Merge tag 'mm-stable-2025-10-01-19-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - "mm, swap: improve cluster scan strategy" from Kairui Song improves
   performance and reduces the failure rate of swap cluster allocation

 - "support large align and nid in Rust allocators" from Vitaly Wool
   permits Rust allocators to set NUMA node and large alignment when
   perforning slub and vmalloc reallocs

 - "mm/damon/vaddr: support stat-purpose DAMOS" from Yueyang Pan extend
   DAMOS_STAT's handling of the DAMON operations sets for virtual
   address spaces for ops-level DAMOS filters

 - "execute PROCMAP_QUERY ioctl under per-vma lock" from Suren
   Baghdasaryan reduces mmap_lock contention during reads of
   /proc/pid/maps

 - "mm/mincore: minor clean up for swap cache checking" from Kairui Song
   performs some cleanup in the swap code

 - "mm: vm_normal_page*() improvements" from David Hildenbrand provides
   code cleanup in the pagemap code

 - "add persistent huge zero folio support" from Pankaj Raghav provides
   a block layer speedup by optionalls making the
   huge_zero_pagepersistent, instead of releasing it when its refcount
   falls to zero

 - "kho: fixes and cleanups" from Mike Rapoport adds a few touchups to
   the recently added Kexec Handover feature

 - "mm: make mm->flags a bitmap and 64-bit on all arches" from Lorenzo
   Stoakes turns mm_struct.flags into a bitmap. To end the constant
   struggle with space shortage on 32-bit conflicting with 64-bit's
   needs

 - "mm/swapfile.c and swap.h cleanup" from Chris Li cleans up some swap
   code

 - "selftests/mm: Fix false positives and skip unsupported tests" from
   Donet Tom fixes a few things in our selftests code

 - "prctl: extend PR_SET_THP_DISABLE to only provide THPs when advised"
   from David Hildenbrand "allows individual processes to opt-out of
   THP=always into THP=madvise, without affecting other workloads on the
   system".

   It's a long story - the [1/N] changelog spells out the considerations

 - "Add and use memdesc_flags_t" from Matthew Wilcox gets us started on
   the memdesc project. Please see

      https://kernelnewbies.org/MatthewWilcox/Memdescs and
      https://blogs.oracle.com/linux/post/introducing-memdesc

 - "Tiny optimization for large read operations" from Chi Zhiling
   improves the efficiency of the pagecache read path

 - "Better split_huge_page_test result check" from Zi Yan improves our
   folio splitting selftest code

 - "test that rmap behaves as expected" from Wei Yang adds some rmap
   selftests

 - "remove write_cache_pages()" from Christoph Hellwig removes that
   function and converts its two remaining callers

 - "selftests/mm: uffd-stress fixes" from Dev Jain fixes some UFFD
   selftests issues

 - "introduce kernel file mapped folios" from Boris Burkov introduces
   the concept of "kernel file pages". Using these permits btrfs to
   account its metadata pages to the root cgroup, rather than to the
   cgroups of random inappropriate tasks

 - "mm/pageblock: improve readability of some pageblock handling" from
   Wei Yang provides some readability improvements to the page allocator
   code

 - "mm/damon: support ARM32 with LPAE" from SeongJae Park teaches DAMON
   to understand arm32 highmem

 - "tools: testing: Use existing atomic.h for vma/maple tests" from
   Brendan Jackman performs some code cleanups and deduplication under
   tools/testing/

 - "maple_tree: Fix testing for 32bit compiles" from Liam Howlett fixes
   a couple of 32-bit issues in tools/testing/radix-tree.c

 - "kasan: unify kasan_enabled() and remove arch-specific
   implementations" from Sabyrzhan Tasbolatov moves KASAN arch-specific
   initialization code into a common arch-neutral implementation

 - "mm: remove zpool" from Johannes Weiner removes zspool - an
   indirection layer which now only redirects to a single thing
   (zsmalloc)

 - "mm: task_stack: Stack handling cleanups" from Pasha Tatashin makes a
   couple of cleanups in the fork code

 - "mm: remove nth_page()" from David Hildenbrand makes rather a lot of
   adjustments at various nth_page() callsites, eventually permitting
   the removal of that undesirable helper function

 - "introduce kasan.write_only option in hw-tags" from Yeoreum Yun
   creates a KASAN read-only mode for ARM, using that architecture's
   memory tagging feature. It is felt that a read-only mode KASAN is
   suitable for use in production systems rather than debug-only

 - "mm: hugetlb: cleanup hugetlb folio allocation" from Kefeng Wang does
   some tidying in the hugetlb folio allocation code

 - "mm: establish const-correctness for pointer parameters" from Max
   Kellermann makes quite a number of the MM API functions more accurate
   about the constness of their arguments. This was getting in the way
   of subsystems (in this case CEPH) when they attempt to improving
   their own const/non-const accuracy

 - "Cleanup free_pages() misuse" from Vishal Moola fixes a number of
   code sites which were confused over when to use free_pages() vs
   __free_pages()

 - "Add Rust abstraction for Maple Trees" from Alice Ryhl makes the
   mapletree code accessible to Rust. Required by nouveau and by its
   forthcoming successor: the new Rust Nova driver

 - "selftests/mm: split_huge_page_test: split_pte_mapped_thp
   improvements" from David Hildenbrand adds a fix and some cleanups to
   the thp selftesting code

 - "mm, swap: introduce swap table as swap cache (phase I)" from Chris
   Li and Kairui Song is the first step along the path to implementing
   "swap tables" - a new approach to swap allocation and state tracking
   which is expected to yield speed and space improvements. This
   patchset itself yields a 5-20% performance benefit in some situations

 - "Some ptdesc cleanups" from Matthew Wilcox utilizes the new memdesc
   layer to clean up the ptdesc code a little

 - "Fix va_high_addr_switch.sh test failure" from Chunyu Hu fixes some
   issues in our 5-level pagetable selftesting code

 - "Minor fixes for memory allocation profiling" from Suren Baghdasaryan
   addresses a couple of minor issues in relatively new memory
   allocation profiling feature

 - "Small cleanups" from Matthew Wilcox has a few cleanups in
   preparation for more memdesc work

 - "mm/damon: add addr_unit for DAMON_LRU_SORT and DAMON_RECLAIM" from
   Quanmin Yan makes some changes to DAMON in furtherance of supporting
   arm highmem

 - "selftests/mm: Add -Wunreachable-code and fix warnings" from Muhammad
   Anjum adds that compiler check to selftests code and fixes the
   fallout, by removing dead code

 - "Improvements to Victim Process Thawing and OOM Reaper Traversal
   Order" from zhongjinji makes a number of improvements in the OOM
   killer: mainly thawing a more appropriate group of victim threads so
   they can release resources

 - "mm/damon: misc fixups and improvements for 6.18" from SeongJae Park
   is a bunch of small and unrelated fixups for DAMON

 - "mm/damon: define and use DAMON initialization check function" from
   SeongJae Park implement reliability and maintainability improvements
   to a recently-added bug fix

 - "mm/damon/stat: expose auto-tuned intervals and non-idle ages" from
   SeongJae Park provides additional transparency to userspace clients
   of the DAMON_STAT information

 - "Expand scope of khugepaged anonymous collapse" from Dev Jain removes
   some constraints on khubepaged's collapsing of anon VMAs. It also
   increases the success rate of MADV_COLLAPSE against an anon vma

 - "mm: do not assume file == vma->vm_file in compat_vma_mmap_prepare()"
   from Lorenzo Stoakes moves us further towards removal of
   file_operations.mmap(). This patchset concentrates upon clearing up
   the treatment of stacked filesystems

 - "mm: Improve mlock tracking for large folios" from Kiryl Shutsemau
   provides some fixes and improvements to mlock's tracking of large
   folios. /proc/meminfo's "Mlocked" field became more accurate

 - "mm/ksm: Fix incorrect accounting of KSM counters during fork" from
   Donet Tom fixes several user-visible KSM stats inaccuracies across
   forks and adds selftest code to verify these counters

 - "mm_slot: fix the usage of mm_slot_entry" from Wei Yang addresses
   some potential but presently benign issues in KSM's mm_slot handling

* tag 'mm-stable-2025-10-01-19-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (372 commits)
  mm: swap: check for stable address space before operating on the VMA
  mm: convert folio_page() back to a macro
  mm/khugepaged: use start_addr/addr for improved readability
  hugetlbfs: skip VMAs without shareable locks in hugetlb_vmdelete_list
  alloc_tag: fix boot failure due to NULL pointer dereference
  mm: silence data-race in update_hiwater_rss
  mm/memory-failure: don't select MEMORY_ISOLATION
  mm/khugepaged: remove definition of struct khugepaged_mm_slot
  mm/ksm: get mm_slot by mm_slot_entry() when slot is !NULL
  hugetlb: increase number of reserving hugepages via cmdline
  selftests/mm: add fork inheritance test for ksm_merging_pages counter
  mm/ksm: fix incorrect KSM counter handling in mm_struct during fork
  drivers/base/node: fix double free in register_one_node()
  mm: remove PMD alignment constraint in execmem_vmalloc()
  mm/memory_hotplug: fix typo 'esecially' -> 'especially'
  mm/rmap: improve mlock tracking for large folios
  mm/filemap: map entire large folio faultaround
  mm/fault: try to map the entire file folio in finish_fault()
  mm/rmap: mlock large folios in try_to_unmap_one()
  mm/rmap: fix a mlock race condition in folio_referenced_one()
  ...

1 files changed, 34 insertions, 31 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 674999999cd0..b2fc8b626d3d 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -398,14 +398,7 @@ unsigned long zone_reclaimable_pages(struct zone *zone)
 	if (can_reclaim_anon_pages(NULL, zone_to_nid(zone), NULL))
 		nr += zone_page_state_snapshot(zone, NR_ZONE_INACTIVE_ANON) +
 			zone_page_state_snapshot(zone, NR_ZONE_ACTIVE_ANON);
-	/*
-	 * If there are no reclaimable file-backed or anonymous pages,
-	 * ensure zones with sufficient free pages are not skipped.
-	 * This prevents zones like DMA32 from being ignored in reclaim
-	 * scenarios where they can still help alleviate memory pressure.
-	 */
-	if (nr == 0)
-		nr = zone_page_state_snapshot(zone, NR_FREE_PAGES);
+
 	return nr;
 }
 
@@ -525,7 +518,7 @@ static bool skip_throttle_noprogress(pg_data_t *pgdat)
 	 * If kswapd is disabled, reschedule if necessary but do not
 	 * throttle as the system is likely near OOM.
 	 */
-	if (pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES)
+	if (atomic_read(&pgdat->kswapd_failures) >= MAX_RECLAIM_RETRIES)
 		return true;
 
 	/*
@@ -737,13 +730,18 @@ static int __remove_mapping(struct address_space *mapping, struct folio *folio,
 {
 	int refcount;
 	void *shadow = NULL;
+	struct swap_cluster_info *ci;
 
 	BUG_ON(!folio_test_locked(folio));
 	BUG_ON(mapping != folio_mapping(folio));
 
-	if (!folio_test_swapcache(folio))
+	if (folio_test_swapcache(folio)) {
+		ci = swap_cluster_get_and_lock_irq(folio);
+	} else {
 		spin_lock(&mapping->host->i_lock);
-	xa_lock_irq(&mapping->i_pages);
+		xa_lock_irq(&mapping->i_pages);
+	}
+
 	/*
 	 * The non racy check for a busy folio.
 	 *
@@ -783,9 +781,9 @@ static int __remove_mapping(struct address_space *mapping, struct folio *folio,
 
 		if (reclaimed && !mapping_exiting(mapping))
 			shadow = workingset_eviction(folio, target_memcg);
-		__delete_from_swap_cache(folio, swap, shadow);
+		__swap_cache_del_folio(ci, folio, swap, shadow);
 		memcg1_swapout(folio, swap);
-		xa_unlock_irq(&mapping->i_pages);
+		swap_cluster_unlock_irq(ci);
 		put_swap_folio(folio, swap);
 	} else {
 		void (*free_folio)(struct folio *);
@@ -823,9 +821,12 @@ static int __remove_mapping(struct address_space *mapping, struct folio *folio,
 	return 1;
 
 cannot_free:
-	xa_unlock_irq(&mapping->i_pages);
-	if (!folio_test_swapcache(folio))
+	if (folio_test_swapcache(folio)) {
+		swap_cluster_unlock_irq(ci);
+	} else {
+		xa_unlock_irq(&mapping->i_pages);
 		spin_unlock(&mapping->host->i_lock);
+	}
 	return 0;
 }
 
@@ -888,11 +889,11 @@ static bool lru_gen_set_refs(struct folio *folio)
 {
 	/* see the comment on LRU_REFS_FLAGS */
 	if (!folio_test_referenced(folio) && !folio_test_workingset(folio)) {
-		set_mask_bits(&folio->flags, LRU_REFS_MASK, BIT(PG_referenced));
+		set_mask_bits(&folio->flags.f, LRU_REFS_MASK, BIT(PG_referenced));
 		return false;
 	}
 
-	set_mask_bits(&folio->flags, LRU_REFS_FLAGS, BIT(PG_workingset));
+	set_mask_bits(&folio->flags.f, LRU_REFS_FLAGS, BIT(PG_workingset));
 	return true;
 }
 #else
@@ -3257,13 +3258,13 @@ static bool positive_ctrl_err(struct ctrl_pos *sp, struct ctrl_pos *pv)
 /* promote pages accessed through page tables */
 static int folio_update_gen(struct folio *folio, int gen)
 {
-	unsigned long new_flags, old_flags = READ_ONCE(folio->flags);
+	unsigned long new_flags, old_flags = READ_ONCE(folio->flags.f);
 
 	VM_WARN_ON_ONCE(gen >= MAX_NR_GENS);
 
 	/* see the comment on LRU_REFS_FLAGS */
 	if (!folio_test_referenced(folio) && !folio_test_workingset(folio)) {
-		set_mask_bits(&folio->flags, LRU_REFS_MASK, BIT(PG_referenced));
+		set_mask_bits(&folio->flags.f, LRU_REFS_MASK, BIT(PG_referenced));
 		return -1;
 	}
 
@@ -3274,7 +3275,7 @@ static int folio_update_gen(struct folio *folio, int gen)
 
 		new_flags = old_flags & ~(LRU_GEN_MASK | LRU_REFS_FLAGS);
 		new_flags |= ((gen + 1UL) << LRU_GEN_PGOFF) | BIT(PG_workingset);
-	} while (!try_cmpxchg(&folio->flags, &old_flags, new_flags));
+	} while (!try_cmpxchg(&folio->flags.f, &old_flags, new_flags));
 
 	return ((old_flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1;
 }
@@ -3285,7 +3286,7 @@ static int folio_inc_gen(struct lruvec *lruvec, struct folio *folio, bool reclai
 	int type = folio_is_file_lru(folio);
 	struct lru_gen_folio *lrugen = &lruvec->lrugen;
 	int new_gen, old_gen = lru_gen_from_seq(lrugen->min_seq[type]);
-	unsigned long new_flags, old_flags = READ_ONCE(folio->flags);
+	unsigned long new_flags, old_flags = READ_ONCE(folio->flags.f);
 
 	VM_WARN_ON_ONCE_FOLIO(!(old_flags & LRU_GEN_MASK), folio);
 
@@ -3302,7 +3303,7 @@ static int folio_inc_gen(struct lruvec *lruvec, struct folio *folio, bool reclai
 		/* for folio_end_writeback() */
 		if (reclaiming)
 			new_flags |= BIT(PG_reclaim);
-	} while (!try_cmpxchg(&folio->flags, &old_flags, new_flags));
+	} while (!try_cmpxchg(&folio->flags.f, &old_flags, new_flags));
 
 	lru_gen_update_size(lruvec, folio, old_gen, new_gen);
 
@@ -4553,7 +4554,7 @@ static bool isolate_folio(struct lruvec *lruvec, struct folio *folio, struct sca
 
 	/* see the comment on LRU_REFS_FLAGS */
 	if (!folio_test_referenced(folio))
-		set_mask_bits(&folio->flags, LRU_REFS_MASK, 0);
+		set_mask_bits(&folio->flags.f, LRU_REFS_MASK, 0);
 
 	/* for shrink_folio_list() */
 	folio_clear_reclaim(folio);
@@ -4766,7 +4767,7 @@ retry:
 
 		/* don't add rejected folios to the oldest generation */
 		if (lru_gen_folio_seq(lruvec, folio, false) == min_seq[type])
-			set_mask_bits(&folio->flags, LRU_REFS_FLAGS, BIT(PG_active));
+			set_mask_bits(&folio->flags.f, LRU_REFS_FLAGS, BIT(PG_active));
 	}
 
 	spin_lock_irq(&lruvec->lru_lock);
@@ -5100,7 +5101,7 @@ static void lru_gen_shrink_node(struct pglist_data *pgdat, struct scan_control *
 	blk_finish_plug(&plug);
 done:
 	if (sc->nr_reclaimed > reclaimed)
-		pgdat->kswapd_failures = 0;
+		atomic_set(&pgdat->kswapd_failures, 0);
 }
 
 /******************************************************************************
@@ -5561,6 +5562,7 @@ static int run_cmd(char cmd, int memcg_id, int nid, unsigned long seq,
 	if (memcg_id != mem_cgroup_id(memcg))
 		goto done;
 
+	sc->target_mem_cgroup = memcg;
 	lruvec = get_lruvec(memcg, nid);
 
 	if (swappiness < MIN_SWAPPINESS)
@@ -5597,6 +5599,7 @@ static ssize_t lru_gen_seq_write(struct file *file, const char __user *src,
 		.may_swap = true,
 		.reclaim_idx = MAX_NR_ZONES - 1,
 		.gfp_mask = GFP_KERNEL,
+		.proactive = true,
 	};
 
 	buf = kvmalloc(len + 1, GFP_KERNEL);
@@ -6177,7 +6180,7 @@ again:
 	 * successful direct reclaim run will revive a dormant kswapd.
 	 */
 	if (reclaimable)
-		pgdat->kswapd_failures = 0;
+		atomic_set(&pgdat->kswapd_failures, 0);
 	else if (sc->cache_trim_mode)
 		sc->cache_trim_mode_failed = 1;
 }
@@ -6489,11 +6492,11 @@ static bool allow_direct_reclaim(pg_data_t *pgdat)
 	int i;
 	bool wmark_ok;
 
-	if (pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES)
+	if (atomic_read(&pgdat->kswapd_failures) >= MAX_RECLAIM_RETRIES)
 		return true;
 
 	for_each_managed_zone_pgdat(zone, pgdat, i, ZONE_NORMAL) {
-		if (!zone_reclaimable_pages(zone))
+		if (!zone_reclaimable_pages(zone) && zone_page_state_snapshot(zone, NR_FREE_PAGES))
 			continue;
 
 		pfmemalloc_reserve += min_wmark_pages(zone);
@@ -6899,7 +6902,7 @@ static bool prepare_kswapd_sleep(pg_data_t *pgdat, int order,
 		wake_up_all(&pgdat->pfmemalloc_wait);
 
 	/* Hopeless node, leave it to direct reclaim */
-	if (pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES)
+	if (atomic_read(&pgdat->kswapd_failures) >= MAX_RECLAIM_RETRIES)
 		return true;
 
 	if (pgdat_balanced(pgdat, order, highest_zoneidx)) {
@@ -7167,7 +7170,7 @@ restart:
 	}
 
 	if (!sc.nr_reclaimed)
-		pgdat->kswapd_failures++;
+		atomic_inc(&pgdat->kswapd_failures);
 
 out:
 	clear_reclaim_active(pgdat, highest_zoneidx);
@@ -7426,7 +7429,7 @@ void wakeup_kswapd(struct zone *zone, gfp_t gfp_flags, int order,
 		return;
 
 	/* Hopeless node, leave it to direct reclaim if possible */
-	if (pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES ||
+	if (atomic_read(&pgdat->kswapd_failures) >= MAX_RECLAIM_RETRIES ||
 	    (pgdat_balanced(pgdat, order, highest_zoneidx) &&
 	     !pgdat_watermark_boosted(pgdat, highest_zoneidx))) {
 		/*