Merge tag 'mm-stable-2024-11-18-19-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - The series "zram: optimal post-processing target selection" from
   Sergey Senozhatsky improves zram's post-processing selection
   algorithm. This leads to improved memory savings.

 - Wei Yang has gone to town on the mapletree code, contributing several
   series which clean up the implementation:
	- "refine mas_mab_cp()"
	- "Reduce the space to be cleared for maple_big_node"
	- "maple_tree: simplify mas_push_node()"
	- "Following cleanup after introduce mas_wr_store_type()"
	- "refine storing null"

 - The series "selftests/mm: hugetlb_fault_after_madv improvements" from
   David Hildenbrand fixes this selftest for s390.

 - The series "introduce pte_offset_map_{ro|rw}_nolock()" from Qi Zheng
   implements some rationaizations and cleanups in the page mapping
   code.

 - The series "mm: optimize shadow entries removal" from Shakeel Butt
   optimizes the file truncation code by speeding up the handling of
   shadow entries.

 - The series "Remove PageKsm()" from Matthew Wilcox completes the
   migration of this flag over to being a folio-based flag.

 - The series "Unify hugetlb into arch_get_unmapped_area functions" from
   Oscar Salvador implements a bunch of consolidations and cleanups in
   the hugetlb code.

 - The series "Do not shatter hugezeropage on wp-fault" from Dev Jain
   takes away the wp-fault time practice of turning a huge zero page
   into small pages. Instead we replace the whole thing with a THP. More
   consistent cleaner and potentiall saves a large number of pagefaults.

 - The series "percpu: Add a test case and fix for clang" from Andy
   Shevchenko enhances and fixes the kernel's built in percpu test code.

 - The series "mm/mremap: Remove extra vma tree walk" from Liam Howlett
   optimizes mremap() by avoiding doing things which we didn't need to
   do.

 - The series "Improve the tmpfs large folio read performance" from
   Baolin Wang teaches tmpfs to copy data into userspace at the folio
   size rather than as individual pages. A 20% speedup was observed.

 - The series "mm/damon/vaddr: Fix issue in
   damon_va_evenly_split_region()" fro Zheng Yejian fixes DAMON
   splitting.

 - The series "memcg-v1: fully deprecate charge moving" from Shakeel
   Butt removes the long-deprecated memcgv2 charge moving feature.

 - The series "fix error handling in mmap_region() and refactor" from
   Lorenzo Stoakes cleanup up some of the mmap() error handling and
   addresses some potential performance issues.

 - The series "x86/module: use large ROX pages for text allocations"
   from Mike Rapoport teaches x86 to use large pages for
   read-only-execute module text.

 - The series "page allocation tag compression" from Suren Baghdasaryan
   is followon maintenance work for the new page allocation profiling
   feature.

 - The series "page->index removals in mm" from Matthew Wilcox remove
   most references to page->index in mm/. A slow march towards shrinking
   struct page.

 - The series "damon/{self,kunit}tests: minor fixups for DAMON debugfs
   interface tests" from Andrew Paniakin performs maintenance work for
   DAMON's self testing code.

 - The series "mm: zswap swap-out of large folios" from Kanchana Sridhar
   improves zswap's batching of compression and decompression. It is a
   step along the way towards using Intel IAA hardware acceleration for
   this zswap operation.

 - The series "kasan: migrate the last module test to kunit" from
   Sabyrzhan Tasbolatov completes the migration of the KASAN built-in
   tests over to the KUnit framework.

 - The series "implement lightweight guard pages" from Lorenzo Stoakes
   permits userapace to place fault-generating guard pages within a
   single VMA, rather than requiring that multiple VMAs be created for
   this. Improved efficiencies for userspace memory allocators are
   expected.

 - The series "memcg: tracepoint for flushing stats" from JP Kobryn uses
   tracepoints to provide increased visibility into memcg stats flushing
   activity.

 - The series "zram: IDLE flag handling fixes" from Sergey Senozhatsky
   fixes a zram buglet which potentially affected performance.

 - The series "mm: add more kernel parameters to control mTHP" from
   Maíra Canal enhances our ability to control/configuremultisize THP
   from the kernel boot command line.

 - The series "kasan: few improvements on kunit tests" from Sabyrzhan
   Tasbolatov has a couple of fixups for the KASAN KUnit tests.

 - The series "mm/list_lru: Split list_lru lock into per-cgroup scope"
   from Kairui Song optimizes list_lru memory utilization when lockdep
   is enabled.

* tag 'mm-stable-2024-11-18-19-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (215 commits)
  cma: enforce non-zero pageblock_order during cma_init_reserved_mem()
  mm/kfence: add a new kunit test test_use_after_free_read_nofault()
  zram: fix NULL pointer in comp_algorithm_show()
  memcg/hugetlb: add hugeTLB counters to memcg
  vmstat: call fold_vm_zone_numa_events() before show per zone NUMA event
  mm: mmap_lock: check trace_mmap_lock_$type_enabled() instead of regcount
  zram: ZRAM_DEF_COMP should depend on ZRAM
  MAINTAINERS/MEMORY MANAGEMENT: add document files for mm
  Docs/mm/damon: recommend academic papers to read and/or cite
  mm: define general function pXd_init()
  kmemleak: iommu/iova: fix transient kmemleak false positive
  mm/list_lru: simplify the list_lru walk callback function
  mm/list_lru: split the lock to per-cgroup scope
  mm/list_lru: simplify reparenting and initial allocation
  mm/list_lru: code clean up for reparenting
  mm/list_lru: don't export list_lru_add
  mm/list_lru: don't pass unnecessary key parameters
  kasan: add kunit tests for kmalloc_track_caller, kmalloc_node_track_caller
  kasan: change kasan_atomics kunit test as KUNIT_CASE_SLOW
  kasan: use EXPORT_SYMBOL_IF_KUNIT to export symbols
  ...

1 files changed, 8 insertions, 31 deletions

diff --git a/mm/mmap_lock.c b/mm/mmap_lock.c
index 368b840e7508..f186d57df2c6 100644
--- a/mm/mmap_lock.c
+++ b/mm/mmap_lock.c
@@ -19,43 +19,23 @@ EXPORT_TRACEPOINT_SYMBOL(mmap_lock_released);
 
 #ifdef CONFIG_MEMCG
 
-static atomic_t reg_refcount;
-
 /*
  * Size of the buffer for memcg path names. Ignoring stack trace support,
  * trace_events_hist.c uses MAX_FILTER_STR_VAL for this, so we also use it.
  */
 #define MEMCG_PATH_BUF_SIZE MAX_FILTER_STR_VAL
 
-int trace_mmap_lock_reg(void)
-{
-	atomic_inc(&reg_refcount);
-	return 0;
-}
-
-void trace_mmap_lock_unreg(void)
-{
-	atomic_dec(&reg_refcount);
-}
-
-#define TRACE_MMAP_LOCK_EVENT(type, mm, ...)                    \
-	do {                                                    \
-		char buf[MEMCG_PATH_BUF_SIZE];                  \
-		get_mm_memcg_path(mm, buf, sizeof(buf));        \
-		trace_mmap_lock_##type(mm, buf, ##__VA_ARGS__); \
+#define TRACE_MMAP_LOCK_EVENT(type, mm, ...)				\
+	do {								\
+		if (trace_mmap_lock_##type##_enabled()) {		\
+			char buf[MEMCG_PATH_BUF_SIZE];                  \
+			get_mm_memcg_path(mm, buf, sizeof(buf));        \
+			trace_mmap_lock_##type(mm, buf, ##__VA_ARGS__); \
+		}							\
 	} while (0)
 
 #else /* !CONFIG_MEMCG */
 
-int trace_mmap_lock_reg(void)
-{
-	return 0;
-}
-
-void trace_mmap_lock_unreg(void)
-{
-}
-
 #define TRACE_MMAP_LOCK_EVENT(type, mm, ...)                                   \
 	trace_mmap_lock_##type(mm, "", ##__VA_ARGS__)
 
@@ -65,16 +45,13 @@ void trace_mmap_lock_unreg(void)
 #ifdef CONFIG_MEMCG
 /*
  * Write the given mm_struct's memcg path to a buffer. If the path cannot be
- * determined or the trace event is being unregistered, empty string is written.
+ * determined, empty string is written.
  */
 static void get_mm_memcg_path(struct mm_struct *mm, char *buf, size_t buflen)
 {
 	struct mem_cgroup *memcg;
 
 	buf[0] = '\0';
-	/* No need to get path if no trace event is registered. */
-	if (!atomic_read(&reg_refcount))
-		return;
 	memcg = get_mem_cgroup_from_mm(mm);
 	if (memcg == NULL)
 		return;