Commit Graph

1429 Commits

Author SHA1 Message Date
Kees Cook
69050f8d6d treewide: Replace kmalloc with kmalloc_obj for non-scalar types
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook <kees@kernel.org>
2026-02-21 01:02:28 -08:00
Bing Jiao
7ec9ecf217 mm/vmscan: select the closest preferred node in demote_folio_list()
The preferred demotion node (migration_target_control.nid) should be the
one closest to the source node to minimize migration latency.  Currently,
a discrepancy exists where demote_folio_list() randomly selects an allowed
node if the preferred node from next_demotion_node() is not set in
mems_effective.

To address it, update next_demotion_node() to select a preferred target
against allowed nodes; and to return the closest demotion target if all
preferred nodes are not in mems_effective via next_demotion_node().

It ensures that the preferred demotion target is consistently the closest
available node to the source node.

[akpm@linux-foundation.org: fix comment typo, per Shakeel]
Link: https://lkml.kernel.org/r/20260114205305.2869796-3-bingjiao@google.com
Signed-off-by: Bing Jiao <bingjiao@google.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Gregory Price <gourry@gourry.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-02-12 15:42:53 -08:00
Bing Jiao
1aceed565f mm/vmscan: fix demotion targets checks in reclaim/demotion
Patch series "mm/vmscan: fix demotion targets checks in reclaim/demotion",
v9.

This patch series addresses two issues in demote_folio_list(),
can_demote(), and next_demotion_node() in reclaim/demotion.

1. demote_folio_list() and can_demote() do not correctly check
   demotion target against cpuset.mems_effective, which will cause (a)
   pages to be demoted to not-allowed nodes and (b) pages fail demotion
   even if the system still has allowed demotion nodes.

   Patch 1 fixes this bug by updating cpuset_node_allowed() and
   mem_cgroup_node_allowed() to return effective_mems, allowing directly
   logic-and operation against demotion targets.

2. next_demotion_node() returns a preferred demotion target, but it
   does not check the node against allowed nodes.

   Patch 2 ensures that next_demotion_node() filters against the allowed
   node mask and selects the closest demotion target to the source node.


This patch (of 2):

Fix two bugs in demote_folio_list() and can_demote() due to incorrect
demotion target checks against cpuset.mems_effective in reclaim/demotion.

Commit 7d709f49ba ("vmscan,cgroup: apply mems_effective to reclaim")
introduces the cpuset.mems_effective check and applies it to can_demote().
However:

  1. It does not apply this check in demote_folio_list(), which leads
     to situations where pages are demoted to nodes that are
     explicitly excluded from the task's cpuset.mems.

  2. It checks only the nodes in the immediate next demotion hierarchy
     and does not check all allowed demotion targets in can_demote().
     This can cause pages to never be demoted if the nodes in the next
     demotion hierarchy are not set in mems_effective.

These bugs break resource isolation provided by cpuset.mems.  This is
visible from userspace because pages can either fail to be demoted
entirely or are demoted to nodes that are not allowed in multi-tier memory
systems.

To address these bugs, update cpuset_node_allowed() and
mem_cgroup_node_allowed() to return effective_mems, allowing directly
logic-and operation against demotion targets.  Also update can_demote()
and demote_folio_list() accordingly.

Bug 1 reproduction:
  Assume a system with 4 nodes, where nodes 0-1 are top-tier and
  nodes 2-3 are far-tier memory. All nodes have equal capacity.

  Test script:
    echo 1 > /sys/kernel/mm/numa/demotion_enabled
    mkdir /sys/fs/cgroup/test
    echo +cpuset > /sys/fs/cgroup/cgroup.subtree_control
    echo "0-2" > /sys/fs/cgroup/test/cpuset.mems
    echo $$ > /sys/fs/cgroup/test/cgroup.procs
    swapoff -a
    # Expectation: Should respect node 0-2 limit.
    # Observation: Node 3 shows significant allocation (MemFree drops)
    stress-ng --oomable --vm 1 --vm-bytes 150% --mbind 0,1

Bug 2 reproduction:
  Assume a system with 6 nodes, where nodes 0-2 are top-tier,
  node 3 is a far-tier node, and nodes 4-5 are the farthest-tier nodes.
  All nodes have equal capacity.

  Test script:
    echo 1 > /sys/kernel/mm/numa/demotion_enabled
    mkdir /sys/fs/cgroup/test
    echo +cpuset > /sys/fs/cgroup/cgroup.subtree_control
    echo "0-2,4-5" > /sys/fs/cgroup/test/cpuset.mems
    echo $$ > /sys/fs/cgroup/test/cgroup.procs
    swapoff -a
    # Expectation: Pages are demoted to Nodes 4-5
    # Observation: No pages are demoted before oom.
    stress-ng --oomable --vm 1 --vm-bytes 150% --mbind 0,1,2

Link: https://lkml.kernel.org/r/20260114205305.2869796-1-bingjiao@google.com
Link: https://lkml.kernel.org/r/20260114205305.2869796-2-bingjiao@google.com
Fixes: 7d709f49ba ("vmscan,cgroup: apply mems_effective to reclaim")
Signed-off-by: Bing Jiao <bingjiao@google.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Gregory Price <gourry@gourry.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-02-12 15:42:52 -08:00
Sahil Chandna
4a8eabc6e4 mm/vmscan: use %pe to print error pointers
Use the %pe printk format specifier to report error pointers directly
instead of printing PTR_ERR() as a long value.  This improves clarity,
produces more readable error messages.

This instance was flagged by the Coccinelle script
(misc/ptr_err_to_pe.cocci) as an opportunity to adopt %pe.

Found by: make coccicheck MODE=report M=mm/
No functional change intended

Link: https://lkml.kernel.org/r/80a6643657a60e75ddf48b4869b3e7fdc101f855.1770230135.git.chandna.sahil@gmail.com
Signed-off-by: Sahil Chandna <chandna.sahil@gmail.com>
Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Yosry Ahmed <yosry.ahmed@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-02-06 15:47:16 -08:00
Kairui Song
2732acda82 mm, swap: use swap cache as the swap in synchronize layer
Current swap in synchronization mostly uses the swap_map's SWAP_HAS_CACHE
bit.  Whoever sets the bit first does the actual work to swap in a folio.

This has been causing many issues as it's just a poor implementation of a
bit lock.  Raced users have no idea what is pinning a slot, so it has to
loop with a schedule_timeout_uninterruptible(1), which is ugly and causes
long-tailing or other performance issues.  Besides, the abuse of
SWAP_HAS_CACHE has been causing many other troubles for synchronization or
maintenance.

This is the first step to remove this bit completely.

Now all swap in paths are using the swap cache, and both the swap cache
and swap map are protected by the cluster lock.  So we can just resolve
the swap synchronization with the swap cache layer directly using the
cluster lock and folio lock.  Whoever inserts a folio in the swap cache
first does the swap in work.  And because folios are locked during swap
operations, other raced swap operations will just wait on the folio lock.

The SWAP_HAS_CACHE will be removed in later commit.  For now, we still set
it for some remaining users.  But now we do the bit setting and swap cache
folio adding in the same critical section, after swap cache is ready.  No
one will have to spin on the SWAP_HAS_CACHE bit anymore.

This both simplifies the logic and should improve the performance,
eliminating issues like the one solved in commit 01626a1823 ("mm: avoid
unconditional one-tick sleep when swapcache_prepare fails"), or the
"skip_if_exists" from commit a65b0e7607 ("zswap: make shrinking
memcg-aware"), which will be removed very soon.

[kasong@tencent.com: fix cgroup v1 accounting issue]
 Link: https://lkml.kernel.org/r/CAMgjq7CGUnzOVG7uSaYjzw9wD7w2dSKOHprJfaEp4CcGLgE3iw@mail.gmail.com
Link: https://lkml.kernel.org/r/20251220-swap-table-p2-v5-12-8862a265a033@tencent.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Cc: Yosry Ahmed <yosry.ahmed@linux.dev>
Cc: Deepanshu Kartikey <kartikey406@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <ryncsn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-31 14:22:56 -08:00
Jiayuan Chen
a45088376d mm/vmscan: add tracepoint and reason for kswapd_failures reset
Currently, kswapd_failures is reset in multiple places (kswapd, direct
reclaim, PCP freeing, memory-tiers), but there's no way to trace when and
why it was reset, making it difficult to debug memory reclaim issues.

This patch:

1. Introduce kswapd_clear_hopeless() as a wrapper function to
   centralize kswapd_failures reset logic.

2. Introduce kswapd_test_hopeless() to encapsulate hopeless node
   checks, replacing all open-coded kswapd_failures comparisons.

3. Add kswapd_clear_hopeless_reason enum to distinguish reset sources:
   - KSWAPD_CLEAR_HOPELESS_KSWAPD: reset from kswapd context
   - KSWAPD_CLEAR_HOPELESS_DIRECT: reset from direct reclaim
   - KSWAPD_CLEAR_HOPELESS_PCP: reset from PCP page freeing
   - KSWAPD_CLEAR_HOPELESS_OTHER: reset from other paths

4. Add tracepoints for better observability:
   - mm_vmscan_kswapd_clear_hopeless: traces each reset with reason
   - mm_vmscan_kswapd_reclaim_fail: traces each kswapd reclaim failure

Test results:

$ trace-cmd record -e vmscan:mm_vmscan_kswapd_clear_hopeless -e vmscan:mm_vmscan_kswapd_reclaim_fail
$ # generate memory pressure
$ trace-cmd report
cpus=4
 kswapd0-71    [000]    27.216563: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=1
 kswapd0-71    [000]    27.217169: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=2
 kswapd0-71    [000]    27.217764: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=3
 kswapd0-71    [000]    27.218353: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=4
 kswapd0-71    [000]    27.218993: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=5
 kswapd0-71    [000]    27.219744: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=6
 kswapd0-71    [000]    27.220488: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=7
 kswapd0-71    [000]    27.221206: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=8
 kswapd0-71    [000]    27.221806: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=9
 kswapd0-71    [000]    27.222634: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=10
 kswapd0-71    [000]    27.223286: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=11
 kswapd0-71    [000]    27.223894: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=12
 kswapd0-71    [000]    27.224712: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=13
 kswapd0-71    [000]    27.225424: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=14
 kswapd0-71    [000]    27.226082: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=15
 kswapd0-71    [000]    27.226810: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=16
 kswapd1-72    [002]    27.386869: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=1
 kswapd1-72    [002]    27.387435: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=2
 kswapd1-72    [002]    27.388016: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=3
 kswapd1-72    [002]    27.388586: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=4
 kswapd1-72    [002]    27.389155: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=5
 kswapd1-72    [002]    27.389723: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=6
 kswapd1-72    [002]    27.390292: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=7
 kswapd1-72    [002]    27.392364: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=8
 kswapd1-72    [002]    27.392934: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=9
 kswapd1-72    [002]    27.393504: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=10
 kswapd1-72    [002]    27.394073: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=11
 kswapd1-72    [002]    27.394899: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=12
 kswapd1-72    [002]    27.395472: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=13
 kswapd1-72    [002]    27.396055: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=14
 kswapd1-72    [002]    27.396628: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=15
 kswapd1-72    [002]    27.397199: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=16
kworker/u18:0-40    [002]    27.410151: mm_vmscan_kswapd_clear_hopeless: nid=0 reason=DIRECT
 kswapd0-71    [000]    27.439454: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=1
 kswapd0-71    [000]    27.440048: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=2
 kswapd0-71    [000]    27.440634: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=3
 kswapd0-71    [000]    27.441211: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=4
 kswapd0-71    [000]    27.441787: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=5
 kswapd0-71    [000]    27.442363: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=6
 kswapd0-71    [000]    27.443030: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=7
 kswapd0-71    [000]    27.443725: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=8
 kswapd0-71    [000]    27.444315: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=9
 kswapd0-71    [000]    27.444898: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=10
 kswapd0-71    [000]    27.445476: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=11
 kswapd0-71    [000]    27.446053: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=12
 kswapd0-71    [000]    27.446646: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=13
 kswapd0-71    [000]    27.447230: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=14
 kswapd0-71    [000]    27.447812: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=15
 kswapd0-71    [000]    27.448391: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=16
 ann-423   [003]    28.028285: mm_vmscan_kswapd_clear_hopeless: nid=0 reason=PCP

Link: https://lkml.kernel.org/r/20260120024402.387576-3-jiayuan.chen@linux.dev
Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com>
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>	[tracing]
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-31 14:22:38 -08:00
Jiayuan Chen
dc9fe9b705 mm/vmscan: mitigate spurious kswapd_failures reset from direct reclaim
Patch series "mm/vmscan: add tracepoint and reason for kswapd_failures
reset", v4.

Currently, kswapd_failures is reset in multiple places (kswapd,
direct reclaim, PCP freeing, memory-tiers), but there's no way to
trace when and why it was reset, making it difficult to debug
memory reclaim issues.

This patch:

1. Introduce kswapd_clear_hopeless() as a wrapper function to
   centralize kswapd_failures reset logic.

2. Introduce kswapd_test_hopeless() to encapsulate hopeless node
   checks, replacing all open-coded kswapd_failures comparisons.

3. Add kswapd_clear_hopeless_reason enum to distinguish reset sources:
   - KSWAPD_CLEAR_HOPELESS_KSWAPD: reset from kswapd context
   - KSWAPD_CLEAR_HOPELESS_DIRECT: reset from direct reclaim
   - KSWAPD_CLEAR_HOPELESS_PCP: reset from PCP page freeing
   - KSWAPD_CLEAR_HOPELESS_OTHER: reset from other paths

4. Add tracepoints for better observability:
   - mm_vmscan_kswapd_clear_hopeless: traces each reset with reason
   - mm_vmscan_kswapd_reclaim_fail: traces each kswapd reclaim failure

Test results:

$ trace-cmd record -e vmscan:mm_vmscan_kswapd_clear_hopeless -e vmscan:mm_vmscan_kswapd_reclaim_fail
$ # generate memory pressure
$ trace-cmd report
cpus=4
 kswapd0-71    [000]    27.216563: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=1
 kswapd0-71    [000]    27.217169: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=2
 kswapd0-71    [000]    27.217764: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=3
 kswapd0-71    [000]    27.218353: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=4
 kswapd0-71    [000]    27.218993: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=5
 kswapd0-71    [000]    27.219744: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=6
 kswapd0-71    [000]    27.220488: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=7
 kswapd0-71    [000]    27.221206: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=8
 kswapd0-71    [000]    27.221806: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=9
 kswapd0-71    [000]    27.222634: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=10
 kswapd0-71    [000]    27.223286: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=11
 kswapd0-71    [000]    27.223894: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=12
 kswapd0-71    [000]    27.224712: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=13
 kswapd0-71    [000]    27.225424: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=14
 kswapd0-71    [000]    27.226082: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=15
 kswapd0-71    [000]    27.226810: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=16
 kswapd1-72    [002]    27.386869: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=1
 kswapd1-72    [002]    27.387435: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=2
 kswapd1-72    [002]    27.388016: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=3
 kswapd1-72    [002]    27.388586: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=4
 kswapd1-72    [002]    27.389155: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=5
 kswapd1-72    [002]    27.389723: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=6
 kswapd1-72    [002]    27.390292: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=7
 kswapd1-72    [002]    27.392364: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=8
 kswapd1-72    [002]    27.392934: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=9
 kswapd1-72    [002]    27.393504: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=10
 kswapd1-72    [002]    27.394073: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=11
 kswapd1-72    [002]    27.394899: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=12
 kswapd1-72    [002]    27.395472: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=13
 kswapd1-72    [002]    27.396055: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=14
 kswapd1-72    [002]    27.396628: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=15
 kswapd1-72    [002]    27.397199: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=16
kworker/u18:0-40    [002]    27.410151: mm_vmscan_kswapd_clear_hopeless: nid=0 reason=DIRECT
 kswapd0-71    [000]    27.439454: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=1
 kswapd0-71    [000]    27.440048: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=2
 kswapd0-71    [000]    27.440634: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=3
 kswapd0-71    [000]    27.441211: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=4
 kswapd0-71    [000]    27.441787: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=5
 kswapd0-71    [000]    27.442363: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=6
 kswapd0-71    [000]    27.443030: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=7
 kswapd0-71    [000]    27.443725: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=8
 kswapd0-71    [000]    27.444315: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=9
 kswapd0-71    [000]    27.444898: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=10
 kswapd0-71    [000]    27.445476: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=11
 kswapd0-71    [000]    27.446053: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=12
 kswapd0-71    [000]    27.446646: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=13
 kswapd0-71    [000]    27.447230: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=14
 kswapd0-71    [000]    27.447812: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=15
 kswapd0-71    [000]    27.448391: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=16
 ann-423   [003]    28.028285: mm_vmscan_kswapd_clear_hopeless: nid=0 reason=PCP


This patch (of 2):

When kswapd fails to reclaim memory, kswapd_failures is incremented.  Once
it reaches MAX_RECLAIM_RETRIES, kswapd stops running to avoid futile
reclaim attempts.  However, any successful direct reclaim unconditionally
resets kswapd_failures to 0, which can cause problems.

We observed an issue in production on a multi-NUMA system where a process
allocated large amounts of anonymous pages on a single NUMA node, causing
its watermark to drop below high and evicting most file pages:

$ numastat -m
Per-node system memory usage (in MBs):
                          Node 0          Node 1           Total
                 --------------- --------------- ---------------
MemTotal               128222.19       127983.91       256206.11
MemFree                  1414.48         1432.80         2847.29
MemUsed                126807.71       126551.11       252358.82
SwapCached                  0.00            0.00            0.00
Active                  29017.91        25554.57        54572.48
Inactive                92749.06        95377.00       188126.06
Active(anon)            28998.96        23356.47        52355.43
Inactive(anon)          92685.27        87466.11       180151.39
Active(file)               18.95         2198.10         2217.05
Inactive(file)             63.79         7910.89         7974.68

With swap disabled, only file pages can be reclaimed.  When kswapd is
woken (e.g., via wake_all_kswapds()), it runs continuously but cannot
raise free memory above the high watermark since reclaimable file pages
are insufficient.  Normally, kswapd would eventually stop after
kswapd_failures reaches MAX_RECLAIM_RETRIES.

However, containers on this machine have memory.high set in their cgroup. 
Business processes continuously trigger the high limit, causing frequent
direct reclaim that keeps resetting kswapd_failures to 0.  This prevents
kswapd from ever stopping.

The key insight is that direct reclaim triggered by cgroup memory.high
performs aggressive scanning to throttle the allocating process.  With
sufficiently aggressive scanning, even hot pages will eventually be
reclaimed, making direct reclaim "successful" at freeing some memory. 
However, this success does not mean the node has reached a balanced state
- the freed memory may still be insufficient to bring free pages above the
high watermark.  Unconditionally resetting kswapd_failures in this case
keeps kswapd alive indefinitely.

The result is that kswapd runs endlessly.  Unlike direct reclaim which
only reclaims from the allocating cgroup, kswapd scans the entire node's
memory.  This causes hot file pages from all workloads on the node to be
evicted, not just those from the cgroup triggering memory.high.  These
pages constantly refault, generating sustained heavy IO READ pressure
across the entire system.

Fix this by only resetting kswapd_failures when the node is actually
balanced.  This allows both kswapd and direct reclaim to clear
kswapd_failures upon successful reclaim, but only when the reclaim
actually resolves the memory pressure (i.e., the node becomes balanced).

Link: https://lkml.kernel.org/r/20260120024402.387576-1-jiayuan.chen@linux.dev
Link: https://lkml.kernel.org/r/20260120024402.387576-2-jiayuan.chen@linux.dev
Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com>
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-31 14:22:38 -08:00
David Hildenbrand (Red Hat)
a3db9e136c mm/vmscan: drop inclusion of balloon_compaction.h
Before commit b1123ea6d3 ("mm: balloon: use general non-lru movable page
feature"), the include was required because of isolated_balloon_page().

It's no longer required, so let's remove it.

Link: https://lkml.kernel.org/r/20260119230133.3551867-20-david@kernel.org
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-31 14:22:35 -08:00
Shakeel Butt
95296536eb memcg: rename mem_cgroup_ino() to mem_cgroup_id()
Rename mem_cgroup_ino() to mem_cgroup_id() and mem_cgroup_get_from_ino()
to mem_cgroup_get_from_id().  These functions now use cgroup IDs (from
cgroup_id()) rather than inode numbers, so the names should reflect that.

[shakeel.butt@linux.dev: replace ino with id, per SeongJae]
  Link: https://lkml.kernel.org/r/flkqanhyettp5uq22bjwg37rtmnpeg3mghznsylxcxxgaafpl4@nov2x7tagma7
[akpm@linux-foundation.org: build fix]
Link: https://lkml.kernel.org/r/20251225232116.294540-9-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26 20:02:25 -08:00
Shakeel Butt
20ccbd89af mm/vmscan: use cgroup ID instead of private memcg ID in lru_gen interface
The LRU gen debugfs interface was using the internal private memcg ID
which is meant for tracking kernel objects that outlive their cgroup. 
Switch to using the public cgroup ID instead.

Link: https://lkml.kernel.org/r/20251225232116.294540-7-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: SeongJae Park <sj@kernel.org>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26 20:02:25 -08:00
Kevin Lourenco
62451ae347 mm: fix minor spelling mistakes in comments
Correct several typos in comments across files in mm/

[akpm@linux-foundation.org: also fix comment grammar, per SeongJae]
Link: https://lkml.kernel.org/r/20251218150906.25042-1-klourencodev@gmail.com
Signed-off-by: Kevin Lourenco <klourencodev@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-20 19:24:48 -08:00
Johannes Weiner
64dd89ae01 mm/block/fs: remove laptop_mode
Laptop mode was introduced to save battery, by delaying and consolidating
writes and thereby maximize the time rotating hard drives wouldn't have to
spin.

Luckily, rotating hard drives, with their high spin-up times and power
draw, are a thing of the past for battery-powered devices.  Reclaim has
also since changed to not write single filesystem pages anymore, and
regular filesystem writeback is lumpy by design.

The juice doesn't appear worth the squeeze anymore.  The footprint of the
feature is small, but nevertheless it's a complicating factor in mm,
block, filesystems.  Developers don't think about it, and it likely hasn't
been tested with new reclaim and writeback changes in years.

Let's sunset it.  Keep the sysctl with a deprecation warning around for a
few more cycles, but remove all functionality behind it.

[akpm@linux-foundation.org: fix Documentation/admin-guide/laptops/index.rst]
Link: https://lkml.kernel.org/r/20251216185201.GH905277@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Deepanshu Kartikey <kartikey406@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-20 19:24:47 -08:00
Chen Ridong
055059ed72 memcg: remove mem_cgroup_size()
The mem_cgroup_size helper is used only in apply_proportional_protection
to read the current memory usage.  Its semantics are unclear and
inconsistent with other sites, which directly call page_counter_read for
the same purpose.

Remove this helper and get its usage via mem_cgroup_protection for
clarity.  Additionally, rename the local variable 'cgroup_size' to 'usage'
to better reflect its meaning.

No functional changes intended.

Link: https://lkml.kernel.org/r/20251211013019.2080004-3-chenridong@huaweicloud.com
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Lu Jialin <lujialin4@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-20 19:24:42 -08:00
Andrew Morton
7adc97bc93 mm/vmscan.c:shrink_folio_list(): save a tabstop
We have some needlessly deep indentation in this huge function due to

	if (expr1) {
		if (expr2) {
			...
		}
	}

Convert this to

	if (expr1 && expr2) {
		...
	}

Also, reflow that big block comment to fit in 80 cols.

Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Wei Xu <weixugc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-20 19:24:36 -08:00
Kevin Brodsky
0a096ab7a3 mm: introduce generic lazy_mmu helpers
The implementation of the lazy MMU mode is currently entirely
arch-specific; core code directly calls arch helpers:
arch_{enter,leave}_lazy_mmu_mode().

We are about to introduce support for nested lazy MMU sections.  As things
stand we'd have to duplicate that logic in every arch implementing
lazy_mmu - adding to a fair amount of logic already duplicated across
lazy_mmu implementations.

This patch therefore introduces a new generic layer that calls the
existing arch_* helpers. Two pair of calls are introduced:

* lazy_mmu_mode_enable() ... lazy_mmu_mode_disable()
    This is the standard case where the mode is enabled for a given
    block of code by surrounding it with enable() and disable()
    calls.

* lazy_mmu_mode_pause() ... lazy_mmu_mode_resume()
    This is for situations where the mode is temporarily disabled
    by first calling pause() and then resume() (e.g. to prevent any
    batching from occurring in a critical section).

The documentation in <linux/pgtable.h> will be updated in a subsequent
patch.

No functional change should be introduced at this stage.  The
implementation of enable()/resume() and disable()/pause() is currently
identical, but nesting support will change that.

Most of the call sites have been updated using the following Coccinelle
script:

@@
@@
{
...
- arch_enter_lazy_mmu_mode();
+ lazy_mmu_mode_enable();
...
- arch_leave_lazy_mmu_mode();
+ lazy_mmu_mode_disable();
...
}

@@
@@
{
...
- arch_leave_lazy_mmu_mode();
+ lazy_mmu_mode_pause();
...
- arch_enter_lazy_mmu_mode();
+ lazy_mmu_mode_resume();
...
}

A couple of notes regarding x86:

* Xen is currently the only case where explicit handling is required
  for lazy MMU when context-switching. This is purely an
  implementation detail and using the generic lazy_mmu_mode_*
  functions would cause trouble when nesting support is introduced,
  because the generic functions must be called from the current task.
  For that reason we still use arch_leave() and arch_enter() there.

* x86 calls arch_flush_lazy_mmu_mode() unconditionally in a few
  places, but only defines it if PARAVIRT_XXL is selected, and we
  are removing the fallback in <linux/pgtable.h>. Add a new fallback
  definition to <asm/pgtable.h> to keep things building.

Link: https://lkml.kernel.org/r/20251215150323.2218608-8-kevin.brodsky@arm.com
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David Hildenbrand (Red Hat) <david@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Juegren Gross <jgross@suse.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-20 19:24:33 -08:00
Yosry Ahmed
16aca2c98a mm: restore per-memcg proactive reclaim with !CONFIG_NUMA
Commit 2b7226af73 ("mm/memcg: make memory.reclaim interface generic")
moved proactive reclaim logic from memory.reclaim handler to a generic
user_proactive_reclaim() helper to be used for per-node proactive reclaim.

However, user_proactive_reclaim() was only defined under CONFIG_NUMA, with
a stub always returning 0 otherwise.  This broke memory.reclaim on
!CONFIG_NUMA configs, causing it to report success without actually
attempting reclaim.

Move the definition of user_proactive_reclaim() outside CONFIG_NUMA, and
instead define a stub for __node_reclaim() in the !CONFIG_NUMA case. 
__node_reclaim() is only called from user_proactive_reclaim() when a write
is made to sys/devices/system/node/nodeX/reclaim, which is only defined
with CONFIG_NUMA.

Link: https://lkml.kernel.org/r/20260116205247.928004-1-yosry.ahmed@linux.dev
Fixes: 2b7226af73 ("mm/memcg: make memory.reclaim interface generic")
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-20 09:34:27 -08:00
Linus Torvalds
2516a87153 Merge tag 'mm-stable-2025-12-11-11-39' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull more MM updates from Andrew Morton:

 - "powerpc/pseries/cmm: two smaller fixes" (David Hildenbrand)
   fixes a couple of minor things in ppc land

 - "Improve folio split related functions" (Zi Yan)
   some cleanups and minorish fixes in the folio splitting code

* tag 'mm-stable-2025-12-11-11-39' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mm/damon/tests/core-kunit: avoid damos_test_commit stack warning
  mm: vmscan: correct nr_requested tracing in scan_folios
  MAINTAINERS: add idr core-api doc file to XARRAY
  mm/hugetlb: fix incorrect error return from hugetlb_reserve_pages()
  mm: fix CONFIG_STACK_GROWSUP typo in mm.h
  mm/huge_memory: fix folio split stats counting
  mm/huge_memory: make min_order_for_split() always return an order
  mm/huge_memory: replace can_split_folio() with direct refcount calculation
  mm/huge_memory: change folio_split_supported() to folio_check_splittable()
  mm/sparse: fix sparse_vmemmap_init_nid_early definition without CONFIG_SPARSEMEM
  powerpc/pseries/cmm: adjust BALLOON_MIGRATE when migrating pages
  powerpc/pseries/cmm: call balloon_devinfo_init() also without CONFIG_BALLOON_COMPACTION
2025-12-13 20:35:41 +12:00
Chen Ridong
49d921b471 mm: vmscan: correct nr_requested tracing in scan_folios
When enabling vmscan tracing, it is observed that nr_requested is always
4096, which is confusing.

        mm_vmscan_lru_isolate: classzone=3 order=0 nr_requested=4096 ...
        mm_vmscan_lru_isolate: classzone=3 order=0 nr_requested=4096 ...
        mm_vmscan_lru_isolate: classzone=3 order=0 nr_requested=4096 ...
        mm_vmscan_lru_isolate: classzone=3 order=0 nr_requested=4096 ...
        mm_vmscan_lru_isolate: classzone=3 order=0 nr_requested=4096 ...
        mm_vmscan_lru_isolate: classzone=3 order=0 nr_requested=4096 ...
        mm_vmscan_lru_isolate: classzone=3 order=0 nr_requested=4096 ...

This is because it prints MAX_LRU_BATCH, which is meaningless as it's a
constant.  To fix this, modify it to print capped valued.

Link: https://lkml.kernel.org/r/20251204122355.1822919-1-chenridong@huaweicloud.com
Fixes: 8c2214fc9a ("mm: multi-gen LRU: reuse some legacy trace events")
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Jaewon Kim <jaewon31.kim@samsung.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Lu Jialin <lujialin4@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-12-09 11:25:34 -08:00
Zi Yan
5842bcbfc3 mm/huge_memory: replace can_split_folio() with direct refcount calculation
can_split_folio() is just a refcount comparison, making sure only the
split caller holds an extra pin.  Open code it with
folio_expected_ref_count() != folio_ref_count() - 1.  For the extra_pins
used by folio_ref_freeze(), add folio_cache_ref_count() to calculate it. 
Also replace folio_expected_ref_count() with folio_cache_ref_count() used
by folio_ref_unfreeze(), since they are returning the same values when a
folio is frozen and folio_cache_ref_count() does not have unnecessary
folio_mapcount() in its implementation.

Link: https://lkml.kernel.org/r/20251126210618.1971206-3-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Suggested-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-12-09 11:25:32 -08:00
Linus Torvalds
7203ca412f Merge tag 'mm-stable-2025-12-03-21-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:

  "__vmalloc()/kvmalloc() and no-block support" (Uladzislau Rezki)
     Rework the vmalloc() code to support non-blocking allocations
     (GFP_ATOIC, GFP_NOWAIT)

  "ksm: fix exec/fork inheritance" (xu xin)
     Fix a rare case where the KSM MMF_VM_MERGE_ANY prctl state is not
     inherited across fork/exec

  "mm/zswap: misc cleanup of code and documentations" (SeongJae Park)
     Some light maintenance work on the zswap code

  "mm/page_owner: add debugfs files 'show_handles' and 'show_stacks_handles'" (Mauricio Faria de Oliveira)
     Enhance the /sys/kernel/debug/page_owner debug feature by adding
     unique identifiers to differentiate the various stack traces so
     that userspace monitoring tools can better match stack traces over
     time

  "mm/page_alloc: pcp->batch cleanups" (Joshua Hahn)
     Minor alterations to the page allocator's per-cpu-pages feature

  "Improve UFFDIO_MOVE scalability by removing anon_vma lock" (Lokesh Gidra)
     Address a scalability issue in userfaultfd's UFFDIO_MOVE operation

  "kasan: cleanups for kasan_enabled() checks" (Sabyrzhan Tasbolatov)

  "drivers/base/node: fold node register and unregister functions" (Donet Tom)
     Clean up the NUMA node handling code a little

  "mm: some optimizations for prot numa" (Kefeng Wang)
     Cleanups and small optimizations to the NUMA allocation hinting
     code

  "mm/page_alloc: Batch callers of free_pcppages_bulk" (Joshua Hahn)
     Address long lock hold times at boot on large machines. These were
     causing (harmless) softlockup warnings

  "optimize the logic for handling dirty file folios during reclaim" (Baolin Wang)
     Remove some now-unnecessary work from page reclaim

  "mm/damon: allow DAMOS auto-tuned for per-memcg per-node memory usage" (SeongJae Park)
     Enhance the DAMOS auto-tuning feature

  "mm/damon: fixes for address alignment issues in DAMON_LRU_SORT and DAMON_RECLAIM" (Quanmin Yan)
     Fix DAMON_LRU_SORT and DAMON_RECLAIM with certain userspace
     configuration

  "expand mmap_prepare functionality, port more users" (Lorenzo Stoakes)
     Enhance the new(ish) file_operations.mmap_prepare() method and port
     additional callsites from the old ->mmap() over to ->mmap_prepare()

  "Fix stale IOTLB entries for kernel address space" (Lu Baolu)
     Fix a bug (and possible security issue on non-x86) in the IOMMU
     code. In some situations the IOMMU could be left hanging onto a
     stale kernel pagetable entry

  "mm/huge_memory: cleanup __split_unmapped_folio()" (Wei Yang)
     Clean up and optimize the folio splitting code

  "mm, swap: misc cleanup and bugfix" (Kairui Song)
     Some cleanups and a minor fix in the swap discard code

  "mm/damon: misc documentation fixups" (SeongJae Park)

  "mm/damon: support pin-point targets removal" (SeongJae Park)
     Permit userspace to remove a specific monitoring target in the
     middle of the current targets list

  "mm: MISC follow-up patches for linux/pgalloc.h" (Harry Yoo)
     A couple of cleanups related to mm header file inclusion

  "mm/swapfile.c: select swap devices of default priority round robin" (Baoquan He)
     improve the selection of swap devices for NUMA machines

  "mm: Convert memory block states (MEM_*) macros to enums" (Israel Batista)
     Change the memory block labels from macros to enums so they will
     appear in kernel debug info

  "ksm: perform a range-walk to jump over holes in break_ksm" (Pedro Demarchi Gomes)
     Address an inefficiency when KSM unmerges an address range

  "mm/damon/tests: fix memory bugs in kunit tests" (SeongJae Park)
     Fix leaks and unhandled malloc() failures in DAMON userspace unit
     tests

  "some cleanups for pageout()" (Baolin Wang)
     Clean up a couple of minor things in the page scanner's
     writeback-for-eviction code

  "mm/hugetlb: refactor sysfs/sysctl interfaces" (Hui Zhu)
     Move hugetlb's sysfs/sysctl handling code into a new file

  "introduce VM_MAYBE_GUARD and make it sticky" (Lorenzo Stoakes)
     Make the VMA guard regions available in /proc/pid/smaps and
     improves the mergeability of guarded VMAs

  "mm: perform guard region install/remove under VMA lock" (Lorenzo Stoakes)
     Reduce mmap lock contention for callers performing VMA guard region
     operations

  "vma_start_write_killable" (Matthew Wilcox)
     Start work on permitting applications to be killed when they are
     waiting on a read_lock on the VMA lock

  "mm/damon/tests: add more tests for online parameters commit" (SeongJae Park)
     Add additional userspace testing of DAMON's "commit" feature

  "mm/damon: misc cleanups" (SeongJae Park)

  "make VM_SOFTDIRTY a sticky VMA flag" (Lorenzo Stoakes)
     Address the possible loss of a VMA's VM_SOFTDIRTY flag when that
     VMA is merged with another

  "mm: support device-private THP" (Balbir Singh)
     Introduce support for Transparent Huge Page (THP) migration in zone
     device-private memory

  "Optimize folio split in memory failure" (Zi Yan)

  "mm/huge_memory: Define split_type and consolidate split support checks" (Wei Yang)
     Some more cleanups in the folio splitting code

  "mm: remove is_swap_[pte, pmd]() + non-swap entries, introduce leaf entries" (Lorenzo Stoakes)
     Clean up our handling of pagetable leaf entries by introducing the
     concept of 'software leaf entries', of type softleaf_t

  "reparent the THP split queue" (Muchun Song)
     Reparent the THP split queue to its parent memcg. This is in
     preparation for addressing the long-standing "dying memcg" problem,
     wherein dead memcg's linger for too long, consuming memory
     resources

  "unify PMD scan results and remove redundant cleanup" (Wei Yang)
     A little cleanup in the hugepage collapse code

  "zram: introduce writeback bio batching" (Sergey Senozhatsky)
     Improve zram writeback efficiency by introducing batched bio
     writeback support

  "memcg: cleanup the memcg stats interfaces" (Shakeel Butt)
     Clean up our handling of the interrupt safety of some memcg stats

  "make vmalloc gfp flags usage more apparent" (Vishal Moola)
     Clean up vmalloc's handling of incoming GFP flags

  "mm: Add soft-dirty and uffd-wp support for RISC-V" (Chunyan Zhang)
     Teach soft dirty and userfaultfd write protect tracking to use
     RISC-V's Svrsw60t59b extension

  "mm: swap: small fixes and comment cleanups" (Youngjun Park)
     Fix a small bug and clean up some of the swap code

  "initial work on making VMA flags a bitmap" (Lorenzo Stoakes)
     Start work on converting the vma struct's flags to a bitmap, so we
     stop running out of them, especially on 32-bit

  "mm/swapfile: fix and cleanup swap list iterations" (Youngjun Park)
     Address a possible bug in the swap discard code and clean things
     up a little

[ This merge also reverts commit ebb9aeb980 ("vfio/nvgrace-gpu:
  register device memory for poison handling") because it looks
  broken to me, I've asked for clarification   - Linus ]

* tag 'mm-stable-2025-12-03-21-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits)
  mm: fix vma_start_write_killable() signal handling
  mm/swapfile: use plist_for_each_entry in __folio_throttle_swaprate
  mm/swapfile: fix list iteration when next node is removed during discard
  fs/proc/task_mmu.c: fix make_uffd_wp_huge_pte() huge pte handling
  mm/kfence: add reboot notifier to disable KFENCE on shutdown
  memcg: remove inc/dec_lruvec_kmem_state helpers
  selftests/mm/uffd: initialize char variable to Null
  mm: fix DEBUG_RODATA_TEST indentation in Kconfig
  mm: introduce VMA flags bitmap type
  tools/testing/vma: eliminate dependency on vma->__vm_flags
  mm: simplify and rename mm flags function for clarity
  mm: declare VMA flags by bit
  zram: fix a spelling mistake
  mm/page_alloc: optimize lowmem_reserve max lookup using its semantic monotonicity
  mm/vmscan: skip increasing kswapd_failures when reclaim was boosted
  pagemap: update BUDDY flag documentation
  mm: swap: remove scan_swap_map_slots() references from comments
  mm: swap: change swap_alloc_slow() to void
  mm, swap: remove redundant comment for read_swap_cache_async
  mm, swap: use SWP_SOLIDSTATE to determine if swap is rotational
  ...
2025-12-05 13:52:43 -08:00
Jiayuan Chen
3cf41edc20 mm/vmscan: skip increasing kswapd_failures when reclaim was boosted
We have a colocation cluster used for deploying both offline and online
services simultaneously.  In this environment, we encountered a
scenario where direct memory reclamation was triggered due to kswapd
not running.

1. When applications start up, rapidly consume memory, or experience
   network traffic bursts, the kernel reaches steal_suitable_fallback(),
   which sets watermark_boost and subsequently wakes kswapd.

2. In the core logic of kswapd thread (balance_pgdat()), when reclaim is
   triggered by watermark_boost, the maximum priority is 10. Higher
   priority values mean less aggressive LRU scanning, which can result in
   no pages being reclaimed during a single scan cycle:

   if (nr_boost_reclaim && sc.priority == DEF_PRIORITY - 2)
       raise_priority = false;

3. Additionally, many of our pods are configured with memory.low, which
   prevents memory reclamation in certain cgroups, further increasing the
   chance of failing to reclaim memory.

4. This eventually causes pgdat->kswapd_failures to continuously
   accumulate, exceeding MAX_RECLAIM_RETRIES, and consequently kswapd
   stops working.  At this point, the system's available memory is still
   significantly above the high watermark -- it's inappropriate for kswapd
   to stop under these conditions.

The final observable issue is that a brief period of rapid memory
allocation causes kswapd to stop running, ultimately triggering direct
reclaim and making the applications unresponsive.

This problem leading to direct memory reclamation has been a
long-standing issue in our production environment.  We initially held
the simple assumption that it was caused by applications allocating
memory too rapidly for kswapd to keep up with reclamation.  However,
after we began monitoring kswapd's runtime behavior, we discovered a
different pattern:

kswapd initially exhibits very aggressive activity even when there is
still considerable free memory, but it subsequently stops running
entirely, even as memory levels approach the low watermark.

In summary, both boosted watermarks and memory.low increase the
probability of kswapd operation failures.

This patch specifically addresses the scenario involving boosted
watermarks by not incrementing kswapd_failures when reclamation fails. 
A more general solution, potentially addressing memory.low or other
cases, requires further discussion.

Link: https://lkml.kernel.org/r/53de0b3ee0b822418e909db29bfa6513faff9d36@linux.dev
Link: https://lkml.kernel.org/r/20251024022711.382238-1-jiayuan.chen@linux.dev
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-29 10:41:07 -08:00
Mateusz Guzik
4c6b40877b fs: cosmetic fixes to lru handling
1. inode_bit_waitqueue() was somehow placed between __inode_add_lru() and
   inode_add_lru(). move it up
2. assert ->i_lock is held in __inode_add_lru instead of just claiming it is
   needed
3. s/__inode_add_lru/__inode_lru_list_add/ for consistency with itself
   (inode_lru_list_del()) and similar routines for sb and io list
   management
4. push list presence check into inode_lru_list_del(), just like sb and
   io list

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://patch.msgid.link/20251029131428.654761-2-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-25 10:34:49 +01:00
Shakeel Butt
5b3eb779a2 memcg: remove __mod_lruvec_state
__mod_lruvec_state() is already safe against irqs, so there is no need to
have a separate interface (i.e.  mod_lruvec_state) which wraps calls to it
with irq disabling and reenabling.  Let's rename __mod_lruvec_state() to
mod_lruvec_state().

Link: https://lkml.kernel.org/r/20251110232008.1352063-4-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-24 15:08:54 -08:00
Baolin Wang
4f8961b295 mm: vmscan: simplify the folio refcount check in pageout()
Since we no longer attempt to write back filesystem folios in pageout()
(they will be filtered out by the following check in pageout()), and only
tmpfs/shmem folios and anonymous swapcache folios can be written back, we
can remove the redundant folio_test_private() when checking the folio's
refcount, as tmpfs/shmem and swapcache folios do not use the PG_private
flag.

While we're at it, we can open-code the folio refcount check instead of
adding a simple helper that has only one user.

Link: https://lkml.kernel.org/r/4cbbec5bb92397aa4597105f1f499aabf7a1901c.1758166683.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-20 13:43:56 -08:00
Baolin Wang
d94d9293a1 mm: vmscan: remove folio_test_private() check in pageout()
Patch series "some cleanups for pageout()", v2.

Since we no longer attempt to write back filesystem folios in pageout(),
and only tmpfs/shmem folios and anonymous swapcache folios can be written
back, we can remove the redundant folio_test_private() related logic to
simplify the logic of pageout(), as tmpfs/shmem and swapcache folios do
not use the PG_private flag.


This patch (of 2):

The folio_test_private() check in pageout() was introduced by commit
ce91b575332b ("orphaned pagecache memleak fix") in 2005 (checked from a
history tree[1]).  As the commit message mentioned, it was to address the
issue where reiserfs pagecache may be truncated while still pinned.  To
further explain, the truncation removes the page->mapping, but the page is
still listed in the VM queues because it still has buffers.

In 2008, commit a2b345642f ("Fix dirty page accounting leak with ext3
data=journal") seems to be dealing with a similar issue, where the page
becomes dirty after truncation, and it provides a very useful call stack:

truncate_complete_page()
      cancel_dirty_page() // PG_dirty cleared, decr. dirty pages
      do_invalidatepage()
        ext3_invalidatepage()
          journal_invalidatepage()
            journal_unmap_buffer()
              __dispose_buffer()
                __journal_unfile_buffer()
                  __journal_temp_unlink_buffer()
                    mark_buffer_dirty(); // PG_dirty set, incr. dirty pages

In this commit a2b345642f, we forcefully clear the page's dirty flag
during truncation (in truncate_complete_page()).

Now it seems this was just a peculiar usage specific to reiserfs.  Maybe
reiserfs had some extra refcount on these pages, which caused them to pass
the is_page_cache_freeable() check.

With the fix provided by commit a2b345642f and reiserfs being removed
in 2024 by commit fb6f20ecb1 ("reiserfs: The last commit"), such a case
is unlikely to occur again.  So let's remove the redundant
folio_test_private() checks and related buffer_head release logic, and
just leave a warning here to catch such a bug.

[akpm@linux-foundation.org: redo comment, per David]
  Link: https://lkml.kernel.org/r/17d1b293-e393-4989-a357-7eea74b3c805@redhat.com
[baolin.wang@linux.alibaba.com: remove comment and WARNing, per Hugh and others]
  Link: https://lkml.kernel.org/r/392a9ca3-31ac-4447-bd44-3c656d63e4ca@linux.alibaba.com
Link: https://lkml.kernel.org/r/cover.1758166683.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/9ef0e560dc83650bc538eb5dcd1594e112c1369f.1758166683.git.baolin.wang@linux.alibaba.com
Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git [1]
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-20 13:43:56 -08:00
Kairui Song
a983471cfc mm, swap: cleanup swap entry allocation parameter
We no longer need this GFP parameter after commit 8578e0c00d ("mm, swap:
use the swap table for the swap cache and switch API").  Before that
commit the GFP parameter is already almost identical for all callers, so
nothing changed by that commit.  Swap table just moved the GFP to lower
layer and make it more defined and changes depend on atomic or sleep
allocation.

Now this parameter is no longer used, just remove it.  No behavior change.

Link: https://lkml.kernel.org/r/20251024-swap-clean-after-swap-table-p1-v2-3-a709469052e7@tencent.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Acked-by: Chris Li <chrisl@kernel.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:20 -08:00
Baolin Wang
2f05435df9 mm: vmscan: simplify the logic for activating dirty file folios
After commit 6b0dfabb35 ("fs: Remove aops->writepage"), we no longer
attempt to write back filesystem folios through reclaim.

However, in the shrink_folio_list() function, there still remains some
logic related to writeback control of dirty file folios.  The original
logic was that, for direct reclaim, or when folio_test_reclaim() is false,
or the PGDAT_DIRTY flag is not set, the dirty file folios would be
directly activated to avoid being scanned again; otherwise, it will try to
writeback the dirty file folios.  However, since we can no longer perform
writeback on dirty folios, the dirty file folios will still be activated.

Additionally, under the original logic, if we continue to try writeback
dirty file folios, we will also check the references flag,
sc->may_writepage, and may_enter_fs(), which may result in dirty file
folios being left in the inactive list.  This is unreasonable.  Even if
these dirty folios are scanned again, we still cannot clean them.

Therefore, the checks on these dirty file folios appear to be redundant
and can be removed.  Dirty file folios should be directly moved to the
active list to avoid being scanned again.  Since we set the PG_reclaim
flag for the dirty folios, once the writeback is completed, they will be
moved back to the tail of the inactive list to be retried for quick
reclaim.

Link: https://lkml.kernel.org/r/ba5c49955fd93c6850bcc19abf0e02e1573768aa.1760687075.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:06 -08:00
Baolin Wang
b34619af9c mm: vmscan: filter out the dirty file folios for node_reclaim()
Patch series "optimize the logic for handling dirty file folios during
reclaim", v2.

Since we no longer attempt to write back filesystem folios during reclaim,
some logic for handling dirty file folios in the reclaim process also
needs to be updated.  Please check the details in each patch.  


This patch (of 2):

After commit 6b0dfabb35 ("fs: Remove aops->writepage"), we no longer
attempt to write back filesystem folios in pageout(), and only tmpfs/shmem
folios and anonymous swapcache folios can be written back.  Therefore, we
should also filter out the dirty filesystem folios for node_reclaim() to
avoid unnecessary LRU scans.

Link: https://lkml.kernel.org/r/cover.1760687075.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/c91f5ecc5152b647904c7503618a01885d913928.1760687075.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:06 -08:00
Fushuai Wang
bd63d0fde2 mm/vmscan: remove redundant __GFP_NOWARN
The __GFP_NOWARN flag was included in GFP_NOWAIT since commit 16f5dfbc85
("gfp: include __GFP_NOWARN in GFP_NOWAIT").  So remove the redundant
__GFP_NOWARN flag.

Link: https://lkml.kernel.org/r/20251006014948.44695-1-wangfushuai@baidu.com
Signed-off-by: Fushuai Wang <wangfushuai@baidu.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:27:56 -08:00
Anshuman Khandual
c0efdb373c mm: replace READ_ONCE() with standard page table accessors
Replace all READ_ONCE() with a standard page table accessors i.e
pxdp_get() that defaults into READ_ONCE() in cases where platform does not
override.

Link: https://lkml.kernel.org/r/20251007063100.2396936-1-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:27:56 -08:00
Chanwon Park
e7a5f249e6 mm: re-enable kswapd when memory pressure subsides or demotion is toggled
If kswapd fails to reclaim pages from a node MAX_RECLAIM_RETRIES in a
row, kswapd on that node gets disabled. That is, the system won't wakeup
kswapd for that node until page reclamation is observed at least once.
That reclamation is mostly done by direct reclaim, which in turn enables
kswapd back.

However, on systems with CXL memory nodes, workloads with high anon page
usage can disable kswapd indefinitely, without triggering direct
reclaim. This can be reproduced with following steps:

   numa node 0   (32GB memory, 48 CPUs)
   numa node 2~5 (512GB CXL memory, 128GB each)
   (numa node 1 is disabled)
   swap space 8GB

   1) Set /sys/kernel/mm/demotion_enabled to 0.
   2) Set /proc/sys/kernel/numa_balancing to 0.
   3) Run a process that allocates and random accesses 500GB of anon
      pages.
   4) Let the process exit normally.

During 3), free memory on node 0 gets lower than low watermark, and
kswapd runs and depletes swap space. Then, kswapd fails consecutively
and gets disabled. Allocation afterwards happens on CXL memory, so node
0 never gains more memory pressure to trigger direct reclaim.

After 4), kswapd on node 0 remains disabled, and tasks running on that
node are unable to swap. If you turn on NUMA_BALANCING_MEMORY_TIERING
and demotion now, it won't work properly since kswapd is disabled.

To mitigate this problem, reset kswapd_failures to 0 on following
conditions:

   a) ZONE_BELOW_HIGH bit of a zone in hopeless node with a fallback
      memory node gets cleared.
   b) demotion_enabled is changed from false to true.

Rationale for a):
   ZONE_BELOW_HIGH bit being cleared might be a sign that the node may
   be reclaimable afterwards. This won't help much if the memory-hungry
   process keeps running without freeing anything, but at least the node
   will go back to reclaimable state when the process exits.

Rationale for b):
   When demotion_enabled is false, kswapd can only reclaim anon pages by
   swapping them out to swap space. If demotion_enabled is turned on,
   kswapd can demote anon pages to another node for reclaiming. So, the
   original failure count for determining reclaimability is no longer
   valid.

Since kswapd_failures resets may be missed by ++ operation, it is
changed from int to atomic_t.

[akpm@linux-foundation.org: tweak whitespace]
Link: https://lkml.kernel.org/r/aL6qGi69jWXfPc4D@pcw-MS-7D22
Signed-off-by: Chanwon Park <flyinrm@gmail.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-09-21 14:22:29 -07:00
Kairui Song
8578e0c00d mm, swap: use the swap table for the swap cache and switch API
Introduce basic swap table infrastructures, which are now just a
fixed-sized flat array inside each swap cluster, with access wrappers.

Each cluster contains a swap table of 512 entries.  Each table entry is an
opaque atomic long.  It could be in 3 types: a shadow type (XA_VALUE), a
folio type (pointer), or NULL.

In this first step, it only supports storing a folio or shadow, and it is
a drop-in replacement for the current swap cache.  Convert all swap cache
users to use the new sets of APIs.  Chris Li has been suggesting using a
new infrastructure for swap cache for better performance, and that idea
combined well with the swap table as the new backing structure.  Now the
lock contention range is reduced to 2M clusters, which is much smaller
than the 64M address_space.  And we can also drop the multiple
address_space design.

All the internal works are done with swap_cache_get_* helpers.  Swap cache
lookup is still lock-less like before, and the helper's contexts are same
with original swap cache helpers.  They still require a pin on the swap
device to prevent the backing data from being freed.

Swap cache updates are now protected by the swap cluster lock instead of
the XArray lock.  This is mostly handled internally, but new
__swap_cache_* helpers require the caller to lock the cluster.  So, a few
new cluster access and locking helpers are also introduced.

A fully cluster-based unified swap table can be implemented on top of this
to take care of all count tracking and synchronization work, with dynamic
allocation.  It should reduce the memory usage while making the
performance even better.

Link: https://lkml.kernel.org/r/20250916160100.31545-12-ryncsn@gmail.com
Co-developed-by: Chris Li <chrisl@kernel.org>
Signed-off-by: Chris Li <chrisl@kernel.org>
Signed-off-by: Kairui Song <kasong@tencent.com>
Acked-by: Chris Li <chrisl@kernel.org>
Suggested-by: Chris Li <chrisl@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: kernel test robot <oliver.sang@intel.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-09-21 14:22:24 -07:00
Kairui Song
fd8d4f862f mm, swap: cleanup swap cache API and add kerneldoc
In preparation for replacing the swap cache backend with the swap table,
clean up and add proper kernel doc for all swap cache APIs.  Now all swap
cache APIs are well-defined with consistent names.

No feature change, only renaming and documenting.

Link: https://lkml.kernel.org/r/20250916160100.31545-9-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Acked-by: Chris Li <chrisl@kernel.org>
Reviewed-by: Barry Song <baohua@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Suggested-by: Chris Li <chrisl@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: kernel test robot <oliver.sang@intel.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-09-21 14:22:23 -07:00
Andrew Morton
bc9950b56f Merge branch 'mm-hotfixes-stable' into mm-stable in order to pick up
changes required by mm-stable material: hugetlb and damon.
2025-09-21 14:19:36 -07:00
liuqiqi
4bd22a7ae5 mm: fix duplicate accounting of free pages in should_reclaim_retry()
In the zone_reclaimable_pages() function, if the page counts for
NR_ZONE_INACTIVE_FILE, NR_ZONE_ACTIVE_FILE, NR_ZONE_INACTIVE_ANON, and
NR_ZONE_ACTIVE_ANON are all zero, the function returns the number of free
pages as the result.

In this case, when should_reclaim_retry() calculates reclaimable pages, it
will inadvertently double-count the free pages in its accounting.

static inline bool
should_reclaim_retry(gfp_t gfp_mask, unsigned order,
                     struct alloc_context *ac, int alloc_flags,
                     bool did_some_progress, int *no_progress_loops)
{
        ...
                available = reclaimable = zone_reclaimable_pages(zone);
                available += zone_page_state_snapshot(zone, NR_FREE_PAGES);

This may result in an increase in the number of retries of
__alloc_pages_slowpath(), causing increased kswapd load.

Link: https://lkml.kernel.org/r/20250812070210.1624218-1-liuqiqi@kylinos.cn
Fixes: 6aaced5abd ("mm: vmscan: account for free pages to prevent infinite Loop in throttle_direct_reclaim()")
Signed-off-by: liuqiqi <liuqiqi@kylinos.cn>
Reviewed-by: Ye Liu <liuye@kylinos.cn>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-09-13 16:55:10 -07:00
Matthew Wilcox (Oracle)
53fbef56e0 mm: introduce memdesc_flags_t
Patch series "Add and use memdesc_flags_t".

At some point struct page will be separated from struct slab and struct
folio.  This is a step towards that by introducing a type for the 'flags'
word of all three structures.  This gives us a certain amount of type
safety by establishing that some of these unsigned longs are different
from other unsigned longs in that they contain things like node ID,
section number and zone number in the upper bits.  That lets us have
functions that can be easily called by anyone who has a slab, folio or
page (but not easily by anyone else) to get the node or zone.

There's going to be some unusual merge problems with this as some odd bits
of the kernel decide they want to print out the flags value or something
similar by writing page->flags and now they'll need to write page->flags.f
instead.  That's most of the churn here.  Maybe we should be removing
these things from the debug output?


This patch (of 11):

Wrap the unsigned long flags in a typedef.  In upcoming patches, this will
provide a strong hint that you can't just pass a random unsigned long to
functions which take this as an argument.

[willy@infradead.org: s/flags/flags.f/ in several architectures]
  Link: https://lkml.kernel.org/r/aKMgPRLD-WnkPxYm@casper.infradead.org
[nicola.vetrini@gmail.com: mips: fix compilation error]
  Link: https://lore.kernel.org/lkml/CA+G9fYvkpmqGr6wjBNHY=dRp71PLCoi2341JxOudi60yqaeUdg@mail.gmail.com/
  Link: https://lkml.kernel.org/r/20250825214245.1838158-1-nicola.vetrini@gmail.com
Link: https://lkml.kernel.org/r/20250805172307.1302730-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20250805172307.1302730-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Zi Yan <ziy@nvidia.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-09-13 16:55:07 -07:00
Hao Jia
915a4022b5 mm/mglru: update MG-LRU proactive reclaim statistics only to memcg
Users can use /sys/kernel/debug/lru_gen to trigger proactive memory
reclaim of a specified memcg.  Currently, statistics such as pgrefill,
pgscan and pgsteal will be updated to the /proc/vmstat system memory
statistics.

This will confuse some system memory pressure monitoring tools, making it
difficult to determine whether pgscan and pgsteal are caused by
system-level pressure or by proactive memory reclaim of some specific
memory cgroup.

Therefore, make this interface behave similarly to memory.reclaim.  Update
proactive memory reclaim statistics only to its memory cgroup.

Link: https://lkml.kernel.org/r/20250717082845.34673-1-jiahao.kernel@gmail.com
Signed-off-by: Hao Jia <jiahao1@lixiang.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kinsey Ho <kinseyho@google.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-09-13 16:54:42 -07:00
Hugh Dickins
8d79ed36bf mm: revert "mm: vmscan.c: fix OOM on swap stress test"
This reverts commit 0885ef4705: that was a fix to the reverted
33dfe9204f.

Link: https://lkml.kernel.org/r/aa0e9d67-fbcd-9d79-88a1-641dfbe1d9d1@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Keir Fraser <keirf@google.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Li Zhe <lizhe.67@bytedance.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shivank Garg <shivankg@amd.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Xu <weixugc@google.com>
Cc: Will Deacon <will@kernel.org>
Cc: yangge <yangge1116@126.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-09-13 13:05:36 -07:00
Danilo Krummrich
eb5ca9094a mm/vmscan: fix inverted polarity in lru_gen_seq_show()
Commit a7694ff11a ("vmscan: don't bother with debugfs_real_fops()")
started using debugfs_get_aux_num() to distinguish between the RW
"lru_gen" and the RO "lru_gen_full" file [1].

Willy reported the inverted polarity [2] and Al fixed it up in [3].

However, the patch in [1] was applied. Hence, fix this up accordingly.

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/all/20250704040720.GP1880847@ZenIV/ [1]
Link: https://lore.kernel.org/all/aGZu3Z730FQtqxsE@casper.infradead.org/ [2]
Link: https://lore.kernel.org/all/20250704040720.GP1880847@ZenIV/ [3]
Fixes: a7694ff11a ("vmscan: don't bother with debugfs_real_fops()")
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250727105937.7480-1-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-08-10 19:02:56 +02:00
Linus Torvalds
beace86e61 Merge tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
 "As usual, many cleanups. The below blurbiage describes 42 patchsets.
  21 of those are partially or fully cleanup work. "cleans up",
  "cleanup", "maintainability", "rationalizes", etc.

  I never knew the MM code was so dirty.

  "mm: ksm: prevent KSM from breaking merging of new VMAs" (Lorenzo Stoakes)
     addresses an issue with KSM's PR_SET_MEMORY_MERGE mode: newly
     mapped VMAs were not eligible for merging with existing adjacent
     VMAs.

  "mm/damon: introduce DAMON_STAT for simple and practical access monitoring" (SeongJae Park)
     adds a new kernel module which simplifies the setup and usage of
     DAMON in production environments.

  "stop passing a writeback_control to swap/shmem writeout" (Christoph Hellwig)
     is a cleanup to the writeback code which removes a couple of
     pointers from struct writeback_control.

  "drivers/base/node.c: optimization and cleanups" (Donet Tom)
     contains largely uncorrelated cleanups to the NUMA node setup and
     management code.

  "mm: userfaultfd: assorted fixes and cleanups" (Tal Zussman)
     does some maintenance work on the userfaultfd code.

  "Readahead tweaks for larger folios" (Ryan Roberts)
     implements some tuneups for pagecache readahead when it is reading
     into order>0 folios.

  "selftests/mm: Tweaks to the cow test" (Mark Brown)
     provides some cleanups and consistency improvements to the
     selftests code.

  "Optimize mremap() for large folios" (Dev Jain)
     does that. A 37% reduction in execution time was measured in a
     memset+mremap+munmap microbenchmark.

  "Remove zero_user()" (Matthew Wilcox)
     expunges zero_user() in favor of the more modern memzero_page().

  "mm/huge_memory: vmf_insert_folio_*() and vmf_insert_pfn_pud() fixes" (David Hildenbrand)
     addresses some warts which David noticed in the huge page code.
     These were not known to be causing any issues at this time.

  "mm/damon: use alloc_migrate_target() for DAMOS_MIGRATE_{HOT,COLD" (SeongJae Park)
     provides some cleanup and consolidation work in DAMON.

  "use vm_flags_t consistently" (Lorenzo Stoakes)
     uses vm_flags_t in places where we were inappropriately using other
     types.

  "mm/memfd: Reserve hugetlb folios before allocation" (Vivek Kasireddy)
     increases the reliability of large page allocation in the memfd
     code.

  "mm: Remove pXX_devmap page table bit and pfn_t type" (Alistair Popple)
     removes several now-unneeded PFN_* flags.

  "mm/damon: decouple sysfs from core" (SeongJae Park)
     implememnts some cleanup and maintainability work in the DAMON
     sysfs layer.

  "madvise cleanup" (Lorenzo Stoakes)
     does quite a lot of cleanup/maintenance work in the madvise() code.

  "madvise anon_name cleanups" (Vlastimil Babka)
     provides additional cleanups on top or Lorenzo's effort.

  "Implement numa node notifier" (Oscar Salvador)
     creates a standalone notifier for NUMA node memory state changes.
     Previously these were lumped under the more general memory
     on/offline notifier.

  "Make MIGRATE_ISOLATE a standalone bit" (Zi Yan)
     cleans up the pageblock isolation code and fixes a potential issue
     which doesn't seem to cause any problems in practice.

  "selftests/damon: add python and drgn based DAMON sysfs functionality tests" (SeongJae Park)
     adds additional drgn- and python-based DAMON selftests which are
     more comprehensive than the existing selftest suite.

  "Misc rework on hugetlb faulting path" (Oscar Salvador)
     fixes a rather obscure deadlock in the hugetlb fault code and
     follows that fix with a series of cleanups.

  "cma: factor out allocation logic from __cma_declare_contiguous_nid" (Mike Rapoport)
     rationalizes and cleans up the highmem-specific code in the CMA
     allocator.

  "mm/migration: rework movable_ops page migration (part 1)" (David Hildenbrand)
     provides cleanups and future-preparedness to the migration code.

  "mm/damon: add trace events for auto-tuned monitoring intervals and DAMOS quota" (SeongJae Park)
     adds some tracepoints to some DAMON auto-tuning code.

  "mm/damon: fix misc bugs in DAMON modules" (SeongJae Park)
     does that.

  "mm/damon: misc cleanups" (SeongJae Park)
     also does what it claims.

  "mm: folio_pte_batch() improvements" (David Hildenbrand)
     cleans up the large folio PTE batching code.

  "mm/damon/vaddr: Allow interleaving in migrate_{hot,cold} actions" (SeongJae Park)
     facilitates dynamic alteration of DAMON's inter-node allocation
     policy.

  "Remove unmap_and_put_page()" (Vishal Moola)
     provides a couple of page->folio conversions.

  "mm: per-node proactive reclaim" (Davidlohr Bueso)
     implements a per-node control of proactive reclaim - beyond the
     current memcg-based implementation.

  "mm/damon: remove damon_callback" (SeongJae Park)
     replaces the damon_callback interface with a more general and
     powerful damon_call()+damos_walk() interface.

  "mm/mremap: permit mremap() move of multiple VMAs" (Lorenzo Stoakes)
     implements a number of mremap cleanups (of course) in preparation
     for adding new mremap() functionality: newly permit the remapping
     of multiple VMAs when the user is specifying MREMAP_FIXED. It still
     excludes some specialized situations where this cannot be performed
     reliably.

  "drop hugetlb_free_pgd_range()" (Anthony Yznaga)
     switches some sparc hugetlb code over to the generic version and
     removes the thus-unneeded hugetlb_free_pgd_range().

  "mm/damon/sysfs: support periodic and automated stats update" (SeongJae Park)
     augments the present userspace-requested update of DAMON sysfs
     monitoring files. Automatic update is now provided, along with a
     tunable to control the update interval.

  "Some randome fixes and cleanups to swapfile" (Kemeng Shi)
     does what is claims.

  "mm: introduce snapshot_page" (Luiz Capitulino and David Hildenbrand)
     provides (and uses) a means by which debug-style functions can grab
     a copy of a pageframe and inspect it locklessly without tripping
     over the races inherent in operating on the live pageframe
     directly.

  "use per-vma locks for /proc/pid/maps reads" (Suren Baghdasaryan)
     addresses the large contention issues which can be triggered by
     reads from that procfs file. Latencies are reduced by more than
     half in some situations. The series also introduces several new
     selftests for the /proc/pid/maps interface.

  "__folio_split() clean up" (Zi Yan)
     cleans up __folio_split()!

  "Optimize mprotect() for large folios" (Dev Jain)
     provides some quite large (>3x) speedups to mprotect() when dealing
     with large folios.

  "selftests/mm: reuse FORCE_READ to replace "asm volatile("" : "+r" (XXX));" and some cleanup" (wang lian)
     does some cleanup work in the selftests code.

  "tools/testing: expand mremap testing" (Lorenzo Stoakes)
     extends the mremap() selftest in several ways, including adding
     more checking of Lorenzo's recently added "permit mremap() move of
     multiple VMAs" feature.

  "selftests/damon/sysfs.py: test all parameters" (SeongJae Park)
     extends the DAMON sysfs interface selftest so that it tests all
     possible user-requested parameters. Rather than the present minimal
     subset"

* tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (370 commits)
  MAINTAINERS: add missing headers to mempory policy & migration section
  MAINTAINERS: add missing file to cgroup section
  MAINTAINERS: add MM MISC section, add missing files to MISC and CORE
  MAINTAINERS: add missing zsmalloc file
  MAINTAINERS: add missing files to page alloc section
  MAINTAINERS: add missing shrinker files
  MAINTAINERS: move memremap.[ch] to hotplug section
  MAINTAINERS: add missing mm_slot.h file THP section
  MAINTAINERS: add missing interval_tree.c to memory mapping section
  MAINTAINERS: add missing percpu-internal.h file to per-cpu section
  mm/page_alloc: remove trace_mm_alloc_contig_migrate_range_info()
  selftests/damon: introduce _common.sh to host shared function
  selftests/damon/sysfs.py: test runtime reduction of DAMON parameters
  selftests/damon/sysfs.py: test non-default parameters runtime commit
  selftests/damon/sysfs.py: generalize DAMON context commit assertion
  selftests/damon/sysfs.py: generalize monitoring attributes commit assertion
  selftests/damon/sysfs.py: generalize DAMOS schemes commit assertion
  selftests/damon/sysfs.py: test DAMOS filters commitment
  selftests/damon/sysfs.py: generalize DAMOS scheme commit assertion
  selftests/damon/sysfs.py: test DAMOS destinations commitment
  ...
2025-07-31 14:57:54 -07:00
Linus Torvalds
22c5696e3f Merge tag 'driver-core-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core
Pull driver core updates from Danilo Krummrich:
 "debugfs:
   - Remove unneeded debugfs_file_{get,put}() instances
   - Remove last remnants of debugfs_real_fops()
   - Allow storing non-const void * in struct debugfs_inode_info::aux

  sysfs:
   - Switch back to attribute_group::bin_attrs (treewide)
   - Switch back to bin_attribute::read()/write() (treewide)
   - Constify internal references to 'struct bin_attribute'

  Support cache-ids for device-tree systems:
   - Add arch hook arch_compact_of_hwid()
   - Use arch_compact_of_hwid() to compact MPIDR values on arm64

  Rust:
   - Device:
       - Introduce CoreInternal device context (for bus internal methods)
       - Provide generic drvdata accessors for bus devices
       - Provide Driver::unbind() callbacks
       - Use the infrastructure above for auxiliary, PCI and platform
       - Implement Device::as_bound()
       - Rename Device::as_ref() to Device::from_raw() (treewide)
       - Implement fwnode and device property abstractions
       - Implement example usage in the Rust platform sample driver
   - Devres:
       - Remove the inner reference count (Arc) and use pin-init instead
       - Replace Devres::new_foreign_owned() with devres::register()
       - Require T to be Send in Devres<T>
       - Initialize the data kept inside a Devres last
       - Provide an accessor for the Devres associated Device
   - Device ID:
       - Add support for ACPI device IDs and driver match tables
       - Split up generic device ID infrastructure
       - Use generic device ID infrastructure in net::phy
   - DMA:
       - Implement the dma::Device trait
       - Add DMA mask accessors to dma::Device
       - Implement dma::Device for PCI and platform devices
       - Use DMA masks from the DMA sample module
   - I/O:
       - Implement abstraction for resource regions (struct resource)
       - Implement resource-based ioremap() abstractions
       - Provide platform device accessors for I/O (remap) requests
   - Misc:
       - Support fallible PinInit types in Revocable
       - Implement Wrapper<T> for Opaque<T>
       - Merge pin-init blanket dependencies (for Devres)

  Misc:
   - Fix OF node leak in auxiliary_device_create()
   - Use util macros in device property iterators
   - Improve kobject sample code
   - Add device_link_test() for testing device link flags
   - Fix typo in Documentation/ABI/testing/sysfs-kernel-address_bits
   - Hint to prefer container_of_const() over container_of()"

* tag 'driver-core-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core: (84 commits)
  rust: io: fix broken intra-doc links to `platform::Device`
  rust: io: fix broken intra-doc link to missing `flags` module
  rust: io: mem: enable IoRequest doc-tests
  rust: platform: add resource accessors
  rust: io: mem: add a generic iomem abstraction
  rust: io: add resource abstraction
  rust: samples: dma: set DMA mask
  rust: platform: implement the `dma::Device` trait
  rust: pci: implement the `dma::Device` trait
  rust: dma: add DMA addressing capabilities
  rust: dma: implement `dma::Device` trait
  rust: net::phy Change module_phy_driver macro to use module_device_table macro
  rust: net::phy represent DeviceId as transparent wrapper over mdio_device_id
  rust: device_id: split out index support into a separate trait
  device: rust: rename Device::as_ref() to Device::from_raw()
  arm64: cacheinfo: Provide helper to compress MPIDR value into u32
  cacheinfo: Add arch hook to compress CPU h/w id into 32 bits for cache-id
  cacheinfo: Set cache 'id' based on DT data
  container_of: Document container_of() is not to be used in new code
  driver core: auxiliary bus: fix OF node leak
  ...
2025-07-29 12:15:39 -07:00
Hugh Dickins
3865301dc5 mm: optimize lru_note_cost() by adding lru_note_cost_unlock_irq()
Dropping a lock, just to demand it again for an afterthought, cannot be
good if contended: convert lru_note_cost() to lru_note_cost_unlock_irq().

[hughd@google.com: delete unneeded comment]
  Link: https://lkml.kernel.org/r/dbf9352a-1ed9-a021-c0c7-9309ac73e174@google.com
Link: https://lkml.kernel.org/r/21100102-51b6-79d5-03db-1bb7f97fa94c@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Tested-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: David Hildenbrand <david@redhat.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-07-24 19:12:28 -07:00
Hao Jia
526660b950 mm/mglru: stop try_to_inc_min_seq() if min_seq[type] has not increased
In try_to_inc_min_seq(), if min_seq[type] has not increased.  In other
words, min_seq[type] == lrugen->min_seq[type].  Then we should return
directly to avoid unnecessary overhead later.

Corollary: If min_seq[type] of both anonymous and file is not increased,
try_to_inc_min_seq() will fail.

Proof:
It is known that min_seq[type] has not increased, that is, min_seq[type]
is equal to lrugen->min_seq[type], then the following:

case 1: min_seq[type] has not been reassigned and changed before
judgment min_seq[type] <= lrugen->min_seq[type].
Then the subsequent min_seq[type] <= lrugen->min_seq[type] judgment
will always be true.

case 2: min_seq[type] is reassigned to seq, before judgment
min_seq[type] <= lrugen->min_seq[type].
Then at least the condition of min_seq[type] > seq must be met
before min_seq[type] will be reassigned to seq.
That is to say, before the reassignment, lrugen->min_seq[type] > seq
is met, and then min_seq[type] = seq.
Then the following min_seq[type](seq) <= lrugen->min_seq[type] judgment
is always true.

Therefore, in try_to_inc_min_seq(), If min_seq[type] of both anonymous
and file is not increased, we can return false directly to avoid
unnecessary overhead.

Link: https://lkml.kernel.org/r/20250703023946.65315-1-jiahao.kernel@gmail.com
Signed-off-by: Hao Jia <jiahao1@lixiang.com>
Suggested-by: Yuanchu Xie <yuanchu@google.com>
Reviewed-by: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kinsey Ho <kinseyho@google.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-07-24 19:12:28 -07:00
Jinjiang Tu
9f1e8cd0b7 mm/vmscan: fix hwpoisoned large folio handling in shrink_folio_list
In shrink_folio_list(), the hwpoisoned folio may be large folio, which
can't be handled by unmap_poisoned_folio().  For THP, try_to_unmap_one()
must be passed with TTU_SPLIT_HUGE_PMD to split huge PMD first and then
retry.  Without TTU_SPLIT_HUGE_PMD, we will trigger null-ptr deref of
pvmw.pte.  Even we passed TTU_SPLIT_HUGE_PMD, we will trigger a
WARN_ON_ONCE due to the page isn't in swapcache.

Since UCE is rare in real world, and race with reclaimation is more rare,
just skipping the hwpoisoned large folio is enough.  memory_failure() will
handle it if the UCE is triggered again.

This happens when memory reclaim for large folio races with
memory_failure(), and will lead to kernel panic.  The race is as
follows:

cpu0      cpu1
 shrink_folio_list memory_failure
  TestSetPageHWPoison
  unmap_poisoned_folio
  --> trigger BUG_ON due to
  unmap_poisoned_folio couldn't
   handle large folio

[tujinjiang@huawei.com: add comment to unmap_poisoned_folio()]
  Link: https://lkml.kernel.org/r/69fd4e00-1b13-d5f7-1c82-705c7d977ea4@huawei.com
Link: https://lkml.kernel.org/r/20250627125747.3094074-2-tujinjiang@huawei.com
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
Fixes: 1b0449544c ("mm/vmscan: don't try to reclaim hwpoison folio")
Reported-by: syzbot+3b220254df55d8ca8a61@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/68412d57.050a0220.2461cf.000e.GAE@google.com/
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-07-19 19:26:15 -07:00
Davidlohr Bueso
b980077899 mm: introduce per-node proactive reclaim interface
This adds support for allowing proactive reclaim in general on a NUMA
system.  A per-node interface extends support for beyond a memcg-specific
interface, respecting the current semantics of memory.reclaim: respecting
aging LRU and not supporting artificially triggering eviction on nodes
belonging to non-bottom tiers.

This patch allows userspace to do:

     echo "512M swappiness=10" > /sys/devices/system/node/nodeX/reclaim

One of the premises for this is to semantically align as best as possible
with memory.reclaim.  During a brief time memcg did support nodemask until
55ab834a86 (Revert "mm: add nodes= arg to memory.reclaim"), for which
semantics around reclaim (eviction) vs demotion were not clear, rendering
charging expectations to be broken.

With this approach:

1. Users who do not use memcg can benefit from proactive reclaim.  The
   memcg interface is not NUMA aware and there are usecases that are
   focusing on NUMA balancing rather than workload memory footprint.

2. Proactive reclaim on top tiers will trigger demotion, for which
   memory is still byte-addressable.  Reclaiming on the bottom nodes will
   trigger evicting to swap (the traditional sense of reclaim).  This
   follows the semantics of what is today part of the aging process on
   tiered memory, mirroring what every other form of reclaim does
   (reactive and memcg proactive reclaim).  Furthermore per-node proactive
   reclaim is not as susceptible to the memcg charging problem mentioned
   above.

3. Unlike the nodes= arg, this interface avoids confusing semantics,
   such as what exactly the user wants when mixing top-tier and low-tier
   nodes in the nodemask.  Further per-node interface is less exposed to
   "free up memory in my container" usecases, where eviction is intended.

4. Users that *really* want to free up memory can use proactive
   reclaim on nodes knowingly to be on the bottom tiers to force eviction
   in a natural way - higher access latencies are still better than swap. 
   If compelled, while no guarantees and perhaps not worth the effort,
   users could also also potentially follow a ladder-like approach to
   eventually free up the memory.  Alternatively, perhaps an 'evict'
   option could be added to the parameters for both memory.reclaim and
   per-node interfaces to force this action unconditionally.

[akpm@linux-foundation.org: user_proactive_reclaim(): return -EBUSY on PGDAT_RECLAIM_LOCKED contention, per Roman]
[dave@stgolabs.net: memcg && node is also a bogus case, per Shakeel]
  Link: https://lkml.kernel.org/r/20250717235604.2atyx2aobwowpge3@offworld
Link: https://lkml.kernel.org/r/20250623185851.830632-5-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-07-19 18:59:53 -07:00
Davidlohr Bueso
57972c78e6 mm/vmscan: make __node_reclaim() more generic
As this will be called from non page allocator paths for proactive
reclaim, allow users to pass the sc and nr of pages, and adjust the return
value as well.  No change in semantics.

Link: https://lkml.kernel.org/r/20250623185851.830632-4-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-07-19 18:59:52 -07:00
Davidlohr Bueso
2b7226af73 mm/memcg: make memory.reclaim interface generic
This adds a general call for both parsing as well as the common reclaim
semantics.  memcg is still the only user and no change in semantics.

[akpm@linux-foundation.org: fix CONFIG_NUMA=n build]
Link: https://lkml.kernel.org/r/20250623185851.830632-3-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-07-19 18:59:52 -07:00
Davidlohr Bueso
7a92f4f591 mm/vmscan: respect psi_memstall region in node reclaim
Patch series "mm: per-node proactive reclaim", v2.

This adds support for allowing proactive reclaim in general on a NUMA
system.  A per-node interface extends support for beyond a memcg-specific
interface, respecting the current semantics of memory.reclaim: respecting
aging LRU and not supporting artificially triggering eviction on nodes
belonging to non-bottom tiers.

This patch allows userspace to do:

     echo 512M swappiness=10 > /sys/devices/system/node/nodeX/reclaim

One of the premises for this is to semantically align as best as possible
with memory.reclaim.  During a brief time memcg did support nodemask until
55ab834a86 (Revert "mm: add nodes= arg to memory.reclaim"), for which
semantics around reclaim (eviction) vs demotion were not clear, rendering
charging expectations to be broken.

With this approach:

1. Users who do not use memcg can benefit from proactive reclaim.

2. Proactive reclaim on top tiers will trigger demotion, for which
   memory is still byte-addressable.  Reclaiming on the bottom nodes will
   trigger evicting to swap (the traditional sense of reclaim).  This
   follows the semantics of what is today part of the aging process on
   tiered memory, mirroring what every other form of reclaim does
   (reactive and memcg proactive reclaim).  Furthermore per-node proactive
   reclaim is not as susceptible to the memcg charging problem mentioned
   above.

3. Unlike memcg, there should be no surprises of callers expecting
   reclaim but instead got a demotion.  Essentially relying on behavior of
   shrink_folio_list() after 6b426d0714 ("mm: disable top-tier fallback
   to reclaim on proactive reclaim"), without the expectations of
   try_to_free_mem_cgroup_pages().

4. Unlike the nodes= arg, this interface avoids confusing semantics,
   such as what exactly the user wants when mixing top-tier and low-tier
   nodes in the nodemask.  Further per-node interface is less exposed to
   "free up memory in my container" usecases, where eviction is intended.

5. Users that *really* want to free up memory can use proactive
   reclaim on nodes knowingly to be on the bottom tiers to force eviction
   in a natural way - higher access latencies are still better than swap. 
   If compelled, while no guarantees and perhaps not worth the effort,
   users could also also potentially follow a ladder-like approach to
   eventually free up the memory.  Alternatively, perhaps an 'evict'
   option could be added to the parameters for both memory.reclaim and
   per-node interfaces to force this action unconditionally.


This patch (of 4):

... rather benign but keep proper ending order.

Link: https://lkml.kernel.org/r/20250623185851.830632-1-dave@stgolabs.net
Link: https://lkml.kernel.org/r/20250623185851.830632-2-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-07-19 18:59:52 -07:00
David Hildenbrand
457d7b3adb mm: remove __folio_test_movable()
Convert to page_has_movable_ops().  While at it, cleanup relevant code a
bit.

The data_race() in migrate_folio_unmap() is questionable: we already hold
a page reference, and concurrent modifications can no longer happen (iow:
__ClearPageMovable() no longer exists).  Drop it for now, we'll rework
page_has_movable_ops() soon either way to no longer rely on page->mapping.

Wherever we cast from folio to page now is a clear sign that this code has
to be decoupled.

Link: https://lkml.kernel.org/r/20250704102524.326966-19-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Eugenio Pé rez <eperezma@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-07-13 16:38:29 -07:00
Alistair Popple
8a6a984c2e mm: remove redundant pXd_devmap calls
DAX was the only thing that created pmd_devmap and pud_devmap entries
however it no longer does as DAX pages are now refcounted normally and
pXd_trans_huge() returns true for those.  Therefore checking both
pXd_devmap and pXd_trans_huge() is redundant and the former can be removed
without changing behaviour as it will always be false.

Link: https://lkml.kernel.org/r/d58f089dc16b7feb7c6728164f37dea65d64a0d3.1750323463.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Björn Töpel <bjorn@kernel.org>
Cc: Björn Töpel <bjorn@rivosinc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Deepak Gupta <debug@rivosinc.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Inki Dae <m.szyprowski@samsung.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Groves <john@groves.net>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-07-09 22:42:17 -07:00