linux.git/include/trace/events/writeback.h, branch v7.1-rc4

Merge tag 'mm-stable-2026-04-18-02-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-04-19T15:01:17+00:00

Pull more MM updates from Andrew Morton:

 - "Eliminate Dying Memory Cgroup" (Qi Zheng and Muchun Song)

   Address the longstanding "dying memcg problem". A situation wherein a
   no-longer-used memory control group will hang around for an extended
   period pointlessly consuming memory

 - "fix unexpected type conversions and potential overflows" (Qi Zheng)

   Fix a couple of potential 32-bit/64-bit issues which were identified
   during review of the "Eliminate Dying Memory Cgroup" series

 - "kho: history: track previous kernel version and kexec boot count"
   (Breno Leitao)

   Use Kexec Handover (KHO) to pass the previous kernel's version string
   and the number of kexec reboots since the last cold boot to the next
   kernel, and print it at boot time

 - "liveupdate: prevent double preservation" (Pasha Tatashin)

   Teach LUO to avoid managing the same file across different active
   sessions

 - "liveupdate: Fix module unloading and unregister API" (Pasha
   Tatashin)

   Address an issue with how LUO handles module reference counting and
   unregistration during module unloading

 - "zswap pool per-CPU acomp_ctx simplifications" (Kanchana Sridhar)

   Simplify and clean up the zswap crypto compression handling and
   improve the lifecycle management of zswap pool's per-CPU acomp_ctx
   resources

 - "mm/damon/core: fix damon_call()/damos_walk() vs kdmond exit race"
   (SeongJae Park)

   Address unlikely but possible leaks and deadlocks in damon_call() and
   damon_walk()

 - "mm/damon/core: validate damos_quota_goal->nid" (SeongJae Park)

   Fix a couple of root-only wild pointer dereferences

 - "Docs/admin-guide/mm/damon: warn commit_inputs vs other params race"
   (SeongJae Park)

   Update the DAMON documentation to warn operators about potential
   races which can occur if the commit_inputs parameter is altered at
   the wrong time

 - "Minor hmm_test fixes and cleanups" (Alistair Popple)

   Bugfixes and a cleanup for the HMM kernel selftests

 - "Modify memfd_luo code" (Chenghao Duan)

   Cleanups, simplifications and speedups to the memfd_lou code

 - "mm, kvm: allow uffd support in guest_memfd" (Mike Rapoport)

   Support for userfaultfd in guest_memfd

 - "selftests/mm: skip several tests when thp is not available" (Chunyu
   Hu)

   Fix several issues in the selftests code which were causing breakage
   when the tests were run on CONFIG_THP=n kernels

 - "mm/mprotect: micro-optimization work" (Pedro Falcato)

   A couple of nice speedups for mprotect()

 - "MAINTAINERS: update KHO and LIVE UPDATE entries" (Pratyush Yadav)

   Document upcoming changes in the maintenance of KHO, LUO, memfd_luo,
   kexec, crash, kdump and probably other kexec-based things - they are
   being moved out of mm.git and into a new git tree

* tag 'mm-stable-2026-04-18-02-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (121 commits)
  MAINTAINERS: add page cache reviewer
  mm/vmscan: avoid false-positive -Wuninitialized warning
  MAINTAINERS: update Dave's kdump reviewer email address
  MAINTAINERS: drop include/linux/liveupdate from LIVE UPDATE
  MAINTAINERS: drop include/linux/kho/abi/ from KHO
  MAINTAINERS: update KHO and LIVE UPDATE maintainers
  MAINTAINERS: update kexec/kdump maintainers entries
  mm/migrate_device: remove dead migration entry check in migrate_vma_collect_huge_pmd()
  selftests: mm: skip charge_reserved_hugetlb without killall
  userfaultfd: allow registration of ranges below mmap_min_addr
  mm/vmstat: fix vmstat_shepherd double-scheduling vmstat_update
  mm/hugetlb: fix early boot crash on parameters without '=' separator
  zram: reject unrecognized type= values in recompress_store()
  docs: proc: document ProtectionKey in smaps
  mm/mprotect: special-case small folios when applying permissions
  mm/mprotect: move softleaf code out of the main function
  mm: remove '!root_reclaim' checking in should_abort_scan()
  mm/sparse: fix comment for section map alignment
  mm/page_io: use sio->len for PSWPIN accounting in sio_read_complete()
  selftests/mm: transhuge_stress: skip the test when thp not available
  ...

writeback: prevent memory cgroup release in writeback module

2026-04-18T07:10:45+00:00

In the near future, a folio will no longer pin its corresponding memory
cgroup.  To ensure safety, it will only be appropriate to hold the rcu
read lock or acquire a reference to the memory cgroup returned by
folio_memcg(), thereby preventing it from being released.

In the current patch, the function get_mem_cgroup_css_from_folio() and the
rcu read lock are employed to safeguard against the release of the memory
cgroup.

This serves as a preparatory measure for the reparenting of the
LRU pages.

Link: https://lore.kernel.org/645f99bc344575417f67def3744f975596df2793.1772711148.git.zhengqi.arch@bytedance.com
Signed-off-by: Muchun Song 
Signed-off-by: Qi Zheng 
Reviewed-by: Harry Yoo 
Acked-by: Johannes Weiner 
Acked-by: Shakeel Butt 
Cc: Allen Pais 
Cc: Axel Rasmussen 
Cc: Baoquan He 
Cc: Chengming Zhou 
Cc: Chen Ridong 
Cc: David Hildenbrand 
Cc: Hamza Mahfooz 
Cc: Hugh Dickins 
Cc: Imran Khan 
Cc: Kamalesh Babulal 
Cc: Lance Yang 
Cc: Liam Howlett 
Cc: Lorenzo Stoakes (Oracle) 
Cc: Michal Hocko 
Cc: Michal Koutný 
Cc: Mike Rapoport 
Cc: Muchun Song 
Cc: Nhat Pham 
Cc: Roman Gushchin 
Cc: Suren Baghdasaryan 
Cc: Usama Arif 
Cc: Vlastimil Babka 
Cc: Wei Xu 
Cc: Yosry Ahmed 
Cc: Yuanchu Xie 
Cc: Zi Yan 
Signed-off-by: Andrew Morton

vfs: widen trace event i_ino fields to u64

2026-03-06T13:31:26+00:00

Update VFS-layer trace event definitions to use u64 instead of
ino_t/unsigned long for inode number fields. Update TP_printk format
strings to use %llu/%llx to match the widened field type. Remove
now-unnecessary (unsigned long) casts since __entry->ino is already
u64.

Signed-off-by: Jeff Layton 
Link: https://patch.msgid.link/20260304-iino-u64-v3-4-2257ad83d372@kernel.org
Reviewed-by: Jan Kara 
Signed-off-by: Christian Brauner

Merge tag 'mm-stable-2026-02-11-19-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-02-12T19:32:37+00:00

Pull MM updates from Andrew Morton:

 - "powerpc/64s: do not re-activate batched TLB flush" makes
   arch_{enter|leave}_lazy_mmu_mode() nest properly (Alexander Gordeev)

   It adds a generic enter/leave layer and switches architectures to use
   it. Various hacks were removed in the process.

 - "zram: introduce compressed data writeback" implements data
   compression for zram writeback (Richard Chang and Sergey Senozhatsky)

 - "mm: folio_zero_user: clear page ranges" adds clearing of contiguous
   page ranges for hugepages. Large improvements during demand faulting
   are demonstrated (David Hildenbrand)

 - "memcg cleanups" tidies up some memcg code (Chen Ridong)

 - "mm/damon: introduce {,max_}nr_snapshots and tracepoint for damos
   stats" improves DAMOS stat's provided information, deterministic
   control, and readability (SeongJae Park)

 - "selftests/mm: hugetlb cgroup charging: robustness fixes" fixes a few
   issues in the hugetlb cgroup charging selftests (Li Wang)

 - "Fix va_high_addr_switch.sh test failure - again" addresses several
   issues in the va_high_addr_switch test (Chunyu Hu)

 - "mm/damon/tests/core-kunit: extend existing test scenarios" improves
   the KUnit test coverage for DAMON (Shu Anzai)

 - "mm/khugepaged: fix dirty page handling for MADV_COLLAPSE" fixes a
   glitch in khugepaged which was causing madvise(MADV_COLLAPSE) to
   transiently return -EAGAIN (Shivank Garg)

 - "arch, mm: consolidate hugetlb early reservation" reworks and
   consolidates a pile of straggly code related to reservation of
   hugetlb memory from bootmem and creation of CMA areas for hugetlb
   (Mike Rapoport)

 - "mm: clean up anon_vma implementation" cleans up the anon_vma
   implementation in various ways (Lorenzo Stoakes)

 - "tweaks for __alloc_pages_slowpath()" does a little streamlining of
   the page allocator's slowpath code (Vlastimil Babka)

 - "memcg: separate private and public ID namespaces" cleans up the
   memcg ID code and prevents the internal-only private IDs from being
   exposed to userspace (Shakeel Butt)

 - "mm: hugetlb: allocate frozen gigantic folio" cleans up the
   allocation of frozen folios and avoids some atomic refcount
   operations (Kefeng Wang)

 - "mm/damon: advance DAMOS-based LRU sorting" improves DAMOS's movement
   of memory betewwn the active and inactive LRUs and adds auto-tuning
   of the ratio-based quotas and of monitoring intervals (SeongJae Park)

 - "Support page table check on PowerPC" makes
   CONFIG_PAGE_TABLE_CHECK_ENFORCED work on powerpc (Andrew Donnellan)

 - "nodemask: align nodes_and{,not} with underlying bitmap ops" makes
   nodes_and() and nodes_andnot() propagate the return values from the
   underlying bit operations, enabling some cleanup in calling code
   (Yury Norov)

 - "mm/damon: hide kdamond and kdamond_lock from API callers" cleans up
   some DAMON internal interfaces (SeongJae Park)

 - "mm/khugepaged: cleanups and scan limit fix" does some cleanup work
   in khupaged and fixes a scan limit accounting issue (Shivank Garg)

 - "mm: balloon infrastructure cleanups" goes to town on the balloon
   infrastructure and its page migration function. Mainly cleanups, also
   some locking simplification (David Hildenbrand)

 - "mm/vmscan: add tracepoint and reason for kswapd_failures reset" adds
   additional tracepoints to the page reclaim code (Jiayuan Chen)

 - "Replace wq users and add WQ_PERCPU to alloc_workqueue() users" is
   part of Marco's kernel-wide migration from the legacy workqueue APIs
   over to the preferred unbound workqueues (Marco Crivellari)

 - "Various mm kselftests improvements/fixes" provides various unrelated
   improvements/fixes for the mm kselftests (Kevin Brodsky)

 - "mm: accelerate gigantic folio allocation" greatly speeds up gigantic
   folio allocation, mainly by avoiding unnecessary work in
   pfn_range_valid_contig() (Kefeng Wang)

 - "selftests/damon: improve leak detection and wss estimation
   reliability" improves the reliability of two of the DAMON selftests
   (SeongJae Park)

 - "mm/damon: cleanup kdamond, damon_call(), damos filter and
   DAMON_MIN_REGION" does some cleanup work in the core DAMON code
   (SeongJae Park)

 - "Docs/mm/damon: update intro, modules, maintainer profile, and misc"
   performs maintenance work on the DAMON documentation (SeongJae Park)

 - "mm: add and use vma_assert_stabilised() helper" refactors and cleans
   up the core VMA code. The main aim here is to be able to use the mmap
   write lock's lockdep state to perform various assertions regarding
   the locking which the VMA code requires (Lorenzo Stoakes)

 - "mm, swap: swap table phase II: unify swapin use" removes some old
   swap code (swap cache bypassing and swap synchronization) which
   wasn't working very well. Various other cleanups and simplifications
   were made. The end result is a 20% speedup in one benchmark (Kairui
   Song)

 - "enable PT_RECLAIM on more 64-bit architectures" makes PT_RECLAIM
   available on 64-bit alpha, loongarch, mips, parisc, and um. Various
   cleanups were performed along the way (Qi Zheng)

* tag 'mm-stable-2026-02-11-19-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (325 commits)
  mm/memory: handle non-split locks correctly in zap_empty_pte_table()
  mm: move pte table reclaim code to memory.c
  mm: make PT_RECLAIM depends on MMU_GATHER_RCU_TABLE_FREE
  mm: convert __HAVE_ARCH_TLB_REMOVE_TABLE to CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE config
  um: mm: enable MMU_GATHER_RCU_TABLE_FREE
  parisc: mm: enable MMU_GATHER_RCU_TABLE_FREE
  mips: mm: enable MMU_GATHER_RCU_TABLE_FREE
  LoongArch: mm: enable MMU_GATHER_RCU_TABLE_FREE
  alpha: mm: enable MMU_GATHER_RCU_TABLE_FREE
  mm: change mm/pt_reclaim.c to use asm/tlb.h instead of asm-generic/tlb.h
  mm/damon/stat: remove __read_mostly from memory_idle_ms_percentiles
  zsmalloc: make common caches global
  mm: add SPDX id lines to some mm source files
  mm/zswap: use %pe to print error pointers
  mm/vmscan: use %pe to print error pointers
  mm/readahead: fix typo in comment
  mm: khugepaged: fix NR_FILE_PAGES and NR_SHMEM in collapse_file()
  mm: refactor vma_map_pages to use vm_insert_pages
  mm/damon: unify address range representation with damon_addr_range
  mm/cma: replace snprintf with strscpy in cma_new_area
  ...

mm/block/fs: remove laptop_mode

2026-01-21T03:24:47+00:00

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 
Suggested-by: Christoph Hellwig 
Reviewed-by: Christoph Hellwig 
Acked-by: Jens Axboe 
Reviewed-by: Shakeel Butt 
Acked-by: Michal Hocko 
Cc: Deepanshu Kartikey 
Signed-off-by: Andrew Morton

fs: factor out a sync_lazytime helper

2026-01-12T13:01:33+00:00

Centralize how we synchronize a lazytime update into the actual on-disk
timestamp into a single helper.

Signed-off-by: Christoph Hellwig 
Link: https://patch.msgid.link/20260108141934.2052404-7-hch@lst.de
Reviewed-by: Jan Kara 
Reviewed-by: Chaitanya Kulkarni 
Reviewed-by: Jeff Layton 
Signed-off-by: Christian Brauner

Manual conversion to use ->i_state accessors of all places not covered by coccinelle

2025-10-20T18:22:26+00:00

Nothing to look at apart from iput_final().

Signed-off-by: Mateusz Guzik 
Signed-off-by: Christian Brauner

writeback: Add tracepoint to track pending inode switches

2025-09-19T11:11:06+00:00

Add trace_inode_switch_wbs_queue tracepoint to allow insight into how
many inodes are queued to switch their bdi_writeback structure.

Acked-by: Tejun Heo 
Signed-off-by: Jan Kara 
Signed-off-by: Christian Brauner

mm: remove the for_reclaim field from struct writeback_control

2025-07-10T05:41:58+00:00

This field is now only set to one in the i915 gem code that only calls
writeback_iter on it, which ignores the flag.  All other checks are thuse
dead code and the field can be removed.

Link: https://lkml.kernel.org/r/20250610054959.2057526-7-hch@lst.de
Signed-off-by: Christoph Hellwig 
Cc: Baolin Wang 
Cc: Chengming Zhou 
Cc: Hugh Dickins 
Cc: Johannes Weiner 
Cc: Matthew Wilcox (Oracle) 
Cc: Nhat Pham 
Signed-off-by: Andrew Morton

writeback: fix calculations in trace_balance_dirty_pages() for cgwb

2025-03-17T07:05:37+00:00

In the commit dcc25ae76eb7 ("writeback: move global_dirty_limit into
wb_domain") of the cgroup writeback backpressure propagation patchset,
Tejun made some adaptations to trace_balance_dirty_pages() for cgroup
writeback.  However, this adaptation was incomplete and Tejun missed
further adaptation in the subsequent patches.

In the cgroup writeback scenario, if sdtc in balance_dirty_pages() is
assigned to mdtc, then upon entering trace_balance_dirty_pages(),
__entry->limit should be assigned based on the dirty_limit of the
corresponding memcg's wb_domain, rather than global_wb_domain.

To address this issue and simplify the implementation, introduce a 'limit'
field in struct dirty_throttle_control to store the hard_limit value
computed in wb_position_ratio() by calling hard_dirty_limit().  This field
will then be used in trace_balance_dirty_pages() to assign the value to
__entry->limit.

Link: https://lkml.kernel.org/r/20250304110318.159567-4-yizhou.tang@shopee.com
Fixes: dcc25ae76eb7 ("writeback: move global_dirty_limit into wb_domain")
Signed-off-by: Tang Yizhou 
Acked-by: Tejun Heo 
Cc: Alexei Starovoitov 
Cc: Christian Brauner 
Cc: Jan Kara 
Cc: "Masami Hiramatsu (Google)" 
Cc: Matthew Wilcow (Oracle) 
Cc: Steven Rostedt 
Signed-off-by: Andrew Morton