mm, sl[aou]b: Extract common fields from struct kmem_cache

Define a struct that describes common fields used in all slab allocators.
A slab allocator either uses the common definition (like SLOB) or is
required to provide members of kmem_cache with the definition given.

After that it will be possible to share code that
only operates on those fields of kmem_cache.

The patch basically takes the slob definition of kmem cache and
uses the field namees for the other allocators.

It also standardizes the names used for basic object lengths in
allocators:

object_size	Struct size specified at kmem_cache_create. Basically
		the payload expected to be used by the subsystem.

size		The size of memory allocator for each object. This size
		is larger than object_size and includes padding, alignment
		and extra metadata for each object (f.e. for debugging
		and rcu).

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

1 files changed, 58 insertions, 59 deletions

diff --git a/mm/slab.c b/mm/slab.c
index 28a8f7d..e2b3907 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -424,8 +424,8 @@ static void kmem_list3_init(struct kmem_list3 *parent)
  * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
  * 		redzone word.
  * cachep->obj_offset: The real object.
- * cachep->buffer_size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
- * cachep->buffer_size - 1* BYTES_PER_WORD: last caller address
+ * cachep->size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
+ * cachep->size - 1* BYTES_PER_WORD: last caller address
  *					[BYTES_PER_WORD long]
  */
 static int obj_offset(struct kmem_cache *cachep)
@@ -435,7 +435,7 @@ static int obj_offset(struct kmem_cache *cachep)
 
 static int obj_size(struct kmem_cache *cachep)
 {
-	return cachep->obj_size;
+	return cachep->object_size;
 }
 
 static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
@@ -449,23 +449,23 @@ static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
 {
 	BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
 	if (cachep->flags & SLAB_STORE_USER)
-		return (unsigned long long *)(objp + cachep->buffer_size -
+		return (unsigned long long *)(objp + cachep->size -
 					      sizeof(unsigned long long) -
 					      REDZONE_ALIGN);
-	return (unsigned long long *) (objp + cachep->buffer_size -
+	return (unsigned long long *) (objp + cachep->size -
 				       sizeof(unsigned long long));
 }
 
 static void **dbg_userword(struct kmem_cache *cachep, void *objp)
 {
 	BUG_ON(!(cachep->flags & SLAB_STORE_USER));
-	return (void **)(objp + cachep->buffer_size - BYTES_PER_WORD);
+	return (void **)(objp + cachep->size - BYTES_PER_WORD);
 }
 
 #else
 
 #define obj_offset(x)			0
-#define obj_size(cachep)		(cachep->buffer_size)
+#define obj_size(cachep)		(cachep->size)
 #define dbg_redzone1(cachep, objp)	({BUG(); (unsigned long long *)NULL;})
 #define dbg_redzone2(cachep, objp)	({BUG(); (unsigned long long *)NULL;})
 #define dbg_userword(cachep, objp)	({BUG(); (void **)NULL;})
@@ -475,7 +475,7 @@ static void **dbg_userword(struct kmem_cache *cachep, void *objp)
 #ifdef CONFIG_TRACING
 size_t slab_buffer_size(struct kmem_cache *cachep)
 {
-	return cachep->buffer_size;
+	return cachep->size;
 }
 EXPORT_SYMBOL(slab_buffer_size);
 #endif
@@ -513,13 +513,13 @@ static inline struct slab *virt_to_slab(const void *obj)
 static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab,
 				 unsigned int idx)
 {
-	return slab->s_mem + cache->buffer_size * idx;
+	return slab->s_mem + cache->size * idx;
 }
 
 /*
- * We want to avoid an expensive divide : (offset / cache->buffer_size)
- *   Using the fact that buffer_size is a constant for a particular cache,
- *   we can replace (offset / cache->buffer_size) by
+ * We want to avoid an expensive divide : (offset / cache->size)
+ *   Using the fact that size is a constant for a particular cache,
+ *   we can replace (offset / cache->size) by
  *   reciprocal_divide(offset, cache->reciprocal_buffer_size)
  */
 static inline unsigned int obj_to_index(const struct kmem_cache *cache,
@@ -565,7 +565,7 @@ static struct kmem_cache cache_cache = {
 	.batchcount = 1,
 	.limit = BOOT_CPUCACHE_ENTRIES,
 	.shared = 1,
-	.buffer_size = sizeof(struct kmem_cache),
+	.size = sizeof(struct kmem_cache),
 	.name = "kmem_cache",
 };
 
@@ -1134,7 +1134,7 @@ static int init_cache_nodelists_node(int node)
 	struct kmem_list3 *l3;
 	const int memsize = sizeof(struct kmem_list3);
 
-	list_for_each_entry(cachep, &cache_chain, next) {
+	list_for_each_entry(cachep, &cache_chain, list) {
 		/*
 		 * Set up the size64 kmemlist for cpu before we can
 		 * begin anything. Make sure some other cpu on this
@@ -1172,7 +1172,7 @@ static void __cpuinit cpuup_canceled(long cpu)
 	int node = cpu_to_mem(cpu);
 	const struct cpumask *mask = cpumask_of_node(node);
 
-	list_for_each_entry(cachep, &cache_chain, next) {
+	list_for_each_entry(cachep, &cache_chain, list) {
 		struct array_cache *nc;
 		struct array_cache *shared;
 		struct array_cache **alien;
@@ -1222,7 +1222,7 @@ free_array_cache:
 	 * the respective cache's slabs,  now we can go ahead and
 	 * shrink each nodelist to its limit.
 	 */
-	list_for_each_entry(cachep, &cache_chain, next) {
+	list_for_each_entry(cachep, &cache_chain, list) {
 		l3 = cachep->nodelists[node];
 		if (!l3)
 			continue;
@@ -1251,7 +1251,7 @@ static int __cpuinit cpuup_prepare(long cpu)
 	 * Now we can go ahead with allocating the shared arrays and
 	 * array caches
 	 */
-	list_for_each_entry(cachep, &cache_chain, next) {
+	list_for_each_entry(cachep, &cache_chain, list) {
 		struct array_cache *nc;
 		struct array_cache *shared = NULL;
 		struct array_cache **alien = NULL;
@@ -1383,7 +1383,7 @@ static int __meminit drain_cache_nodelists_node(int node)
 	struct kmem_cache *cachep;
 	int ret = 0;
 
-	list_for_each_entry(cachep, &cache_chain, next) {
+	list_for_each_entry(cachep, &cache_chain, list) {
 		struct kmem_list3 *l3;
 
 		l3 = cachep->nodelists[node];
@@ -1526,7 +1526,7 @@ void __init kmem_cache_init(void)
 
 	/* 1) create the cache_cache */
 	INIT_LIST_HEAD(&cache_chain);
-	list_add(&cache_cache.next, &cache_chain);
+	list_add(&cache_cache.list, &cache_chain);
 	cache_cache.colour_off = cache_line_size();
 	cache_cache.array[smp_processor_id()] = &initarray_cache.cache;
 	cache_cache.nodelists[node] = &initkmem_list3[CACHE_CACHE + node];
@@ -1534,18 +1534,16 @@ void __init kmem_cache_init(void)
 	/*
 	 * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids
 	 */
-	cache_cache.buffer_size = offsetof(struct kmem_cache, array[nr_cpu_ids]) +
+	cache_cache.size = offsetof(struct kmem_cache, array[nr_cpu_ids]) +
 				  nr_node_ids * sizeof(struct kmem_list3 *);
-#if DEBUG
-	cache_cache.obj_size = cache_cache.buffer_size;
-#endif
-	cache_cache.buffer_size = ALIGN(cache_cache.buffer_size,
+	cache_cache.object_size = cache_cache.size;
+	cache_cache.size = ALIGN(cache_cache.size,
 					cache_line_size());
 	cache_cache.reciprocal_buffer_size =
-		reciprocal_value(cache_cache.buffer_size);
+		reciprocal_value(cache_cache.size);
 
 	for (order = 0; order < MAX_ORDER; order++) {
-		cache_estimate(order, cache_cache.buffer_size,
+		cache_estimate(order, cache_cache.size,
 			cache_line_size(), 0, &left_over, &cache_cache.num);
 		if (cache_cache.num)
 			break;
@@ -1671,7 +1669,7 @@ void __init kmem_cache_init_late(void)
 
 	/* 6) resize the head arrays to their final sizes */
 	mutex_lock(&cache_chain_mutex);
-	list_for_each_entry(cachep, &cache_chain, next)
+	list_for_each_entry(cachep, &cache_chain, list)
 		if (enable_cpucache(cachep, GFP_NOWAIT))
 			BUG();
 	mutex_unlock(&cache_chain_mutex);
@@ -1724,7 +1722,7 @@ slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid)
 		"SLAB: Unable to allocate memory on node %d (gfp=0x%x)\n",
 		nodeid, gfpflags);
 	printk(KERN_WARNING "  cache: %s, object size: %d, order: %d\n",
-		cachep->name, cachep->buffer_size, cachep->gfporder);
+		cachep->name, cachep->size, cachep->gfporder);
 
 	for_each_online_node(node) {
 		unsigned long active_objs = 0, num_objs = 0, free_objects = 0;
@@ -2028,10 +2026,10 @@ static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slab
 
 		if (cachep->flags & SLAB_POISON) {
 #ifdef CONFIG_DEBUG_PAGEALLOC
-			if (cachep->buffer_size % PAGE_SIZE == 0 &&
+			if (cachep->size % PAGE_SIZE == 0 &&
 					OFF_SLAB(cachep))
 				kernel_map_pages(virt_to_page(objp),
-					cachep->buffer_size / PAGE_SIZE, 1);
+					cachep->size / PAGE_SIZE, 1);
 			else
 				check_poison_obj(cachep, objp);
 #else
@@ -2281,7 +2279,7 @@ kmem_cache_create (const char *name, size_t size, size_t align,
 		mutex_lock(&cache_chain_mutex);
 	}
 
-	list_for_each_entry(pc, &cache_chain, next) {
+	list_for_each_entry(pc, &cache_chain, list) {
 		char tmp;
 		int res;
 
@@ -2294,7 +2292,7 @@ kmem_cache_create (const char *name, size_t size, size_t align,
 		if (res) {
 			printk(KERN_ERR
 			       "SLAB: cache with size %d has lost its name\n",
-			       pc->buffer_size);
+			       pc->size);
 			continue;
 		}
 
@@ -2399,8 +2397,9 @@ kmem_cache_create (const char *name, size_t size, size_t align,
 		goto oops;
 
 	cachep->nodelists = (struct kmem_list3 **)&cachep->array[nr_cpu_ids];
+	cachep->object_size = size;
+	cachep->align = align;
 #if DEBUG
-	cachep->obj_size = size;
 
 	/*
 	 * Both debugging options require word-alignment which is calculated
@@ -2423,7 +2422,7 @@ kmem_cache_create (const char *name, size_t size, size_t align,
 	}
 #if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
 	if (size >= malloc_sizes[INDEX_L3 + 1].cs_size
-	    && cachep->obj_size > cache_line_size() && ALIGN(size, align) < PAGE_SIZE) {
+	    && cachep->object_size > cache_line_size() && ALIGN(size, align) < PAGE_SIZE) {
 		cachep->obj_offset += PAGE_SIZE - ALIGN(size, align);
 		size = PAGE_SIZE;
 	}
@@ -2492,7 +2491,7 @@ kmem_cache_create (const char *name, size_t size, size_t align,
 	cachep->gfpflags = 0;
 	if (CONFIG_ZONE_DMA_FLAG && (flags & SLAB_CACHE_DMA))
 		cachep->gfpflags |= GFP_DMA;
-	cachep->buffer_size = size;
+	cachep->size = size;
 	cachep->reciprocal_buffer_size = reciprocal_value(size);
 
 	if (flags & CFLGS_OFF_SLAB) {
@@ -2526,7 +2525,7 @@ kmem_cache_create (const char *name, size_t size, size_t align,
 	}
 
 	/* cache setup completed, link it into the list */
-	list_add(&cachep->next, &cache_chain);
+	list_add(&cachep->list, &cache_chain);
 oops:
 	if (!cachep && (flags & SLAB_PANIC))
 		panic("kmem_cache_create(): failed to create slab `%s'\n",
@@ -2721,10 +2720,10 @@ void kmem_cache_destroy(struct kmem_cache *cachep)
 	/*
 	 * the chain is never empty, cache_cache is never destroyed
 	 */
-	list_del(&cachep->next);
+	list_del(&cachep->list);
 	if (__cache_shrink(cachep)) {
 		slab_error(cachep, "Can't free all objects");
-		list_add(&cachep->next, &cache_chain);
+		list_add(&cachep->list, &cache_chain);
 		mutex_unlock(&cache_chain_mutex);
 		put_online_cpus();
 		return;
@@ -2821,10 +2820,10 @@ static void cache_init_objs(struct kmem_cache *cachep,
 				slab_error(cachep, "constructor overwrote the"
 					   " start of an object");
 		}
-		if ((cachep->buffer_size % PAGE_SIZE) == 0 &&
+		if ((cachep->size % PAGE_SIZE) == 0 &&
 			    OFF_SLAB(cachep) && cachep->flags & SLAB_POISON)
 			kernel_map_pages(virt_to_page(objp),
-					 cachep->buffer_size / PAGE_SIZE, 0);
+					 cachep->size / PAGE_SIZE, 0);
 #else
 		if (cachep->ctor)
 			cachep->ctor(objp);
@@ -3058,10 +3057,10 @@ static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
 #endif
 	if (cachep->flags & SLAB_POISON) {
 #ifdef CONFIG_DEBUG_PAGEALLOC
-		if ((cachep->buffer_size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) {
+		if ((cachep->size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) {
 			store_stackinfo(cachep, objp, (unsigned long)caller);
 			kernel_map_pages(virt_to_page(objp),
-					 cachep->buffer_size / PAGE_SIZE, 0);
+					 cachep->size / PAGE_SIZE, 0);
 		} else {
 			poison_obj(cachep, objp, POISON_FREE);
 		}
@@ -3211,9 +3210,9 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
 		return objp;
 	if (cachep->flags & SLAB_POISON) {
 #ifdef CONFIG_DEBUG_PAGEALLOC
-		if ((cachep->buffer_size % PAGE_SIZE) == 0 && OFF_SLAB(cachep))
+		if ((cachep->size % PAGE_SIZE) == 0 && OFF_SLAB(cachep))
 			kernel_map_pages(virt_to_page(objp),
-					 cachep->buffer_size / PAGE_SIZE, 1);
+					 cachep->size / PAGE_SIZE, 1);
 		else
 			check_poison_obj(cachep, objp);
 #else
@@ -3243,7 +3242,7 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
 		unsigned objnr;
 
 		slabp = virt_to_head_page(objp)->slab_page;
-		objnr = (unsigned)(objp - slabp->s_mem) / cachep->buffer_size;
+		objnr = (unsigned)(objp - slabp->s_mem) / cachep->size;
 		slab_bufctl(slabp)[objnr] = BUFCTL_ACTIVE;
 	}
 #endif
@@ -3747,7 +3746,7 @@ void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
 	void *ret = __cache_alloc(cachep, flags, __builtin_return_address(0));
 
 	trace_kmem_cache_alloc(_RET_IP_, ret,
-			       obj_size(cachep), cachep->buffer_size, flags);
+			       obj_size(cachep), cachep->size, flags);
 
 	return ret;
 }
@@ -3775,7 +3774,7 @@ void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
 				       __builtin_return_address(0));
 
 	trace_kmem_cache_alloc_node(_RET_IP_, ret,
-				    obj_size(cachep), cachep->buffer_size,
+				    obj_size(cachep), cachep->size,
 				    flags, nodeid);
 
 	return ret;
@@ -3857,7 +3856,7 @@ static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
 	ret = __cache_alloc(cachep, flags, caller);
 
 	trace_kmalloc((unsigned long) caller, ret,
-		      size, cachep->buffer_size, flags);
+		      size, cachep->size, flags);
 
 	return ret;
 }
@@ -4011,7 +4010,7 @@ static int alloc_kmemlist(struct kmem_cache *cachep, gfp_t gfp)
 	return 0;
 
 fail:
-	if (!cachep->next.next) {
+	if (!cachep->list.next) {
 		/* Cache is not active yet. Roll back what we did */
 		node--;
 		while (node >= 0) {
@@ -4105,13 +4104,13 @@ static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp)
 	 * The numbers are guessed, we should auto-tune as described by
 	 * Bonwick.
 	 */
-	if (cachep->buffer_size > 131072)
+	if (cachep->size > 131072)
 		limit = 1;
-	else if (cachep->buffer_size > PAGE_SIZE)
+	else if (cachep->size > PAGE_SIZE)
 		limit = 8;
-	else if (cachep->buffer_size > 1024)
+	else if (cachep->size > 1024)
 		limit = 24;
-	else if (cachep->buffer_size > 256)
+	else if (cachep->size > 256)
 		limit = 54;
 	else
 		limit = 120;
@@ -4126,7 +4125,7 @@ static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp)
 	 * to a larger limit. Thus disabled by default.
 	 */
 	shared = 0;
-	if (cachep->buffer_size <= PAGE_SIZE && num_possible_cpus() > 1)
+	if (cachep->size <= PAGE_SIZE && num_possible_cpus() > 1)
 		shared = 8;
 
 #if DEBUG
@@ -4196,7 +4195,7 @@ static void cache_reap(struct work_struct *w)
 		/* Give up. Setup the next iteration. */
 		goto out;
 
-	list_for_each_entry(searchp, &cache_chain, next) {
+	list_for_each_entry(searchp, &cache_chain, list) {
 		check_irq_on();
 
 		/*
@@ -4289,7 +4288,7 @@ static void s_stop(struct seq_file *m, void *p)
 
 static int s_show(struct seq_file *m, void *p)
 {
-	struct kmem_cache *cachep = list_entry(p, struct kmem_cache, next);
+	struct kmem_cache *cachep = list_entry(p, struct kmem_cache, list);
 	struct slab *slabp;
 	unsigned long active_objs;
 	unsigned long num_objs;
@@ -4345,7 +4344,7 @@ static int s_show(struct seq_file *m, void *p)
 		printk(KERN_ERR "slab: cache %s error: %s\n", name, error);
 
 	seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
-		   name, active_objs, num_objs, cachep->buffer_size,
+		   name, active_objs, num_objs, cachep->size,
 		   cachep->num, (1 << cachep->gfporder));
 	seq_printf(m, " : tunables %4u %4u %4u",
 		   cachep->limit, cachep->batchcount, cachep->shared);
@@ -4437,7 +4436,7 @@ static ssize_t slabinfo_write(struct file *file, const char __user *buffer,
 	/* Find the cache in the chain of caches. */
 	mutex_lock(&cache_chain_mutex);
 	res = -EINVAL;
-	list_for_each_entry(cachep, &cache_chain, next) {
+	list_for_each_entry(cachep, &cache_chain, list) {
 		if (!strcmp(cachep->name, kbuf)) {
 			if (limit < 1 || batchcount < 1 ||
 					batchcount > limit || shared < 0) {
@@ -4513,7 +4512,7 @@ static void handle_slab(unsigned long *n, struct kmem_cache *c, struct slab *s)
 	int i;
 	if (n[0] == n[1])
 		return;
-	for (i = 0, p = s->s_mem; i < c->num; i++, p += c->buffer_size) {
+	for (i = 0, p = s->s_mem; i < c->num; i++, p += c->size) {
 		if (slab_bufctl(s)[i] != BUFCTL_ACTIVE)
 			continue;
 		if (!add_caller(n, (unsigned long)*dbg_userword(c, p)))