Add /sys/kernel/debug/lru_gen to monitor the multigenerational lru and
-    invoke the aging and the eviction. This file has the following output:
-      memcg  memcg_id  memcg_path
-        node  node_id
-          min_gen  birth_time  anon_size  file_size
-          ...
-          max_gen  birth_time  anon_size  file_size
-
-    min_gen is the oldest generation number and max_gen is the youngest
-    generation number. birth_time is in milliseconds. anon_size and
-    file_size are in pages.
-
-    This file takes the following input:
-      + memcg_id node_id max_gen [swappiness] [use_bloom_filter]
-      - memcg_id node_id min_gen [swappiness] [nr_to_reclaim]
-
-    The first command line invokes the aging, which scans PTEs for
-    accessed pages and then creates the next generation max_gen+1. A swap
-    file and a non-zero swappiness, which overrides vm.swappiness, are
-    required to scan PTEs mapping anon pages. The second command line
-    invokes the eviction, which evicts generations less than or equal to
-    min_gen. min_gen should be less than max_gen-1 as max_gen and
-    max_gen-1 are not fully aged and therefore cannot be evicted.
-    Setting nr_to_reclaim to N limits the number of pages to evict.
-    Setting use_bloom_filter to 0 overrides the default behavior which
-    only scans PTE tables found populated. Multiple command lines are
-    supported, as is concatenation with delimiters "," and ";".
-
-    Signed-off-by: Yu Zhao <yuzhao@google.com>
-    Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
-
-commit 273f053f193dcca266045fabef04e6083e65e7a7
-Author: Yu Zhao <yuzhao@google.com>
-Date:   Wed Nov 10 21:15:07 2021 -0700
-
-    mm: multigenerational lru: eviction
-
-    The eviction consumes old generations. Given an lruvec, the eviction
-    scans pages on lrugen->lists indexed by anon and file min_seq[]
-    (modulo MAX_NR_GENS). It first tries to select a type based on the
-    values of min_seq[]. If they are equal, it selects the type that has
-    a lower refaulted %. The eviction sorts a page according to its
-    updated generation number if the aging has found this page accessed.
-    It also moves a page to the next generation if this page is from an
-    upper tier that has a higher refaulted % than the base tier. The
-    eviction increments min_seq[] of a selected type when it finds
-    lrugen->lists indexed by min_seq[] of this selected type are empty.
-
-    Each generation is divided into multiple tiers. Tiers represent
-    different ranges of numbers of accesses from file descriptors only.
-    Pages accessed N times via file descriptors belong to tier
-    order_base_2(N). Each generation contains at most MAX_NR_TIERS tiers,
-    and they require additional MAX_NR_TIERS-2 bits in page->flags. In
-    contrast to moving between generations which requires list operations,
-    moving between tiers only involves operations on page->flags and
-    therefore has a negligible cost. A feedback loop modeled after the PID
-    controller monitors refaulted % across all tiers and decides when to
-    protect pages from which tiers.
-
-    Unmapped pages are initially added to the oldest generation and then
-    conditionally protected by tiers. Each tier keeps track of how many
-    pages from it have refaulted. Tier 0 is the base tier and pages from
-    it are evicted unconditionally because there are no better candidates.
-    Pages from an upper tier are either evicted or moved to the next
-    generation, depending on whether this upper tier has a higher
-    refaulted % than the base tier. This model has the following
-    advantages:
-      1) It removes the cost in the buffered access path and reduces the
-      overall cost of protection because pages are conditionally protected
-      in the reclaim path.
-      2) It takes mapped pages into account and avoids overprotecting
-      pages accessed multiple times via file descriptors.
-      3 Additional tiers improve the protection of pages accessed more
-      than twice.
-
-    Signed-off-by: Yu Zhao <yuzhao@google.com>
-    Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
-
-commit b8ff3328e2852e88df92042311f4169d231b8628
-Author: Yu Zhao <yuzhao@google.com>
-Date:   Wed Nov 10 21:15:06 2021 -0700
-
-    mm: multigenerational lru: aging
-
-    The aging produces young generations. Given an lruvec, the aging
-    traverses lruvec_memcg()->mm_list and calls walk_page_range() to scan
-    PTEs for accessed pages. Upon finding one, the aging updates its
-    generation number to max_seq (modulo MAX_NR_GENS). After each round of
-    traversal, the aging increments max_seq. The aging is due when
-    min_seq[] reaches max_seq-1.
-
-    The aging uses the following optimizations when walking page tables:
-      1) It skips non-leaf PMD entries that have the accessed bit cleared
-      when CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG=y.
-      2) It does not zigzag between a PGD table and the same PMD or PTE
-      table spanning multiple VMAs. In other words, it finishes all the
-      VMAs within the range of the same PMD or PTE table before it returns
-      to this PGD table. This optimizes workloads that have large numbers
-      of tiny VMAs, especially when CONFIG_PGTABLE_LEVELS=5.
-
-    Signed-off-by: Yu Zhao <yuzhao@google.com>
-    Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
-
-commit 18f292b52b7de4353ea1083a9f985fa69381ada8
-Author: Yu Zhao <yuzhao@google.com>
-Date:   Wed Nov 10 21:15:05 2021 -0700
-
-    mm: multigenerational lru: mm_struct list
-
-    To scan PTEs for accessed pages, a mm_struct list is maintained for
-    each memcg. When multiple threads traverse the same memcg->mm_list,
-    each of them gets a unique mm_struct and therefore they can run
-    walk_page_range() concurrently to reach page tables of all processes
-    of this memcg.
-
-    This infrastructure also provides the following optimizations:
-      1) it allows walkers to skip processes that have been sleeping since
-      the last walk by tracking the usage of mm_struct between context
-      switches.
-      2) it allows walkers to add interesting items they find during a
-      walk to a Bloom filter so that they can skip uninteresting items
-      during the next walk by testing whether an item is in this Bloom
-      filter.
-
-    Signed-off-by: Yu Zhao <yuzhao@google.com>
-    Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
-
-commit 089e38620dad513b66f01490392cb9dd40667853
-Author: Yu Zhao <yuzhao@google.com>
-Date:   Wed Nov 10 21:15:04 2021 -0700
-
-    mm: multigenerational lru: groundwork
-
-    For each lruvec, evictable pages are divided into multiple
-    generations. The youngest generation number is stored in
-    lrugen->max_seq for both anon and file types as they are aged on an
-    equal footing. The oldest generation numbers are stored in
-    lrugen->min_seq[] separately for anon and file types as clean file
-    pages can be evicted regardless of swap constraints. These three
-    variables are monotonically increasing. Generation numbers are
-    truncated into order_base_2(MAX_NR_GENS+1) bits in order to fit into
-    page->flags. The sliding window technique is used to prevent truncated
-    generation numbers from overlapping. Each truncated generation number
-    is an index to
-    lrugen->lists[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES].
-
-    The framework comprises two conceptually independent components: the
-    aging, which produces young generations, and the eviction, which
-    consumes old generations. Both can be invoked independently from user
-    space for the purpose of working set estimation and proactive reclaim.
-
-    The protection of hot pages and the selection of cold pages are based
-    on page access types and patterns. There are two access types: one via
-    page tables and the other via file descriptors. The protection of the
-    former type is by design stronger because:
-      1) The uncertainty in determining the access patterns of the former
-      type is higher due to the coalesced nature of the accessed bit.
-      2) The cost of evicting the former type is higher due to the TLB
-      flushes required and the likelihood of involving I/O.
-      3) The penalty of under-protecting the former type is higher because
-      applications usually do not prepare themselves for major faults like
-      they do for blocked I/O. For example, client applications commonly
-      dedicate blocked I/O to separate threads to avoid UI janks that
-      negatively affect user experience.
-
-    There are also two access patterns: one with temporal locality and the
-    other without. The latter pattern, e.g., random and sequential, needs
-    to be explicitly excluded to avoid weakening the protection of the
-    former pattern. Generally the former type follows the former pattern
-    unless MADV_SEQUENTIAL is specified and the latter type follows the
-    latter pattern unless outlying refaults have been observed.
-
-    Upon faulting, a page is added to the youngest generation, which
-    provides the strongest protection as the eviction will not consider
-    this page before the aging has scanned it at least twice. The first
-    scan clears the accessed bit set during the initial fault. And the
-    second scan makes sure this page has not been used since the first
-    scan. A page from any other generations is brought back to the
-    youngest generation whenever the aging finds the accessed bit set on
-    any of the PTEs mapping this page.
-
-    Unmapped pages are initially added to the oldest generation and then
-    conditionally protected by tiers. This is done later [PATCH 07/10].
-
-    Signed-off-by: Yu Zhao <yuzhao@google.com>
-    Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
-
-commit ece1399ffe2c76ce020e7041c4790f1ace13f77c
-Author: Yu Zhao <yuzhao@google.com>
-Date:   Wed Nov 10 21:15:03 2021 -0700
-
-    mm/vmscan.c: refactor shrink_node()
-
-    This patch refactors shrink_node(). This will make the upcoming
-    changes to mm/vmscan.c more readable.
-
-    Signed-off-by: Yu Zhao <yuzhao@google.com>
-    Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
-
-commit 103c3bb04169ccac581e524ca267961377e474fb
-Author: Yu Zhao <yuzhao@google.com>
-Date:   Wed Nov 10 21:15:02 2021 -0700
-
-    mm: x86: add CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG
-
-    Some architectures support the accessed bit on non-leaf PMD entries,
-    e.g., x86_64 sets the accessed bit on a non-leaf PMD entry when using
-    it as part of linear address translation [1]. As an optimization, page
-    table walkers who are interested in the accessed bit can skip the PTEs
-    under a non-leaf PMD entry if the accessed bit is cleared on this PMD
-    entry.
-
-    Although an inline function may be preferable, this capability is
-    added as a configuration option to look consistent when used with the
-    existing macros.
-
-    [1]: Intel 64 and IA-32 Architectures Software Developer's Manual
-         Volume 3 (June 2021), section 4.8
-
-    Signed-off-by: Yu Zhao <yuzhao@google.com>
-    Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
-
-commit fa446f371f7398741969012da6364558fe209d9a
-Author: Yu Zhao <yuzhao@google.com>
-Date:   Wed Nov 10 21:15:01 2021 -0700
-
-    mm: x86, arm64: add arch_has_hw_pte_young()
-
-    Some architectures automatically set the accessed bit in PTEs, e.g.,
-    x86 and arm64 v8.2. On architectures that do not have this capability,
-    clearing the accessed bit in a PTE triggers a page fault following the
-    TLB miss of this PTE.
-
-    Being aware of this capability can help make better decisions, i.e.,
-    whether to limit the size of each batch of PTEs and the burst of
-    batches when clearing the accessed bit.
-
-    Signed-off-by: Yu Zhao <yuzhao@google.com>
-    Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
----
- Documentation/vm/index.rst          |    1 +
- Documentation/vm/multigen_lru.rst   |  132 ++
- arch/Kconfig                        |    9 +
- arch/arm64/include/asm/cpufeature.h |    5 +
- arch/arm64/include/asm/pgtable.h    |   13 +-
- arch/arm64/kernel/cpufeature.c      |   10 +
- arch/arm64/tools/cpucaps            |    1 +
- arch/x86/Kconfig                    |    1 +
- arch/x86/include/asm/pgtable.h      |    9 +-
- arch/x86/mm/pgtable.c               |    5 +-
- fs/exec.c                           |    2 +
- fs/fuse/dev.c                       |    3 +-
- include/linux/cgroup.h              |   15 +-
- include/linux/memcontrol.h          |    7 +
- include/linux/mm.h                  |   36 +
- include/linux/mm_inline.h           |  198 ++
- include/linux/mm_types.h            |  106 ++
- include/linux/mmzone.h              |  175 ++
- include/linux/nodemask.h            |    1 +
- include/linux/oom.h                 |   16 +
- include/linux/page-flags-layout.h   |   19 +-
- include/linux/page-flags.h          |    4 +-
- include/linux/pgtable.h             |   17 +-
- include/linux/sched.h               |    3 +
- include/linux/swap.h                |    3 +
- kernel/bounds.c                     |    3 +
- kernel/cgroup/cgroup-internal.h     |    1 -
- kernel/exit.c                       |    1 +
- kernel/fork.c                       |   10 +
- kernel/kthread.c                    |    1 +
- kernel/sched/core.c                 |    2 +
- mm/Kconfig                          |   59 +
- mm/huge_memory.c                    |    3 +-
- mm/memcontrol.c                     |   31 +
- mm/memory.c                         |   21 +-
- mm/mm_init.c                        |    6 +-
- mm/oom_kill.c                       |    4 +-
- mm/page_alloc.c                     |    1 +
- mm/rmap.c                           |    8 +
- mm/swap.c                           |   51 +-
- mm/swapfile.c                       |    2 +
- mm/vmscan.c                         | 2697 ++++++++++++++++++++++++++-
- mm/workingset.c                     |  120 +-
- 43 files changed, 3679 insertions(+), 133 deletions(-)
- create mode 100644 Documentation/vm/multigen_lru.rst
-
-diff --git a/Documentation/vm/index.rst b/Documentation/vm/index.rst
-index b51f0d8992f8..779772a025a0 100644
---- a/Documentation/vm/index.rst
-+++ b/Documentation/vm/index.rst
-@@ -17,6 +17,7 @@ various features of the Linux memory management
- 
-    swap_numa
-    zswap
-+   multigen_lru
- 
- Kernel developers MM documentation
- ==================================
-diff --git a/Documentation/vm/multigen_lru.rst b/Documentation/vm/multigen_lru.rst
-new file mode 100644
-index 000000000000..7c064a378b85
---- /dev/null
-+++ b/Documentation/vm/multigen_lru.rst
-@@ -0,0 +1,132 @@
-+.. SPDX-License-Identifier: GPL-2.0
-+
-+=====================
-+Multigenerational LRU
-+=====================
-+
-+Quick Start
-+===========
-+Build Configurations
-+--------------------
-+:Required: Set ``CONFIG_LRU_GEN=y``.
-+
-+:Optional: Set ``CONFIG_LRU_GEN_ENABLED=y`` to turn the feature on by
-+ default.
-+
-+Runtime Configurations
-+----------------------
-+:Required: Write ``1`` to ``/sys/kernel/mm/lru_gen/enable`` if the
-+ feature was not turned on by default.
-+
-+:Optional: Write ``N`` to ``/sys/kernel/mm/lru_gen/min_ttl_ms`` to
-+ protect the working set of ``N`` milliseconds. The OOM killer is
-+ invoked if this working set cannot be kept in memory.
-+
-+:Optional: Read ``/sys/kernel/debug/lru_gen`` to confirm the feature
-+ is turned on. This file has the following output:
-+
-+::
-+
-+  memcg  memcg_id  memcg_path
-+    node  node_id
-+      min_gen  birth_time  anon_size  file_size
-+      ...
-+      max_gen  birth_time  anon_size  file_size
-+
-+``min_gen`` is the oldest generation number and ``max_gen`` is the
-+youngest generation number. ``birth_time`` is in milliseconds.
-+``anon_size`` and ``file_size`` are in pages.
-+
-+Phones/Laptops/Workstations
-+---------------------------
-+No additional configurations required.
-+
-+Servers/Data Centers
-+--------------------
-+:To support more generations: Change ``CONFIG_NR_LRU_GENS`` to a
-+ larger number.
-+
-+:To support more tiers: Change ``CONFIG_TIERS_PER_GEN`` to a larger
-+ number.
-+
-+:To support full stats: Set ``CONFIG_LRU_GEN_STATS=y``.
-+
-+:Working set estimation: Write ``+ memcg_id node_id max_gen
-+ [swappiness] [use_bloom_filter]`` to ``/sys/kernel/debug/lru_gen`` to
-+ invoke the aging, which scans PTEs for accessed pages and then
-+ creates the next generation ``max_gen+1``. A swap file and a non-zero
-+ ``swappiness``, which overrides ``vm.swappiness``, are required to
-+ scan PTEs mapping anon pages. Set ``use_bloom_filter`` to 0 to
-+ override the default behavior which only scans PTE tables found
-+ populated.
-+
-+:Proactive reclaim: Write ``- memcg_id node_id min_gen [swappiness]
-+ [nr_to_reclaim]`` to ``/sys/kernel/debug/lru_gen`` to invoke the
-+ eviction, which evicts generations less than or equal to ``min_gen``.
-+ ``min_gen`` should be less than ``max_gen-1`` as ``max_gen`` and
-+ ``max_gen-1`` are not fully aged and therefore cannot be evicted.
-+ Use ``nr_to_reclaim`` to limit the number of pages to evict. Multiple
-+ command lines are supported, so does concatenation with delimiters
-+ ``,`` and ``;``.
-+
-+Framework
-+=========
-+For each ``lruvec``, evictable pages are divided into multiple
-+generations. The youngest generation number is stored in
-+``lrugen->max_seq`` for both anon and file types as they are aged on
-+an equal footing. The oldest generation numbers are stored in
-+``lrugen->min_seq[]`` separately for anon and file types as clean
-+file pages can be evicted regardless of swap and writeback
-+constraints. These three variables are monotonically increasing.
-+Generation numbers are truncated into
-+``order_base_2(CONFIG_NR_LRU_GENS+1)`` bits in order to fit into
-+``page->flags``. The sliding window technique is used to prevent
-+truncated generation numbers from overlapping. Each truncated
-+generation number is an index to an array of per-type and per-zone
-+lists ``lrugen->lists``.
-+
-+Each generation is divided into multiple tiers. Tiers represent
-+different ranges of numbers of accesses from file descriptors only.
-+Pages accessed ``N`` times via file descriptors belong to tier
-+``order_base_2(N)``. Each generation contains at most
-+``CONFIG_TIERS_PER_GEN`` tiers, and they require additional
-+``CONFIG_TIERS_PER_GEN-2`` bits in ``page->flags``. In contrast to
-+moving between generations which requires list operations, moving
-+between tiers only involves operations on ``page->flags`` and
-+therefore has a negligible cost. A feedback loop modeled after the PID
-+controller monitors refaulted % across all tiers and decides when to
-+protect pages from which tiers.
-+
-+The framework comprises two conceptually independent components: the
-+aging and the eviction, which can be invoked separately from user
-+space for the purpose of working set estimation and proactive reclaim.
-+
-+Aging
-+-----
-+The aging produces young generations. Given an ``lruvec``, the aging
-+traverses ``lruvec_memcg()->mm_list`` and calls ``walk_page_range()``
-+to scan PTEs for accessed pages (a ``mm_struct`` list is maintained
-+for each ``memcg``). Upon finding one, the aging updates its
-+generation number to ``max_seq`` (modulo ``CONFIG_NR_LRU_GENS``).
-+After each round of traversal, the aging increments ``max_seq``. The
-+aging is due when ``min_seq[]`` reaches ``max_seq-1``.
-+
-+Eviction
-+--------
-+The eviction consumes old generations. Given an ``lruvec``, the
-+eviction scans pages on the per-zone lists indexed by anon and file
-+``min_seq[]`` (modulo ``CONFIG_NR_LRU_GENS``). It first tries to
-+select a type based on the values of ``min_seq[]``. If they are
-+equal, it selects the type that has a lower refaulted %. The eviction
-+sorts a page according to its updated generation number if the aging
-+has found this page accessed. It also moves a page to the next
-+generation if this page is from an upper tier that has a higher
-+refaulted % than the base tier. The eviction increments ``min_seq[]``
-+of a selected type when it finds all the per-zone lists indexed by
-+``min_seq[]`` of this selected type are empty.
-+
-+To-do List
-+==========
-+KVM Optimization
-+----------------
-+Support shadow page table walk.
-diff --git a/arch/Kconfig b/arch/Kconfig
-index 8df1c7102643..7392fcc88777 100644
---- a/arch/Kconfig
-+++ b/arch/Kconfig
-@@ -1288,6 +1288,15 @@ config ARCH_HAS_ELFCORE_COMPAT
- config ARCH_HAS_PARANOID_L1D_FLUSH
- 	bool
- 
-+config ARCH_HAS_NONLEAF_PMD_YOUNG
-+	bool
-+	depends on PGTABLE_LEVELS > 2
-+	help
-+	  Architectures that select this are able to set the accessed bit on
-+	  non-leaf PMD entries in addition to leaf PTE entries where pages are
-+	  mapped. For them, page table walkers that clear the accessed bit may
-+	  stop at non-leaf PMD entries if they do not see the accessed bit.
-+
- source "kernel/gcov/Kconfig"
- 
- source "scripts/gcc-plugins/Kconfig"
-diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
-index ef6be92b1921..99518b4b2a9e 100644
---- a/arch/arm64/include/asm/cpufeature.h
-+++ b/arch/arm64/include/asm/cpufeature.h
-@@ -779,6 +779,11 @@ static inline bool system_supports_tlb_range(void)
- 		cpus_have_const_cap(ARM64_HAS_TLB_RANGE);
- }
- 
-+static inline bool system_has_hw_af(void)
-+{
-+	return IS_ENABLED(CONFIG_ARM64_HW_AFDBM) && cpus_have_const_cap(ARM64_HW_AF);
-+}
-+
- extern int do_emulate_mrs(struct pt_regs *regs, u32 sys_reg, u32 rt);
- 
- static inline u32 id_aa64mmfr0_parange_to_phys_shift(int parange)
-diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
-index dfa76afa0ccf..880ae658a69a 100644
---- a/arch/arm64/include/asm/pgtable.h
-+++ b/arch/arm64/include/asm/pgtable.h
-@@ -993,13 +993,16 @@ static inline void update_mmu_cache(struct vm_area_struct *vma,
-  * page after fork() + CoW for pfn mappings. We don't always have a
-  * hardware-managed access flag on arm64.
-  */
--static inline bool arch_faults_on_old_pte(void)
-+static inline bool arch_has_hw_pte_young(bool local)
- {
--	WARN_ON(preemptible());
-+	if (local) {
-+		WARN_ON(preemptible());
-+		return cpu_has_hw_af();
-+	}
- 
--	return !cpu_has_hw_af();
-+	return system_has_hw_af();
- }
--#define arch_faults_on_old_pte		arch_faults_on_old_pte
-+#define arch_has_hw_pte_young		arch_has_hw_pte_young
- 
- /*
-  * Experimentally, it's cheap to set the access flag in hardware and we
-@@ -1007,7 +1010,7 @@ static inline bool arch_faults_on_old_pte(void)
-  */
- static inline bool arch_wants_old_prefaulted_pte(void)
- {
--	return !arch_faults_on_old_pte();
-+	return arch_has_hw_pte_young(true);
- }
- #define arch_wants_old_prefaulted_pte	arch_wants_old_prefaulted_pte
- 
-diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
-index 6ec7036ef7e1..940615d33845 100644
---- a/arch/arm64/kernel/cpufeature.c
-+++ b/arch/arm64/kernel/cpufeature.c
-@@ -2157,6 +2157,16 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
- 		.matches = has_hw_dbm,
- 		.cpu_enable = cpu_enable_hw_dbm,
- 	},
-+	{
-+		.desc = "Hardware update of the Access flag",
-+		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
-+		.capability = ARM64_HW_AF,
-+		.sys_reg = SYS_ID_AA64MMFR1_EL1,
-+		.sign = FTR_UNSIGNED,
-+		.field_pos = ID_AA64MMFR1_HADBS_SHIFT,
-+		.min_field_value = 1,
-+		.matches = has_cpuid_feature,
-+	},
- #endif
- 	{
- 		.desc = "CRC32 instructions",
-diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
-index 49305c2e6dfd..d52f50671e60 100644
---- a/arch/arm64/tools/cpucaps
-+++ b/arch/arm64/tools/cpucaps
-@@ -35,6 +35,7 @@ HAS_STAGE2_FWB
- HAS_SYSREG_GIC_CPUIF
- HAS_TLB_RANGE
- HAS_VIRT_HOST_EXTN
-+HW_AF
- HW_DBM
- KVM_PROTECTED_MODE
- MISMATCHED_CACHE_TYPE
-diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
-index d9830e7e1060..245742b79be9 100644
---- a/arch/x86/Kconfig
-+++ b/arch/x86/Kconfig
-@@ -84,6 +84,7 @@ config X86
- 	select ARCH_HAS_PMEM_API		if X86_64
- 	select ARCH_HAS_PTE_DEVMAP		if X86_64
- 	select ARCH_HAS_PTE_SPECIAL
-+	select ARCH_HAS_NONLEAF_PMD_YOUNG	if X86_64
- 	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
- 	select ARCH_HAS_COPY_MC			if X86_64
- 	select ARCH_HAS_SET_MEMORY
-diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
-index 448cd01eb3ec..36205ec0acac 100644
---- a/arch/x86/include/asm/pgtable.h
-+++ b/arch/x86/include/asm/pgtable.h
-@@ -817,7 +817,8 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
- 
- static inline int pmd_bad(pmd_t pmd)
- {
--	return (pmd_flags(pmd) & ~_PAGE_USER) != _KERNPG_TABLE;
-+	return (pmd_flags(pmd) & ~(_PAGE_USER | _PAGE_ACCESSED)) !=
-+	       (_KERNPG_TABLE & ~_PAGE_ACCESSED);
- }
- 
- static inline unsigned long pages_to_mb(unsigned long npg)
-@@ -1397,10 +1398,10 @@ static inline bool arch_has_pfn_modify_check(void)
- 	return boot_cpu_has_bug(X86_BUG_L1TF);
- }
- 
--#define arch_faults_on_old_pte arch_faults_on_old_pte
--static inline bool arch_faults_on_old_pte(void)
-+#define arch_has_hw_pte_young arch_has_hw_pte_young
-+static inline bool arch_has_hw_pte_young(bool local)
- {
--	return false;
-+	return true;
- }
- 
- #endif	/* __ASSEMBLY__ */
-diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
-index 3481b35cb4ec..a224193d84bf 100644
---- a/arch/x86/mm/pgtable.c
-+++ b/arch/x86/mm/pgtable.c
-@@ -550,7 +550,7 @@ int ptep_test_and_clear_young(struct vm_area_struct *vma,
- 	return ret;
- }
- 
--#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG)
- int pmdp_test_and_clear_young(struct vm_area_struct *vma,
- 			      unsigned long addr, pmd_t *pmdp)
- {
-@@ -562,6 +562,9 @@ int pmdp_test_and_clear_young(struct vm_area_struct *vma,
- 
- 	return ret;
- }
-+#endif
-+
-+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
- int pudp_test_and_clear_young(struct vm_area_struct *vma,
- 			      unsigned long addr, pud_t *pudp)
- {
-diff --git a/fs/exec.c b/fs/exec.c
-index a098c133d8d7..c7e55b757e87 100644
---- a/fs/exec.c
-+++ b/fs/exec.c
-@@ -1007,6 +1007,7 @@ static int exec_mmap(struct mm_struct *mm)
- 	active_mm = tsk->active_mm;
- 	tsk->active_mm = mm;
- 	tsk->mm = mm;
-+	lru_gen_add_mm(mm);
- 	/*
- 	 * This prevents preemption while active_mm is being loaded and
- 	 * it and mm are being updated, which could cause problems for
-@@ -1017,6 +1018,7 @@ static int exec_mmap(struct mm_struct *mm)
- 	if (!IS_ENABLED(CONFIG_ARCH_WANT_IRQS_OFF_ACTIVATE_MM))
- 		local_irq_enable();
- 	activate_mm(active_mm, mm);
-+	lru_gen_switch_mm(active_mm, mm);
- 	if (IS_ENABLED(CONFIG_ARCH_WANT_IRQS_OFF_ACTIVATE_MM))
- 		local_irq_enable();
- 	tsk->mm->vmacache_seqnum = 0;
-diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
-index dde341a6388a..33a2fda7462e 100644
---- a/fs/fuse/dev.c
-+++ b/fs/fuse/dev.c
-@@ -785,7 +785,8 @@ static int fuse_check_page(struct page *page)
- 	       1 << PG_active |
- 	       1 << PG_workingset |
- 	       1 << PG_reclaim |
--	       1 << PG_waiters))) {
-+	       1 << PG_waiters |
-+	       LRU_GEN_MASK | LRU_REFS_MASK))) {
- 		dump_page(page, "fuse: trying to steal weird page");
- 		return 1;
- 	}
-diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
-index 75c151413fda..b145025f3eac 100644
---- a/include/linux/cgroup.h
-+++ b/include/linux/cgroup.h
-@@ -432,6 +432,18 @@ static inline void cgroup_put(struct cgroup *cgrp)
- 	css_put(&cgrp->self);
- }
- 
-+extern struct mutex cgroup_mutex;
-+
-+static inline void cgroup_lock(void)
-+{
-+	mutex_lock(&cgroup_mutex);
-+}
-+
-+static inline void cgroup_unlock(void)
-+{
-+	mutex_unlock(&cgroup_mutex);
-+}
-+
- /**
-  * task_css_set_check - obtain a task's css_set with extra access conditions
-  * @task: the task to obtain css_set for
-@@ -446,7 +458,6 @@ static inline void cgroup_put(struct cgroup *cgrp)
-  * as locks used during the cgroup_subsys::attach() methods.
-  */
- #ifdef CONFIG_PROVE_RCU
--extern struct mutex cgroup_mutex;
- extern spinlock_t css_set_lock;
- #define task_css_set_check(task, __c)					\
- 	rcu_dereference_check((task)->cgroups,				\
-@@ -707,6 +718,8 @@ struct cgroup;
- static inline u64 cgroup_id(const struct cgroup *cgrp) { return 1; }
- static inline void css_get(struct cgroup_subsys_state *css) {}
- static inline void css_put(struct cgroup_subsys_state *css) {}
-+static inline void cgroup_lock(void) {}
-+static inline void cgroup_unlock(void) {}
- static inline int cgroup_attach_task_all(struct task_struct *from,
- 					 struct task_struct *t) { return 0; }
- static inline int cgroupstats_build(struct cgroupstats *stats,
-diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
-index 3096c9a0ee01..e284a4aa1bd8 100644
---- a/include/linux/memcontrol.h
-+++ b/include/linux/memcontrol.h
-@@ -347,6 +347,10 @@ struct mem_cgroup {
- 	struct deferred_split deferred_split_queue;
- #endif
- 
-+#ifdef CONFIG_LRU_GEN
-+	struct lru_gen_mm_list mm_list;
-+#endif
-+
- 	struct mem_cgroup_per_node *nodeinfo[];
- };
- 
-@@ -1350,10 +1354,13 @@ mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg)
- 
- static inline void lock_page_memcg(struct page *page)
- {
-+	/* to match page_memcg_rcu() */
-+	rcu_read_lock();
- }
- 
- static inline void unlock_page_memcg(struct page *page)
- {
-+	rcu_read_unlock();
- }
- 
- static inline void mem_cgroup_handle_over_high(void)
-diff --git a/include/linux/mm.h b/include/linux/mm.h
-index 73a52aba448f..9d3bcc30dfda 100644
---- a/include/linux/mm.h
-+++ b/include/linux/mm.h
-@@ -1093,6 +1093,8 @@ vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf);
- #define ZONES_PGOFF		(NODES_PGOFF - ZONES_WIDTH)
- #define LAST_CPUPID_PGOFF	(ZONES_PGOFF - LAST_CPUPID_WIDTH)
- #define KASAN_TAG_PGOFF		(LAST_CPUPID_PGOFF - KASAN_TAG_WIDTH)
-+#define LRU_GEN_PGOFF		(KASAN_TAG_PGOFF - LRU_GEN_WIDTH)
-+#define LRU_REFS_PGOFF		(LRU_GEN_PGOFF - LRU_REFS_WIDTH)
- 
- /*
-  * Define the bit shifts to access each section.  For non-existent
-@@ -1800,6 +1802,40 @@ static inline void unmap_mapping_range(struct address_space *mapping,
- 		loff_t const holebegin, loff_t const holelen, int even_cows) { }
- #endif
- 
-+#ifdef CONFIG_LRU_GEN
-+static inline void task_enter_nonseq_fault(void)
-+{
-+	WARN_ON(current->in_nonseq_fault);
-+
-+	current->in_nonseq_fault = 1;
-+}
-+
-+static inline void task_exit_nonseq_fault(void)
-+{
-+	WARN_ON(!current->in_nonseq_fault);
-+
-+	current->in_nonseq_fault = 0;
-+}
-+
-+static inline bool task_in_nonseq_fault(void)
-+{
-+	return current->in_nonseq_fault;
-+}
-+#else
-+static inline void task_enter_nonseq_fault(void)
-+{
-+}
-+
-+static inline void task_exit_nonseq_fault(void)
-+{
-+}
-+
-+static inline bool task_in_nonseq_fault(void)
-+{
-+	return false;
-+}
-+#endif /* CONFIG_LRU_GEN */
-+
- static inline void unmap_shared_mapping_range(struct address_space *mapping,
- 		loff_t const holebegin, loff_t const holelen)
- {
-diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
-index 355ea1ee32bd..7d520f45e612 100644
---- a/include/linux/mm_inline.h
-+++ b/include/linux/mm_inline.h
-@@ -79,11 +79,203 @@ static __always_inline enum lru_list page_lru(struct page *page)
- 	return lru;
- }
- 
-+#ifdef CONFIG_LRU_GEN
-+
-+static inline bool lru_gen_enabled(void)
-+{
-+#ifdef CONFIG_LRU_GEN_ENABLED
-+	DECLARE_STATIC_KEY_TRUE(lru_gen_static_key);
-+
-+	return static_branch_likely(&lru_gen_static_key);
-+#else
-+	DECLARE_STATIC_KEY_FALSE(lru_gen_static_key);
-+
-+	return static_branch_unlikely(&lru_gen_static_key);
-+#endif
-+}
-+
-+/* Return an index within the sliding window that tracks MAX_NR_GENS generations. */
-+static inline int lru_gen_from_seq(unsigned long seq)
-+{
-+	return seq % MAX_NR_GENS;
-+}
-+
-+/* Return a proper index regardless whether we keep stats for historical generations. */
-+static inline int lru_hist_from_seq(unsigned long seq)
-+{
-+	return seq % NR_HIST_GENS;
-+}
-+
-+/* Convert the number of accesses to a tier. See the comment on MAX_NR_TIERS. */
-+static inline int lru_tier_from_refs(int refs)
-+{
-+	VM_BUG_ON(refs > BIT(LRU_REFS_WIDTH));
-+
-+	return order_base_2(refs + 1);
-+}
-+
-+/* The youngest and the second youngest generations are counted as active. */
-+static inline bool lru_gen_is_active(struct lruvec *lruvec, int gen)
-+{
-+	unsigned long max_seq = lruvec->evictable.max_seq;
-+
-+	VM_BUG_ON(gen >= MAX_NR_GENS);
-+
-+	return gen == lru_gen_from_seq(max_seq) || gen == lru_gen_from_seq(max_seq - 1);
-+}
-+
-+/* Update the sizes of the multigenerational lru lists. */
-+static inline void lru_gen_update_size(struct page *page, struct lruvec *lruvec,
-+				       int old_gen, int new_gen)
-+{
-+	int type = page_is_file_lru(page);
-+	int zone = page_zonenum(page);
-+	int delta = thp_nr_pages(page);
-+	enum lru_list lru = type * LRU_FILE;
-+	struct lrugen *lrugen = &lruvec->evictable;
-+
-+	lockdep_assert_held(&lruvec->lru_lock);
-+	VM_BUG_ON(old_gen != -1 && old_gen >= MAX_NR_GENS);
-+	VM_BUG_ON(new_gen != -1 && new_gen >= MAX_NR_GENS);
-+	VM_BUG_ON(old_gen == -1 && new_gen == -1);
-+
-+	if (old_gen >= 0)
-+		WRITE_ONCE(lrugen->sizes[old_gen][type][zone],
-+			   lrugen->sizes[old_gen][type][zone] - delta);
-+	if (new_gen >= 0)
-+		WRITE_ONCE(lrugen->sizes[new_gen][type][zone],
-+			   lrugen->sizes[new_gen][type][zone] + delta);
-+
-+	if (old_gen < 0) {
-+		if (lru_gen_is_active(lruvec, new_gen))
-+			lru += LRU_ACTIVE;
-+		update_lru_size(lruvec, lru, zone, delta);
-+		return;
-+	}
-+
-+	if (new_gen < 0) {
-+		if (lru_gen_is_active(lruvec, old_gen))
-+			lru += LRU_ACTIVE;
-+		update_lru_size(lruvec, lru, zone, -delta);
-+		return;
-+	}
-+
-+	if (!lru_gen_is_active(lruvec, old_gen) && lru_gen_is_active(lruvec, new_gen)) {
-+		update_lru_size(lruvec, lru, zone, -delta);
-+		update_lru_size(lruvec, lru + LRU_ACTIVE, zone, delta);
-+	}
-+
-+	VM_BUG_ON(lru_gen_is_active(lruvec, old_gen) && !lru_gen_is_active(lruvec, new_gen));
-+}
-+
-+/* Add a page to one of the multigenerational lru lists. Return true on success. */
-+static inline bool lru_gen_add_page(struct page *page, struct lruvec *lruvec, bool reclaiming)
-+{
-+	int gen;
-+	unsigned long old_flags, new_flags;
-+	int type = page_is_file_lru(page);
-+	int zone = page_zonenum(page);
-+	struct lrugen *lrugen = &lruvec->evictable;
-+
-+	if (PageUnevictable(page) || !lrugen->enabled[type])
-+		return false;
-+	/*
-+	 * If a page shouldn't be considered for eviction, i.e., a page mapped
-+	 * upon fault during which the accessed bit is set, add it to the
-+	 * youngest generation.
-+	 *
-+	 * If a page can't be evicted immediately, i.e., an anon page not in
-+	 * swap cache or a dirty page pending writeback, add it to the second
-+	 * oldest generation.
-+	 *
-+	 * If a page could be evicted immediately, e.g., a clean page, add it to
-+	 * the oldest generation.
-+	 */
-+	if (PageActive(page))
-+		gen = lru_gen_from_seq(lrugen->max_seq);
-+	else if ((!type && !PageSwapCache(page)) ||
-+		 (PageReclaim(page) && (PageDirty(page) || PageWriteback(page))))
-+		gen = lru_gen_from_seq(lrugen->min_seq[type] + 1);
-+	else
-+		gen = lru_gen_from_seq(lrugen->min_seq[type]);
-+
-+	do {
-+		new_flags = old_flags = READ_ONCE(page->flags);
-+		VM_BUG_ON_PAGE(new_flags & LRU_GEN_MASK, page);
-+
-+		new_flags &= ~(LRU_GEN_MASK | BIT(PG_active));
-+		new_flags |= (gen + 1UL) << LRU_GEN_PGOFF;
-+	} while (cmpxchg(&page->flags, old_flags, new_flags) != old_flags);
-+
-+	lru_gen_update_size(page, lruvec, -1, gen);
-+	/* for rotate_reclaimable_page() */
-+	if (reclaiming)
-+		list_add_tail(&page->lru, &lrugen->lists[gen][type][zone]);
-+	else
-+		list_add(&page->lru, &lrugen->lists[gen][type][zone]);
-+
-+	return true;
-+}
-+
-+/* Delete a page from one of the multigenerational lru lists. Return true on success. */
-+static inline bool lru_gen_del_page(struct page *page, struct lruvec *lruvec, bool reclaiming)
-+{
-+	int gen;
-+	unsigned long old_flags, new_flags;
-+
-+	do {
-+		new_flags = old_flags = READ_ONCE(page->flags);
-+		if (!(new_flags & LRU_GEN_MASK))
-+			return false;
-+
-+		VM_BUG_ON_PAGE(PageActive(page), page);
-+		VM_BUG_ON_PAGE(PageUnevictable(page), page);
-+
-+		gen = ((new_flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1;
-+
-+		new_flags &= ~LRU_GEN_MASK;
-+		if ((new_flags & LRU_REFS_FLAGS) != LRU_REFS_FLAGS)
-+			new_flags &= ~(LRU_REFS_MASK | LRU_REFS_FLAGS);
-+		/* for shrink_page_list() */
-+		if (reclaiming)
-+			new_flags &= ~(BIT(PG_referenced) | BIT(PG_reclaim));
-+		else if (lru_gen_is_active(lruvec, gen))
-+			new_flags |= BIT(PG_active);
-+	} while (cmpxchg(&page->flags, old_flags, new_flags) != old_flags);
-+
-+	lru_gen_update_size(page, lruvec, gen, -1);
-+	list_del(&page->lru);
-+
-+	return true;
-+}
-+
-+#else
-+
-+static inline bool lru_gen_enabled(void)
-+{
-+	return false;
-+}
-+
-+static inline bool lru_gen_add_page(struct page *page, struct lruvec *lruvec, bool reclaiming)
-+{
-+	return false;
-+}
-+
-+static inline bool lru_gen_del_page(struct page *page, struct lruvec *lruvec, bool reclaiming)
-+{
-+	return false;
-+}
-+
-+#endif /* CONFIG_LRU_GEN */
-+
- static __always_inline void add_page_to_lru_list(struct page *page,
- 				struct lruvec *lruvec)
- {
- 	enum lru_list lru = page_lru(page);
- 
-+	if (lru_gen_add_page(page, lruvec, false))
-+		return;
-+
- 	update_lru_size(lruvec, lru, page_zonenum(page), thp_nr_pages(page));
- 	list_add(&page->lru, &lruvec->lists[lru]);
- }
-@@ -93,6 +285,9 @@ static __always_inline void add_page_to_lru_list_tail(struct page *page,
- {
- 	enum lru_list lru = page_lru(page);
- 
-+	if (lru_gen_add_page(page, lruvec, true))
-+		return;
-+
- 	update_lru_size(lruvec, lru, page_zonenum(page), thp_nr_pages(page));
- 	list_add_tail(&page->lru, &lruvec->lists[lru]);
- }
-@@ -100,6 +295,9 @@ static __always_inline void add_page_to_lru_list_tail(struct page *page,
- static __always_inline void del_page_from_lru_list(struct page *page,
- 				struct lruvec *lruvec)
- {
-+	if (lru_gen_del_page(page, lruvec, false))
-+		return;
-+
- 	list_del(&page->lru);
- 	update_lru_size(lruvec, page_lru(page), page_zonenum(page),
- 			-thp_nr_pages(page));
-diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
-index 7f8ee09c711f..a6ca0607c549 100644
---- a/include/linux/mm_types.h
-+++ b/include/linux/mm_types.h
-@@ -15,6 +15,8 @@
- #include <linux/page-flags-layout.h>
- #include <linux/workqueue.h>
- #include <linux/seqlock.h>
-+#include <linux/nodemask.h>
-+#include <linux/mmdebug.h>
- 
- #include <asm/mmu.h>
- 
-@@ -580,6 +582,22 @@ struct mm_struct {
- #ifdef CONFIG_IOMMU_SUPPORT
- 		u32 pasid;
- #endif
-+#ifdef CONFIG_LRU_GEN
-+		struct {
-+			/* the node of a global or per-memcg mm_struct list */
-+			struct list_head list;
-+#ifdef CONFIG_MEMCG
-+			/* points to the memcg of the owner task above */
-+			struct mem_cgroup *memcg;
-+#endif
-+			/* whether this mm_struct has been used since the last walk */
-+			nodemask_t nodes;
-+#ifndef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
-+			/* the number of CPUs using this mm_struct */
-+			atomic_t nr_cpus;
-+#endif
-+		} lrugen;
-+#endif /* CONFIG_LRU_GEN */
- 	} __randomize_layout;
- 
- 	/*
-@@ -606,6 +624,94 @@ static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
- 	return (struct cpumask *)&mm->cpu_bitmap;
- }
- 
-+#ifdef CONFIG_LRU_GEN
-+
-+struct lru_gen_mm_list {
-+	/* a global or per-memcg mm_struct list */
-+	struct list_head fifo;
-+	/* protects the list above */
-+	spinlock_t lock;
-+};
-+
-+void lru_gen_add_mm(struct mm_struct *mm);
-+void lru_gen_del_mm(struct mm_struct *mm);
-+#ifdef CONFIG_MEMCG
-+void lru_gen_migrate_mm(struct mm_struct *mm);
-+#endif
-+
-+static inline void lru_gen_init_mm(struct mm_struct *mm)
-+{
-+	INIT_LIST_HEAD(&mm->lrugen.list);
-+#ifdef CONFIG_MEMCG
-+	mm->lrugen.memcg = NULL;
-+#endif
-+#ifndef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
-+	atomic_set(&mm->lrugen.nr_cpus, 0);
-+#endif
-+	nodes_clear(mm->lrugen.nodes);
-+}
-+
-+/* Track the usage of each mm_struct so that we can skip inactive ones. */
-+static inline void lru_gen_switch_mm(struct mm_struct *old, struct mm_struct *new)
-+{
-+	/* exclude init_mm, efi_mm, etc. */
-+	if (!core_kernel_data((unsigned long)old)) {
-+		nodes_setall(old->lrugen.nodes);
-+#ifndef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
-+		atomic_dec(&old->lrugen.nr_cpus);
-+#endif
-+	}
-+
-+	if (!core_kernel_data((unsigned long)new)) {
-+		/* unlikely but not a bug when racing with lru_gen_migrate_mm() */
-+		VM_WARN_ON(list_empty(&new->lrugen.list));
-+#ifndef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
-+		atomic_inc(&new->lrugen.nr_cpus);
-+#endif
-+	}
-+}
-+
-+/* Return whether this mm_struct is being used on any CPUs. */
-+static inline bool lru_gen_mm_is_active(struct mm_struct *mm)
-+{
-+#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
-+	return !cpumask_empty(mm_cpumask(mm));
-+#else
-+	return atomic_read(&mm->lrugen.nr_cpus);
-+#endif
-+}
-+
-+#else /* !CONFIG_LRU_GEN */
-+
-+static inline void lru_gen_add_mm(struct mm_struct *mm)
-+{
-+}
-+
-+static inline void lru_gen_del_mm(struct mm_struct *mm)
-+{
-+}
-+
-+#ifdef CONFIG_MEMCG
-+static inline void lru_gen_migrate_mm(struct mm_struct *mm)
-+{
-+}
-+#endif
-+
-+static inline void lru_gen_init_mm(struct mm_struct *mm)
-+{
-+}
-+
-+static inline void lru_gen_switch_mm(struct mm_struct *old, struct mm_struct *new)
-+{
-+}
-+
-+static inline bool lru_gen_mm_is_active(struct mm_struct *mm)
-+{
-+	return false;
-+}
-+
-+#endif /* CONFIG_LRU_GEN */
-+
- struct mmu_gather;
- extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm);
- extern void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm);
-diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
-index 6a1d79d84675..a7544dc4c91b 100644
---- a/include/linux/mmzone.h
-+++ b/include/linux/mmzone.h
-@@ -294,6 +294,172 @@ enum lruvec_flags {
- 					 */
- };
- 
-+struct lruvec;
-+struct page_vma_mapped_walk;
-+
-+#define LRU_GEN_MASK		((BIT(LRU_GEN_WIDTH) - 1) << LRU_GEN_PGOFF)
-+#define LRU_REFS_MASK		((BIT(LRU_REFS_WIDTH) - 1) << LRU_REFS_PGOFF)
-+
-+#ifdef CONFIG_LRU_GEN
-+
-+/*
-+ * For each lruvec, evictable pages are divided into multiple generations. The
-+ * youngest and the oldest generation numbers, AKA max_seq and min_seq, are
-+ * monotonically increasing. The sliding window technique is used to track at
-+ * least MIN_NR_GENS and at most MAX_NR_GENS generations. An offset within the
-+ * window, AKA gen, indexes an array of per-type and per-zone lists for the
-+ * corresponding generation. The counter in page->flags stores gen+1 while a
-+ * page is on one of the multigenerational lru lists. Otherwise, it stores 0.
-+ *
-+ * After a page is faulted in, the aging must check the accessed bit at least
-+ * twice before the eviction would consider it. The first check clears the
-+ * accessed bit set during the initial fault. The second check makes sure this
-+ * page hasn't been used since then.
-+ */
-+#define MIN_NR_GENS		2
-+#define MAX_NR_GENS		((unsigned int)CONFIG_NR_LRU_GENS)
-+
-+/*
-+ * Each generation is divided into multiple tiers. Tiers represent different
-+ * ranges of numbers of accesses from file descriptors, i.e.,
-+ * mark_page_accessed(). In contrast to moving between generations which
-+ * requires the lru lock, moving between tiers only involves an atomic
-+ * operation on page->flags and therefore has a negligible cost.
-+ *
-+ * The purposes of tiers are to:
-+ *   1) estimate whether pages accessed multiple times via file descriptors are
-+ *   more active than pages accessed only via page tables by separating the two
-+ *   access types into upper tiers and the base tier, and comparing refaulted %
-+ *   across all tiers.
-+ *   2) improve buffered io performance by deferring the protection of pages
-+ *   accessed multiple times until the eviction. That is the protection happens
-+ *   in the reclaim path, not the access path.
-+ *
-+ * Pages accessed N times via file descriptors belong to tier order_base_2(N).
-+ * The base tier may be marked by PageReferenced(). All upper tiers are marked
-+ * by PageReferenced() && PageWorkingset(). Additional bits from page->flags are
-+ * used to support more than one upper tier.
-+ */
-+#define MAX_NR_TIERS		((unsigned int)CONFIG_TIERS_PER_GEN)
-+#define LRU_REFS_FLAGS		(BIT(PG_referenced) | BIT(PG_workingset))
-+
-+/* Whether to keep stats for historical generations. */
-+#ifdef CONFIG_LRU_GEN_STATS
-+#define NR_HIST_GENS		((unsigned int)CONFIG_NR_LRU_GENS)
-+#else
-+#define NR_HIST_GENS		1U
-+#endif
-+
-+struct lrugen {
-+	/* the aging increments the max generation number */
-+	unsigned long max_seq;
-+	/* the eviction increments the min generation numbers */
-+	unsigned long min_seq[ANON_AND_FILE];
-+	/* the birth time of each generation in jiffies */
-+	unsigned long timestamps[MAX_NR_GENS];
-+	/* the multigenerational lru lists */
-+	struct list_head lists[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES];
-+	/* the sizes of the multigenerational lru lists in pages */
-+	unsigned long sizes[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES];
-+	/* the exponential moving average of refaulted */
-+	unsigned long avg_refaulted[ANON_AND_FILE][MAX_NR_TIERS];
-+	/* the exponential moving average of protected+evicted */
-+	unsigned long avg_total[ANON_AND_FILE][MAX_NR_TIERS];
-+	/* the base tier isn't protected, hence the minus one */
-+	unsigned long protected[NR_HIST_GENS][ANON_AND_FILE][MAX_NR_TIERS - 1];
-+	/* incremented without holding the lru lock */
-+	atomic_long_t evicted[NR_HIST_GENS][ANON_AND_FILE][MAX_NR_TIERS];
-+	atomic_long_t refaulted[NR_HIST_GENS][ANON_AND_FILE][MAX_NR_TIERS];
-+	/* whether the multigenerational lru is enabled */
-+	bool enabled[ANON_AND_FILE];
-+};
-+
-+enum {
-+	MM_LEAF_TOTAL,		/* total leaf entries */
-+	MM_LEAF_OLD,		/* old leaf entries */
-+	MM_LEAF_YOUNG,		/* young leaf entries */
-+	MM_NONLEAF_TOTAL,	/* total non-leaf entries */
-+	MM_NONLEAF_PREV,	/* previously worthy non-leaf entries */
-+	MM_NONLEAF_CUR,		/* currently worthy non-leaf entries */
-+	NR_MM_STATS
-+};
-+
-+/* mnemonic codes for the stats above */
-+#define MM_STAT_CODES		"toydpc"
-+
-+/* double buffering bloom filters */
-+#define NR_BLOOM_FILTERS	2
-+
-+struct lru_gen_mm_walk {
-+	/* set to max_seq after each round of walk */
-+	unsigned long seq;
-+	/* the next mm_struct on the list to walk */
-+	struct list_head *head;
-+	/* the first mm_struct never walked before */
-+	struct list_head *tail;
-+	/* to wait for the last walker to finish */
-+	struct wait_queue_head wait;
-+	/* bloom filters flip after each round of walk */
-+	unsigned long *filters[NR_BLOOM_FILTERS];
-+	/* page table stats for debugging */
-+	unsigned long stats[NR_HIST_GENS][NR_MM_STATS];
-+	/* the number of concurrent walkers */
-+	int nr_walkers;
-+};
-+
-+#define MIN_BATCH_SIZE		64
-+#define MAX_BATCH_SIZE		8192
-+
-+struct mm_walk_args {
-+	struct mem_cgroup *memcg;
-+	unsigned long max_seq;
-+	unsigned long start_pfn;
-+	unsigned long end_pfn;
-+	unsigned long next_addr;
-+	unsigned long bitmap[BITS_TO_LONGS(MIN_BATCH_SIZE)];
-+	int node_id;
-+	int swappiness;
-+	int batch_size;
-+	int nr_pages[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES];
-+	int mm_stats[NR_MM_STATS];
-+	bool use_filter;
-+};
-+
-+void lru_gen_init_state(struct mem_cgroup *memcg, struct lruvec *lruvec);
-+void lru_gen_change_state(bool enable, bool main, bool swap);
-+void lru_gen_look_around(struct page_vma_mapped_walk *pvmw);
-+
-+#ifdef CONFIG_MEMCG
-+void lru_gen_init_memcg(struct mem_cgroup *memcg);
-+void lru_gen_free_memcg(struct mem_cgroup *memcg);
-+#endif
-+
-+#else /* !CONFIG_LRU_GEN */
-+
-+static inline void lru_gen_init_state(struct mem_cgroup *memcg, struct lruvec *lruvec)
-+{
-+}
-+
-+static inline void lru_gen_change_state(bool enable, bool main, bool swap)
-+{
-+}
-+
-+static inline void lru_gen_look_around(struct page_vma_mapped_walk *pvmw)
-+{
-+}
-+
-+#ifdef CONFIG_MEMCG
-+static inline void lru_gen_init_memcg(struct mem_cgroup *memcg)
-+{
-+}
-+
-+static inline void lru_gen_free_memcg(struct mem_cgroup *memcg)
-+{
-+}
-+#endif
-+
-+#endif /* CONFIG_LRU_GEN */
-+
- struct lruvec {
- 	struct list_head		lists[NR_LRU_LISTS];
- 	/* per lruvec lru_lock for memcg */
-@@ -311,6 +477,12 @@ struct lruvec {
- 	unsigned long			refaults[ANON_AND_FILE];
- 	/* Various lruvec state flags (enum lruvec_flags) */
- 	unsigned long			flags;
-+#ifdef CONFIG_LRU_GEN
-+	/* unevictable pages are on LRU_UNEVICTABLE */
-+	struct lrugen			evictable;
-+	/* state for mm list and page table walks */
-+	struct lru_gen_mm_walk		mm_walk;
-+#endif
- #ifdef CONFIG_MEMCG
- 	struct pglist_data *pgdat;
- #endif
-@@ -895,6 +1067,9 @@ typedef struct pglist_data {
- 
- 	unsigned long		flags;
- 
-+#ifdef CONFIG_LRU_GEN
-+	struct mm_walk_args	mm_walk_args;
-+#endif
- 	ZONE_PADDING(_pad2_)
- 
- 	/* Per-node vmstats */
-diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h
-index 567c3ddba2c4..90840c459abc 100644
---- a/include/linux/nodemask.h
-+++ b/include/linux/nodemask.h
-@@ -486,6 +486,7 @@ static inline int num_node_state(enum node_states state)
- #define first_online_node	0
- #define first_memory_node	0
- #define next_online_node(nid)	(MAX_NUMNODES)
-+#define next_memory_node(nid)	(MAX_NUMNODES)
- #define nr_node_ids		1U
- #define nr_online_nodes		1U
- 
-diff --git a/include/linux/oom.h b/include/linux/oom.h
-index 2db9a1432511..c4c8c7e71099 100644
---- a/include/linux/oom.h
-+++ b/include/linux/oom.h
-@@ -57,6 +57,22 @@ struct oom_control {
- extern struct mutex oom_lock;
- extern struct mutex oom_adj_mutex;
- 
-+#ifdef CONFIG_MMU
-+extern struct task_struct *oom_reaper_list;
-+extern struct wait_queue_head oom_reaper_wait;
-+
-+static inline bool oom_reaping_in_progress(void)
-+{
-+	/* racy check to see if oom reaping could be in progress */
-+	return READ_ONCE(oom_reaper_list) || !waitqueue_active(&oom_reaper_wait);
-+}
-+#else
-+static inline bool oom_reaping_in_progress(void)
-+{
-+	return false;
-+}
-+#endif
-+
- static inline void set_current_oom_origin(void)
- {
- 	current->signal->oom_flag_origin = true;
-diff --git a/include/linux/page-flags-layout.h b/include/linux/page-flags-layout.h
-index ef1e3e736e14..8cdbbdccb5ad 100644
---- a/include/linux/page-flags-layout.h
-+++ b/include/linux/page-flags-layout.h
-@@ -26,6 +26,14 @@
- 
- #define ZONES_WIDTH		ZONES_SHIFT
- 
-+#ifdef CONFIG_LRU_GEN
-+/* LRU_GEN_WIDTH is generated from order_base_2(CONFIG_NR_LRU_GENS + 1). */
-+#define LRU_REFS_WIDTH		(CONFIG_TIERS_PER_GEN - 2)
-+#else
-+#define LRU_GEN_WIDTH		0
-+#define LRU_REFS_WIDTH		0
-+#endif /* CONFIG_LRU_GEN */
-+
- #ifdef CONFIG_SPARSEMEM
- #include <asm/sparsemem.h>
- #define SECTIONS_SHIFT	(MAX_PHYSMEM_BITS - SECTION_SIZE_BITS)
-@@ -55,7 +63,8 @@
- #define SECTIONS_WIDTH		0
- #endif
- 
--#if ZONES_WIDTH + SECTIONS_WIDTH + NODES_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
-+#if ZONES_WIDTH + LRU_GEN_WIDTH + LRU_REFS_WIDTH + SECTIONS_WIDTH + NODES_SHIFT \
-+	<= BITS_PER_LONG - NR_PAGEFLAGS
- #define NODES_WIDTH		NODES_SHIFT
- #elif defined(CONFIG_SPARSEMEM_VMEMMAP)
- #error "Vmemmap: No space for nodes field in page flags"
-@@ -89,8 +98,8 @@
- #define LAST_CPUPID_SHIFT 0
- #endif
- 
--#if ZONES_WIDTH + SECTIONS_WIDTH + NODES_WIDTH + KASAN_TAG_WIDTH + LAST_CPUPID_SHIFT \
--	<= BITS_PER_LONG - NR_PAGEFLAGS
-+#if ZONES_WIDTH + LRU_GEN_WIDTH + LRU_REFS_WIDTH + SECTIONS_WIDTH + NODES_WIDTH + \
-+	KASAN_TAG_WIDTH + LAST_CPUPID_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
- #define LAST_CPUPID_WIDTH LAST_CPUPID_SHIFT
- #else
- #define LAST_CPUPID_WIDTH 0
-@@ -100,8 +109,8 @@
- #define LAST_CPUPID_NOT_IN_PAGE_FLAGS
- #endif
- 
--#if ZONES_WIDTH + SECTIONS_WIDTH + NODES_WIDTH + KASAN_TAG_WIDTH + LAST_CPUPID_WIDTH \
--	> BITS_PER_LONG - NR_PAGEFLAGS
-+#if ZONES_WIDTH + LRU_GEN_WIDTH + LRU_REFS_WIDTH + SECTIONS_WIDTH + NODES_WIDTH + \
-+	KASAN_TAG_WIDTH + LAST_CPUPID_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
- #error "Not enough bits in page flags"
- #endif
- 
-diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
-index fbfd3fad48f2..a7d7ff4c621d 100644
---- a/include/linux/page-flags.h
-+++ b/include/linux/page-flags.h
-@@ -845,7 +845,7 @@ static inline void ClearPageSlabPfmemalloc(struct page *page)
- 	 1UL << PG_private	| 1UL << PG_private_2	|	\
- 	 1UL << PG_writeback	| 1UL << PG_reserved	|	\
- 	 1UL << PG_slab		| 1UL << PG_active 	|	\
--	 1UL << PG_unevictable	| __PG_MLOCKED)
-+	 1UL << PG_unevictable	| __PG_MLOCKED | LRU_GEN_MASK)
- 
- /*
-  * Flags checked when a page is prepped for return by the page allocator.
-@@ -856,7 +856,7 @@ static inline void ClearPageSlabPfmemalloc(struct page *page)
-  * alloc-free cycle to prevent from reusing the page.
-  */
- #define PAGE_FLAGS_CHECK_AT_PREP	\
--	(PAGEFLAGS_MASK & ~__PG_HWPOISON)
-+	((PAGEFLAGS_MASK & ~__PG_HWPOISON) | LRU_GEN_MASK | LRU_REFS_MASK)
- 
- #define PAGE_FLAGS_PRIVATE				\
- 	(1UL << PG_private | 1UL << PG_private_2)
-diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
-index e24d2c992b11..afb9004b778a 100644
---- a/include/linux/pgtable.h
-+++ b/include/linux/pgtable.h
-@@ -211,7 +211,7 @@ static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
- #endif
- 
- #ifndef __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
--#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG)
- static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
- 					    unsigned long address,
- 					    pmd_t *pmdp)
-@@ -232,7 +232,7 @@ static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
- 	BUILD_BUG();
- 	return 0;
- }
--#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
-+#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG */
- #endif
- 
- #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
-@@ -258,6 +258,19 @@ static inline int pmdp_clear_flush_young(struct vm_area_struct *vma,
- #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
- #endif
- 
-+#ifndef arch_has_hw_pte_young
-+/*
-+ * Return whether the accessed bit is supported by the local CPU or all CPUs.
-+ *
-+ * Those arches which have hw access flag feature need to implement their own
-+ * helper. By default, "false" means pagefault will be hit on old pte.
-+ */
-+static inline bool arch_has_hw_pte_young(bool local)
-+{
-+	return false;
-+}
-+#endif
-+
- #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
- static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
- 				       unsigned long address,
-diff --git a/include/linux/sched.h b/include/linux/sched.h
-index c1a927ddec64..556b3d66c70d 100644
---- a/include/linux/sched.h
-+++ b/include/linux/sched.h
-@@ -911,6 +911,9 @@ struct task_struct {
- #ifdef CONFIG_MEMCG
- 	unsigned			in_user_fault:1;
- #endif
-+#ifdef CONFIG_LRU_GEN
-+	unsigned			in_nonseq_fault:1;
-+#endif
- #ifdef CONFIG_COMPAT_BRK
- 	unsigned			brk_randomized:1;
- #endif
-diff --git a/include/linux/swap.h b/include/linux/swap.h
-index ba52f3a3478e..2c4a5a88f83c 100644
---- a/include/linux/swap.h
-+++ b/include/linux/swap.h
-@@ -137,6 +137,9 @@ union swap_header {
-  */
- struct reclaim_state {
- 	unsigned long reclaimed_slab;
-+#ifdef CONFIG_LRU_GEN
-+	struct mm_walk_args *mm_walk_args;
-+#endif
- };
- 
- #ifdef __KERNEL__
-diff --git a/kernel/bounds.c b/kernel/bounds.c
-index 9795d75b09b2..aba13aa7336c 100644
---- a/kernel/bounds.c
-+++ b/kernel/bounds.c
-@@ -22,6 +22,9 @@ int main(void)
- 	DEFINE(NR_CPUS_BITS, ilog2(CONFIG_NR_CPUS));
- #endif
- 	DEFINE(SPINLOCK_SIZE, sizeof(spinlock_t));
-+#ifdef CONFIG_LRU_GEN
-+	DEFINE(LRU_GEN_WIDTH, order_base_2(CONFIG_NR_LRU_GENS + 1));
-+#endif
- 	/* End of constants */
- 
- 	return 0;
-diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h
-index bfbeabc17a9d..bec59189e206 100644
---- a/kernel/cgroup/cgroup-internal.h
-+++ b/kernel/cgroup/cgroup-internal.h
-@@ -146,7 +146,6 @@ struct cgroup_mgctx {
- #define DEFINE_CGROUP_MGCTX(name)						\
- 	struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name)
- 
--extern struct mutex cgroup_mutex;
- extern spinlock_t css_set_lock;
- extern struct cgroup_subsys *cgroup_subsys[];
- extern struct list_head cgroup_roots;
-diff --git a/kernel/exit.c b/kernel/exit.c
-index 91a43e57a32e..788a299abb4e 100644
---- a/kernel/exit.c
-+++ b/kernel/exit.c
-@@ -422,6 +422,7 @@ void mm_update_next_owner(struct mm_struct *mm)
- 		goto retry;
- 	}
- 	WRITE_ONCE(mm->owner, c);
-+	lru_gen_migrate_mm(mm);
- 	task_unlock(c);
- 	put_task_struct(c);
- }
-diff --git a/kernel/fork.c b/kernel/fork.c
-index 38681ad44c76..8d6bb4e76904 100644
---- a/kernel/fork.c
-+++ b/kernel/fork.c
-@@ -681,6 +681,7 @@ static void check_mm(struct mm_struct *mm)
- #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
- 	VM_BUG_ON_MM(mm->pmd_huge_pte, mm);
- #endif
-+	VM_BUG_ON_MM(lru_gen_mm_is_active(mm), mm);
- }
- 
- #define allocate_mm()	(kmem_cache_alloc(mm_cachep, GFP_KERNEL))
-@@ -1080,6 +1081,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
- 		goto fail_nocontext;
- 
- 	mm->user_ns = get_user_ns(user_ns);
-+	lru_gen_init_mm(mm);
- 	return mm;
- 
- fail_nocontext:
-@@ -1122,6 +1124,7 @@ static inline void __mmput(struct mm_struct *mm)
- 	}
- 	if (mm->binfmt)
- 		module_put(mm->binfmt->module);
-+	lru_gen_del_mm(mm);
- 	mmdrop(mm);
- }
- 
-@@ -2605,6 +2608,13 @@ pid_t kernel_clone(struct kernel_clone_args *args)
- 		get_task_struct(p);
- 	}
- 
-+	if (IS_ENABLED(CONFIG_LRU_GEN) && !(clone_flags & CLONE_VM)) {
-+		/* lock the task to synchronize with memcg migration */
-+		task_lock(p);
-+		lru_gen_add_mm(p->mm);
-+		task_unlock(p);
-+	}
-+
- 	wake_up_new_task(p);
- 
- 	/* forking complete and child started to run, tell ptracer */
-diff --git a/kernel/kthread.c b/kernel/kthread.c
-index 5b37a8567168..fd827fdad26b 100644
---- a/kernel/kthread.c
-+++ b/kernel/kthread.c
-@@ -1361,6 +1361,7 @@ void kthread_use_mm(struct mm_struct *mm)
- 	tsk->mm = mm;
- 	membarrier_update_current_mm(mm);
- 	switch_mm_irqs_off(active_mm, mm, tsk);
-+	lru_gen_switch_mm(active_mm, mm);
- 	local_irq_enable();
- 	task_unlock(tsk);
- #ifdef finish_arch_post_lock_switch
-diff --git a/kernel/sched/core.c b/kernel/sched/core.c
-index f21714ea3db8..e5e4cc86e296 100644
---- a/kernel/sched/core.c
-+++ b/kernel/sched/core.c
-@@ -4924,6 +4924,7 @@ context_switch(struct rq *rq, struct task_struct *prev,
- 		 * finish_task_switch()'s mmdrop().
- 		 */
- 		switch_mm_irqs_off(prev->active_mm, next->mm, next);
-+		lru_gen_switch_mm(prev->active_mm, next->mm);
- 
- 		if (!prev->mm) {                        // from kernel
- 			/* will mmdrop() in finish_task_switch(). */
-@@ -8792,6 +8793,7 @@ void idle_task_exit(void)
- 
- 	if (mm != &init_mm) {
- 		switch_mm(mm, &init_mm, current);
-+		lru_gen_switch_mm(mm, &init_mm);
- 		finish_arch_post_lock_switch();
- 	}
- 
-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
-diff --git a/mm/huge_memory.c b/mm/huge_memory.c
-index c5142d237e48..875ed5559d95 100644
---- a/mm/huge_memory.c
-+++ b/mm/huge_memory.c
-@@ -2364,7 +2364,8 @@ static void __split_huge_page_tail(struct page *head, int tail,
- #ifdef CONFIG_64BIT
- 			 (1L << PG_arch_2) |
- #endif
--			 (1L << PG_dirty)));
-+			 (1L << PG_dirty) |
-+			 LRU_GEN_MASK | LRU_REFS_MASK));
- 
- 	/* ->mapping in first tail page is compound_mapcount */
- 	VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING,
-diff --git a/mm/memcontrol.c b/mm/memcontrol.c
-index 6da5020a8656..49100d053e3b 100644
---- a/mm/memcontrol.c
-+++ b/mm/memcontrol.c
-@@ -1239,12 +1239,17 @@ void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
- 		*lru_size += nr_pages;
- 
- 	size = *lru_size;
-+#ifdef CONFIG_LRU_GEN
-+	/* unlikely but not a bug when reset_batch_size() is pending */
-+	VM_WARN_ON(size + MAX_BATCH_SIZE < 0);
-+#else
- 	if (WARN_ONCE(size < 0,
- 		"%s(%p, %d, %d): lru_size %ld\n",
- 		__func__, lruvec, lru, nr_pages, size)) {
- 		VM_BUG_ON(1);
- 		*lru_size = 0;
- 	}
-+#endif
- 
- 	if (nr_pages > 0)
- 		*lru_size += nr_pages;
-@@ -5110,6 +5115,7 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg)
- 
- static void mem_cgroup_free(struct mem_cgroup *memcg)
- {
-+	lru_gen_free_memcg(memcg);
- 	memcg_wb_domain_exit(memcg);
- 	__mem_cgroup_free(memcg);
- }
-@@ -5173,6 +5179,7 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
- 	memcg->deferred_split_queue.split_queue_len = 0;
- #endif
- 	idr_replace(&mem_cgroup_idr, memcg, memcg->id.id);
-+	lru_gen_init_memcg(memcg);
- 	return memcg;
- fail:
- 	mem_cgroup_id_remove(memcg);
-@@ -6156,6 +6163,29 @@ static void mem_cgroup_move_task(void)
- }
- #endif
- 
-+#ifdef CONFIG_LRU_GEN
-+static void mem_cgroup_attach(struct cgroup_taskset *tset)
-+{
-+	struct cgroup_subsys_state *css;
-+	struct task_struct *task = NULL;
-+
-+	cgroup_taskset_for_each_leader(task, css, tset)
-+		break;
-+
-+	if (!task)
-+		return;
-+
-+	task_lock(task);
-+	if (task->mm && task->mm->owner == task)
-+		lru_gen_migrate_mm(task->mm);
-+	task_unlock(task);
-+}
-+#else
-+static void mem_cgroup_attach(struct cgroup_taskset *tset)
-+{
-+}
-+#endif /* CONFIG_LRU_GEN */
-+
- static int seq_puts_memcg_tunable(struct seq_file *m, unsigned long value)
- {
- 	if (value == PAGE_COUNTER_MAX)
-@@ -6499,6 +6529,7 @@ struct cgroup_subsys memory_cgrp_subsys = {
- 	.css_reset = mem_cgroup_css_reset,
- 	.css_rstat_flush = mem_cgroup_css_rstat_flush,
- 	.can_attach = mem_cgroup_can_attach,
-+	.attach = mem_cgroup_attach,
- 	.cancel_attach = mem_cgroup_cancel_attach,
- 	.post_attach = mem_cgroup_move_task,
- 	.dfl_cftypes = memory_files,
-diff --git a/mm/memory.c b/mm/memory.c
-index c52be6d6b605..6b2b665c0866 100644
---- a/mm/memory.c
-+++ b/mm/memory.c
-@@ -121,18 +121,6 @@ int randomize_va_space __read_mostly =
- 					2;
- #endif
- 
--#ifndef arch_faults_on_old_pte
--static inline bool arch_faults_on_old_pte(void)
--{
--	/*
--	 * Those arches which don't have hw access flag feature need to
--	 * implement their own helper. By default, "true" means pagefault
--	 * will be hit on old pte.
--	 */
--	return true;
--}
--#endif
--
- #ifndef arch_wants_old_prefaulted_pte
- static inline bool arch_wants_old_prefaulted_pte(void)
- {
-@@ -2769,7 +2757,7 @@ static inline bool cow_user_page(struct page *dst, struct page *src,
- 	 * On architectures with software "accessed" bits, we would
- 	 * take a double page fault, so mark it accessed here.
- 	 */
--	if (arch_faults_on_old_pte() && !pte_young(vmf->orig_pte)) {
-+	if (!arch_has_hw_pte_young(true) && !pte_young(vmf->orig_pte)) {
- 		pte_t entry;
- 
- 		vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl);
-@@ -4774,6 +4762,7 @@ vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
- 			   unsigned int flags, struct pt_regs *regs)
- {
- 	vm_fault_t ret;
-+	bool nonseq_fault = !(vma->vm_flags & VM_SEQ_READ);
- 
- 	__set_current_state(TASK_RUNNING);
- 
-@@ -4795,11 +4784,17 @@ vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
- 	if (flags & FAULT_FLAG_USER)
- 		mem_cgroup_enter_user_fault();
- 
-+	if (nonseq_fault)
-+		task_enter_nonseq_fault();
-+
- 	if (unlikely(is_vm_hugetlb_page(vma)))
- 		ret = hugetlb_fault(vma->vm_mm, vma, address, flags);
- 	else
- 		ret = __handle_mm_fault(vma, address, flags);
- 
-+	if (nonseq_fault)
-+		task_exit_nonseq_fault();
-+
- 	if (flags & FAULT_FLAG_USER) {
- 		mem_cgroup_exit_user_fault();
- 		/*
-diff --git a/mm/mm_init.c b/mm/mm_init.c
-index 9ddaf0e1b0ab..0d7b2bd2454a 100644
---- a/mm/mm_init.c
-+++ b/mm/mm_init.c
-@@ -65,14 +65,16 @@ void __init mminit_verify_pageflags_layout(void)
- 
- 	shift = 8 * sizeof(unsigned long);
- 	width = shift - SECTIONS_WIDTH - NODES_WIDTH - ZONES_WIDTH
--		- LAST_CPUPID_SHIFT - KASAN_TAG_WIDTH;
-+		- LAST_CPUPID_SHIFT - KASAN_TAG_WIDTH - LRU_GEN_WIDTH - LRU_REFS_WIDTH;
- 	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_widths",
--		"Section %d Node %d Zone %d Lastcpupid %d Kasantag %d Flags %d\n",
-+		"Section %d Node %d Zone %d Lastcpupid %d Kasantag %d Gen %d Tier %d Flags %d\n",
- 		SECTIONS_WIDTH,
- 		NODES_WIDTH,
- 		ZONES_WIDTH,
- 		LAST_CPUPID_WIDTH,
- 		KASAN_TAG_WIDTH,
-+		LRU_GEN_WIDTH,
-+		LRU_REFS_WIDTH,
- 		NR_PAGEFLAGS);
- 	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_shifts",
- 		"Section %d Node %d Zone %d Lastcpupid %d Kasantag %d\n",
-diff --git a/mm/oom_kill.c b/mm/oom_kill.c
-index 989f35a2bbb1..72855b7bde09 100644
---- a/mm/oom_kill.c
-+++ b/mm/oom_kill.c
-@@ -508,8 +508,8 @@ bool process_shares_mm(struct task_struct *p, struct mm_struct *mm)
-  * victim (if that is possible) to help the OOM killer to move on.
-  */
- static struct task_struct *oom_reaper_th;
--static DECLARE_WAIT_QUEUE_HEAD(oom_reaper_wait);
--static struct task_struct *oom_reaper_list;
-+DECLARE_WAIT_QUEUE_HEAD(oom_reaper_wait);
-+struct task_struct *oom_reaper_list;
- static DEFINE_SPINLOCK(oom_reaper_lock);
- 
- bool __oom_reap_task_mm(struct mm_struct *mm)
-diff --git a/mm/page_alloc.c b/mm/page_alloc.c
-index 23d3339ac4e8..5bee46999f60 100644
---- a/mm/page_alloc.c
-+++ b/mm/page_alloc.c
-@@ -7405,6 +7405,7 @@ static void __meminit pgdat_init_internals(struct pglist_data *pgdat)
- 
- 	pgdat_page_ext_init(pgdat);
- 	lruvec_init(&pgdat->__lruvec);
-+	lru_gen_init_state(NULL, &pgdat->__lruvec);
- }
- 
- static void __meminit zone_init_internals(struct zone *zone, enum zone_type idx, int nid,
-diff --git a/mm/rmap.c b/mm/rmap.c
-index 6aebd1747251..a6b522fe871a 100644
---- a/mm/rmap.c
-+++ b/mm/rmap.c
-@@ -73,6 +73,7 @@
- #include <linux/page_idle.h>
- #include <linux/memremap.h>
- #include <linux/userfaultfd_k.h>
-+#include <linux/mm_inline.h>
- 
- #include <asm/tlbflush.h>
- 
-@@ -790,6 +791,13 @@ static bool page_referenced_one(struct page *page, struct vm_area_struct *vma,
- 		}
- 
- 		if (pvmw.pte) {
-+			/* the multigenerational lru exploits the spatial locality */
-+			if (lru_gen_enabled() && pte_young(*pvmw.pte) &&
-+			    !(vma->vm_flags & VM_SEQ_READ)) {
-+				lru_gen_look_around(&pvmw);
-+				referenced++;
-+			}
-+
- 			if (ptep_clear_flush_young_notify(vma, address,
- 						pvmw.pte)) {
- 				/*
-diff --git a/mm/swap.c b/mm/swap.c
-index af3cad4e5378..93f5fe5f99ca 100644
---- a/mm/swap.c
-+++ b/mm/swap.c
-@@ -389,6 +389,43 @@ static void __lru_cache_activate_page(struct page *page)
- 	local_unlock(&lru_pvecs.lock);
- }
- 
-+#ifdef CONFIG_LRU_GEN
-+static void page_inc_refs(struct page *page)
-+{
-+	unsigned long refs;
-+	unsigned long old_flags, new_flags;
-+
-+	if (PageUnevictable(page))
-+		return;
-+
-+	/* see the comment on MAX_NR_TIERS */
-+	do {
-+		new_flags = old_flags = READ_ONCE(page->flags);
-+
-+		if (!(new_flags & BIT(PG_referenced))) {
-+			new_flags |= BIT(PG_referenced);
-+			continue;
-+		}
-+
-+		if (!(new_flags & BIT(PG_workingset))) {
-+			new_flags |= BIT(PG_workingset);
-+			continue;
-+		}
-+
-+		refs = new_flags & LRU_REFS_MASK;
-+		refs = min(refs + BIT(LRU_REFS_PGOFF), LRU_REFS_MASK);
-+
-+		new_flags &= ~LRU_REFS_MASK;
-+		new_flags |= refs;
-+	} while (new_flags != old_flags &&
-+		 cmpxchg(&page->flags, old_flags, new_flags) != old_flags);
-+}
-+#else
-+static void page_inc_refs(struct page *page)
-+{
-+}
-+#endif /* CONFIG_LRU_GEN */
-+
- /*
-  * Mark a page as having seen activity.
-  *
-@@ -403,6 +440,11 @@ void mark_page_accessed(struct page *page)
- {
- 	page = compound_head(page);
- 
-+	if (lru_gen_enabled()) {
-+		page_inc_refs(page);
-+		return;
-+	}
-+
- 	if (!PageReferenced(page)) {
- 		SetPageReferenced(page);
- 	} else if (PageUnevictable(page)) {
-@@ -446,6 +488,11 @@ void lru_cache_add(struct page *page)
- 	VM_BUG_ON_PAGE(PageActive(page) && PageUnevictable(page), page);
- 	VM_BUG_ON_PAGE(PageLRU(page), page);
- 
-+	/* see the comment in lru_gen_add_page() */
-+	if (lru_gen_enabled() && !PageUnevictable(page) &&
-+	    task_in_nonseq_fault() && !(current->flags & PF_MEMALLOC))
-+		SetPageActive(page);
-+
- 	get_page(page);
- 	local_lock(&lru_pvecs.lock);
- 	pvec = this_cpu_ptr(&lru_pvecs.lru_add);
-@@ -547,7 +594,7 @@ static void lru_deactivate_file_fn(struct page *page, struct lruvec *lruvec)
- 
- static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec)
- {
--	if (PageActive(page) && !PageUnevictable(page)) {
-+	if (!PageUnevictable(page) && (PageActive(page) || lru_gen_enabled())) {
- 		int nr_pages = thp_nr_pages(page);
- 
- 		del_page_from_lru_list(page, lruvec);
-@@ -661,7 +708,7 @@ void deactivate_file_page(struct page *page)
-  */
- void deactivate_page(struct page *page)
- {
--	if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) {
-+	if (PageLRU(page) && !PageUnevictable(page) && (PageActive(page) || lru_gen_enabled())) {
- 		struct pagevec *pvec;
- 
- 		local_lock(&lru_pvecs.lock);
-diff --git a/mm/swapfile.c b/mm/swapfile.c
-index 22d10f713848..2ac9ac0b5ec3 100644
---- a/mm/swapfile.c
-+++ b/mm/swapfile.c
-@@ -2688,6 +2688,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
- 	err = 0;
- 	atomic_inc(&proc_poll_event);
- 	wake_up_interruptible(&proc_poll_wait);
-+	lru_gen_change_state(false, false, true);
- 
- out_dput:
- 	filp_close(victim, NULL);
-@@ -3349,6 +3350,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
- 	mutex_unlock(&swapon_mutex);
- 	atomic_inc(&proc_poll_event);
- 	wake_up_interruptible(&proc_poll_wait);
-+	lru_gen_change_state(true, false, true);
- 
- 	error = 0;
- 	goto out;
-diff --git a/mm/vmscan.c b/mm/vmscan.c
-index 74296c2d1fed..7c3a49173902 100644
---- a/mm/vmscan.c
-+++ b/mm/vmscan.c
-@@ -50,6 +50,11 @@
- #include <linux/printk.h>
- #include <linux/dax.h>
- #include <linux/psi.h>
-+#include <linux/memory.h>
-+#include <linux/pagewalk.h>
-+#include <linux/shmem_fs.h>
-+#include <linux/ctype.h>
-+#include <linux/debugfs.h>
- 
- #include <asm/tlbflush.h>
- #include <asm/div64.h>
-@@ -1142,9 +1147,11 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
- 
- 	if (PageSwapCache(page)) {
- 		swp_entry_t swap = { .val = page_private(page) };
--		mem_cgroup_swapout(page, swap);
-+
-+		/* get a shadow entry before page_memcg() is cleared */
- 		if (reclaimed && !mapping_exiting(mapping))
- 			shadow = workingset_eviction(page, target_memcg);
-+		mem_cgroup_swapout(page, swap);
- 		__delete_from_swap_cache(page, swap, shadow);
- 		xa_unlock_irq(&mapping->i_pages);
- 		put_swap_page(page, swap);
-@@ -1407,6 +1414,11 @@ static unsigned int shrink_page_list(struct list_head *page_list,
- 		if (!sc->may_unmap && page_mapped(page))
- 			goto keep_locked;
- 
-+		/* lru_gen_look_around() has updated this page? */
-+		if (lru_gen_enabled() && !ignore_references &&
-+		    page_mapped(page) && PageReferenced(page))
-+			goto keep_locked;
-+
- 		may_enter_fs = (sc->gfp_mask & __GFP_FS) ||
- 			(PageSwapCache(page) && (sc->gfp_mask & __GFP_IO));
- 
-@@ -2562,6 +2574,106 @@ enum scan_balance {
- 	SCAN_FILE,
- };
- 
-+static void prepare_scan_count(pg_data_t *pgdat, struct scan_control *sc)
-+{
-+	unsigned long file;
-+	struct lruvec *target_lruvec;
-+
-+	if (lru_gen_enabled())
-+		return;
-+
-+	target_lruvec = mem_cgroup_lruvec(sc->target_mem_cgroup, pgdat);
-+
-+	/*
-+	 * Determine the scan balance between anon and file LRUs.
-+	 */
-+	spin_lock_irq(&target_lruvec->lru_lock);
-+	sc->anon_cost = target_lruvec->anon_cost;
-+	sc->file_cost = target_lruvec->file_cost;
-+	spin_unlock_irq(&target_lruvec->lru_lock);
-+
-+	/*
-+	 * Target desirable inactive:active list ratios for the anon
-+	 * and file LRU lists.
-+	 */
-+	if (!sc->force_deactivate) {
-+		unsigned long refaults;
-+
-+		refaults = lruvec_page_state(target_lruvec,
-+				WORKINGSET_ACTIVATE_ANON);
-+		if (refaults != target_lruvec->refaults[0] ||
-+			inactive_is_low(target_lruvec, LRU_INACTIVE_ANON))
-+			sc->may_deactivate |= DEACTIVATE_ANON;
-+		else
-+			sc->may_deactivate &= ~DEACTIVATE_ANON;
-+
-+		/*
-+		 * When refaults are being observed, it means a new
-+		 * workingset is being established. Deactivate to get
-+		 * rid of any stale active pages quickly.
-+		 */
-+		refaults = lruvec_page_state(target_lruvec,
-+				WORKINGSET_ACTIVATE_FILE);
-+		if (refaults != target_lruvec->refaults[1] ||
-+		    inactive_is_low(target_lruvec, LRU_INACTIVE_FILE))
-+			sc->may_deactivate |= DEACTIVATE_FILE;
-+		else
-+			sc->may_deactivate &= ~DEACTIVATE_FILE;
-+	} else
-+		sc->may_deactivate = DEACTIVATE_ANON | DEACTIVATE_FILE;
-+
-+	/*
-+	 * If we have plenty of inactive file pages that aren't
-+	 * thrashing, try to reclaim those first before touching
-+	 * anonymous pages.
-+	 */
-+	file = lruvec_page_state(target_lruvec, NR_INACTIVE_FILE);
-+	if (file >> sc->priority && !(sc->may_deactivate & DEACTIVATE_FILE))
-+		sc->cache_trim_mode = 1;
-+	else
-+		sc->cache_trim_mode = 0;
-+
-+	/*
-+	 * Prevent the reclaimer from falling into the cache trap: as
-+	 * cache pages start out inactive, every cache fault will tip
-+	 * the scan balance towards the file LRU.  And as the file LRU
-+	 * shrinks, so does the window for rotation from references.
-+	 * This means we have a runaway feedback loop where a tiny
-+	 * thrashing file LRU becomes infinitely more attractive than
-+	 * anon pages.  Try to detect this based on file LRU size.
-+	 */
-+	if (!cgroup_reclaim(sc)) {
-+		unsigned long total_high_wmark = 0;
-+		unsigned long free, anon;
-+		int z;
-+
-+		free = sum_zone_node_page_state(pgdat->node_id, NR_FREE_PAGES);
-+		file = node_page_state(pgdat, NR_ACTIVE_FILE) +
-+			   node_page_state(pgdat, NR_INACTIVE_FILE);
-+
-+		for (z = 0; z < MAX_NR_ZONES; z++) {
-+			struct zone *zone = &pgdat->node_zones[z];
-+
-+			if (!managed_zone(zone))
-+				continue;
-+
-+			total_high_wmark += high_wmark_pages(zone);
-+		}
-+
-+		/*
-+		 * Consider anon: if that's low too, this isn't a
-+		 * runaway file reclaim problem, but rather just
-+		 * extreme pressure. Reclaim as per usual then.
-+		 */
-+		anon = node_page_state(pgdat, NR_INACTIVE_ANON);
-+
-+		sc->file_is_tiny =
-+			file + free <= total_high_wmark &&
-+			!(sc->may_deactivate & DEACTIVATE_ANON) &&
-+			anon >> sc->priority;
-+	}
-+}
-+
- /*
-  * Determine how aggressively the anon and file LRU lists should be
-  * scanned.  The relative value of each set of LRU lists is determined
-@@ -2783,6 +2895,2487 @@ static bool can_age_anon_pages(struct pglist_data *pgdat,
- 	return can_demote(pgdat->node_id, sc);
- }
- 
-+#ifdef CONFIG_LRU_GEN
-+
-+/******************************************************************************
-+ *                          shorthand helpers
-+ ******************************************************************************/
-+
-+#define DEFINE_MAX_SEQ(lruvec)						\
-+	unsigned long max_seq = READ_ONCE((lruvec)->evictable.max_seq)
-+
-+#define DEFINE_MIN_SEQ(lruvec)						\
-+	unsigned long min_seq[ANON_AND_FILE] = {			\
-+		READ_ONCE((lruvec)->evictable.min_seq[0]),		\
-+		READ_ONCE((lruvec)->evictable.min_seq[1]),		\
-+	}
-+
-+#define for_each_gen_type_zone(gen, type, zone)				\
-+	for ((gen) = 0; (gen) < MAX_NR_GENS; (gen)++)			\
-+		for ((type) = 0; (type) < ANON_AND_FILE; (type)++)	\
-+			for ((zone) = 0; (zone) < MAX_NR_ZONES; (zone)++)
-+
-+static int page_lru_gen(struct page *page)
-+{
-+	unsigned long flags = READ_ONCE(page->flags);
-+
-+	return ((flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1;
-+}
-+
-+static int page_lru_tier(struct page *page)
-+{
-+	int refs;
-+	unsigned long flags = READ_ONCE(page->flags);
-+
-+	refs = (flags & LRU_REFS_FLAGS) == LRU_REFS_FLAGS ?
-+	       ((flags & LRU_REFS_MASK) >> LRU_REFS_PGOFF) + 1 : 0;
-+
-+	return lru_tier_from_refs(refs);
-+}
-+
-+static int get_swappiness(struct mem_cgroup *memcg)
-+{
-+	return mem_cgroup_get_nr_swap_pages(memcg) >= MIN_BATCH_SIZE ?
-+	       mem_cgroup_swappiness(memcg) : 0;
-+}
-+
-+static struct lruvec *get_lruvec(int nid, struct mem_cgroup *memcg)
-+{
-+	struct pglist_data *pgdat = NODE_DATA(nid);
-+
-+#ifdef CONFIG_MEMCG
-+	if (memcg)
-+		return &memcg->nodeinfo[nid]->lruvec;
-+#endif
-+	return pgdat ? &pgdat->__lruvec : NULL;
-+}
-+
-+static int get_nr_gens(struct lruvec *lruvec, int type)
-+{
-+	return lruvec->evictable.max_seq - lruvec->evictable.min_seq[type] + 1;
-+}
-+
-+static bool __maybe_unused seq_is_valid(struct lruvec *lruvec)
-+{
-+	return get_nr_gens(lruvec, 1) >= MIN_NR_GENS &&
-+	       get_nr_gens(lruvec, 1) <= get_nr_gens(lruvec, 0) &&
-+	       get_nr_gens(lruvec, 0) <= MAX_NR_GENS;
-+}
-+
-+/******************************************************************************
-+ *                          mm_struct list
-+ ******************************************************************************/
-+
-+static struct lru_gen_mm_list *get_mm_list(struct mem_cgroup *memcg)
-+{
-+	static struct lru_gen_mm_list mm_list = {
-+		.fifo = LIST_HEAD_INIT(mm_list.fifo),
-+		.lock = __SPIN_LOCK_UNLOCKED(mm_list.lock),
-+	};
-+
-+#ifdef CONFIG_MEMCG
-+	if (memcg)
-+		return &memcg->mm_list;
-+#endif
-+	return &mm_list;
-+}
-+
-+void lru_gen_add_mm(struct mm_struct *mm)
-+{
-+	int nid;
-+	struct mem_cgroup *memcg = get_mem_cgroup_from_mm(mm);
-+	struct lru_gen_mm_list *mm_list = get_mm_list(memcg);
-+
-+	VM_BUG_ON_MM(!list_empty(&mm->lrugen.list), mm);
-+#ifdef CONFIG_MEMCG
-+	VM_BUG_ON_MM(mm->lrugen.memcg, mm);
-+	mm->lrugen.memcg = memcg;
-+#endif
-+	spin_lock(&mm_list->lock);
-+
-+	list_add_tail(&mm->lrugen.list, &mm_list->fifo);
-+
-+	for_each_node(nid) {
-+		struct lruvec *lruvec = get_lruvec(nid, memcg);
-+
-+		if (!lruvec)
-+			continue;
-+
-+		if (lruvec->mm_walk.tail == &mm_list->fifo)
-+			lruvec->mm_walk.tail = lruvec->mm_walk.tail->prev;
-+	}
-+
-+	spin_unlock(&mm_list->lock);
-+}
-+
-+void lru_gen_del_mm(struct mm_struct *mm)
-+{
-+	int nid;
-+	struct lru_gen_mm_list *mm_list;
-+	struct mem_cgroup *memcg = NULL;
-+
-+	if (list_empty(&mm->lrugen.list))
-+		return;
-+
-+#ifdef CONFIG_MEMCG
-+	memcg = mm->lrugen.memcg;
-+#endif
-+	mm_list = get_mm_list(memcg);
-+
-+	spin_lock(&mm_list->lock);
-+
-+	for_each_node(nid) {
-+		struct lruvec *lruvec = get_lruvec(nid, memcg);
-+
-+		if (!lruvec)
-+			continue;
-+
-+		if (lruvec->mm_walk.tail == &mm->lrugen.list)
-+			lruvec->mm_walk.tail = lruvec->mm_walk.tail->next;
-+
-+		if (lruvec->mm_walk.head != &mm->lrugen.list)
-+			continue;
-+
-+		lruvec->mm_walk.head = lruvec->mm_walk.head->next;
-+		if (lruvec->mm_walk.head == &mm_list->fifo)
-+			WRITE_ONCE(lruvec->mm_walk.seq, lruvec->mm_walk.seq + 1);
-+	}
-+
-+	list_del_init(&mm->lrugen.list);
-+
-+	spin_unlock(&mm_list->lock);
-+
-+#ifdef CONFIG_MEMCG
-+	mem_cgroup_put(mm->lrugen.memcg);
-+	mm->lrugen.memcg = NULL;
-+#endif
-+}
-+
-+#ifdef CONFIG_MEMCG
-+void lru_gen_migrate_mm(struct mm_struct *mm)
-+{
-+	struct mem_cgroup *memcg;
-+
-+	lockdep_assert_held(&mm->owner->alloc_lock);
-+
-+	if (mem_cgroup_disabled())
-+		return;
-+
-+	rcu_read_lock();
-+	memcg = mem_cgroup_from_task(mm->owner);
-+	rcu_read_unlock();
-+	if (memcg == mm->lrugen.memcg)
-+		return;
-+
-+	VM_BUG_ON_MM(!mm->lrugen.memcg, mm);
-+	VM_BUG_ON_MM(list_empty(&mm->lrugen.list), mm);
-+
-+	lru_gen_del_mm(mm);
-+	lru_gen_add_mm(mm);
-+}
-+#endif
-+
-+#define BLOOM_FILTER_SHIFT	15
-+
-+static inline int filter_gen_from_seq(unsigned long seq)
-+{
-+	return seq % NR_BLOOM_FILTERS;
-+}
-+
-+static void get_item_key(void *item, int *key)
-+{
-+	u32 hash = hash_ptr(item, BLOOM_FILTER_SHIFT * 2);
-+
-+	BUILD_BUG_ON(BLOOM_FILTER_SHIFT * 2 > BITS_PER_TYPE(u32));
-+
-+	key[0] = hash & (BIT(BLOOM_FILTER_SHIFT) - 1);
-+	key[1] = hash >> BLOOM_FILTER_SHIFT;
-+}
-+
-+static void clear_bloom_filter(struct lruvec *lruvec, unsigned long seq)
-+{
-+	unsigned long *filter;
-+	int gen = filter_gen_from_seq(seq);
-+
-+	lockdep_assert_held(&get_mm_list(lruvec_memcg(lruvec))->lock);
-+
-+	filter = lruvec->mm_walk.filters[gen];
-+	if (filter) {
-+		bitmap_clear(filter, 0, BIT(BLOOM_FILTER_SHIFT));
-+		return;
-+	}
-+
-+	filter = bitmap_zalloc(BIT(BLOOM_FILTER_SHIFT), GFP_ATOMIC);
-+	WRITE_ONCE(lruvec->mm_walk.filters[gen], filter);
-+}
-+
-+static void set_bloom_filter(struct lruvec *lruvec, unsigned long seq, void *item)
-+{
-+	int key[2];
-+	unsigned long *filter;
-+	int gen = filter_gen_from_seq(seq);
-+
-+	filter = READ_ONCE(lruvec->mm_walk.filters[gen]);
-+	if (!filter)
-+		return;
-+
-+	get_item_key(item, key);
-+
-+	if (!test_bit(key[0], filter))
-+		set_bit(key[0], filter);
-+	if (!test_bit(key[1], filter))
-+		set_bit(key[1], filter);
-+}
-+
-+static bool test_bloom_filter(struct lruvec *lruvec, unsigned long seq, void *item)
-+{
-+	int key[2];
-+	unsigned long *filter;
-+	int gen = filter_gen_from_seq(seq);
-+
-+	filter = READ_ONCE(lruvec->mm_walk.filters[gen]);
-+	if (!filter)
-+		return false;
-+
-+	get_item_key(item, key);
-+
-+	return test_bit(key[0], filter) && test_bit(key[1], filter);
-+}
-+
-+static void reset_mm_stats(struct lruvec *lruvec, bool last, struct mm_walk_args *args)
-+{
-+	int i;
-+	int hist = lru_hist_from_seq(args->max_seq);
-+
-+	lockdep_assert_held(&get_mm_list(lruvec_memcg(lruvec))->lock);
-+
-+	for (i = 0; i < NR_MM_STATS; i++) {
-+		WRITE_ONCE(lruvec->mm_walk.stats[hist][i],
-+			   lruvec->mm_walk.stats[hist][i] + args->mm_stats[i]);
-+		args->mm_stats[i] = 0;
-+	}
-+
-+	if (!last || NR_HIST_GENS == 1)
-+		return;
-+
-+	hist = lru_hist_from_seq(args->max_seq + 1);
-+	for (i = 0; i < NR_MM_STATS; i++)
-+		WRITE_ONCE(lruvec->mm_walk.stats[hist][i], 0);
-+}
-+
-+static bool should_skip_mm(struct mm_struct *mm, struct mm_walk_args *args)
-+{
-+	int type;
-+	unsigned long size = 0;
-+
-+	if (!lru_gen_mm_is_active(mm) && !node_isset(args->node_id, mm->lrugen.nodes))
-+		return true;
-+
-+	if (mm_is_oom_victim(mm))
-+		return true;
-+
-+	for (type = !args->swappiness; type < ANON_AND_FILE; type++) {
-+		size += type ? get_mm_counter(mm, MM_FILEPAGES) :
-+			       get_mm_counter(mm, MM_ANONPAGES) +
-+			       get_mm_counter(mm, MM_SHMEMPAGES);
-+	}
-+
-+	if (size < MIN_BATCH_SIZE)
-+		return true;
-+
-+	if (!mmget_not_zero(mm))
-+		return true;
-+
-+	node_clear(args->node_id, mm->lrugen.nodes);
-+
-+	return false;
-+}
-+
-+/* To support multiple walkers that concurrently walk an mm_struct list. */
-+static bool get_next_mm(struct lruvec *lruvec, struct mm_walk_args *args,
-+			struct mm_struct **iter)
-+{
-+	bool first = false;
-+	bool last = true;
-+	struct mm_struct *mm = NULL;
-+	struct lru_gen_mm_walk *mm_walk = &lruvec->mm_walk;
-+	struct lru_gen_mm_list *mm_list = get_mm_list(args->memcg);
-+
-+	if (*iter)
-+		mmput_async(*iter);
-+	else if (args->max_seq <= READ_ONCE(mm_walk->seq))
-+		return false;
-+
-+	spin_lock(&mm_list->lock);
-+
-+	VM_BUG_ON(args->max_seq > mm_walk->seq + 1);
-+	VM_BUG_ON(*iter && args->max_seq < mm_walk->seq);
-+	VM_BUG_ON(*iter && !mm_walk->nr_walkers);
-+
-+	if (args->max_seq <= mm_walk->seq) {
-+		if (!*iter)
-+			last = false;
-+		goto done;
-+	}
-+
-+	if (mm_walk->head == &mm_list->fifo) {
-+		VM_BUG_ON(mm_walk->nr_walkers);
-+		mm_walk->head = mm_walk->head->next;
-+		first = true;
-+	}
-+
-+	while (!mm && mm_walk->head != &mm_list->fifo) {
-+		mm = list_entry(mm_walk->head, struct mm_struct, lrugen.list);
-+
-+		mm_walk->head = mm_walk->head->next;
-+
-+		if (mm_walk->tail == &mm->lrugen.list) {
-+			mm_walk->tail = mm_walk->tail->next;
-+			args->use_filter = false;
-+		}
-+
-+		if (should_skip_mm(mm, args))
-+			mm = NULL;
-+	}
-+
-+	if (mm_walk->head == &mm_list->fifo)
-+		WRITE_ONCE(mm_walk->seq, mm_walk->seq + 1);
-+done:
-+	if (*iter && !mm)
-+		mm_walk->nr_walkers--;
-+	if (!*iter && mm)
-+		mm_walk->nr_walkers++;
-+
-+	if (mm_walk->nr_walkers)
-+		last = false;
-+
-+	if (mm && first)
-+		clear_bloom_filter(lruvec, args->max_seq + 1);
-+
-+	if (*iter || last)
-+		reset_mm_stats(lruvec, last, args);
-+
-+	spin_unlock(&mm_list->lock);
-+
-+	*iter = mm;
-+
-+	return last;
-+}
-+
-+/******************************************************************************
-+ *                          refault feedback loop
-+ ******************************************************************************/
-+
-+/*
-+ * A feedback loop modeled after the PID controller. Currently supports the
-+ * proportional (P) and the integral (I) terms; the derivative (D) term can be
-+ * added if necessary. The setpoint (SP) is the desired position; the process
-+ * variable (PV) is the measured position. The error is the difference between
-+ * the SP and the PV. A positive error results in a positive control output
-+ * correction, which, in our case, is to allow eviction.
-+ *
-+ * The P term is refaulted % of the current generation being evicted. The I
-+ * term is the exponential moving average of refaulted % of previously evicted
-+ * generations, using the smoothing factor 1/2.
-+ *
-+ * Our goal is to maintain proportional refaulted % across all tiers.
-+ */
-+struct ctrl_pos {
-+	unsigned long refaulted;
-+	unsigned long total;
-+	int gain;
-+};
-+
-+static void read_ctrl_pos(struct lruvec *lruvec, int type, int tier, int gain,
-+			  struct ctrl_pos *pos)
-+{
-+	struct lrugen *lrugen = &lruvec->evictable;
-+	int hist = lru_hist_from_seq(lrugen->min_seq[type]);
-+
-+	pos->refaulted = lrugen->avg_refaulted[type][tier] +
-+			 atomic_long_read(&lrugen->refaulted[hist][type][tier]);
-+	pos->total = lrugen->avg_total[type][tier] +
-+		     atomic_long_read(&lrugen->evicted[hist][type][tier]);
-+	if (tier)
-+		pos->total += lrugen->protected[hist][type][tier - 1];
-+	pos->gain = gain;
-+}
-+
-+static void reset_ctrl_pos(struct lruvec *lruvec, int gen, int type)
-+{
-+	int tier;
-+	int hist = lru_hist_from_seq(gen);
-+	struct lrugen *lrugen = &lruvec->evictable;
-+	bool carryover = gen == lru_gen_from_seq(lrugen->min_seq[type]);
-+	bool clear = carryover ? NR_HIST_GENS == 1 : NR_HIST_GENS > 1;
-+
-+	if (!carryover && !clear)
-+		return;
-+
-+	for (tier = 0; tier < MAX_NR_TIERS; tier++) {
-+		if (carryover) {
-+			unsigned long sum;
-+
-+			sum = lrugen->avg_refaulted[type][tier] +
-+			      atomic_long_read(&lrugen->refaulted[hist][type][tier]);
-+			WRITE_ONCE(lrugen->avg_refaulted[type][tier], sum / 2);
-+
-+			sum = lrugen->avg_total[type][tier] +
-+			      atomic_long_read(&lrugen->evicted[hist][type][tier]);
-+			if (tier)
-+				sum += lrugen->protected[hist][type][tier - 1];
-+			WRITE_ONCE(lrugen->avg_total[type][tier], sum / 2);
-+		}
-+
-+		if (clear) {
-+			atomic_long_set(&lrugen->refaulted[hist][type][tier], 0);
-+			atomic_long_set(&lrugen->evicted[hist][type][tier], 0);
-+			if (tier)
-+				WRITE_ONCE(lrugen->protected[hist][type][tier - 1], 0);
-+		}
-+	}
-+}
-+
-+static bool positive_ctrl_err(struct ctrl_pos *sp, struct ctrl_pos *pv)
-+{
-+	/*
-+	 * Allow eviction if the PV has a limited number of refaulted pages or a
-+	 * lower refaulted % than the SP.
-+	 */
-+	return pv->refaulted < MIN_BATCH_SIZE ||
-+	       pv->refaulted * max(sp->total, 1UL) * sp->gain <=
-+	       sp->refaulted * max(pv->total, 1UL) * pv->gain;
-+}
-+
-+/******************************************************************************
-+ *                          the aging
-+ ******************************************************************************/
-+
-+static int page_update_gen(struct page *page, int gen)
-+{
-+	unsigned long old_flags, new_flags;
-+
-+	VM_BUG_ON(gen >= MAX_NR_GENS);
-+
-+	do {
-+		new_flags = old_flags = READ_ONCE(page->flags);
-+
-+		if (!(new_flags & LRU_GEN_MASK)) {
-+			new_flags |= BIT(PG_referenced);
-+			continue;
-+		}
-+
-+		new_flags &= ~LRU_GEN_MASK;
-+		new_flags |= (gen + 1UL) << LRU_GEN_PGOFF;
-+		new_flags &= ~(LRU_REFS_MASK | LRU_REFS_FLAGS);
-+	} while (new_flags != old_flags &&
-+		 cmpxchg(&page->flags, old_flags, new_flags) != old_flags);
-+
-+	return ((old_flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1;
-+}
-+
-+static void page_inc_gen(struct page *page, struct lruvec *lruvec, bool reclaiming)
-+{
-+	int old_gen, new_gen;
-+	unsigned long old_flags, new_flags;
-+	int type = page_is_file_lru(page);
-+	int zone = page_zonenum(page);
-+	struct lrugen *lrugen = &lruvec->evictable;
-+
-+	old_gen = lru_gen_from_seq(lrugen->min_seq[type]);
-+
-+	do {
-+		new_flags = old_flags = READ_ONCE(page->flags);
-+		VM_BUG_ON_PAGE(!(new_flags & LRU_GEN_MASK), page);
-+
-+		new_gen = ((new_flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1;
-+		/* page_update_gen() has updated this page? */
-+		if (new_gen >= 0 && new_gen != old_gen) {
-+			list_move(&page->lru, &lrugen->lists[new_gen][type][zone]);
-+			return;
-+		}
-+
-+		new_gen = (old_gen + 1) % MAX_NR_GENS;
-+
-+		new_flags &= ~LRU_GEN_MASK;
-+		new_flags |= (new_gen + 1UL) << LRU_GEN_PGOFF;
-+		new_flags &= ~(LRU_REFS_MASK | LRU_REFS_FLAGS);
-+		/* for end_page_writeback() */
-+		if (reclaiming)
-+			new_flags |= BIT(PG_reclaim);
-+	} while (cmpxchg(&page->flags, old_flags, new_flags) != old_flags);
-+
-+	lru_gen_update_size(page, lruvec, old_gen, new_gen);
-+	if (reclaiming)
-+		list_move(&page->lru, &lrugen->lists[new_gen][type][zone]);
-+	else
-+		list_move_tail(&page->lru, &lrugen->lists[new_gen][type][zone]);
-+}
-+
-+static void update_batch_size(struct page *page, int old_gen, int new_gen,
-+			      struct mm_walk_args *args)
-+{
-+	int type = page_is_file_lru(page);
-+	int zone = page_zonenum(page);
-+	int delta = thp_nr_pages(page);
-+
-+	VM_BUG_ON(old_gen >= MAX_NR_GENS);
-+	VM_BUG_ON(new_gen >= MAX_NR_GENS);
-+
-+	args->batch_size++;
-+
-+	args->nr_pages[old_gen][type][zone] -= delta;
-+	args->nr_pages[new_gen][type][zone] += delta;
-+}
-+
-+static void reset_batch_size(struct lruvec *lruvec, struct mm_walk_args *args)
-+{
-+	int gen, type, zone;
-+	struct lrugen *lrugen = &lruvec->evictable;
-+
-+	args->batch_size = 0;
-+
-+	for_each_gen_type_zone(gen, type, zone) {
-+		enum lru_list lru = type * LRU_FILE;
-+		int delta = args->nr_pages[gen][type][zone];
-+
-+		if (!delta)
-+			continue;
-+
-+		args->nr_pages[gen][type][zone] = 0;
-+		WRITE_ONCE(lrugen->sizes[gen][type][zone],
-+			   lrugen->sizes[gen][type][zone] + delta);
-+
-+		if (lru_gen_is_active(lruvec, gen))
-+			lru += LRU_ACTIVE;
-+		update_lru_size(lruvec, lru, zone, delta);
-+	}
-+}
-+
-+static int should_skip_vma(unsigned long start, unsigned long end, struct mm_walk *walk)
-+{
-+	struct address_space *mapping;
-+	struct vm_area_struct *vma = walk->vma;
-+	struct mm_walk_args *args = walk->private;
-+
-+	if (!vma_is_accessible(vma) || is_vm_hugetlb_page(vma) ||
-+	    (vma->vm_flags & (VM_LOCKED | VM_SPECIAL | VM_SEQ_READ)))
-+		return true;
-+
-+	if (vma_is_anonymous(vma))
-+		return !args->swappiness;
-+
-+	if (WARN_ON_ONCE(!vma->vm_file || !vma->vm_file->f_mapping))
-+		return true;
-+
-+	mapping = vma->vm_file->f_mapping;
-+	if (!mapping->a_ops->writepage)
-+		return true;
-+
-+	return (shmem_mapping(mapping) && !args->swappiness) || mapping_unevictable(mapping);
-+}
-+
-+/*
-+ * Some userspace memory allocators create many single-page VMAs. So instead of
-+ * returning back to the PGD table for each of such VMAs, we finish at least an
-+ * entire PMD table and therefore avoid many zigzags.
-+ */
-+static bool get_next_vma(struct mm_walk *walk, unsigned long mask, unsigned long size,
-+			 unsigned long *start, unsigned long *end)
-+{
-+	unsigned long next = round_up(*end, size);
-+
-+	VM_BUG_ON(mask & size);
-+	VM_BUG_ON(*start >= *end);
-+	VM_BUG_ON((next & mask) != (*start & mask));
-+
-+	while (walk->vma) {
-+		if (next >= walk->vma->vm_end) {
-+			walk->vma = walk->vma->vm_next;
-+			continue;
-+		}
-+
-+		if ((next & mask) != (walk->vma->vm_start & mask))
-+			return false;
-+
-+		if (should_skip_vma(walk->vma->vm_start, walk->vma->vm_end, walk)) {
-+			walk->vma = walk->vma->vm_next;
-+			continue;
-+		}
-+
-+		*start = max(next, walk->vma->vm_start);
-+		next = (next | ~mask) + 1;
-+		/* rounded-up boundaries can wrap to 0 */
-+		*end = next && next < walk->vma->vm_end ? next : walk->vma->vm_end;
-+
-+		return true;
-+	}
-+
-+	return false;
-+}
-+
-+static bool walk_pte_range(pmd_t *pmd, unsigned long start, unsigned long end,
-+			   struct mm_walk *walk)
-+{
-+	int i;
-+	pte_t *pte;
-+	spinlock_t *ptl;
-+	unsigned long addr;
-+	int worth = 0;
-+	struct mm_walk_args *args = walk->private;
-+	int old_gen, new_gen = lru_gen_from_seq(args->max_seq);
-+
-+	VM_BUG_ON(pmd_leaf(*pmd));
-+
-+	pte = pte_offset_map_lock(walk->mm, pmd, start & PMD_MASK, &ptl);
-+	arch_enter_lazy_mmu_mode();
-+restart:
-+	for (i = pte_index(start), addr = start; addr != end; i++, addr += PAGE_SIZE) {
-+		struct page *page;
-+		unsigned long pfn = pte_pfn(pte[i]);
-+
-+		args->mm_stats[MM_LEAF_TOTAL]++;
-+
-+		if (!pte_present(pte[i]) || is_zero_pfn(pfn))
-+			continue;
-+
-+		if (WARN_ON_ONCE(pte_devmap(pte[i]) || pte_special(pte[i])))
-+			continue;
-+
-+		if (!pte_young(pte[i])) {
-+			args->mm_stats[MM_LEAF_OLD]++;
-+			continue;
-+		}
-+
-+		VM_BUG_ON(!pfn_valid(pfn));
-+		if (pfn < args->start_pfn || pfn >= args->end_pfn)
-+			continue;
-+
-+		page = compound_head(pfn_to_page(pfn));
-+		if (page_to_nid(page) != args->node_id)
-+			continue;
-+
-+		if (page_memcg_rcu(page) != args->memcg)
-+			continue;
-+
-+		VM_BUG_ON(addr < walk->vma->vm_start || addr >= walk->vma->vm_end);
-+		if (!ptep_test_and_clear_young(walk->vma, addr, pte + i))
-+			continue;
-+
-+		args->mm_stats[MM_LEAF_YOUNG]++;
-+
-+		if (pte_dirty(pte[i]) && !PageDirty(page) &&
-+		    !(PageAnon(page) && PageSwapBacked(page) && !PageSwapCache(page)))
-+			set_page_dirty(page);
-+
-+		old_gen = page_update_gen(page, new_gen);
-+		if (old_gen >= 0 && old_gen != new_gen)
-+			update_batch_size(page, old_gen, new_gen, args);
-+
-+		worth++;
-+	}
-+
-+	if (i < PTRS_PER_PTE && get_next_vma(walk, PMD_MASK, PAGE_SIZE, &start, &end))
-+		goto restart;
-+
-+	arch_leave_lazy_mmu_mode();
-+	pte_unmap_unlock(pte, ptl);
-+
-+	return worth >= MIN_BATCH_SIZE / 2;
-+}
-+
-+/*
-+ * We scan PMD entries in two passes. The first pass reaches to PTE tables and
-+ * doesn't take the PMD lock. The second pass clears the accessed bit on PMD
-+ * entries and needs to take the PMD lock.
-+ */
-+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG)
-+static void walk_pmd_range_locked(pud_t *pud, unsigned long start, int offset,
-+				  struct vm_area_struct *vma, struct mm_walk *walk)
-+{
-+	int i;
-+	pmd_t *pmd;
-+	spinlock_t *ptl;
-+	struct mm_walk_args *args = walk->private;
-+	int old_gen, new_gen = lru_gen_from_seq(args->max_seq);
-+
-+	VM_BUG_ON(pud_leaf(*pud));
-+
-+	start = (start & PUD_MASK) + offset * PMD_SIZE;
-+	pmd = pmd_offset(pud, start);
-+	ptl = pmd_lock(walk->mm, pmd);
-+	arch_enter_lazy_mmu_mode();
-+
-+	for_each_set_bit(i, args->bitmap, MIN_BATCH_SIZE) {
-+		struct page *page;
-+		unsigned long pfn = pmd_pfn(pmd[i]);
-+		unsigned long addr = start + i * PMD_SIZE;
-+
-+		if (!pmd_present(pmd[i]) || is_huge_zero_pmd(pmd[i]))
-+			continue;
-+
-+		if (WARN_ON_ONCE(pmd_devmap(pmd[i])))
-+			continue;
-+
-+		if (!pmd_trans_huge(pmd[i])) {
-+			if (IS_ENABLED(CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG))
-+				pmdp_test_and_clear_young(vma, addr, pmd + i);
-+			continue;
-+		}
-+
-+		VM_BUG_ON(!pfn_valid(pfn));
-+		if (pfn < args->start_pfn || pfn >= args->end_pfn)
-+			continue;
-+
-+		page = pfn_to_page(pfn);
-+		VM_BUG_ON_PAGE(PageTail(page), page);
-+		if (page_to_nid(page) != args->node_id)
-+			continue;
-+
-+		if (page_memcg_rcu(page) != args->memcg)
-+			continue;
-+
-+		VM_BUG_ON(addr < vma->vm_start || addr >= vma->vm_end);
-+		if (!pmdp_test_and_clear_young(vma, addr, pmd + i))
-+			continue;
-+
-+		args->mm_stats[MM_LEAF_YOUNG]++;
-+
-+		if (pmd_dirty(pmd[i]) && !PageDirty(page) &&
-+		    !(PageAnon(page) && PageSwapBacked(page) && !PageSwapCache(page)))
-+			set_page_dirty(page);
-+
-+		old_gen = page_update_gen(page, new_gen);
-+		if (old_gen >= 0 && old_gen != new_gen)
-+			update_batch_size(page, old_gen, new_gen, args);
-+	}
-+
-+	arch_leave_lazy_mmu_mode();
-+	spin_unlock(ptl);
-+
-+	bitmap_zero(args->bitmap, MIN_BATCH_SIZE);
-+}
-+#else
-+static void walk_pmd_range_locked(pud_t *pud, unsigned long start, int offset,
-+				  struct vm_area_struct *vma, struct mm_walk *walk)
-+{
-+}
-+#endif
-+
-+static void walk_pmd_range(pud_t *pud, unsigned long start, unsigned long end,
-+			   struct mm_walk *walk)
-+{
-+	int i;
-+	pmd_t *pmd;
-+	unsigned long next;
-+	unsigned long addr;
-+	struct vm_area_struct *vma;
-+	int offset = -1;
-+	bool reset = false;
-+	struct mm_walk_args *args = walk->private;
-+	struct lruvec *lruvec = get_lruvec(args->node_id, args->memcg);
-+
-+	VM_BUG_ON(pud_leaf(*pud));
-+
-+	pmd = pmd_offset(pud, start & PUD_MASK);
-+restart:
-+	vma = walk->vma;
-+	for (i = pmd_index(start), addr = start; addr != end; i++, addr = next) {
-+		pmd_t val = pmd_read_atomic(pmd + i);
-+
-+		/* for pmd_read_atomic() */
-+		barrier();
-+
-+		next = pmd_addr_end(addr, end);
-+
-+		if (!pmd_present(val)) {
-+			args->mm_stats[MM_LEAF_TOTAL]++;
-+			continue;
-+		}
-+
-+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-+		if (pmd_trans_huge(val)) {
-+			unsigned long pfn = pmd_pfn(val);
-+
-+			args->mm_stats[MM_LEAF_TOTAL]++;
-+
-+			if (is_huge_zero_pmd(val))
-+				continue;
-+
-+			if (!pmd_young(val)) {
-+				args->mm_stats[MM_LEAF_OLD]++;
-+				continue;
-+			}
-+
-+			if (pfn < args->start_pfn || pfn >= args->end_pfn)
-+				continue;
-+
-+			if (offset < 0)
-+				offset = i;
-+			else if (i - offset >= MIN_BATCH_SIZE) {
-+				walk_pmd_range_locked(pud, start, offset, vma, walk);
-+				offset = i;
-+			}
-+			__set_bit(i - offset, args->bitmap);
-+			reset = true;
-+			continue;
-+		}
-+#endif
-+		args->mm_stats[MM_NONLEAF_TOTAL]++;
-+
-+#ifdef CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG
-+		if (!pmd_young(val))
-+			continue;
-+
-+		if (offset < 0)
-+			offset = i;
-+		else if (i - offset >= MIN_BATCH_SIZE) {
-+			walk_pmd_range_locked(pud, start, offset, vma, walk);
-+			offset = i;
-+			reset = false;
-+		}
-+		__set_bit(i - offset, args->bitmap);
-+#endif
-+		if (args->use_filter && !test_bloom_filter(lruvec, args->max_seq, pmd + i))
-+			continue;
-+
-+		args->mm_stats[MM_NONLEAF_PREV]++;
-+
-+		if (!walk_pte_range(&val, addr, next, walk))
-+			continue;
-+
-+		args->mm_stats[MM_NONLEAF_CUR]++;
-+
-+		set_bloom_filter(lruvec, args->max_seq + 1, pmd + i);
-+	}
-+
-+	if (reset) {
-+		walk_pmd_range_locked(pud, start, offset, vma, walk);
-+		offset = -1;
-+		reset = false;
-+	}
-+
-+	if (i < PTRS_PER_PMD && get_next_vma(walk, PUD_MASK, PMD_SIZE, &start, &end))
-+		goto restart;
-+
-+	if (offset >= 0)
-+		walk_pmd_range_locked(pud, start, offset, vma, walk);
-+}
-+
-+static int walk_pud_range(p4d_t *p4d, unsigned long start, unsigned long end,
-+			  struct mm_walk *walk)
-+{
-+	int i;
-+	pud_t *pud;
-+	unsigned long addr;
-+	unsigned long next;
-+	struct mm_walk_args *args = walk->private;
-+
-+	VM_BUG_ON(p4d_leaf(*p4d));
-+
-+	pud = pud_offset(p4d, start & P4D_MASK);
-+restart:
-+	for (i = pud_index(start), addr = start; addr != end; i++, addr = next) {
-+		pud_t val = READ_ONCE(pud[i]);
-+
-+		next = pud_addr_end(addr, end);
-+
-+		if (!pud_present(val) || WARN_ON_ONCE(pud_leaf(val)))
-+			continue;
-+
-+		walk_pmd_range(&val, addr, next, walk);
-+
-+		if (args->batch_size >= MAX_BATCH_SIZE) {
-+			end = (addr | ~PUD_MASK) + 1;
-+			goto done;
-+		}
-+	}
-+
-+	if (i < PTRS_PER_PUD && get_next_vma(walk, P4D_MASK, PUD_SIZE, &start, &end))
-+		goto restart;
-+
-+	end = round_up(end, P4D_SIZE);
-+done:
-+	/* rounded-up boundaries can wrap to 0 */
-+	args->next_addr = end && walk->vma ? max(end, walk->vma->vm_start) : 0;
-+
-+	return -EAGAIN;
-+}
-+
-+static void walk_mm(struct lruvec *lruvec, struct mm_struct *mm, struct mm_walk_args *args)
-+{
-+	static const struct mm_walk_ops mm_walk_ops = {
-+		.test_walk = should_skip_vma,
-+		.p4d_entry = walk_pud_range,
-+	};
-+
-+	int err;
-+
-+	args->next_addr = FIRST_USER_ADDRESS;
-+
-+	do {
-+		unsigned long start = args->next_addr;
-+		unsigned long end = mm->highest_vm_end;
-+
-+		err = -EBUSY;
-+
-+		rcu_read_lock();
-+#ifdef CONFIG_MEMCG
-+		if (args->memcg && atomic_read(&args->memcg->moving_account))
-+			goto contended;
-+#endif
-+		if (!mmap_read_trylock(mm))
-+			goto contended;
-+
-+		err = walk_page_range(mm, start, end, &mm_walk_ops, args);
-+
-+		mmap_read_unlock(mm);
-+
-+		if (args->batch_size) {
-+			spin_lock_irq(&lruvec->lru_lock);
-+			reset_batch_size(lruvec, args);
-+			spin_unlock_irq(&lruvec->lru_lock);
-+		}
-+contended:
-+		rcu_read_unlock();
-+
-+		cond_resched();
-+	} while (err == -EAGAIN && args->next_addr && !mm_is_oom_victim(mm));
-+}
-+
-+static struct mm_walk_args *alloc_mm_walk_args(void)
-+{
-+	if (!current->reclaim_state || !current->reclaim_state->mm_walk_args)
-+		return kvzalloc(sizeof(struct mm_walk_args), GFP_KERNEL);
-+
-+	return current->reclaim_state->mm_walk_args;
-+}
-+
-+static void free_mm_walk_args(struct mm_walk_args *args)
-+{
-+	if (!current->reclaim_state || !current->reclaim_state->mm_walk_args)
-+		kvfree(args);
-+}
-+
-+static bool inc_min_seq(struct lruvec *lruvec, int type)
-+{
-+	int gen, zone;
-+	int remaining = MAX_BATCH_SIZE;
-+	struct lrugen *lrugen = &lruvec->evictable;
-+
-+	VM_BUG_ON(!seq_is_valid(lruvec));
-+
-+	if (get_nr_gens(lruvec, type) != MAX_NR_GENS)
-+		return true;
-+
-+	gen = lru_gen_from_seq(lrugen->min_seq[type]);
-+
-+	for (zone = 0; zone < MAX_NR_ZONES; zone++) {
-+		struct list_head *head = &lrugen->lists[gen][type][zone];
-+
-+		while (!list_empty(head)) {
-+			struct page *page = lru_to_page(head);
-+
-+			VM_BUG_ON_PAGE(PageTail(page), page);
-+			VM_BUG_ON_PAGE(PageUnevictable(page), page);
-+			VM_BUG_ON_PAGE(PageActive(page), page);
-+			VM_BUG_ON_PAGE(page_is_file_lru(page) != type, page);
-+			VM_BUG_ON_PAGE(page_zonenum(page) != zone, page);
-+
-+			prefetchw_prev_lru_page(page, head, flags);
-+
-+			page_inc_gen(page, lruvec, false);
-+
-+			if (!--remaining)
-+				return false;
-+		}
-+	}
-+
-+	reset_ctrl_pos(lruvec, gen, type);
-+	WRITE_ONCE(lrugen->min_seq[type], lrugen->min_seq[type] + 1);
-+
-+	return true;
-+}
-+
-+static bool try_to_inc_min_seq(struct lruvec *lruvec, int swappiness)
-+{
-+	int gen, type, zone;
-+	bool success = false;
-+	struct lrugen *lrugen = &lruvec->evictable;
-+	DEFINE_MIN_SEQ(lruvec);
-+
-+	VM_BUG_ON(!seq_is_valid(lruvec));
-+
-+	for (type = 0; type < ANON_AND_FILE; type++) {
-+		while (lrugen->max_seq - min_seq[type] >= MIN_NR_GENS) {
-+			gen = lru_gen_from_seq(min_seq[type]);
-+
-+			for (zone = 0; zone < MAX_NR_ZONES; zone++) {
-+				if (!list_empty(&lrugen->lists[gen][type][zone]))
-+					goto next;
-+			}
-+
-+			min_seq[type]++;
-+		}
-+next:
-+		;
-+	}
-+
-+	min_seq[0] = min(min_seq[0], min_seq[1]);
-+	if (swappiness)
-+		min_seq[1] = max(min_seq[0], lrugen->min_seq[1]);
-+
-+	for (type = 0; type < ANON_AND_FILE; type++) {
-+		if (min_seq[type] == lrugen->min_seq[type])
-+			continue;
-+
-+		gen = lru_gen_from_seq(lrugen->min_seq[type]);
-+		reset_ctrl_pos(lruvec, gen, type);
-+		WRITE_ONCE(lrugen->min_seq[type], min_seq[type]);
-+		success = true;
-+	}
-+
-+	return success;
-+}
-+
-+static void inc_max_seq(struct lruvec *lruvec, unsigned long max_seq)
-+{
-+	int gen, type, zone;
-+	struct lrugen *lrugen = &lruvec->evictable;
-+
-+	spin_lock_irq(&lruvec->lru_lock);
-+
-+	VM_BUG_ON(!seq_is_valid(lruvec));
-+
-+	if (max_seq != lrugen->max_seq)
-+		goto unlock;
-+
-+	if (!try_to_inc_min_seq(lruvec, true)) {
-+		for (type = ANON_AND_FILE - 1; type >= 0; type--) {
-+			while (!inc_min_seq(lruvec, type)) {
-+				spin_unlock_irq(&lruvec->lru_lock);
-+				cond_resched();
-+				spin_lock_irq(&lruvec->lru_lock);
-+			}
-+		}
-+	}
-+
-+	gen = lru_gen_from_seq(lrugen->max_seq - 1);
-+	for (type = 0; type < ANON_AND_FILE; type++) {
-+		for (zone = 0; zone < MAX_NR_ZONES; zone++) {
-+			enum lru_list lru = type * LRU_FILE;
-+			long delta = lrugen->sizes[gen][type][zone];
-+
-+			if (!delta)
-+				continue;
-+
-+			WARN_ON_ONCE(delta != (int)delta);
-+
-+			update_lru_size(lruvec, lru, zone, delta);
-+			update_lru_size(lruvec, lru + LRU_ACTIVE, zone, -delta);
-+		}
-+	}
-+
-+	gen = lru_gen_from_seq(lrugen->max_seq + 1);
-+	for (type = 0; type < ANON_AND_FILE; type++) {
-+		for (zone = 0; zone < MAX_NR_ZONES; zone++) {
-+			enum lru_list lru = type * LRU_FILE;
-+			long delta = lrugen->sizes[gen][type][zone];
-+
-+			if (!delta)
-+				continue;
-+
-+			WARN_ON_ONCE(delta != (int)delta);
-+
-+			update_lru_size(lruvec, lru, zone, -delta);
-+			update_lru_size(lruvec, lru + LRU_ACTIVE, zone, delta);
-+		}
-+	}
-+
-+	for (type = 0; type < ANON_AND_FILE; type++)
-+		reset_ctrl_pos(lruvec, gen, type);
-+
-+	WRITE_ONCE(lrugen->timestamps[gen], jiffies);
-+	/* make sure all preceding modifications appear first */
-+	smp_store_release(&lrugen->max_seq, lrugen->max_seq + 1);
-+unlock:
-+	spin_unlock_irq(&lruvec->lru_lock);
-+}
-+
-+/* Main function used by the foreground, the background and the user-triggered aging. */
-+static bool try_to_inc_max_seq(struct lruvec *lruvec, struct scan_control *sc, int swappiness,
-+			       unsigned long max_seq, bool use_filter)
-+{
-+	bool last;
-+	struct mm_walk_args *args;
-+	struct mm_struct *mm = NULL;
-+	struct lrugen *lrugen = &lruvec->evictable;
-+	struct mem_cgroup *memcg = lruvec_memcg(lruvec);
-+	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
-+	int nid = pgdat->node_id;
-+
-+	VM_BUG_ON(max_seq > READ_ONCE(lrugen->max_seq));
-+
-+	/*
-+	 * If we are not from run_aging() and clearing the accessed bit may
-+	 * trigger page faults, then don't proceed to clearing all accessed
-+	 * PTEs. Instead, fallback to lru_gen_look_around(), which only clears a
-+	 * handful of accessed PTEs. This is less efficient but causes fewer
-+	 * page faults on CPUs that don't have the capability.
-+	 */
-+	if ((current->flags & PF_MEMALLOC) && !arch_has_hw_pte_young(false)) {
-+		inc_max_seq(lruvec, max_seq);
-+		return true;
-+	}
-+
-+	args = alloc_mm_walk_args();
-+	if (!args)
-+		return false;
-+
-+	args->memcg = memcg;
-+	args->max_seq = max_seq;
-+	args->start_pfn = pgdat->node_start_pfn;
-+	args->end_pfn = pgdat_end_pfn(pgdat);
-+	args->node_id = nid;
-+	args->swappiness = swappiness;
-+	args->use_filter = use_filter;
-+
-+	do {
-+		last = get_next_mm(lruvec, args, &mm);
-+		if (mm)
-+			walk_mm(lruvec, mm, args);
-+
-+		cond_resched();
-+	} while (mm);
-+
-+	free_mm_walk_args(args);
-+
-+	if (!last) {
-+		/* don't wait unless we may have trouble reclaiming */
-+		if (!current_is_kswapd() && sc->priority < DEF_PRIORITY - 2)
-+			wait_event_killable(lruvec->mm_walk.wait,
-+					    max_seq < READ_ONCE(lrugen->max_seq));
-+
-+		return max_seq < READ_ONCE(lrugen->max_seq);
-+	}
-+
-+	VM_BUG_ON(max_seq != READ_ONCE(lrugen->max_seq));
-+
-+	inc_max_seq(lruvec, max_seq);
-+	/* either we see any waiters or they will see updated max_seq */
-+	if (wq_has_sleeper(&lruvec->mm_walk.wait))
-+		wake_up_all(&lruvec->mm_walk.wait);
-+
-+	wakeup_flusher_threads(WB_REASON_VMSCAN);
-+
-+	return true;
-+}
-+
-+static long get_nr_evictable(struct lruvec *lruvec, struct scan_control *sc, int swappiness,
-+			     unsigned long max_seq, unsigned long *min_seq, bool *low)
-+{
-+	int gen, type, zone;
-+	long max = 0;
-+	long min = 0;
-+	struct lrugen *lrugen = &lruvec->evictable;
-+
-+	for (type = !swappiness; type < ANON_AND_FILE; type++) {
-+		unsigned long seq;
-+
-+		for (seq = min_seq[type]; seq <= max_seq; seq++) {
-+			long size = 0;
-+
-+			gen = lru_gen_from_seq(seq);
-+
-+			for (zone = 0; zone <= sc->reclaim_idx; zone++)
-+				size += READ_ONCE(lrugen->sizes[gen][type][zone]);
-+
-+			max += size;
-+			if (type && max_seq - seq >= MIN_NR_GENS)
-+				min += size;
-+		}
-+	}
-+
-+	*low = max_seq - min_seq[1] <= MIN_NR_GENS && min < MIN_BATCH_SIZE;
-+
-+	return max > 0 ? max : 0;
-+}
-+
-+static bool age_lruvec(struct lruvec *lruvec, struct scan_control *sc,
-+		       unsigned long min_ttl)
-+{
-+	bool low;
-+	long nr_to_scan;
-+	struct mem_cgroup *memcg = lruvec_memcg(lruvec);
-+	int swappiness = get_swappiness(memcg);
-+	DEFINE_MAX_SEQ(lruvec);
-+	DEFINE_MIN_SEQ(lruvec);
-+
-+	if (mem_cgroup_below_min(memcg))
-+		return false;
-+
-+	if (min_ttl) {
-+		int gen = lru_gen_from_seq(min_seq[1]);
-+		unsigned long birth = READ_ONCE(lruvec->evictable.timestamps[gen]);
-+
-+		if (time_is_after_jiffies(birth + min_ttl))
-+			return false;
-+	}
-+
-+	nr_to_scan = get_nr_evictable(lruvec, sc, swappiness, max_seq, min_seq, &low);
-+	if (!nr_to_scan)
-+		return false;
-+
-+	nr_to_scan >>= sc->priority;
-+
-+	if (!mem_cgroup_online(memcg))
-+		nr_to_scan++;
-+
-+	if (nr_to_scan && low && (!mem_cgroup_below_low(memcg) || sc->memcg_low_reclaim))
-+		try_to_inc_max_seq(lruvec, sc, swappiness, max_seq, true);
-+
-+	return true;
-+}
-+
-+/* Protect the working set accessed within the last N milliseconds. */
-+static unsigned long lru_gen_min_ttl __read_mostly;
-+
-+static void lru_gen_age_node(struct pglist_data *pgdat, struct scan_control *sc)
-+{
-+	struct mem_cgroup *memcg;
-+	bool success = false;
-+	unsigned long min_ttl = READ_ONCE(lru_gen_min_ttl);
-+
-+	VM_BUG_ON(!current_is_kswapd());
-+
-+	if (!sc->force_deactivate) {
-+		sc->force_deactivate = 1;
-+		return;
-+	}
-+
-+	current->reclaim_state->mm_walk_args = &pgdat->mm_walk_args;
-+
-+	memcg = mem_cgroup_iter(NULL, NULL, NULL);
-+	do {
-+		struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
-+
-+		if (age_lruvec(lruvec, sc, min_ttl))
-+			success = true;
-+
-+		cond_resched();
-+	} while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)));
-+
-+	if (!success && mutex_trylock(&oom_lock)) {
-+		struct oom_control oc = {
-+			.gfp_mask = sc->gfp_mask,
-+			.order = sc->order,
-+		};
-+
-+		/* to avoid overkilling */
-+		if (!oom_reaping_in_progress())
-+			out_of_memory(&oc);
-+
-+		mutex_unlock(&oom_lock);
-+	}
-+
-+	current->reclaim_state->mm_walk_args = NULL;
-+}
-+
-+/* Scan the vicinity of an accessed PTE when shrink_page_list() uses the rmap. */
-+void lru_gen_look_around(struct page_vma_mapped_walk *pvmw)
-+{
-+	int i;
-+	pte_t *pte;
-+	struct page *page;
-+	int old_gen, new_gen;
-+	unsigned long start;
-+	unsigned long end;
-+	unsigned long addr;
-+	struct mm_walk_args *args;
-+	int worth = 0;
-+	struct mem_cgroup *memcg = page_memcg(pvmw->page);
-+	struct pglist_data *pgdat = page_pgdat(pvmw->page);
-+	struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
-+	DEFINE_MAX_SEQ(lruvec);
-+
-+	lockdep_assert_held(pvmw->ptl);
-+	VM_BUG_ON_PAGE(PageLRU(pvmw->page), pvmw->page);
-+
-+	args = current->reclaim_state ? current->reclaim_state->mm_walk_args : NULL;
-+	if (!args)
-+		return;
-+
-+	start = max(pvmw->address & PMD_MASK, pvmw->vma->vm_start);
-+	end = pmd_addr_end(pvmw->address, pvmw->vma->vm_end);
-+
-+	if (end - start > MIN_BATCH_SIZE * PAGE_SIZE) {
-+		if (pvmw->address - start < MIN_BATCH_SIZE * PAGE_SIZE / 2)
-+			end = start + MIN_BATCH_SIZE * PAGE_SIZE;
-+		else if (end - pvmw->address < MIN_BATCH_SIZE * PAGE_SIZE / 2)
-+			start = end - MIN_BATCH_SIZE * PAGE_SIZE;
-+		else {
-+			start = pvmw->address - MIN_BATCH_SIZE * PAGE_SIZE / 2;
-+			end = pvmw->address + MIN_BATCH_SIZE * PAGE_SIZE / 2;
-+		}
-+	}
-+
-+	pte = pvmw->pte - (pvmw->address - start) / PAGE_SIZE;
-+	new_gen = lru_gen_from_seq(max_seq);
-+
-+	lock_page_memcg(pvmw->page);
-+	arch_enter_lazy_mmu_mode();
-+
-+	for (i = 0, addr = start; addr != end; i++, addr += PAGE_SIZE) {
-+		unsigned long pfn = pte_pfn(pte[i]);
-+
-+		if (!pte_present(pte[i]) || is_zero_pfn(pfn))
-+			continue;
-+
-+		if (WARN_ON_ONCE(pte_devmap(pte[i]) || pte_special(pte[i])))
-+			continue;
-+
-+		VM_BUG_ON(!pfn_valid(pfn));
-+		if (pfn < pgdat->node_start_pfn || pfn >= pgdat_end_pfn(pgdat))
-+			continue;
-+
-+		worth++;
-+
-+		if (!pte_young(pte[i]))
-+			continue;
-+
-+		page = compound_head(pfn_to_page(pfn));
-+		if (page_to_nid(page) != pgdat->node_id)
-+			continue;
-+
-+		if (page_memcg_rcu(page) != memcg)
-+			continue;
-+
-+		VM_BUG_ON(addr < pvmw->vma->vm_start || addr >= pvmw->vma->vm_end);
-+		if (!ptep_test_and_clear_young(pvmw->vma, addr, pte + i))
-+			continue;
-+
-+		if (pte_dirty(pte[i]) && !PageDirty(page) &&
-+		    !(PageAnon(page) && PageSwapBacked(page) && !PageSwapCache(page)))
-+			__set_bit(i, args->bitmap);
-+
-+		old_gen = page_update_gen(page, new_gen);
-+		if (old_gen >= 0 && old_gen != new_gen)
-+			update_batch_size(page, old_gen, new_gen, args);
-+	}
-+
-+	arch_leave_lazy_mmu_mode();
-+	unlock_page_memcg(pvmw->page);
-+
-+	if (worth >= MIN_BATCH_SIZE / 2)
-+		set_bloom_filter(lruvec, max_seq, pvmw->pmd);
-+
-+	for_each_set_bit(i, args->bitmap, MIN_BATCH_SIZE)
-+		set_page_dirty(pte_page(pte[i]));
-+
-+	bitmap_zero(args->bitmap, MIN_BATCH_SIZE);
-+}
-+
-+/******************************************************************************
-+ *                          the eviction
-+ ******************************************************************************/
-+
-+static bool sort_page(struct page *page, struct lruvec *lruvec, int tier_idx)
-+{
-+	bool success;
-+	int gen = page_lru_gen(page);
-+	int type = page_is_file_lru(page);
-+	int zone = page_zonenum(page);
-+	int tier = page_lru_tier(page);
-+	int delta = thp_nr_pages(page);
-+	struct lrugen *lrugen = &lruvec->evictable;
-+
-+	VM_BUG_ON_PAGE(gen >= MAX_NR_GENS, page);
-+
-+	/* an mlocked page? */
-+	if (!page_evictable(page)) {
-+		success = lru_gen_del_page(page, lruvec, true);
-+		VM_BUG_ON_PAGE(!success, page);
-+		SetPageUnevictable(page);
-+		add_page_to_lru_list(page, lruvec);
-+		__count_vm_events(UNEVICTABLE_PGCULLED, delta);
-+		return true;
-+	}
-+
-+	/* a lazy-free page that has been written into? */
-+	if (type && PageDirty(page) && PageAnon(page)) {
-+		success = lru_gen_del_page(page, lruvec, true);
-+		VM_BUG_ON_PAGE(!success, page);
-+		SetPageSwapBacked(page);
-+		add_page_to_lru_list_tail(page, lruvec);
-+		return true;
-+	}
-+
-+	/* page_update_gen() has updated this page? */
-+	if (gen != lru_gen_from_seq(lrugen->min_seq[type])) {
-+		list_move(&page->lru, &lrugen->lists[gen][type][zone]);
-+		return true;
-+	}
-+
-+	/* protect this page if its tier has a higher refaulted % */
-+	if (tier > tier_idx) {
-+		int hist = lru_hist_from_seq(gen);
-+
-+		page_inc_gen(page, lruvec, false);
-+		WRITE_ONCE(lrugen->protected[hist][type][tier - 1],
-+			   lrugen->protected[hist][type][tier - 1] + delta);
-+		__mod_lruvec_state(lruvec, WORKINGSET_ACTIVATE_BASE + type, delta);
-+		return true;
-+	}
-+
-+	/* mark this page for reclaim if it's pending writeback */
-+	if (PageWriteback(page) || (type && PageDirty(page))) {
-+		page_inc_gen(page, lruvec, true);
-+		return true;
-+	}
-+
-+	return false;
-+}
-+
-+static bool isolate_page(struct page *page, struct lruvec *lruvec, struct scan_control *sc)
-+{
-+	bool success;
-+
-+	if (!sc->may_unmap && page_mapped(page))
-+		return false;
-+
-+	if (!(sc->may_writepage && (sc->gfp_mask & __GFP_IO)) &&
-+	    (PageDirty(page) || (PageAnon(page) && !PageSwapCache(page))))
-+		return false;
-+
-+	if (!get_page_unless_zero(page))
-+		return false;
-+
-+	if (!TestClearPageLRU(page)) {
-+		put_page(page);
-+		return false;
-+	}
-+
-+	success = lru_gen_del_page(page, lruvec, true);
-+	VM_BUG_ON_PAGE(!success, page);
-+
-+	return true;
-+}
-+
-+static int scan_pages(struct lruvec *lruvec, struct scan_control *sc,
-+		      int type, int tier, struct list_head *list)
-+{
-+	int gen, zone;
-+	enum vm_event_item item;
-+	int sorted = 0;
-+	int scanned = 0;
-+	int isolated = 0;
-+	int remaining = MAX_BATCH_SIZE;
-+	struct lrugen *lrugen = &lruvec->evictable;
-+	struct mem_cgroup *memcg = lruvec_memcg(lruvec);
-+
-+	VM_BUG_ON(!list_empty(list));
-+
-+	if (get_nr_gens(lruvec, type) == MIN_NR_GENS)
-+		return 0;
-+
-+	gen = lru_gen_from_seq(lrugen->min_seq[type]);
-+
-+	for (zone = sc->reclaim_idx; zone >= 0; zone--) {
-+		LIST_HEAD(moved);
-+		int skipped = 0;
-+		struct list_head *head = &lrugen->lists[gen][type][zone];
-+
-+		while (!list_empty(head)) {
-+			struct page *page = lru_to_page(head);
-+			int delta = thp_nr_pages(page);
-+
-+			VM_BUG_ON_PAGE(PageTail(page), page);
-+			VM_BUG_ON_PAGE(PageUnevictable(page), page);
-+			VM_BUG_ON_PAGE(PageActive(page), page);
-+			VM_BUG_ON_PAGE(page_is_file_lru(page) != type, page);
-+			VM_BUG_ON_PAGE(page_zonenum(page) != zone, page);
-+
-+			prefetchw_prev_lru_page(page, head, flags);
-+
-+			scanned += delta;
-+
-+			if (sort_page(page, lruvec, tier))
-+				sorted += delta;
-+			else if (isolate_page(page, lruvec, sc)) {
-+				list_add(&page->lru, list);
-+				isolated += delta;
-+			} else {
-+				list_move(&page->lru, &moved);
-+				skipped += delta;
-+			}
-+
-+			if (!--remaining || max(isolated, skipped) >= MIN_BATCH_SIZE)
-+				break;
-+		}
-+
-+		if (skipped) {
-+			list_splice(&moved, head);
-+			__count_zid_vm_events(PGSCAN_SKIP, zone, skipped);
-+		}
-+
-+		if (!remaining || isolated >= MIN_BATCH_SIZE)
-+			break;
-+	}
-+
-+	item = current_is_kswapd() ? PGSCAN_KSWAPD : PGSCAN_DIRECT;
-+	if (!cgroup_reclaim(sc)) {
-+		__count_vm_events(item, isolated);
-+		__count_vm_events(PGREFILL, sorted);
-+	}
-+	__count_memcg_events(memcg, item, isolated);
-+	__count_memcg_events(memcg, PGREFILL, sorted);
-+	__count_vm_events(PGSCAN_ANON + type, isolated);
-+
-+	/*
-+	 * We may have trouble finding eligible pages due to reclaim_idx,
-+	 * may_unmap and may_writepage. Check `remaining` to make sure we won't
-+	 * be stuck if we aren't making enough progress.
-+	 */
-+	return isolated || !remaining ? scanned : 0;
-+}
-+
-+static int get_tier_idx(struct lruvec *lruvec, int type)
-+{
-+	int tier;
-+	struct ctrl_pos sp, pv;
-+
-+	/*
-+	 * Ideally we don't want to evict upper tiers that have higher refaulted
-+	 * %. However, we need to leave a margin for the fluctuation in
-+	 * refaulted %. So we use a larger gain factor to make sure upper tiers
-+	 * are indeed more active. We choose 2 because the lowest upper tier
-+	 * would have twice of refaulted % of the base tier, according to their
-+	 * numbers of accesses.
-+	 */
-+	read_ctrl_pos(lruvec, type, 0, 1, &sp);
-+	for (tier = 1; tier < MAX_NR_TIERS; tier++) {
-+		read_ctrl_pos(lruvec, type, tier, 2, &pv);
-+		if (!positive_ctrl_err(&sp, &pv))
-+			break;
-+	}
-+
-+	return tier - 1;
-+}
-+
-+static int get_type_to_scan(struct lruvec *lruvec, int swappiness, int *tier_idx)
-+{
-+	int type, tier;
-+	struct ctrl_pos sp, pv;
-+	int gain[ANON_AND_FILE] = { swappiness, 200 - swappiness };
-+
-+	/*
-+	 * Compare refaulted % between the base tiers of anon and file to
-+	 * determine which type to evict. Also need to compare refaulted % of
-+	 * the upper tiers of the selected type with that of the base tier of
-+	 * the other type to determine which tier of the selected type to evict.
-+	 */
-+	read_ctrl_pos(lruvec, 0, 0, gain[0], &sp);
-+	read_ctrl_pos(lruvec, 1, 0, gain[1], &pv);
-+	type = positive_ctrl_err(&sp, &pv);
-+
-+	read_ctrl_pos(lruvec, !type, 0, gain[!type], &sp);
-+	for (tier = 1; tier < MAX_NR_TIERS; tier++) {
-+		read_ctrl_pos(lruvec, type, tier, gain[type], &pv);
-+		if (!positive_ctrl_err(&sp, &pv))
-+			break;
-+	}
-+
-+	*tier_idx = tier - 1;
-+
-+	return type;
-+}
-+
-+static int isolate_pages(struct lruvec *lruvec, struct scan_control *sc, int swappiness,
-+			 int *type_scanned, struct list_head *list)
-+{
-+	int i;
-+	int type;
-+	int scanned;
-+	int tier = -1;
-+	DEFINE_MIN_SEQ(lruvec);
-+
-+	VM_BUG_ON(!seq_is_valid(lruvec));
-+
-+	/*
-+	 * Try to select a type based on generations and swappiness, and if that
-+	 * fails, fall back to get_type_to_scan(). When anon and file are both
-+	 * available from the same generation, swappiness 200 is interpreted as
-+	 * anon first and swappiness 1 is interpreted as file first.
-+	 */
-+	if (!swappiness)
-+		type = 1;
-+	else if (min_seq[0] < min_seq[1])
-+		type = 0;
-+	else if (swappiness == 1)
-+		type = 1;
-+	else if (swappiness == 200)
-+		type = 0;
-+	else
-+		type = get_type_to_scan(lruvec, swappiness, &tier);
-+
-+	for (i = !swappiness; i < ANON_AND_FILE; i++) {
-+		if (tier < 0)
-+			tier = get_tier_idx(lruvec, type);
-+
-+		scanned = scan_pages(lruvec, sc, type, tier, list);
-+		if (scanned)
-+			break;
-+
-+		type = !type;
-+		tier = -1;
-+	}
-+
-+	*type_scanned = type;
-+
-+	return scanned;
-+}
-+
-+/* Main function used by the foreground, the background and the user-triggered eviction. */
-+static int evict_pages(struct lruvec *lruvec, struct scan_control *sc, int swappiness)
-+{
-+	int type;
-+	int scanned;
-+	int reclaimed;
-+	LIST_HEAD(list);
-+	struct page *page;
-+	enum vm_event_item item;
-+	struct reclaim_stat stat;
-+	struct mm_walk_args *args;
-+	struct mem_cgroup *memcg = lruvec_memcg(lruvec);
-+	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
-+
-+	spin_lock_irq(&lruvec->lru_lock);
-+
-+	scanned = isolate_pages(lruvec, sc, swappiness, &type, &list);
-+
-+	if (try_to_inc_min_seq(lruvec, swappiness))
-+		scanned++;
-+
-+	if (get_nr_gens(lruvec, 1) == MIN_NR_GENS)
-+		scanned = 0;
-+
-+	spin_unlock_irq(&lruvec->lru_lock);
-+
-+	if (list_empty(&list))
-+		return scanned;
-+
-+	reclaimed = shrink_page_list(&list, pgdat, sc, &stat, false);
-+	/*
-+	 * We need to prevent rejected pages from being added back to the same
-+	 * lists they were isolated from. Otherwise we may risk looping on them
-+	 * forever.
-+	 */
-+	list_for_each_entry(page, &list, lru) {
-+		if (!PageReclaim(page) || !(PageDirty(page) || PageWriteback(page)))
-+			SetPageActive(page);
-+
-+		ClearPageReferenced(page);
-+		ClearPageWorkingset(page);
-+	}
-+
-+	spin_lock_irq(&lruvec->lru_lock);
-+
-+	move_pages_to_lru(lruvec, &list);
-+
-+	args = current->reclaim_state ? current->reclaim_state->mm_walk_args : NULL;
-+	if (args && args->batch_size)
-+		reset_batch_size(lruvec, args);
-+
-+	item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT;
-+	if (!cgroup_reclaim(sc))
-+		__count_vm_events(item, reclaimed);
-+	__count_memcg_events(memcg, item, reclaimed);
-+	__count_vm_events(PGSTEAL_ANON + type, reclaimed);
-+
-+	spin_unlock_irq(&lruvec->lru_lock);
-+
-+	mem_cgroup_uncharge_list(&list);
-+	free_unref_page_list(&list);
-+
-+	sc->nr_reclaimed += reclaimed;
-+
-+	return scanned;
-+}
-+
-+static long get_nr_to_scan(struct lruvec *lruvec, struct scan_control *sc, int swappiness)
-+{
-+	bool low;
-+	long nr_to_scan;
-+	struct mem_cgroup *memcg = lruvec_memcg(lruvec);
-+	int priority = sc->priority;
-+	DEFINE_MAX_SEQ(lruvec);
-+	DEFINE_MIN_SEQ(lruvec);
-+
-+	if (mem_cgroup_below_min(memcg) ||
-+	    (mem_cgroup_below_low(memcg) && !sc->memcg_low_reclaim))
-+		return 0;
-+
-+	if (sc->nr_reclaimed >= sc->nr_to_reclaim) {
-+		priority = DEF_PRIORITY;
-+		sc->force_deactivate = 0;
-+	}
-+
-+	nr_to_scan = get_nr_evictable(lruvec, sc, swappiness, max_seq, min_seq, &low);
-+	if (!nr_to_scan)
-+		return 0;
-+
-+	nr_to_scan >>= priority;
-+
-+	if (!mem_cgroup_online(memcg))
-+		nr_to_scan++;
-+
-+	if (!nr_to_scan)
-+		return 0;
-+
-+	if (current_is_kswapd()) {
-+		/* leave the work to lru_gen_age_node() */
-+		if (max_seq - min_seq[1] < MIN_NR_GENS)
-+			return 0;
-+
-+		if (!low)
-+			sc->force_deactivate = 0;
-+
-+		return nr_to_scan;
-+	}
-+
-+	if (max_seq - min_seq[1] >= MIN_NR_GENS)
-+		return nr_to_scan;
-+
-+	/* move onto slab and other memcgs if we haven't tried them all */
-+	if (!sc->force_deactivate) {
-+		sc->skipped_deactivate = 1;
-+		return 0;
-+	}
-+
-+	return try_to_inc_max_seq(lruvec, sc, swappiness, max_seq, true) ? nr_to_scan : 0;
-+}
-+
-+static void lru_gen_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc)
-+{
-+	struct blk_plug plug;
-+	long scanned = 0;
-+	struct mem_cgroup *memcg = lruvec_memcg(lruvec);
-+	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
-+
-+	lru_add_drain();
-+
-+	if (current_is_kswapd())
-+		current->reclaim_state->mm_walk_args = &pgdat->mm_walk_args;
-+
-+	blk_start_plug(&plug);
-+
-+	while (true) {
-+		int delta;
-+		int swappiness;
-+		long nr_to_scan;
-+
-+		if (sc->may_swap)
-+			swappiness = get_swappiness(memcg);
-+		else if (!cgroup_reclaim(sc) && get_swappiness(memcg))
-+			swappiness = 1;
-+		else
-+			swappiness = 0;
-+
-+		nr_to_scan = get_nr_to_scan(lruvec, sc, swappiness);
-+		if (!nr_to_scan)
-+			break;
-+
-+		delta = evict_pages(lruvec, sc, swappiness);
-+		if (!delta)
-+			break;
-+
-+		scanned += delta;
-+		if (scanned >= nr_to_scan)
-+			break;
-+
-+		cond_resched();
-+	}
-+
-+	blk_finish_plug(&plug);
-+
-+	if (current_is_kswapd())
-+		current->reclaim_state->mm_walk_args = NULL;
-+}
-+
-+/******************************************************************************
-+ *                          state change
-+ ******************************************************************************/
-+
-+#ifdef CONFIG_LRU_GEN_ENABLED
-+DEFINE_STATIC_KEY_TRUE(lru_gen_static_key);
-+#else
-+DEFINE_STATIC_KEY_FALSE(lru_gen_static_key);
-+#endif
-+
-+static int lru_gen_nr_swapfiles;
-+
-+static bool __maybe_unused state_is_valid(struct lruvec *lruvec)
-+{
-+	int gen, type, zone;
-+	enum lru_list lru;
-+	struct lrugen *lrugen = &lruvec->evictable;
-+
-+	for_each_evictable_lru(lru) {
-+		type = is_file_lru(lru);
-+
-+		if (lrugen->enabled[type] && !list_empty(&lruvec->lists[lru]))
-+			return false;
-+	}
-+
-+	for_each_gen_type_zone(gen, type, zone) {
-+		if (!lrugen->enabled[type] && !list_empty(&lrugen->lists[gen][type][zone]))
-+			return false;
-+
-+		/* unlikely but not a bug when reset_batch_size() is pending */
-+		VM_WARN_ON(!lrugen->enabled[type] && lrugen->sizes[gen][type][zone]);
-+	}
-+
-+	return true;
-+}
-+
-+static bool fill_lists(struct lruvec *lruvec)
-+{
-+	enum lru_list lru;
-+	int remaining = MAX_BATCH_SIZE;
-+
-+	for_each_evictable_lru(lru) {
-+		int type = is_file_lru(lru);
-+		bool active = is_active_lru(lru);
-+		struct list_head *head = &lruvec->lists[lru];
-+
-+		if (!lruvec->evictable.enabled[type])
-+			continue;
-+
-+		while (!list_empty(head)) {
-+			bool success;
-+			struct page *page = lru_to_page(head);
-+
-+			VM_BUG_ON_PAGE(PageTail(page), page);
-+			VM_BUG_ON_PAGE(PageUnevictable(page), page);
-+			VM_BUG_ON_PAGE(PageActive(page) != active, page);
-+			VM_BUG_ON_PAGE(page_is_file_lru(page) != type, page);
-+			VM_BUG_ON_PAGE(page_lru_gen(page) < MAX_NR_GENS, page);
-+
-+			prefetchw_prev_lru_page(page, head, flags);
-+
-+			del_page_from_lru_list(page, lruvec);
-+			success = lru_gen_add_page(page, lruvec, false);
-+			VM_BUG_ON(!success);
-+
-+			if (!--remaining)
-+				return false;
-+		}
-+	}
-+
-+	return true;
-+}
-+
-+static bool drain_lists(struct lruvec *lruvec)
-+{
-+	int gen, type, zone;
-+	int remaining = MAX_BATCH_SIZE;
-+
-+	for_each_gen_type_zone(gen, type, zone) {
-+		struct list_head *head = &lruvec->evictable.lists[gen][type][zone];
-+
-+		if (lruvec->evictable.enabled[type])
-+			continue;
-+
-+		while (!list_empty(head)) {
-+			bool success;
-+			struct page *page = lru_to_page(head);
-+
-+			VM_BUG_ON_PAGE(PageTail(page), page);
-+			VM_BUG_ON_PAGE(PageUnevictable(page), page);
-+			VM_BUG_ON_PAGE(PageActive(page), page);
-+			VM_BUG_ON_PAGE(page_is_file_lru(page) != type, page);
-+			VM_BUG_ON_PAGE(page_zonenum(page) != zone, page);
-+
-+			prefetchw_prev_lru_page(page, head, flags);
-+
-+			success = lru_gen_del_page(page, lruvec, false);
-+			VM_BUG_ON(!success);
-+			add_page_to_lru_list(page, lruvec);
-+
-+			if (!--remaining)
-+				return false;
-+		}
-+	}
-+
-+	return true;
-+}
-+
-+/*
-+ * For file page tracking, we enable/disable it according to the main switch.
-+ * For anon page tracking, we only enabled it when the main switch is on and
-+ * there is at least one swapfile; we disable it when there are no swapfiles
-+ * regardless of the value of the main switch. Otherwise, we will eventually
-+ * reach the max size of the sliding window and have to call inc_min_seq().
-+ */
-+void lru_gen_change_state(bool enable, bool main, bool swap)
-+{
-+	static DEFINE_MUTEX(state_mutex);
-+
-+	struct mem_cgroup *memcg;
-+
-+	mem_hotplug_begin();
-+	cgroup_lock();
-+	mutex_lock(&state_mutex);
-+
-+	if (swap) {
-+		if (enable)
-+			swap = !lru_gen_nr_swapfiles++;
-+		else
-+			swap = !--lru_gen_nr_swapfiles;
-+	}
-+
-+	if (main && enable != lru_gen_enabled()) {
-+		if (enable)
-+			static_branch_enable(&lru_gen_static_key);
-+		else
-+			static_branch_disable(&lru_gen_static_key);
-+	} else if (!swap || !lru_gen_enabled())
-+		goto unlock;
-+
-+	memcg = mem_cgroup_iter(NULL, NULL, NULL);
-+	do {
-+		int nid;
-+
-+		for_each_node(nid) {
-+			struct lruvec *lruvec = get_lruvec(nid, memcg);
-+
-+			if (!lruvec)
-+				continue;
-+
-+			spin_lock_irq(&lruvec->lru_lock);
-+
-+			VM_BUG_ON(!seq_is_valid(lruvec));
-+			VM_BUG_ON(!state_is_valid(lruvec));
-+
-+			lruvec->evictable.enabled[0] = lru_gen_enabled() && lru_gen_nr_swapfiles;
-+			lruvec->evictable.enabled[1] = lru_gen_enabled();
-+
-+			while (!(enable ? fill_lists(lruvec) : drain_lists(lruvec))) {
-+				spin_unlock_irq(&lruvec->lru_lock);
-+				cond_resched();
-+				spin_lock_irq(&lruvec->lru_lock);
-+			}
-+
-+			spin_unlock_irq(&lruvec->lru_lock);
-+		}
-+
-+		cond_resched();
-+	} while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)));
-+unlock:
-+	mutex_unlock(&state_mutex);
-+	cgroup_unlock();
-+	mem_hotplug_done();
-+}
-+
-+/******************************************************************************
-+ *                          sysfs interface
-+ ******************************************************************************/
-+
-+static ssize_t show_min_ttl(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
-+{
-+	return sprintf(buf, "%u\n", jiffies_to_msecs(READ_ONCE(lru_gen_min_ttl)));
-+}
-+
-+static ssize_t store_min_ttl(struct kobject *kobj, struct kobj_attribute *attr,
-+			     const char *buf, size_t len)
-+{
-+	unsigned int msecs;
-+
-+	if (kstrtouint(buf, 10, &msecs))
-+		return -EINVAL;
-+
-+	WRITE_ONCE(lru_gen_min_ttl, msecs_to_jiffies(msecs));
-+
-+	return len;
-+}
-+
-+static struct kobj_attribute lru_gen_min_ttl_attr = __ATTR(
-+	min_ttl_ms, 0644, show_min_ttl, store_min_ttl
-+);
-+
-+static ssize_t show_enable(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
-+{
-+	return snprintf(buf, PAGE_SIZE, "%d\n", lru_gen_enabled());
-+}
-+
-+static ssize_t store_enable(struct kobject *kobj, struct kobj_attribute *attr,
-+			    const char *buf, size_t len)
-+{
-+	bool enable;
-+
-+	if (kstrtobool(buf, &enable))
-+		return -EINVAL;
-+
-+	lru_gen_change_state(enable, true, false);
-+
-+	return len;
-+}
-+
-+static struct kobj_attribute lru_gen_enabled_attr = __ATTR(
-+	enabled, 0644, show_enable, store_enable
-+);
-+
-+static struct attribute *lru_gen_attrs[] = {
-+	&lru_gen_min_ttl_attr.attr,
-+	&lru_gen_enabled_attr.attr,
-+	NULL
-+};
-+
-+static struct attribute_group lru_gen_attr_group = {
-+	.name = "lru_gen",
-+	.attrs = lru_gen_attrs,
-+};
-+
-+/******************************************************************************
-+ *                          debugfs interface
-+ ******************************************************************************/
-+
-+static void *lru_gen_seq_start(struct seq_file *m, loff_t *pos)
-+{
-+	struct mem_cgroup *memcg;
-+	loff_t nr_to_skip = *pos;
-+
-+	m->private = kvmalloc(PATH_MAX, GFP_KERNEL);
-+	if (!m->private)
-+		return ERR_PTR(-ENOMEM);
-+
-+	memcg = mem_cgroup_iter(NULL, NULL, NULL);
-+	do {
-+		int nid;
-+
-+		for_each_node_state(nid, N_MEMORY) {
-+			if (!nr_to_skip--)
-+				return get_lruvec(nid, memcg);
-+		}
-+	} while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)));
-+
-+	return NULL;
-+}
-+
-+static void lru_gen_seq_stop(struct seq_file *m, void *v)
-+{
-+	if (!IS_ERR_OR_NULL(v))
-+		mem_cgroup_iter_break(NULL, lruvec_memcg(v));
-+
-+	kvfree(m->private);
-+	m->private = NULL;
-+}
-+
-+static void *lru_gen_seq_next(struct seq_file *m, void *v, loff_t *pos)
-+{
-+	int nid = lruvec_pgdat(v)->node_id;
-+	struct mem_cgroup *memcg = lruvec_memcg(v);
-+
-+	++*pos;
-+
-+	nid = next_memory_node(nid);
-+	if (nid == MAX_NUMNODES) {
-+		memcg = mem_cgroup_iter(NULL, memcg, NULL);
-+		if (!memcg)
-+			return NULL;
-+
-+		nid = first_memory_node;
-+	}
-+
-+	return get_lruvec(nid, memcg);
-+}
-+
-+static void lru_gen_seq_show_full(struct seq_file *m, struct lruvec *lruvec,
-+				  unsigned long max_seq, unsigned long *min_seq,
-+				  unsigned long seq)
-+{
-+	int i;
-+	int type, tier;
-+	int hist = lru_hist_from_seq(seq);
-+	struct lrugen *lrugen = &lruvec->evictable;
-+
-+	for (tier = 0; tier < MAX_NR_TIERS; tier++) {
-+		seq_printf(m, "            %10d", tier);
-+		for (type = 0; type < ANON_AND_FILE; type++) {
-+			unsigned long n[3] = {};
-+
-+			if (seq == max_seq) {
-+				n[0] = READ_ONCE(lrugen->avg_refaulted[type][tier]);
-+				n[1] = READ_ONCE(lrugen->avg_total[type][tier]);
-+
-+				seq_printf(m, " %10luR %10luT %10lu ", n[0], n[1], n[2]);
-+			} else if (seq == min_seq[type] || NR_HIST_GENS > 1) {
-+				n[0] = atomic_long_read(&lrugen->refaulted[hist][type][tier]);
-+				n[1] = atomic_long_read(&lrugen->evicted[hist][type][tier]);
-+				if (tier)
-+					n[2] = READ_ONCE(lrugen->protected[hist][type][tier - 1]);
-+
-+				seq_printf(m, " %10lur %10lue %10lup", n[0], n[1], n[2]);
-+			} else
-+				seq_puts(m, "          0           0           0 ");
-+		}
-+		seq_putc(m, '\n');
-+	}
-+
-+	seq_puts(m, "                      ");
-+	for (i = 0; i < NR_MM_STATS; i++) {
-+		if (seq == max_seq && NR_HIST_GENS == 1)
-+			seq_printf(m, " %10lu%c", READ_ONCE(lruvec->mm_walk.stats[hist][i]),
-+				   toupper(MM_STAT_CODES[i]));
-+		else if (seq != max_seq && NR_HIST_GENS > 1)
-+			seq_printf(m, " %10lu%c", READ_ONCE(lruvec->mm_walk.stats[hist][i]),
-+				   MM_STAT_CODES[i]);
-+		else
-+			seq_puts(m, "          0 ");
-+	}
-+	seq_putc(m, '\n');
-+}
-+
-+static int lru_gen_seq_show(struct seq_file *m, void *v)
-+{
-+	unsigned long seq;
-+	bool full = !debugfs_real_fops(m->file)->write;
-+	struct lruvec *lruvec = v;
-+	struct lrugen *lrugen = &lruvec->evictable;
-+	int nid = lruvec_pgdat(lruvec)->node_id;
-+	struct mem_cgroup *memcg = lruvec_memcg(lruvec);
-+	DEFINE_MAX_SEQ(lruvec);
-+	DEFINE_MIN_SEQ(lruvec);
-+
-+	if (nid == first_memory_node) {
-+		const char *path = memcg ? m->private : "";
-+
-+#ifdef CONFIG_MEMCG
-+		if (memcg)
-+			cgroup_path(memcg->css.cgroup, m->private, PATH_MAX);
-+#endif
-+		seq_printf(m, "memcg %5hu %s\n", mem_cgroup_id(memcg), path);
-+	}
-+
-+	seq_printf(m, " node %5d\n", nid);
-+
-+	if (!full)
-+		seq = min_seq[0];
-+	else if (max_seq >= MAX_NR_GENS)
-+		seq = max_seq - MAX_NR_GENS + 1;
-+	else
-+		seq = 0;
-+
-+	for (; seq <= max_seq; seq++) {
-+		int gen, type, zone;
-+		unsigned int msecs;
-+
-+		gen = lru_gen_from_seq(seq);
-+		msecs = jiffies_to_msecs(jiffies - READ_ONCE(lrugen->timestamps[gen]));
-+
-+		seq_printf(m, " %10lu %10u", seq, msecs);
-+
-+		for (type = 0; type < ANON_AND_FILE; type++) {
-+			long size = 0;
-+
-+			if (seq < min_seq[type]) {
-+				seq_puts(m, "         -0 ");
-+				continue;
-+			}
-+
-+			for (zone = 0; zone < MAX_NR_ZONES; zone++)
-+				size += READ_ONCE(lrugen->sizes[gen][type][zone]);
-+
-+			seq_printf(m, " %10lu ", max(size, 0L));
-+		}
-+
-+		seq_putc(m, '\n');
-+
-+		if (full)
-+			lru_gen_seq_show_full(m, lruvec, max_seq, min_seq, seq);
-+	}
-+
-+	return 0;
-+}
-+
-+static const struct seq_operations lru_gen_seq_ops = {
-+	.start = lru_gen_seq_start,
-+	.stop = lru_gen_seq_stop,
-+	.next = lru_gen_seq_next,
-+	.show = lru_gen_seq_show,
-+};
-+
-+static int run_aging(struct lruvec *lruvec, struct scan_control *sc, int swappiness,
-+		     unsigned long seq, bool use_filter)
-+{
-+	DEFINE_MAX_SEQ(lruvec);
-+
-+	if (seq == max_seq)
-+		try_to_inc_max_seq(lruvec, sc, swappiness, max_seq, use_filter);
-+
-+	return seq > max_seq ? -EINVAL : 0;
-+}
-+
-+static int run_eviction(struct lruvec *lruvec, struct scan_control *sc, int swappiness,
-+			unsigned long seq, unsigned long nr_to_reclaim)
-+{
-+	struct blk_plug plug;
-+	int err = -EINTR;
-+	DEFINE_MAX_SEQ(lruvec);
-+
-+	if (seq >= max_seq - 1)
-+		return -EINVAL;
-+
-+	sc->nr_reclaimed = 0;
-+
-+	blk_start_plug(&plug);
-+
-+	while (!signal_pending(current)) {
-+		DEFINE_MIN_SEQ(lruvec);
-+
-+		if (seq < min_seq[!swappiness] || sc->nr_reclaimed >= nr_to_reclaim ||
-+		    !evict_pages(lruvec, sc, swappiness)) {
-+			err = 0;
-+			break;
-+		}
-+
-+		cond_resched();
-+	}
-+
-+	blk_finish_plug(&plug);
-+
-+	return err;
-+}
-+
-+static int run_cmd(char cmd, int memcg_id, int nid, struct scan_control *sc,
-+		   int swappiness, unsigned long seq, unsigned long opt)
-+{
-+	struct lruvec *lruvec;
-+	int err = -EINVAL;
-+	struct mem_cgroup *memcg = NULL;
-+
-+	if (!mem_cgroup_disabled()) {
-+		rcu_read_lock();
-+		memcg = mem_cgroup_from_id(memcg_id);
-+#ifdef CONFIG_MEMCG
-+		if (memcg && !css_tryget(&memcg->css))
-+			memcg = NULL;
-+#endif
-+		rcu_read_unlock();
-+
-+		if (!memcg)
-+			goto done;
-+	}
-+	if (memcg_id != mem_cgroup_id(memcg))
-+		goto done;
-+
-+	if (nid < 0 || nid >= MAX_NUMNODES || !node_state(nid, N_MEMORY))
-+		goto done;
-+
-+	lruvec = get_lruvec(nid, memcg);
-+
-+	if (swappiness < 0)
-+		swappiness = get_swappiness(memcg);
-+	else if (swappiness > 200)
-+		goto done;
-+
-+	switch (cmd) {
-+	case '+':
-+		err = run_aging(lruvec, sc, swappiness, seq, opt);
-+		break;
-+	case '-':
-+		err = run_eviction(lruvec, sc, swappiness, seq, opt);
-+		break;
-+	}
-+done:
-+	mem_cgroup_put(memcg);
-+
-+	return err;
-+}
-+
-+static ssize_t lru_gen_seq_write(struct file *file, const char __user *src,
-+				 size_t len, loff_t *pos)
-+{
-+	void *buf;
-+	char *cur, *next;
-+	unsigned int flags;
-+	int err = 0;
-+	struct scan_control sc = {
-+		.may_writepage = 1,
-+		.may_unmap = 1,
-+		.may_swap = 1,
-+		.reclaim_idx = MAX_NR_ZONES - 1,
-+		.gfp_mask = GFP_KERNEL,
-+	};
-+
-+	buf = kvmalloc(len + 1, GFP_KERNEL);
-+	if (!buf)
-+		return -ENOMEM;
-+
-+	if (copy_from_user(buf, src, len)) {
-+		kvfree(buf);
-+		return -EFAULT;
-+	}
-+
-+	next = buf;
-+	next[len] = '\0';
-+
-+	sc.reclaim_state.mm_walk_args = alloc_mm_walk_args();
-+	if (!sc.reclaim_state.mm_walk_args) {
-+		kvfree(buf);
-+		return -ENOMEM;
-+	}
-+
-+	flags = memalloc_noreclaim_save();
-+	set_task_reclaim_state(current, &sc.reclaim_state);
-+
-+	while ((cur = strsep(&next, ",;\n"))) {
-+		int n;
-+		int end;
-+		char cmd;
-+		unsigned int memcg_id;
-+		unsigned int nid;
-+		unsigned long seq;
-+		unsigned int swappiness = -1;
-+		unsigned long opt = -1;
-+
-+		cur = skip_spaces(cur);
-+		if (!*cur)
-+			continue;
-+
-+		n = sscanf(cur, "%c %u %u %lu %n %u %n %lu %n", &cmd, &memcg_id, &nid,
-+			   &seq, &end, &swappiness, &end, &opt, &end);
-+		if (n < 4 || cur[end]) {
-+			err = -EINVAL;
-+			break;
-+		}
-+
-+		err = run_cmd(cmd, memcg_id, nid, &sc, swappiness, seq, opt);
-+		if (err)
-+			break;
-+	}
-+
-+	set_task_reclaim_state(current, NULL);
-+	memalloc_noreclaim_restore(flags);
-+
-+	free_mm_walk_args(sc.reclaim_state.mm_walk_args);
-+	kvfree(buf);
-+
-+	return err ? : len;
-+}
-+
-+static int lru_gen_seq_open(struct inode *inode, struct file *file)
-+{
-+	return seq_open(file, &lru_gen_seq_ops);
-+}
-+
-+static const struct file_operations lru_gen_rw_fops = {
-+	.open = lru_gen_seq_open,
-+	.read = seq_read,
-+	.write = lru_gen_seq_write,
-+	.llseek = seq_lseek,
-+	.release = seq_release,
-+};
-+
-+static const struct file_operations lru_gen_ro_fops = {
-+	.open = lru_gen_seq_open,
-+	.read = seq_read,
-+	.llseek = seq_lseek,
-+	.release = seq_release,
-+};
-+
-+/******************************************************************************
-+ *                          initialization
-+ ******************************************************************************/
-+
-+void lru_gen_init_state(struct mem_cgroup *memcg, struct lruvec *lruvec)
-+{
-+	int i;
-+	int gen, type, zone;
-+	struct lrugen *lrugen = &lruvec->evictable;
-+	struct lru_gen_mm_list *mm_list = get_mm_list(memcg);
-+
-+	lrugen->max_seq = MIN_NR_GENS + 1;
-+	lrugen->enabled[0] = lru_gen_enabled() && lru_gen_nr_swapfiles;
-+	lrugen->enabled[1] = lru_gen_enabled();
-+
-+	for (i = 0; i <= MIN_NR_GENS + 1; i++)
-+		lrugen->timestamps[i] = jiffies;
-+
-+	for_each_gen_type_zone(gen, type, zone)
-+		INIT_LIST_HEAD(&lrugen->lists[gen][type][zone]);
-+
-+	if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG) && !memcg)
-+		spin_lock(&mm_list->lock);
-+
-+	lruvec->mm_walk.seq = MIN_NR_GENS;
-+	lruvec->mm_walk.head = &mm_list->fifo;
-+	lruvec->mm_walk.tail = &mm_list->fifo;
-+	init_waitqueue_head(&lruvec->mm_walk.wait);
-+
-+	if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG) && !memcg)
-+		spin_unlock(&mm_list->lock);
-+}
-+
-+#ifdef CONFIG_MEMCG
-+void lru_gen_init_memcg(struct mem_cgroup *memcg)
-+{
-+	int nid;
-+
-+	INIT_LIST_HEAD(&memcg->mm_list.fifo);
-+	spin_lock_init(&memcg->mm_list.lock);
-+
-+	for_each_node(nid) {
-+		struct lruvec *lruvec = get_lruvec(nid, memcg);
-+
-+		lru_gen_init_state(memcg, lruvec);
-+	}
-+}
-+
-+void lru_gen_free_memcg(struct mem_cgroup *memcg)
-+{
-+	int nid;
-+
-+	for_each_node(nid) {
-+		int i;
-+		struct lruvec *lruvec = get_lruvec(nid, memcg);
-+
-+		for (i = 0; i < NR_BLOOM_FILTERS; i++) {
-+			bitmap_free(lruvec->mm_walk.filters[i]);
-+			lruvec->mm_walk.filters[i] = NULL;
-+		}
-+	}
-+}
-+#endif
-+
-+static int __init init_lru_gen(void)
-+{
-+	BUILD_BUG_ON(MIN_NR_GENS + 1 >= MAX_NR_GENS);
-+	BUILD_BUG_ON(BIT(LRU_GEN_WIDTH) <= MAX_NR_GENS);
-+	BUILD_BUG_ON(sizeof(MM_STAT_CODES) != NR_MM_STATS + 1);
-+
-+	if (sysfs_create_group(mm_kobj, &lru_gen_attr_group))
-+		pr_err("lru_gen: failed to create sysfs group\n");
-+
-+	debugfs_create_file("lru_gen", 0644, NULL, NULL, &lru_gen_rw_fops);
-+	debugfs_create_file("lru_gen_full", 0444, NULL, NULL, &lru_gen_ro_fops);
-+
-+	return 0;
-+};
-+late_initcall(init_lru_gen);
-+
-+#else
-+
-+static void lru_gen_age_node(struct pglist_data *pgdat, struct scan_control *sc)
-+{
-+}
-+
-+static void lru_gen_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc)
-+{
-+}
-+
-+#endif /* CONFIG_LRU_GEN */
-+
- static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc)
- {
- 	unsigned long nr[NR_LRU_LISTS];
-@@ -2794,6 +5387,11 @@ static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc)
- 	struct blk_plug plug;
- 	bool scan_adjusted;
- 
-+	if (lru_gen_enabled()) {
-+		lru_gen_shrink_lruvec(lruvec, sc);
-+		return;
-+	}
-+
- 	get_scan_count(lruvec, sc, nr);
- 
- 	/* Record the original scan target for proportional adjustments later */
-@@ -3032,7 +5630,6 @@ static void shrink_node(pg_data_t *pgdat, struct scan_control *sc)
- 	unsigned long nr_reclaimed, nr_scanned;
- 	struct lruvec *target_lruvec;
- 	bool reclaimable = false;
--	unsigned long file;
- 
- 	target_lruvec = mem_cgroup_lruvec(sc->target_mem_cgroup, pgdat);
- 
-@@ -3048,93 +5645,7 @@ static void shrink_node(pg_data_t *pgdat, struct scan_control *sc)
- 	nr_reclaimed = sc->nr_reclaimed;
- 	nr_scanned = sc->nr_scanned;
- 
--	/*
--	 * Determine the scan balance between anon and file LRUs.
--	 */
--	spin_lock_irq(&target_lruvec->lru_lock);
--	sc->anon_cost = target_lruvec->anon_cost;
--	sc->file_cost = target_lruvec->file_cost;
--	spin_unlock_irq(&target_lruvec->lru_lock);
--
--	/*
--	 * Target desirable inactive:active list ratios for the anon
--	 * and file LRU lists.
--	 */
--	if (!sc->force_deactivate) {
--		unsigned long refaults;
--
--		refaults = lruvec_page_state(target_lruvec,
--				WORKINGSET_ACTIVATE_ANON);
--		if (refaults != target_lruvec->refaults[0] ||
--			inactive_is_low(target_lruvec, LRU_INACTIVE_ANON))
--			sc->may_deactivate |= DEACTIVATE_ANON;
--		else
--			sc->may_deactivate &= ~DEACTIVATE_ANON;
--
--		/*
--		 * When refaults are being observed, it means a new
--		 * workingset is being established. Deactivate to get
--		 * rid of any stale active pages quickly.
--		 */
--		refaults = lruvec_page_state(target_lruvec,
--				WORKINGSET_ACTIVATE_FILE);
--		if (refaults != target_lruvec->refaults[1] ||
--		    inactive_is_low(target_lruvec, LRU_INACTIVE_FILE))
--			sc->may_deactivate |= DEACTIVATE_FILE;
--		else
--			sc->may_deactivate &= ~DEACTIVATE_FILE;
--	} else
--		sc->may_deactivate = DEACTIVATE_ANON | DEACTIVATE_FILE;
--
--	/*
--	 * If we have plenty of inactive file pages that aren't
--	 * thrashing, try to reclaim those first before touching
--	 * anonymous pages.
--	 */
--	file = lruvec_page_state(target_lruvec, NR_INACTIVE_FILE);
--	if (file >> sc->priority && !(sc->may_deactivate & DEACTIVATE_FILE))
--		sc->cache_trim_mode = 1;
--	else
--		sc->cache_trim_mode = 0;
--
--	/*
--	 * Prevent the reclaimer from falling into the cache trap: as
--	 * cache pages start out inactive, every cache fault will tip
--	 * the scan balance towards the file LRU.  And as the file LRU
--	 * shrinks, so does the window for rotation from references.
--	 * This means we have a runaway feedback loop where a tiny
--	 * thrashing file LRU becomes infinitely more attractive than
--	 * anon pages.  Try to detect this based on file LRU size.
--	 */
--	if (!cgroup_reclaim(sc)) {
--		unsigned long total_high_wmark = 0;
--		unsigned long free, anon;
--		int z;
--
--		free = sum_zone_node_page_state(pgdat->node_id, NR_FREE_PAGES);
--		file = node_page_state(pgdat, NR_ACTIVE_FILE) +
--			   node_page_state(pgdat, NR_INACTIVE_FILE);
--
--		for (z = 0; z < MAX_NR_ZONES; z++) {
--			struct zone *zone = &pgdat->node_zones[z];
--			if (!managed_zone(zone))
--				continue;
--
--			total_high_wmark += high_wmark_pages(zone);
--		}
--
--		/*
--		 * Consider anon: if that's low too, this isn't a
--		 * runaway file reclaim problem, but rather just
--		 * extreme pressure. Reclaim as per usual then.
--		 */
--		anon = node_page_state(pgdat, NR_INACTIVE_ANON);
--
--		sc->file_is_tiny =
--			file + free <= total_high_wmark &&
--			!(sc->may_deactivate & DEACTIVATE_ANON) &&
--			anon >> sc->priority;
--	}
-+	prepare_scan_count(pgdat, sc);
- 
- 	shrink_node_memcgs(pgdat, sc);
- 
-@@ -3354,6 +5865,9 @@ static void snapshot_refaults(struct mem_cgroup *target_memcg, pg_data_t *pgdat)
- 	struct lruvec *target_lruvec;
- 	unsigned long refaults;
- 
-+	if (lru_gen_enabled())
-+		return;
-+
- 	target_lruvec = mem_cgroup_lruvec(target_memcg, pgdat);
- 	refaults = lruvec_page_state(target_lruvec, WORKINGSET_ACTIVATE_ANON);
- 	target_lruvec->refaults[0] = refaults;
-@@ -3724,6 +6238,11 @@ static void age_active_anon(struct pglist_data *pgdat,
- 	struct mem_cgroup *memcg;
- 	struct lruvec *lruvec;
- 
-+	if (lru_gen_enabled()) {
-+		lru_gen_age_node(pgdat, sc);
-+		return;
-+	}
-+
- 	if (!can_age_anon_pages(pgdat, sc))
- 		return;
- 
-diff --git a/mm/workingset.c b/mm/workingset.c
-index d5b81e4f4cbe..27d504a5d998 100644
---- a/mm/workingset.c
-+++ b/mm/workingset.c
-@@ -187,7 +187,6 @@ static unsigned int bucket_order __read_mostly;
- static void *pack_shadow(int memcgid, pg_data_t *pgdat, unsigned long eviction,
- 			 bool workingset)
- {
--	eviction >>= bucket_order;
- 	eviction &= EVICTION_MASK;
- 	eviction = (eviction << MEM_CGROUP_ID_SHIFT) | memcgid;
- 	eviction = (eviction << NODES_SHIFT) | pgdat->node_id;
-@@ -212,10 +211,117 @@ static void unpack_shadow(void *shadow, int *memcgidp, pg_data_t **pgdat,
- 
- 	*memcgidp = memcgid;
- 	*pgdat = NODE_DATA(nid);
--	*evictionp = entry << bucket_order;
-+	*evictionp = entry;
- 	*workingsetp = workingset;
- }
- 
-+#ifdef CONFIG_LRU_GEN
-+
-+static int page_lru_refs(struct page *page)
-+{
-+	unsigned long flags = READ_ONCE(page->flags);
-+
-+	BUILD_BUG_ON(LRU_GEN_WIDTH + LRU_REFS_WIDTH > BITS_PER_LONG - EVICTION_SHIFT);
-+
-+	/* see the comment on MAX_NR_TIERS */
-+	return flags & BIT(PG_workingset) ? (flags & LRU_REFS_MASK) >> LRU_REFS_PGOFF : 0;
-+}
-+
-+/* Return a token to be stored in the shadow entry of a page being evicted. */
-+static void *lru_gen_eviction(struct page *page)
-+{
-+	int hist, tier;
-+	unsigned long token;
-+	unsigned long min_seq;
-+	struct lruvec *lruvec;
-+	struct lrugen *lrugen;
-+	int type = page_is_file_lru(page);
-+	int refs = page_lru_refs(page);
-+	int delta = thp_nr_pages(page);
-+	bool workingset = PageWorkingset(page);
-+	struct mem_cgroup *memcg = page_memcg(page);
-+	struct pglist_data *pgdat = page_pgdat(page);
-+
-+	lruvec = mem_cgroup_lruvec(memcg, pgdat);
-+	lrugen = &lruvec->evictable;
-+	min_seq = READ_ONCE(lrugen->min_seq[type]);
-+	token = (min_seq << LRU_REFS_WIDTH) | refs;
-+
-+	hist = lru_hist_from_seq(min_seq);
-+	tier = lru_tier_from_refs(refs + workingset);
-+	atomic_long_add(delta, &lrugen->evicted[hist][type][tier]);
-+
-+	return pack_shadow(mem_cgroup_id(memcg), pgdat, token, workingset);
-+}
-+
-+/* Count a refaulted page based on the token stored in its shadow entry. */
-+static void lru_gen_refault(struct page *page, void *shadow)
-+{
-+	int hist, tier, refs;
-+	int memcg_id;
-+	bool workingset;
-+	unsigned long token;
-+	unsigned long min_seq;
-+	struct lruvec *lruvec;
-+	struct lrugen *lrugen;
-+	struct mem_cgroup *memcg;
-+	struct pglist_data *pgdat;
-+	int type = page_is_file_lru(page);
-+	int delta = thp_nr_pages(page);
-+
-+	unpack_shadow(shadow, &memcg_id, &pgdat, &token, &workingset);
-+	if (page_pgdat(page) != pgdat)
-+		return;
-+
-+	rcu_read_lock();
-+	memcg = page_memcg_rcu(page);
-+	if (mem_cgroup_id(memcg) != memcg_id)
-+		goto unlock;
-+
-+	refs = token & (BIT(LRU_REFS_WIDTH) - 1);
-+	if (refs && !workingset)
-+		goto unlock;
-+
-+	token >>= LRU_REFS_WIDTH;
-+	lruvec = mem_cgroup_lruvec(memcg, pgdat);
-+	lrugen = &lruvec->evictable;
-+	min_seq = READ_ONCE(lrugen->min_seq[type]);
-+	if (token != (min_seq & (EVICTION_MASK >> LRU_REFS_WIDTH)))
-+		goto unlock;
-+
-+	hist = lru_hist_from_seq(min_seq);
-+	tier = lru_tier_from_refs(refs + workingset);
-+	atomic_long_add(delta, &lrugen->refaulted[hist][type][tier]);
-+	mod_lruvec_state(lruvec, WORKINGSET_REFAULT_BASE + type, delta);
-+
-+	/*
-+	 * Tiers don't offer any protection to pages accessed via page tables.
-+	 * That's what generations do. Tiers can't fully protect pages after
-+	 * their numbers of accesses has exceeded the max value. Conservatively
-+	 * count these two conditions as stalls even though they might not
-+	 * indicate any real memory pressure.
-+	 */
-+	if (task_in_nonseq_fault() || refs + workingset == BIT(LRU_REFS_WIDTH)) {
-+		SetPageWorkingset(page);
-+		mod_lruvec_state(lruvec, WORKINGSET_RESTORE_BASE + type, delta);
-+	}
-+unlock:
-+	rcu_read_unlock();
-+}
-+
-+#else
-+
-+static void *lru_gen_eviction(struct page *page)
-+{
-+	return NULL;
-+}
-+
-+static void lru_gen_refault(struct page *page, void *shadow)
-+{
-+}
-+
-+#endif /* CONFIG_LRU_GEN */
-+
- /**
-  * workingset_age_nonresident - age non-resident entries as LRU ages
-  * @lruvec: the lruvec that was aged
-@@ -264,10 +370,14 @@ void *workingset_eviction(struct page *page, struct mem_cgroup *target_memcg)
- 	VM_BUG_ON_PAGE(page_count(page), page);
- 	VM_BUG_ON_PAGE(!PageLocked(page), page);
- 
-+	if (lru_gen_enabled())
-+		return lru_gen_eviction(page);
-+
- 	lruvec = mem_cgroup_lruvec(target_memcg, pgdat);
- 	/* XXX: target_memcg can be NULL, go through lruvec */
- 	memcgid = mem_cgroup_id(lruvec_memcg(lruvec));
- 	eviction = atomic_long_read(&lruvec->nonresident_age);
-+	eviction >>= bucket_order;
- 	workingset_age_nonresident(lruvec, thp_nr_pages(page));
- 	return pack_shadow(memcgid, pgdat, eviction, PageWorkingset(page));
- }
-@@ -296,7 +406,13 @@ void workingset_refault(struct page *page, void *shadow)
- 	bool workingset;
- 	int memcgid;
- 
-+	if (lru_gen_enabled()) {
-+		lru_gen_refault(page, shadow);
-+		return;
-+	}
-+
- 	unpack_shadow(shadow, &memcgid, &pgdat, &eviction, &workingset);
-+	eviction <<= bucket_order;
- 
- 	rcu_read_lock();
- 	/*
--- 
-2.33.1
-