Merge tag 'slab-for-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

Pull slab updates from Vlastimil Babka:

 - Freelist loading optimization (Chengming Zhou)

   When the per-cpu slab is depleted and a new one loaded from the cpu
   partial list, optimize the loading to avoid an irq enable/disable
   cycle. This results in a 3.5% performance improvement on the "perf
   bench sched messaging" test.

 - Kernel boot parameters cleanup after SLAB removal (Xiongwei Song)

   Due to two different main slab implementations we've had boot
   parameters prefixed either slab_ and slub_ with some later becoming
   an alias as both implementations gained the same functionality (i.e.
   slab_nomerge vs slub_nomerge). In order to eventually get rid of the
   implementation-specific names, the canonical and documented
   parameters are now all prefixed slab_ and the slub_ variants become
   deprecated but still working aliases.

 - SLAB_ kmem_cache creation flags cleanup (Vlastimil Babka)

   The flags had hardcoded #define values which became tedious and
   error-prone when adding new ones. Assign the values via an enum that
   takes care of providing unique bit numbers. Also deprecate
   SLAB_MEM_SPREAD which was only used by SLAB, so it's a no-op since
   SLAB removal. Assign it an explicit zero value. The removals of the
   flag usage are handled independently in the respective subsystems,
   with a final removal of any leftover usage planned for the next
   release.

 - Misc cleanups and fixes (Chengming Zhou, Xiaolei Wang, Zheng Yejian)

   Includes removal of unused code or function parameters and a fix of a
   memleak.

* tag 'slab-for-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
  slab: remove PARTIAL_NODE slab_state
  mm, slab: remove memcg_from_slab_obj()
  mm, slab: remove the corner case of inc_slabs_node()
  mm/slab: Fix a kmemleak in kmem_cache_destroy()
  mm, slab, kasan: replace kasan_never_merge() with SLAB_NO_MERGE
  mm, slab: use an enum to define SLAB_ cache creation flags
  mm, slab: deprecate SLAB_MEM_SPREAD flag
  mm, slab: fix the comment of cpu partial list
  mm, slab: remove unused object_size parameter in kmem_cache_flags()
  mm/slub: remove parameter 'flags' in create_kmalloc_caches()
  mm/slub: remove unused parameter in next_freelist_entry()
  mm/slub: remove full list manipulation for non-debug slab
  mm/slub: directly load freelist from cpu partial slab in the likely case
  mm/slub: make the description of slab_min_objects helpful in doc
  mm/slub: replace slub_$params with slab_$params in slub.rst
  mm/slub: unify all sl[au]b parameters with "slab_$param"
  Documentation: kernel-parameters: remove noaliencache

1 files changed, 6 insertions, 16 deletions

diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
index 1900f8576034..6310a180278b 100644
--- a/mm/kasan/generic.c
+++ b/mm/kasan/generic.c
@@ -334,14 +334,6 @@ DEFINE_ASAN_SET_SHADOW(f3);
 DEFINE_ASAN_SET_SHADOW(f5);
 DEFINE_ASAN_SET_SHADOW(f8);
 
-/* Only allow cache merging when no per-object metadata is present. */
-slab_flags_t kasan_never_merge(void)
-{
-	if (!kasan_requires_meta())
-		return 0;
-	return SLAB_KASAN;
-}
-
 /*
  * Adaptive redzone policy taken from the userspace AddressSanitizer runtime.
  * For larger allocations larger redzones are used.
@@ -370,15 +362,13 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
 		return;
 
 	/*
-	 * SLAB_KASAN is used to mark caches that are sanitized by KASAN
-	 * and that thus have per-object metadata.
-	 * Currently this flag is used in two places:
-	 * 1. In slab_ksize() to account for per-object metadata when
-	 *    calculating the size of the accessible memory within the object.
-	 * 2. In slab_common.c via kasan_never_merge() to prevent merging of
-	 *    caches with per-object metadata.
+	 * SLAB_KASAN is used to mark caches that are sanitized by KASAN and
+	 * that thus have per-object metadata. Currently, this flag is used in
+	 * slab_ksize() to account for per-object metadata when calculating the
+	 * size of the accessible memory within the object. Additionally, we use
+	 * SLAB_NO_MERGE to prevent merging of caches with per-object metadata.
 	 */
-	*flags |= SLAB_KASAN;
+	*flags |= SLAB_KASAN | SLAB_NO_MERGE;
 
 	ok_size = *size;