Merge branch 'slab/for-6.2/cleanups' into slab/for-next

- Removal of dead code from deactivate_slab() by Hyeonggon Yoo.
- Fix of BUILD_BUG_ON() for sufficient early percpu size by Baoquan He.
- Make kmem_cache_alloc() kernel-doc less misleading, by myself.

include/linux/percpu.h

@@ -42,7 +42,7 @@
  * larger than PERCPU_DYNAMIC_EARLY_SIZE.
  */
 #define PERCPU_DYNAMIC_EARLY_SLOTS	128
-#define PERCPU_DYNAMIC_EARLY_SIZE	(12 << 10)
+#define PERCPU_DYNAMIC_EARLY_SIZE	(20 << 10)
 
 /*
  * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy

include/linux/slab.h

@@ -441,7 +441,18 @@ static_assert(PAGE_SHIFT <= 20);
 #endif /* !CONFIG_SLOB */
 
 void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __alloc_size(1);
-void *kmem_cache_alloc(struct kmem_cache *s, gfp_t flags) __assume_slab_alignment __malloc;
+
+/**
+ * kmem_cache_alloc - Allocate an object
+ * @cachep: The cache to allocate from.
+ * @flags: See kmalloc().
+ *
+ * Allocate an object from this cache.
+ * See kmem_cache_zalloc() for a shortcut of adding __GFP_ZERO to flags.
+ *
+ * Return: pointer to the new object or %NULL in case of error
+ */
+void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags) __assume_slab_alignment __malloc;
 void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
 			   gfp_t gfpflags) __assume_slab_alignment __malloc;
 void kmem_cache_free(struct kmem_cache *s, void *objp);
@@ -483,9 +494,9 @@ void *kmalloc_large_node(size_t size, gfp_t flags, int node) __assume_page_align
 							     __alloc_size(1);
 
 /**
- * kmalloc - allocate memory
+ * kmalloc - allocate kernel memory
  * @size: how many bytes of memory are required.
- * @flags: the type of memory to allocate.
+ * @flags: describe the allocation context
  *
  * kmalloc is the normal method of allocating memory
  * for objects smaller than page size in the kernel.
@@ -512,12 +523,12 @@ void *kmalloc_large_node(size_t size, gfp_t flags, int node) __assume_page_align
  * %GFP_ATOMIC
  *	Allocation will not sleep.  May use emergency pools.
  *
- * %GFP_HIGHUSER
- *	Allocate memory from high memory on behalf of user.
- *
  * Also it is possible to set different flags by OR'ing
  * in one or more of the following additional @flags:
  *
+ * %__GFP_ZERO
+ *	Zero the allocated memory before returning. Also see kzalloc().
+ *
  * %__GFP_HIGH
  *	This allocation has high priority and may use emergency pools.
  *

mm/slab.c

@@ -3446,16 +3446,6 @@ void *__kmem_cache_alloc_lru(struct kmem_cache *cachep, struct list_lru *lru,
 	return ret;
 }
 
-/**
- * kmem_cache_alloc - Allocate an object
- * @cachep: The cache to allocate from.
- * @flags: See kmalloc().
- *
- * Allocate an object from this cache.  The flags are only relevant
- * if the cache has no available objects.
- *
- * Return: pointer to the new object or %NULL in case of error
- */
 void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
 {
 	return __kmem_cache_alloc_lru(cachep, NULL, flags);

mm/slub.c

@@ -2411,7 +2411,7 @@ static void init_kmem_cache_cpus(struct kmem_cache *s)
 static void deactivate_slab(struct kmem_cache *s, struct slab *slab,
 			    void *freelist)
 {
-	enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE, M_FULL_NOLIST };
+	enum slab_modes { M_NONE, M_PARTIAL, M_FREE, M_FULL_NOLIST };
 	struct kmem_cache_node *n = get_node(s, slab_nid(slab));
 	int free_delta = 0;
 	enum slab_modes mode = M_NONE;
@@ -2487,14 +2487,6 @@ redo:
 		 * acquire_slab() will see a slab that is frozen
 		 */
 		spin_lock_irqsave(&n->list_lock, flags);
-	} else if (kmem_cache_debug_flags(s, SLAB_STORE_USER)) {
-		mode = M_FULL;
-		/*
-		 * This also ensures that the scanning of full
-		 * slabs from diagnostic functions will not see
-		 * any frozen slabs.
-		 */
-		spin_lock_irqsave(&n->list_lock, flags);
 	} else {
 		mode = M_FULL_NOLIST;
 	}
@@ -2504,7 +2496,7 @@ redo:
 				old.freelist, old.counters,
 				new.freelist, new.counters,
 				"unfreezing slab")) {
-		if (mode == M_PARTIAL || mode == M_FULL)
+		if (mode == M_PARTIAL)
 			spin_unlock_irqrestore(&n->list_lock, flags);
 		goto redo;
 	}
@@ -2518,10 +2510,6 @@ redo:
 		stat(s, DEACTIVATE_EMPTY);
 		discard_slab(s, slab);
 		stat(s, FREE_SLAB);
-	} else if (mode == M_FULL) {
-		add_full(s, n, slab);
-		spin_unlock_irqrestore(&n->list_lock, flags);
-		stat(s, DEACTIVATE_FULL);
 	} else if (mode == M_FULL_NOLIST) {
 		stat(s, DEACTIVATE_FULL);
 	}
@@ -4017,7 +4005,8 @@ init_kmem_cache_node(struct kmem_cache_node *n)
 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
 {
 	BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
-			KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
+			NR_KMALLOC_TYPES * KMALLOC_SHIFT_HIGH *
+			sizeof(struct kmem_cache_cpu));
 
 	/*
 	 * Must align to double word boundary for the double cmpxchg