linux.git/drivers/base/node.c, branch v6.18.21

Merge tag 'mm-stable-2025-10-03-16-49' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-10-05T19:11:07+00:00

Pull more MM updates from Andrew Morton:
"Only two patch series in this pull request:

   - "mm/memory_hotplug: fixup crash during uevent handling" from Hannes
     Reinecke fixes a race that was causing udev to trigger a crash in
     the memory hotplug code

   - "mm_slot: following fixup for usage of mm_slot_entry()" from Wei
     Yang adds some touchups to the just-merged mm_slot changes"

* tag 'mm-stable-2025-10-03-16-49' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mm/khugepaged: use KMEM_CACHE()
  mm/ksm: cleanup mm_slot_entry() invocation
  Documentation/mm: drop pxx_mkdevmap() descriptions from page table helpers
  mm: clean up is_guard_pte_marker()
  drivers/base: move memory_block_add_nid() into the caller
  mm/memory_hotplug: activate node before adding new memory blocks
  drivers/base/memory: add node id parameter to add_memory_block()

Merge tag 'cxl-for-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl

2025-10-04T19:02:50+00:00

Pull CXL updates from Dave Jiang:
 "The changes include adding poison injection support, fixing CXL access
  coordinates when onlining CXL memory, and delaing the enumeration of
  downstream switch ports for CXL hierarchy to ensure that the CXL link
  is established at the time of enumeration to address a few issues
  observed on AMD and Intel platforms.

  Misc changes:
   - Use str_plural() instead of open code for emitting strings.
   - Use str_enabled_disabled() instead of ternary operator
   - Fix emit of type resource_size_t argument for
     validate_region_offset()
   - Typo fixup in CXL driver-api documentation
   - Rename CFMWS coherency restriction defines
   - Add convention doc describe dealing with x86 low memory hole
     and CXL

  Poison Inject support:
   - Move hpa_to_spa callback to new reoot decoder ops structure
   - Define a SPA to HPA callback for interleave calculation with
     XOR math
   - Add support for SPA to DPA address translation with XOR
   - Add locked variants of poison inject and clear functions
   - Add inject and clear poison support by region offset

  CXL access coordinates update fix:
   - A comment update for hotplug memory callback prority defines
   - Add node_update_perf_attrs() for updating perf attrs on a node
   - Update cxl_access_coordinates() to use the new node update function
   - Remove hmat_update_target_coordinates() and related code

  CXL delayed downstream port enumeration and initialization:
   - Add helper to detect top of CXL device topology and remove
     open coding
   - Add helper to delete single dport
   - Add a cached copy of target_map to cxl_decoder
   - Refactor decoder setup to reduce cxl_test burden
   - Defer dport allocation for switch ports
   - Add mock version of devm_cxl_add_dport_by_dev() for cxl_test
   - Adjust the mock version of devm_cxl_switch_port_decoders_setup()
     due to cxl core usage
   - Setup target_map for cxl_test decoder initialization
   - Change SSLBIS handler to handle single dport
   - Move port register setup to when first dport appears"

* tag 'cxl-for-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl: (25 commits)
  cxl: Move port register setup to when first dport appear
  cxl: Change sslbis handler to only handle single dport
  cxl/test: Setup target_map for cxl_test decoder initialization
  cxl/test: Adjust the mock version of devm_cxl_switch_port_decoders_setup()
  cxl/test: Add mock version of devm_cxl_add_dport_by_dev()
  cxl: Defer dport allocation for switch ports
  cxl/test: Refactor decoder setup to reduce cxl_test burden
  cxl: Add a cached copy of target_map to cxl_decoder
  cxl: Add helper to delete dport
  cxl: Add helper to detect top of CXL device topology
  cxl: Documentation/driver-api/cxl: Describe the x86 Low Memory Hole solution
  cxl/acpi: Rename CFMW coherency restrictions
  Documentation/driver-api: Fix typo error in cxl
  acpi/hmat: Remove now unused hmat_update_target_coordinates()
  cxl, acpi/hmat: Update CXL access coordinates directly instead of through HMAT
  drivers/base/node: Add a helper function node_update_perf_attrs()
  mm/memory_hotplug: Update comment for hotplug memory callback priorities
  cxl: Fix emit of type resource_size_t argument for validate_region_offset()
  cxl/region: Add inject and clear poison by region offset
  cxl/core: Add locked variants of the poison inject and clear funcs
  ...

drivers/base: move memory_block_add_nid() into the caller

2025-10-03T23:42:43+00:00

Now the node id only needs to be set for early memory, so move
memory_block_add_nid() into the caller and rename it into
memory_block_add_nid_early().  This allows us to further simplify the code
by dropping the 'context' argument to
do_register_memory_block_under_node().

Link: https://lkml.kernel.org/r/20250729064637.51662-4-hare@kernel.org
Suggested-by: David Hildenbrand 
Signed-off-by: Hannes Reinecke 
Acked-by: David Hildenbrand 
Acked-by: Oscar Salvador 
Reviewed-by: Donet Tom 
Signed-off-by: Andrew Morton

drivers/base/node: fix double free in register_one_node()

2025-09-28T18:51:31+00:00

When device_register() fails in register_node(), it calls
put_device(&node->dev).  This triggers node_device_release(), which calls
kfree(to_node(dev)), thereby freeing the entire node structure.

As a result, when register_node() returns an error, the node memory has
already been freed.  Calling kfree(node) again in register_one_node()
leads to a double free.

This patch removes the redundant kfree(node) from register_one_node() to
prevent the double free.

Link: https://lkml.kernel.org/r/20250918054144.58980-1-donettom@linux.ibm.com
Fixes: 786eb990cfb7 ("drivers/base/node: handle error properly in register_one_node()")
Signed-off-by: Donet Tom 
Acked-by: David Hildenbrand 
Acked-by: Oscar Salvador 
Cc: Alison Schofield 
Cc: Chris Mason 
Cc: Danilo Krummrich 
Cc: Dave Jiang 
Cc: Greg Kroah-Hartman 
Cc: Hiroyouki Kamezawa 
Cc: Joanthan Cameron 
Cc: "Ritesh Harjani (IBM)" 
Cc: Yury Norov (NVIDIA) 
Cc: Zi Yan 
Signed-off-by: Andrew Morton

drivers/base/node: handle error properly in register_one_node()

2025-09-13T23:55:17+00:00

If register_node() returns an error, it is not handled correctly.
The function will proceed further and try to register CPUs under the
node, which is not correct.

So, in this patch, if register_node() returns an error, we return
immediately from the function.

Link: https://lkml.kernel.org/r/20250822084845.19219-1-donettom@linux.ibm.com
Fixes: 76b67ed9dce6 ("[PATCH] node hotplug: register cpu: remove node struct")
Signed-off-by: Donet Tom 
Acked-by: David Hildenbrand 
Cc: Alison Schofield 
Cc: Danilo Krummrich 
Cc: Dave Jiang 
Cc: Donet Tom 
Cc: Greg Kroah-Hartman 
Cc: Hiroyouki Kamezawa 
Cc: Joanthan Cameron 
Cc: Oscar Salvador 
Cc: "Ritesh Harjani (IBM)" 
Cc: Yury Norov (NVIDIA) 
Cc: Zi Yan 
Signed-off-by: Andrew Morton

drivers/base/node: Add a helper function node_update_perf_attrs()

2025-09-02T21:46:47+00:00

Add helper function node_update_perf_attrs() to allow update of node access
coordinates computed by an external agent such as CXL. The helper allows
updating of coordinates after the attribute being created by HMAT.

Acked-by: David Hildenbrand 
Reviewed-by: Jonathan Cameron 
Link: https://patch.msgid.link/20250829222907.1290912-3-dave.jiang@intel.com
Signed-off-by: Dave Jiang

Merge tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-07-31T21:57:54+00:00

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
  ...

mm: introduce per-node proactive reclaim interface

2025-07-20T01:59:53+00:00

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
55ab834a86a9 (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 
Acked-by: Shakeel Butt 
Acked-by: Roman Gushchin 
Cc: Johannes Weiner 
Cc: Michal Hocko 
Cc: Yosry Ahmed 
Signed-off-by: Andrew Morton

mm, vmstat: remove the NR_WRITEBACK_TEMP node_stat_item counter

2025-07-20T01:59:47+00:00

The only user of the counter (FUSE) was removed in commit 0c58a97f919c
("fuse: remove tmp folio for writebacks and internal rb tree") so follow
the established pattern of removing the counter and hardcoding 0 in
meminfo output, as done recently with NR_BOUNCE.  Update documentation for
procfs, including for the value for Bounce that was missed when removing
its counter.

Also remove the mention of NR_WRITEBACK_TEMP implications from a comment
in wb_position_ratio(). The rest of the comment there about fuse setting
bdi->max_ratio to 1% is still correct.

[vbabka@suse.cz: v2]
  Link: https://lkml.kernel.org/r/5a848e15-6a57-4ecb-a015-d4f358b8a5d3@suse.cz
Link: https://lkml.kernel.org/r/20250625-nr_writeback_removal-v1-1-7f2a0df70faa@suse.cz
Signed-off-by: Vlastimil Babka 
Cc: Brendan Jackman 
Cc: Danilo Krummrich 
Cc: Greg Kroah-Hartman 
Cc: Jan Kara 
Cc: Jeff Layton 
Cc: Jeffle Xu 
Cc: Jens Axboe 
Cc: Joanne Koong 
Cc: Johannes Weiner 
Cc: Jonathan Corbet 
Cc: Kirill A. Shuemov 
Cc: Matthew Wilcox (Oracle) 
Cc: Maxim Patlasov 
Cc: Michal Hocko 
Cc: Miklos Szeredi 
Cc: Suren Baghdasaryan 
Cc: Tejun Heo 
Cc: Zach O'Keefe 
Cc: Zi Yan 
Signed-off-by: Andrew Morton

mm,memory_hotplug: implement numa node notifier

2025-07-13T23:38:15+00:00

There are at least six consumers of hotplug_memory_notifier that what they
really are interested in is whether any numa node changed its state, e.g:
going from having memory to not having memory and vice versa.

Implement a specific notifier for numa nodes when their state gets
changed, which will later be used by those consumers that are only
interested in numa node state changes.

Add documentation as well.

[dan.carpenter@linaro.org: set failure reason in offline_pages()]
  Link: https://lkml.kernel.org/r/be4fd31b-7d09-46b0-8329-6d0464ffa7a5@sabinyo.mountain
Link: https://lkml.kernel.org/r/20250616135158.450136-4-osalvador@suse.de
Signed-off-by: Oscar Salvador 
Signed-off-by: Dan Carpenter 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Harry Yoo 
Reviewed-by: Vlastimil Babka 
Acked-by: David Hildenbrand 
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Rakie Kim 
Signed-off-by: Andrew Morton