Merge tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - "Add folio_mk_pte()" from Matthew Wilcox simplifies the act of
   creating a pte which addresses the first page in a folio and reduces
   the amount of plumbing which architecture must implement to provide
   this.

 - "Misc folio patches for 6.16" from Matthew Wilcox is a shower of
   largely unrelated folio infrastructure changes which clean things up
   and better prepare us for future work.

 - "memory,x86,acpi: hotplug memory alignment advisement" from Gregory
   Price adds early-init code to prevent x86 from leaving physical
   memory unused when physical address regions are not aligned to memory
   block size.

 - "mm/compaction: allow more aggressive proactive compaction" from
   Michal Clapinski provides some tuning of the (sadly, hard-coded (more
   sadly, not auto-tuned)) thresholds for our invokation of proactive
   compaction. In a simple test case, the reduction of a guest VM's
   memory consumption was dramatic.

 - "Minor cleanups and improvements to swap freeing code" from Kemeng
   Shi provides some code cleaups and a small efficiency improvement to
   this part of our swap handling code.

 - "ptrace: introduce PTRACE_SET_SYSCALL_INFO API" from Dmitry Levin
   adds the ability for a ptracer to modify syscalls arguments. At this
   time we can alter only "system call information that are used by
   strace system call tampering, namely, syscall number, syscall
   arguments, and syscall return value.

   This series should have been incorporated into mm.git's "non-MM"
   branch, but I goofed.

 - "fs/proc: extend the PAGEMAP_SCAN ioctl to report guard regions" from
   Andrei Vagin extends the info returned by the PAGEMAP_SCAN ioctl
   against /proc/pid/pagemap. This permits CRIU to more efficiently get
   at the info about guard regions.

 - "Fix parameter passed to page_mapcount_is_type()" from Gavin Shan
   implements that fix. No runtime effect is expected because
   validate_page_before_insert() happens to fix up this error.

 - "kernel/events/uprobes: uprobe_write_opcode() rewrite" from David
   Hildenbrand basically brings uprobe text poking into the current
   decade. Remove a bunch of hand-rolled implementation in favor of
   using more current facilities.

 - "mm/ptdump: Drop assumption that pxd_val() is u64" from Anshuman
   Khandual provides enhancements and generalizations to the pte dumping
   code. This might be needed when 128-bit Page Table Descriptors are
   enabled for ARM.

 - "Always call constructor for kernel page tables" from Kevin Brodsky
   ensures that the ctor/dtor is always called for kernel pgtables, as
   it already is for user pgtables.

   This permits the addition of more functionality such as "insert hooks
   to protect page tables". This change does result in various
   architectures performing unnecesary work, but this is fixed up where
   it is anticipated to occur.

 - "Rust support for mm_struct, vm_area_struct, and mmap" from Alice
   Ryhl adds plumbing to permit Rust access to core MM structures.

 - "fix incorrectly disallowed anonymous VMA merges" from Lorenzo
   Stoakes takes advantage of some VMA merging opportunities which we've
   been missing for 15 years.

 - "mm/madvise: batch tlb flushes for MADV_DONTNEED and MADV_FREE" from
   SeongJae Park optimizes process_madvise()'s TLB flushing.

   Instead of flushing each address range in the provided iovec, we
   batch the flushing across all the iovec entries. The syscall's cost
   was approximately halved with a microbenchmark which was designed to
   load this particular operation.

 - "Track node vacancy to reduce worst case allocation counts" from
   Sidhartha Kumar makes the maple tree smarter about its node
   preallocation.

   stress-ng mmap performance increased by single-digit percentages and
   the amount of unnecessarily preallocated memory was dramaticelly
   reduced.

 - "mm/gup: Minor fix, cleanup and improvements" from Baoquan He removes
   a few unnecessary things which Baoquan noted when reading the code.

 - ""Enhance sysfs handling for memory hotplug in weighted interleave"
   from Rakie Kim "enhances the weighted interleave policy in the memory
   management subsystem by improving sysfs handling, fixing memory
   leaks, and introducing dynamic sysfs updates for memory hotplug
   support". Fixes things on error paths which we are unlikely to hit.

 - "mm/damon: auto-tune DAMOS for NUMA setups including tiered memory"
   from SeongJae Park introduces new DAMOS quota goal metrics which
   eliminate the manual tuning which is required when utilizing DAMON
   for memory tiering.

 - "mm/vmalloc.c: code cleanup and improvements" from Baoquan He
   provides cleanups and small efficiency improvements which Baoquan
   found via code inspection.

 - "vmscan: enforce mems_effective during demotion" from Gregory Price
   changes reclaim to respect cpuset.mems_effective during demotion when
   possible. because presently, reclaim explicitly ignores
   cpuset.mems_effective when demoting, which may cause the cpuset
   settings to violated.

   This is useful for isolating workloads on a multi-tenant system from
   certain classes of memory more consistently.

 - "Clean up split_huge_pmd_locked() and remove unnecessary folio
   pointers" from Gavin Guo provides minor cleanups and efficiency gains
   in in the huge page splitting and migrating code.

 - "Use kmem_cache for memcg alloc" from Huan Yang creates a slab cache
   for `struct mem_cgroup', yielding improved memory utilization.

 - "add max arg to swappiness in memory.reclaim and lru_gen" from
   Zhongkun He adds a new "max" argument to the "swappiness=" argument
   for memory.reclaim MGLRU's lru_gen.

   This directs proactive reclaim to reclaim from only anon folios
   rather than file-backed folios.

 - "kexec: introduce Kexec HandOver (KHO)" from Mike Rapoport is the
   first step on the path to permitting the kernel to maintain existing
   VMs while replacing the host kernel via file-based kexec. At this
   time only memblock's reserve_mem is preserved.

 - "mm: Introduce for_each_valid_pfn()" from David Woodhouse provides
   and uses a smarter way of looping over a pfn range. By skipping
   ranges of invalid pfns.

 - "sched/numa: Skip VMA scanning on memory pinned to one NUMA node via
   cpuset.mems" from Libo Chen removes a lot of pointless VMA scanning
   when a task is pinned a single NUMA mode.

   Dramatic performance benefits were seen in some real world cases.

 - "JFS: Implement migrate_folio for jfs_metapage_aops" from Shivank
   Garg addresses a warning which occurs during memory compaction when
   using JFS.

 - "move all VMA allocation, freeing and duplication logic to mm" from
   Lorenzo Stoakes moves some VMA code from kernel/fork.c into the more
   appropriate mm/vma.c.

 - "mm, swap: clean up swap cache mapping helper" from Kairui Song
   provides code consolidation and cleanups related to the folio_index()
   function.

 - "mm/gup: Cleanup memfd_pin_folios()" from Vishal Moola does that.

 - "memcg: Fix test_memcg_min/low test failures" from Waiman Long
   addresses some bogus failures which are being reported by the
   test_memcontrol selftest.

 - "eliminate mmap() retry merge, add .mmap_prepare hook" from Lorenzo
   Stoakes commences the deprecation of file_operations.mmap() in favor
   of the new file_operations.mmap_prepare().

   The latter is more restrictive and prevents drivers from messing with
   things in ways which, amongst other problems, may defeat VMA merging.

 - "memcg: decouple memcg and objcg stocks"" from Shakeel Butt decouples
   the per-cpu memcg charge cache from the objcg's one.

   This is a step along the way to making memcg and objcg charging
   NMI-safe, which is a BPF requirement.

 - "mm/damon: minor fixups and improvements for code, tests, and
   documents" from SeongJae Park is yet another batch of miscellaneous
   DAMON changes. Fix and improve minor problems in code, tests and
   documents.

 - "memcg: make memcg stats irq safe" from Shakeel Butt converts memcg
   stats to be irq safe. Another step along the way to making memcg
   charging and stats updates NMI-safe, a BPF requirement.

 - "Let unmap_hugepage_range() and several related functions take folio
   instead of page" from Fan Ni provides folio conversions in the
   hugetlb code.

* tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (285 commits)
  mm: pcp: increase pcp->free_count threshold to trigger free_high
  mm/hugetlb: convert use of struct page to folio in __unmap_hugepage_range()
  mm/hugetlb: refactor __unmap_hugepage_range() to take folio instead of page
  mm/hugetlb: refactor unmap_hugepage_range() to take folio instead of page
  mm/hugetlb: pass folio instead of page to unmap_ref_private()
  memcg: objcg stock trylock without irq disabling
  memcg: no stock lock for cpu hot-unplug
  memcg: make __mod_memcg_lruvec_state re-entrant safe against irqs
  memcg: make count_memcg_events re-entrant safe against irqs
  memcg: make mod_memcg_state re-entrant safe against irqs
  memcg: move preempt disable to callers of memcg_rstat_updated
  memcg: memcg_rstat_updated re-entrant safe against irqs
  mm: khugepaged: decouple SHMEM and file folios' collapse
  selftests/eventfd: correct test name and improve messages
  alloc_tag: check mem_profiling_support in alloc_tag_init
  Docs/damon: update titles and brief introductions to explain DAMOS
  selftests/damon/_damon_sysfs: read tried regions directories in order
  mm/damon/tests/core-kunit: add a test for damos_set_filters_default_reject()
  mm/damon/paddr: remove unused variable, folio_list, in damon_pa_stat()
  mm/damon/sysfs-schemes: fix wrong comment on damons_sysfs_quota_goal_metric_strs
  ...

5 files changed, 194 insertions, 1 deletions

diff --git a/samples/Makefile b/samples/Makefile
index c95bac31851c..07641e177bd8 100644
--- a/samples/Makefile
+++ b/samples/Makefile
@@ -42,5 +42,6 @@ obj-$(CONFIG_SAMPLE_FPROBE)		+= fprobe/
 obj-$(CONFIG_SAMPLES_RUST)		+= rust/
 obj-$(CONFIG_SAMPLE_DAMON_WSSE)		+= damon/
 obj-$(CONFIG_SAMPLE_DAMON_PRCL)		+= damon/
+obj-$(CONFIG_SAMPLE_DAMON_MTIER)	+= damon/
 obj-$(CONFIG_SAMPLE_HUNG_TASK)		+= hung_task/
 obj-$(CONFIG_SAMPLE_TSM_MR)		+= tsm-mr/
diff --git a/samples/damon/Kconfig b/samples/damon/Kconfig
index 564c49ed69a2..cbf96fd8a8bf 100644
--- a/samples/damon/Kconfig
+++ b/samples/damon/Kconfig
@@ -27,4 +27,17 @@ config SAMPLE_DAMON_PRCL
 
 	  If unsure, say N.
 
+config SAMPLE_DAMON_MTIER
+	bool "DAMON sample module for memory tiering"
+	depends on DAMON && DAMON_PADDR
+	help
+	  Thps builds DAMON sample module for memory tierign.
+
+	  The module assumes the system is constructed with two NUMA nodes,
+	  which seems as local and remote nodes to all CPUs.  For example,
+	  node0 is for DDR5 DRAMs connected via DIMM, while node1 is for DDR4
+	  DRAMs connected via CXL.
+
+	  If unsure, say N.
+
 endmenu
diff --git a/samples/damon/Makefile b/samples/damon/Makefile
index 7f155143f237..72f68cbf422a 100644
--- a/samples/damon/Makefile
+++ b/samples/damon/Makefile
@@ -2,3 +2,4 @@
 
 obj-$(CONFIG_SAMPLE_DAMON_WSSE) += wsse.o
 obj-$(CONFIG_SAMPLE_DAMON_PRCL) += prcl.o
+obj-$(CONFIG_SAMPLE_DAMON_MTIER) += mtier.o
diff --git a/samples/damon/mtier.c b/samples/damon/mtier.c
new file mode 100644
index 000000000000..36d2cd933f5a
--- /dev/null
+++ b/samples/damon/mtier.c
@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * memory tiering: migrate cold pages in node 0 and hot pages in node 1 to node
+ * 1 and node 0, respectively.  Adjust the hotness/coldness threshold aiming
+ * resulting 99.6 % node 0 utilization ratio.
+ */
+
+#define pr_fmt(fmt) "damon_sample_mtier: " fmt
+
+#include <linux/damon.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+static unsigned long node0_start_addr __read_mostly;
+module_param(node0_start_addr, ulong, 0600);
+
+static unsigned long node0_end_addr __read_mostly;
+module_param(node0_end_addr, ulong, 0600);
+
+static unsigned long node1_start_addr __read_mostly;
+module_param(node1_start_addr, ulong, 0600);
+
+static unsigned long node1_end_addr __read_mostly;
+module_param(node1_end_addr, ulong, 0600);
+
+static int damon_sample_mtier_enable_store(
+		const char *val, const struct kernel_param *kp);
+
+static const struct kernel_param_ops enable_param_ops = {
+	.set = damon_sample_mtier_enable_store,
+	.get = param_get_bool,
+};
+
+static bool enable __read_mostly;
+module_param_cb(enable, &enable_param_ops, &enable, 0600);
+MODULE_PARM_DESC(enable, "Enable of disable DAMON_SAMPLE_MTIER");
+
+static struct damon_ctx *ctxs[2];
+
+static struct damon_ctx *damon_sample_mtier_build_ctx(bool promote)
+{
+	struct damon_ctx *ctx;
+	struct damon_attrs attrs;
+	struct damon_target *target;
+	struct damon_region *region;
+	struct damos *scheme;
+	struct damos_quota_goal *quota_goal;
+	struct damos_filter *filter;
+
+	ctx = damon_new_ctx();
+	if (!ctx)
+		return NULL;
+	attrs = (struct damon_attrs) {
+		.sample_interval = 5 * USEC_PER_MSEC,
+		.aggr_interval = 100 * USEC_PER_MSEC,
+		.ops_update_interval = 60 * USEC_PER_MSEC * MSEC_PER_SEC,
+		.min_nr_regions = 10,
+		.max_nr_regions = 1000,
+	};
+
+	/*
+	 * auto-tune sampling and aggregation interval aiming 4% DAMON-observed
+	 * accesses ratio, keeping sampling interval in [5ms, 10s] range.
+	 */
+	attrs.intervals_goal = (struct damon_intervals_goal) {
+		.access_bp = 400, .aggrs = 3,
+		.min_sample_us = 5000, .max_sample_us = 10000000,
+	};
+	if (damon_set_attrs(ctx, &attrs))
+		goto free_out;
+	if (damon_select_ops(ctx, DAMON_OPS_PADDR))
+		goto free_out;
+
+	target = damon_new_target();
+	if (!target)
+		goto free_out;
+	damon_add_target(ctx, target);
+	region = damon_new_region(
+			promote ? node1_start_addr : node0_start_addr,
+			promote ? node1_end_addr : node0_end_addr);
+	if (!region)
+		goto free_out;
+	damon_add_region(region, target);
+
+	scheme = damon_new_scheme(
+			/* access pattern */
+			&(struct damos_access_pattern) {
+				.min_sz_region = PAGE_SIZE,
+				.max_sz_region = ULONG_MAX,
+				.min_nr_accesses = promote ? 1 : 0,
+				.max_nr_accesses = promote ? UINT_MAX : 0,
+				.min_age_region = 0,
+				.max_age_region = UINT_MAX},
+			/* action */
+			promote ? DAMOS_MIGRATE_HOT : DAMOS_MIGRATE_COLD,
+			1000000,	/* apply interval (1s) */
+			&(struct damos_quota){
+				/* 200 MiB per sec by most */
+				.reset_interval = 1000,
+				.sz = 200 * 1024 * 1024,
+				/* ignore size of region when prioritizing */
+				.weight_sz = 0,
+				.weight_nr_accesses = 100,
+				.weight_age = 100,
+			},
+			&(struct damos_watermarks){},
+			promote ? 0 : 1);	/* migrate target node id */
+	if (!scheme)
+		goto free_out;
+	damon_set_schemes(ctx, &scheme, 1);
+	quota_goal = damos_new_quota_goal(
+			promote ? DAMOS_QUOTA_NODE_MEM_USED_BP :
+			DAMOS_QUOTA_NODE_MEM_FREE_BP,
+			promote ? 9970 : 50);
+	if (!quota_goal)
+		goto free_out;
+	quota_goal->nid = 0;
+	damos_add_quota_goal(&scheme->quota, quota_goal);
+	filter = damos_new_filter(DAMOS_FILTER_TYPE_YOUNG, true, promote);
+	if (!filter)
+		goto free_out;
+	damos_add_filter(scheme, filter);
+	return ctx;
+free_out:
+	damon_destroy_ctx(ctx);
+	return NULL;
+}
+
+static int damon_sample_mtier_start(void)
+{
+	struct damon_ctx *ctx;
+
+	ctx = damon_sample_mtier_build_ctx(true);
+	if (!ctx)
+		return -ENOMEM;
+	ctxs[0] = ctx;
+	ctx = damon_sample_mtier_build_ctx(false);
+	if (!ctx) {
+		damon_destroy_ctx(ctxs[0]);
+		return -ENOMEM;
+	}
+	ctxs[1] = ctx;
+	return damon_start(ctxs, 2, true);
+}
+
+static void damon_sample_mtier_stop(void)
+{
+	damon_stop(ctxs, 2);
+	damon_destroy_ctx(ctxs[0]);
+	damon_destroy_ctx(ctxs[1]);
+}
+
+static int damon_sample_mtier_enable_store(
+		const char *val, const struct kernel_param *kp)
+{
+	bool enabled = enable;
+	int err;
+
+	err = kstrtobool(val, &enable);
+	if (err)
+		return err;
+
+	if (enable == enabled)
+		return 0;
+
+	if (enable)
+		return damon_sample_mtier_start();
+	damon_sample_mtier_stop();
+	return 0;
+}
+
+static int __init damon_sample_mtier_init(void)
+{
+	return 0;
+}
+
+module_init(damon_sample_mtier_init);
diff --git a/samples/damon/prcl.c b/samples/damon/prcl.c
index c3acbdab7a62..056b1b21a0fe 100644
--- a/samples/damon/prcl.c
+++ b/samples/damon/prcl.c
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
  * proactive reclamation: monitor access pattern of a given process, find
- * regiosn that seems not accessed, and proactively page out the regions.
+ * regions that seems not accessed, and proactively page out the regions.
  */
 
 #define pr_fmt(fmt) "damon_sample_prcl: " fmt