Merge tag 'slab-for-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

Pull slab updates from Vlastimil Babka:

 - Separate struct slab from struct page - an offshot of the page folio
   work.

   Struct page fields used by slab allocators are moved from struct page
   to a new struct slab, that uses the same physical storage. Similar to
   struct folio, it always is a head page. This brings better type
   safety, separation of large kmalloc allocations from true slabs, and
   cleanup of related objcg code.

 - A SLAB_MERGE_DEFAULT config optimization.

* tag 'slab-for-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: (33 commits)
  mm/slob: Remove unnecessary page_mapcount_reset() function call
  bootmem: Use page->index instead of page->freelist
  zsmalloc: Stop using slab fields in struct page
  mm/slub: Define struct slab fields for CONFIG_SLUB_CPU_PARTIAL only when enabled
  mm/slub: Simplify struct slab slabs field definition
  mm/sl*b: Differentiate struct slab fields by sl*b implementations
  mm/kfence: Convert kfence_guarded_alloc() to struct slab
  mm/kasan: Convert to struct folio and struct slab
  mm/slob: Convert SLOB to use struct slab and struct folio
  mm/memcg: Convert slab objcgs from struct page to struct slab
  mm: Convert struct page to struct slab in functions used by other subsystems
  mm/slab: Finish struct page to struct slab conversion
  mm/slab: Convert most struct page to struct slab by spatch
  mm/slab: Convert kmem_getpages() and kmem_freepages() to struct slab
  mm/slub: Finish struct page to struct slab conversion
  mm/slub: Convert most struct page to struct slab by spatch
  mm/slub: Convert pfmemalloc_match() to take a struct slab
  mm/slub: Convert __free_slab() to use struct slab
  mm/slub: Convert alloc_slab_page() to return a struct slab
  mm/slub: Convert print_page_info() to print_slab_info()
  ...

1 files changed, 30 insertions, 25 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2ed5f2a0879d..4a7b3ebf8e48 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2816,31 +2816,31 @@ static inline void mod_objcg_mlstate(struct obj_cgroup *objcg,
 	rcu_read_unlock();
 }
 
-int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,
-				 gfp_t gfp, bool new_page)
+int memcg_alloc_slab_cgroups(struct slab *slab, struct kmem_cache *s,
+				 gfp_t gfp, bool new_slab)
 {
-	unsigned int objects = objs_per_slab_page(s, page);
+	unsigned int objects = objs_per_slab(s, slab);
 	unsigned long memcg_data;
 	void *vec;
 
 	gfp &= ~OBJCGS_CLEAR_MASK;
 	vec = kcalloc_node(objects, sizeof(struct obj_cgroup *), gfp,
-			   page_to_nid(page));
+			   slab_nid(slab));
 	if (!vec)
 		return -ENOMEM;
 
 	memcg_data = (unsigned long) vec | MEMCG_DATA_OBJCGS;
-	if (new_page) {
+	if (new_slab) {
 		/*
-		 * If the slab page is brand new and nobody can yet access
-		 * it's memcg_data, no synchronization is required and
-		 * memcg_data can be simply assigned.
+		 * If the slab is brand new and nobody can yet access its
+		 * memcg_data, no synchronization is required and memcg_data can
+		 * be simply assigned.
 		 */
-		page->memcg_data = memcg_data;
-	} else if (cmpxchg(&page->memcg_data, 0, memcg_data)) {
+		slab->memcg_data = memcg_data;
+	} else if (cmpxchg(&slab->memcg_data, 0, memcg_data)) {
 		/*
-		 * If the slab page is already in use, somebody can allocate
-		 * and assign obj_cgroups in parallel. In this case the existing
+		 * If the slab is already in use, somebody can allocate and
+		 * assign obj_cgroups in parallel. In this case the existing
 		 * objcg vector should be reused.
 		 */
 		kfree(vec);
@@ -2865,38 +2865,43 @@ int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,
  */
 struct mem_cgroup *mem_cgroup_from_obj(void *p)
 {
-	struct page *page;
+	struct folio *folio;
 
 	if (mem_cgroup_disabled())
 		return NULL;
 
-	page = virt_to_head_page(p);
+	folio = virt_to_folio(p);
 
 	/*
 	 * Slab objects are accounted individually, not per-page.
 	 * Memcg membership data for each individual object is saved in
-	 * the page->obj_cgroups.
+	 * slab->memcg_data.
 	 */
-	if (page_objcgs_check(page)) {
-		struct obj_cgroup *objcg;
+	if (folio_test_slab(folio)) {
+		struct obj_cgroup **objcgs;
+		struct slab *slab;
 		unsigned int off;
 
-		off = obj_to_index(page->slab_cache, page, p);
-		objcg = page_objcgs(page)[off];
-		if (objcg)
-			return obj_cgroup_memcg(objcg);
+		slab = folio_slab(folio);
+		objcgs = slab_objcgs(slab);
+		if (!objcgs)
+			return NULL;
+
+		off = obj_to_index(slab->slab_cache, slab, p);
+		if (objcgs[off])
+			return obj_cgroup_memcg(objcgs[off]);
 
 		return NULL;
 	}
 
 	/*
-	 * page_memcg_check() is used here, because page_has_obj_cgroups()
-	 * check above could fail because the object cgroups vector wasn't set
-	 * at that moment, but it can be set concurrently.
+	 * page_memcg_check() is used here, because in theory we can encounter
+	 * a folio where the slab flag has been cleared already, but
+	 * slab->memcg_data has not been freed yet
 	 * page_memcg_check(page) will guarantee that a proper memory
 	 * cgroup pointer or NULL will be returned.
 	 */
-	return page_memcg_check(page);
+	return page_memcg_check(folio_page(folio, 0));
 }
 
 __always_inline struct obj_cgroup *get_obj_cgroup_from_current(void)