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authorLinus Torvalds <torvalds@linux-foundation.org>2025-12-05 13:52:43 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2025-12-05 13:52:43 -0800
commit7203ca412fc8e8a0588e9adc0f777d3163f8dff3 (patch)
tree7cbdcdb0bc0533f0133d472f95629099c123c3f9 /Documentation/mm
parentac20755937e037e586b1ca18a6717d31b1cbce93 (diff)
parentfaf3c923523e5c8fc3baaa413d62e913774ae52f (diff)
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 ebb9aeb980e5 ("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 ...
Diffstat (limited to 'Documentation/mm')
-rw-r--r--Documentation/mm/damon/design.rst25
-rw-r--r--Documentation/mm/damon/maintainer-profile.rst10
-rw-r--r--Documentation/mm/memory-model.rst2
-rw-r--r--Documentation/mm/page_owner.rst32
-rw-r--r--Documentation/mm/process_addrs.rst9
5 files changed, 62 insertions, 16 deletions
diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst
index 80354f4f42ba..2d8d8ca1e0a3 100644
--- a/Documentation/mm/damon/design.rst
+++ b/Documentation/mm/damon/design.rst
@@ -381,8 +381,8 @@ That is, assumes 4% (20% of 20%) DAMON-observed access events ratio (source)
to capture 64% (80% multipled by 80%) real access events (outcomes).
To know how user-space can use this feature via :ref:`DAMON sysfs interface
-<sysfs_interface>`, refer to :ref:`intervals_goal <sysfs_scheme>` part of
-the documentation.
+<sysfs_interface>`, refer to :ref:`intervals_goal
+<damon_usage_sysfs_monitoring_intervals_goal>` part of the documentation.
.. _damon_design_damos:
@@ -564,9 +564,9 @@ aggressiveness (the quota) of the corresponding scheme. For example, if DAMOS
is under achieving the goal, DAMOS automatically increases the quota. If DAMOS
is over achieving the goal, it decreases the quota.
-The goal can be specified with four parameters, namely ``target_metric``,
-``target_value``, ``current_value`` and ``nid``. The auto-tuning mechanism
-tries to make ``current_value`` of ``target_metric`` be same to
+The goal can be specified with five parameters, namely ``target_metric``,
+``target_value``, ``current_value``, ``nid`` and ``path``. The auto-tuning
+mechanism tries to make ``current_value`` of ``target_metric`` be same to
``target_value``.
- ``user_input``: User-provided value. Users could use any metric that they
@@ -581,9 +581,18 @@ tries to make ``current_value`` of ``target_metric`` be same to
set by users at the initial time. In other words, DAMOS does self-feedback.
- ``node_mem_used_bp``: Specific NUMA node's used memory ratio in bp (1/10,000).
- ``node_mem_free_bp``: Specific NUMA node's free memory ratio in bp (1/10,000).
-
-``nid`` is optionally required for only ``node_mem_used_bp`` and
-``node_mem_free_bp`` to point the specific NUMA node.
+- ``node_memcg_used_bp``: Specific cgroup's node used memory ratio for a
+ specific NUMA node, in bp (1/10,000).
+- ``node_memcg_free_bp``: Specific cgroup's node unused memory ratio for a
+ specific NUMA node, in bp (1/10,000).
+
+``nid`` is optionally required for only ``node_mem_used_bp``,
+``node_mem_free_bp``, ``node_memcg_used_bp`` and ``node_memcg_free_bp`` to
+point the specific NUMA node.
+
+``path`` is optionally required for only ``node_memcg_used_bp`` and
+``node_memcg_free_bp`` to point the path to the cgroup. The value should be
+the path of the memory cgroup from the cgroups mount point.
To know how user-space can set the tuning goal metric, the target value, and/or
the current value via :ref:`DAMON sysfs interface <sysfs_interface>`, refer to
diff --git a/Documentation/mm/damon/maintainer-profile.rst b/Documentation/mm/damon/maintainer-profile.rst
index 58a3fb3c5762..e761edada1e9 100644
--- a/Documentation/mm/damon/maintainer-profile.rst
+++ b/Documentation/mm/damon/maintainer-profile.rst
@@ -27,8 +27,8 @@ maintainer.
Note again the patches for `mm-new tree
<https://git.kernel.org/akpm/mm/h/mm-new>`_ are queued by the memory management
-subsystem maintainer. If the patches requires some patches in `damon/next tree
-<https://git.kernel.org/sj/h/damon/next>`_ which not yet merged in mm-new,
+subsystem maintainer. If the patches require some patches in `damon/next tree
+<https://git.kernel.org/sj/h/damon/next>`_ which have not yet merged in mm-new,
please make sure the requirement is clearly specified.
Submit checklist addendum
@@ -57,7 +57,7 @@ Key cycle dates
Patches can be sent anytime. Key cycle dates of the `mm-new
<https://git.kernel.org/akpm/mm/h/mm-new>`_, `mm-unstable
-<https://git.kernel.org/akpm/mm/h/mm-unstable>`_and `mm-stable
+<https://git.kernel.org/akpm/mm/h/mm-unstable>`_ and `mm-stable
<https://git.kernel.org/akpm/mm/h/mm-stable>`_ trees depend on the memory
management subsystem maintainer.
@@ -99,5 +99,5 @@ Schedules and reservation status are available at the Google `doc
<https://docs.google.com/document/d/1v43Kcj3ly4CYqmAkMaZzLiM2GEnWfgdGbZAH3mi2vpM/edit?usp=sharing>`_.
There is also a public Google `calendar
<https://calendar.google.com/calendar/u/0?cid=ZDIwOTA4YTMxNjc2MDQ3NTIyMmUzYTM5ZmQyM2U4NDA0ZGIwZjBiYmJlZGQxNDM0MmY4ZTRjOTE0NjdhZDRiY0Bncm91cC5jYWxlbmRhci5nb29nbGUuY29t>`_
-that has the events. Anyone can subscribe it. DAMON maintainer will also
-provide periodic reminder to the mailing list (damon@lists.linux.dev).
+that has the events. Anyone can subscribe to it. DAMON maintainer will also
+provide periodic reminders to the mailing list (damon@lists.linux.dev).
diff --git a/Documentation/mm/memory-model.rst b/Documentation/mm/memory-model.rst
index 5f3eafbbc520..7957122039e8 100644
--- a/Documentation/mm/memory-model.rst
+++ b/Documentation/mm/memory-model.rst
@@ -165,7 +165,7 @@ The users of `ZONE_DEVICE` are:
* pmem: Map platform persistent memory to be used as a direct-I/O target
via DAX mappings.
-* hmm: Extend `ZONE_DEVICE` with `->page_fault()` and `->page_free()`
+* hmm: Extend `ZONE_DEVICE` with `->page_fault()` and `->folio_free()`
event callbacks to allow a device-driver to coordinate memory management
events related to device-memory, typically GPU memory. See
Documentation/mm/hmm.rst.
diff --git a/Documentation/mm/page_owner.rst b/Documentation/mm/page_owner.rst
index 3a45a20fc05a..6b12f3b007ec 100644
--- a/Documentation/mm/page_owner.rst
+++ b/Documentation/mm/page_owner.rst
@@ -27,7 +27,10 @@ enabled. Other usages are more than welcome.
It can also be used to show all the stacks and their current number of
allocated base pages, which gives us a quick overview of where the memory
is going without the need to screen through all the pages and match the
-allocation and free operation.
+allocation and free operation. It's also possible to show only a numeric
+identifier of all the stacks (without stack traces) and their number of
+allocated base pages (faster to read and parse, eg, for monitoring) that
+can be matched with stacks later (show_handles and show_stacks_handles).
page owner is disabled by default. So, if you'd like to use it, you need
to add "page_owner=on" to your boot cmdline. If the kernel is built
@@ -116,6 +119,33 @@ Usage
nr_base_pages: 20824
...
+ cat /sys/kernel/debug/page_owner_stacks/show_handles > handles_7000.txt
+ cat handles_7000.txt
+ handle: 42
+ nr_base_pages: 20824
+ ...
+
+ cat /sys/kernel/debug/page_owner_stacks/show_stacks_handles > stacks_handles.txt
+ cat stacks_handles.txt
+ post_alloc_hook+0x177/0x1a0
+ get_page_from_freelist+0xd01/0xd80
+ __alloc_pages+0x39e/0x7e0
+ alloc_pages_mpol+0x22e/0x490
+ folio_alloc+0xd5/0x110
+ filemap_alloc_folio+0x78/0x230
+ page_cache_ra_order+0x287/0x6f0
+ filemap_get_pages+0x517/0x1160
+ filemap_read+0x304/0x9f0
+ xfs_file_buffered_read+0xe6/0x1d0 [xfs]
+ xfs_file_read_iter+0x1f0/0x380 [xfs]
+ __kernel_read+0x3b9/0x730
+ kernel_read_file+0x309/0x4d0
+ __do_sys_finit_module+0x381/0x730
+ do_syscall_64+0x8d/0x150
+ entry_SYSCALL_64_after_hwframe+0x62/0x6a
+ handle: 42
+ ...
+
cat /sys/kernel/debug/page_owner > page_owner_full.txt
./page_owner_sort page_owner_full.txt sorted_page_owner.txt
diff --git a/Documentation/mm/process_addrs.rst b/Documentation/mm/process_addrs.rst
index be49e2a269e4..7f2f3e87071d 100644
--- a/Documentation/mm/process_addrs.rst
+++ b/Documentation/mm/process_addrs.rst
@@ -48,7 +48,8 @@ Terminology
* **VMA locks** - The VMA lock is at VMA granularity (of course) which behaves
as a read/write semaphore in practice. A VMA read lock is obtained via
:c:func:`!lock_vma_under_rcu` (and unlocked via :c:func:`!vma_end_read`) and a
- write lock via :c:func:`!vma_start_write` (all VMA write locks are unlocked
+ write lock via vma_start_write() or vma_start_write_killable()
+ (all VMA write locks are unlocked
automatically when the mmap write lock is released). To take a VMA write lock
you **must** have already acquired an :c:func:`!mmap_write_lock`.
* **rmap locks** - When trying to access VMAs through the reverse mapping via a
@@ -907,3 +908,9 @@ Stack expansion
Stack expansion throws up additional complexities in that we cannot permit there
to be racing page faults, as a result we invoke :c:func:`!vma_start_write` to
prevent this in :c:func:`!expand_downwards` or :c:func:`!expand_upwards`.
+
+------------------------
+Functions and structures
+------------------------
+
+.. kernel-doc:: include/linux/mmap_lock.h