Common11 [00/20] Sl[auo]b: Common code rework V11

DISCUSSION Christoph Lameter 2 participants 23 messages Aug 8, 2012 – Aug 9, 2012

Subsystems (2)

Memory management Slab allocator

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Christoph Lameter

author

2012-08-08 21:03 UTC #0 lore raw

V10->V11
- Fix issues pointed out by Joonsoo and Glauber
- Simplify Slab bootstrap further

V9->V10
- Memory leak was a false alarm
- Resequence patches to make it easier
to apply.
- Do more boot sequence consolidation in slab/slub. [We could still do much more like common kmalloc handling]
- Fixes suggested by David and Glauber

V8->V9:
- Fix numerous things pointed out by Glauber.
- Cleanup the way error handling works in the
common kmem_cache_create() function.
- General cleanup by breaking things up
into multiple patches were necessary.

V7->V8:
- Do not use kfree for kmem_cache in slub.
- Add more patches up to a common
scheme for object alignment.

V6->V7:
- Omit pieces that were merged for 3.6
- Fix issues pointed out by Glauber.
- Include the patches up to the point at which
the slab name handling is unified

V5->V6:
- Patches against Pekka's for-next tree.
- Go slow and cut down to just patches that are safe (there will likely be some churn already due to the mutex unification between slabs)
- More to come next week when I have more time ( took me almost the whole week to catch up after being gone for awhile).

V4->V5
- Rediff against current upstream + Pekka's cleanup branch.

V3->V4:
- Do not use the COMMON macro anymore.
- Fixup various issues
- No general sysfs support yet due to lockdep issues with keys in kmalloc'ed memory.

V2->V3:
- Incorporate more feedback from Joonsoo Kim and Glauber Costa
- And a couple more patches to deal with slab duping and move more code to slab_common.c

V1->V2:
- Incorporate glommers feedback.
- Add 2 more patches dealing with common code in kmem_cache_destroy

This is a series of patches that extracts common functionality from slab allocators into a common code base. The intend is to standardize as much as possible of the allocator behavior while keeping the distinctive features of each allocator which are mostly due to their storage format and serialization approaches.

This patchset makes a beginning by extracting common functionality in kmem_cache_create() and kmem_cache_destroy(). However, there are numerous other areas where such work could be beneficial:

1. Extract the sysfs support from SLUB and make it common. That way all allocators have a common sysfs API and are handleable in the same way regardless of the allocator chose.

2. Extract the error reporting and checking from SLUB and make it available for all allocators. This means that all allocators will gain the resiliency and error handling capabilties.

3. Extract the memory hotplug and cpu hotplug handling. It seems that SLAB may be more sophisticated here. Having common code here will make it easier to maintain the special code.

4. Extract the aliasing capability of SLUB. This will enable fast slab creation without creating too many additional slab caches. The arrays of caches of varying sizes in numerous subsystems do not cause the creation of numerous slab caches. Storage density is increased and the cache footprint is reduced.

Ultimately it is to be hoped that the special code for each allocator shrinks to a mininum. This will also make it easier to make modification to allocators.

In the far future one could envision that the current allocators will just become storage algorithms that can be chosen based on the need of the subsystem. F.e.

Cpu cache dependend performance = Bonwick allocator (SLAB)
Minimal cycle count and cache footprint = SLUB
Maximum storage density = K&R allocator (SLOB)

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Christoph Lameter

author

2012-08-08 21:03 UTC #1 lore raw

Common11 [04/20] Improve error handling in kmem_cache_create

Instead of using s == NULL use an errorcode. This allows much more detailed diagnostics as to what went wrong. As we add more functionality from the slab allocators to the common kmem_cache_create() function we will also add more error conditions.

Print the error code during the panic as well as in a warning if the module can handle failure. The API for kmem_cache_create() currently does not allow the returning of an error code. Return NULL but log the cause of the problem in the syslog.

Acked-by David Rientjes <[email protected]>

Signed-off-by Christoph Lameter <[email protected]>

mm/slab_common.c +19 ~~-10~~

Index: linux-2.6/mm/slab_common.c
===================================================================
@@ -51,13 +51,13 @@
 struct kmem_cache *kmem_cache_create(const char *name, size_t size, size_t align,
 		unsigned long flags, void (*ctor)(void *))
 {
-	struct kmem_cache *s = NULL;
+	struct kmem_cache *s;
+	int err = 0;
 
 #ifdef CONFIG_DEBUG_VM
 	if (!name || in_interrupt() || size < sizeof(void *) ||
 		size > KMALLOC_MAX_SIZE) {
-		printk(KERN_ERR "kmem_cache_create(%s) integrity check"
-			" failed\n", name);
+		err = -EINVAL;
 		goto out;
 	}
 #endif

@@ -84,11 +84,7 @@
 		}
 
 		if (!strcmp(s->name, name)) {
-			printk(KERN_ERR "kmem_cache_create(%s): Cache name"
-				" already exists.\n",
-				name);
-			dump_stack();
-			s = NULL;
+			err = -EEXIST;
 			goto out_locked;
 		}
 	}

@@ -97,6 +93,8 @@
 #endif
 
 	s = __kmem_cache_create(name, size, align, flags, ctor);
+	if (!s)
+		err = -ENOSYS; /* Until __kmem_cache_create returns code */
 
 #ifdef CONFIG_DEBUG_VM
 out_locked:

@@ -107,8 +105,19 @@
 #ifdef CONFIG_DEBUG_VM
 out:
 #endif
-	if (!s && (flags & SLAB_PANIC))
-		panic("kmem_cache_create: Failed to create slab '%s'\n", name);
+	if (err) {
+
+		if (flags & SLAB_PANIC)
+			panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n",
+				name, err);
+		else {
+			printk(KERN_WARNING "kmem_cache_create(%s) failed with error %d",
+				name, err);
+			dump_stack();
+		}
+
+		return NULL;
+	}
 
 	return s;
 }

Christoph Lameter

author

2012-08-08 21:03 UTC #2 lore raw

Common11 [01/20] slub: Add debugging to verify correct cache use on kmem_cache_free()

In reply to Christoph Lameter

Add additional debugging to check that the objects is actually from the cache the caller claims. Doing so currently trips up some other debugging code. It takes a lot to infer from that what was happening.

V2: Only warn once.

Signed-off-by Christoph Lameter <[email protected]>

mm/slub.c +7 -0

Index: linux-2.6/mm/slub.c
===================================================================
@@ -2607,6 +2607,13 @@ void kmem_cache_free(struct kmem_cache *
 
 	page = virt_to_head_page(x);
 
+	if (kmem_cache_debug(s) && page->slab != s) {
+		printk("kmem_cache_free: Wrong slab cache. %s but object"
+			" is from  %s\n", page->slab->name, s->name);
+		WARN_ON_ONCE(1);
+		return;
+	}
+
 	slab_free(s, page, x, _RET_IP_);
 
 	trace_kmem_cache_free(_RET_IP_, x);

Christoph Lameter

author

2012-08-08 21:03 UTC #3 lore raw

Common11 [08/20] Move freeing of kmem_cache structure to common code

In reply to Christoph Lameter

The freeing action is basically the same in all slab allocators. Move to the common kmem_cache_destroy() function.

Reviewed-by Joonsoo Kim <[email protected]>

Signed-off-by Christoph Lameter <[email protected]>

---
 mm/slab.c        |    1 -
 mm/slab_common.c |    1 +
 mm/slob.c        |    2 --
 mm/slub.c        |    1 -
 4 files changed, 1 insertion(+), 4 deletions(-)

mm/slab_common.c +1 -0

Index: linux-2.6/mm/slab_common.c
===================================================================
@@ -144,6 +144,7 @@ void kmem_cache_destroy(struct kmem_cach
 				rcu_barrier();
 
 			__kmem_cache_destroy(s);
+			kmem_cache_free(kmem_cache, s);
 		} else {
 			list_add(&s->list, &slab_caches);
 			printk(KERN_ERR "kmem_cache_destroy %s: Slab cache still has objects\n",

mm/slob.c +0 -2

Index: linux-2.6/mm/slob.c
===================================================================
@@ -540,8 +540,6 @@ struct kmem_cache *__kmem_cache_create(c
 
 void __kmem_cache_destroy(struct kmem_cache *c)
 {
-	kmemleak_free(c);
-	slob_free(c, sizeof(struct kmem_cache));
 }
 
 void *kmem_cache_alloc_node(struct kmem_cache *c, gfp_t flags, int node)

mm/slab.c +0 -1

Index: linux-2.6/mm/slab.c
===================================================================
@@ -2222,7 +2222,6 @@ void __kmem_cache_destroy(struct kmem_ca
 			kfree(l3);
 		}
 	}
-	kmem_cache_free(kmem_cache, cachep);
 }

mm/slub.c +0 -2

Index: linux-2.6/mm/slub.c
===================================================================
@@ -213,7 +213,6 @@ static inline int sysfs_slab_alias(struc
 static inline void sysfs_slab_remove(struct kmem_cache *s)
 {
 	kfree(s->name);
-	kmem_cache_free(kmem_cache, s);
 }
 
 #endif

@@ -5199,7 +5198,6 @@ static void kmem_cache_release(struct ko
 	struct kmem_cache *s = to_slab(kobj);
 
 	kfree(s->name);
-	kmem_cache_free(kmem_cache, s);
 }
 
 static const struct sysfs_ops slab_sysfs_ops = {

Christoph Lameter

author

2012-08-08 21:03 UTC #4 lore raw

Common11 [11/20] Do slab aliasing call from common code

In reply to Christoph Lameter

The slab aliasing logic causes some strange contortions in slub. So add a call to deal with aliases to slab_common.c but disable it for other slab allocators by providng stubs that fail to create aliases.

Full general support for aliases will require additional cleanup passes and more standardization of fields in kmem_cache.

V1->V2:
- Move kstrdup before kmem_cache_alias invocation. (JoonSoo Kim)

Signed-off-by Christoph Lameter <[email protected]>

---
 mm/slab.h        |   10 ++++++++++
 mm/slab_common.c |   16 +++++++---------
 mm/slub.c        |   18 ++++++++++++------
 3 files changed, 29 insertions(+), 15 deletions(-)

mm/slab.h +10 -0

Index: linux-2.6/mm/slab.h
===================================================================
@@ -36,6 +36,16 @@ extern struct kmem_cache *kmem_cache;
 struct kmem_cache *__kmem_cache_create(const char *name, size_t size,
 	size_t align, unsigned long flags, void (*ctor)(void *));
 
+#ifdef CONFIG_SLUB
+struct kmem_cache *__kmem_cache_alias(const char *name, size_t size,
+	size_t align, unsigned long flags, void (*ctor)(void *));
+#else
+static inline struct kmem_cache *__kmem_cache_alias(const char *name, size_t size,
+	size_t align, unsigned long flags, void (*ctor)(void *))
+{ return NULL; }
+#endif
+
+
 int __kmem_cache_shutdown(struct kmem_cache *);
 
 #endif

mm/slab_common.c +4 -0

Index: linux-2.6/mm/slab_common.c
===================================================================
@@ -94,6 +94,10 @@ struct kmem_cache *kmem_cache_create(con
 	WARN_ON(strchr(name, ' '));	/* It confuses parsers */
 #endif
 
+	s = __kmem_cache_alias(name, size, align, flags, ctor);
+	if (s)
+		goto out_locked;
+
 	n = kstrdup(name, GFP_KERNEL);
 	if (!n) {
 		err = -ENOMEM;

mm/slub.c +11 -4

Index: linux-2.6/mm/slub.c
===================================================================
@@ -3701,7 +3701,7 @@ void __init kmem_cache_init(void)
 		slub_max_order = 0;
 
 	kmem_size = offsetof(struct kmem_cache, node) +
-				nr_node_ids * sizeof(struct kmem_cache_node *);
+			nr_node_ids * sizeof(struct kmem_cache_node *);
 
 	/* Allocate two kmem_caches from the page allocator */
 	kmalloc_size = ALIGN(kmem_size, cache_line_size());

@@ -3915,7 +3915,7 @@ static struct kmem_cache *find_mergeable
 	return NULL;
 }
 
-struct kmem_cache *__kmem_cache_create(const char *name, size_t size,
+struct kmem_cache *__kmem_cache_alias(const char *name, size_t size,
 		size_t align, unsigned long flags, void (*ctor)(void *))
 {
 	struct kmem_cache *s;

@@ -3932,11 +3932,18 @@ struct kmem_cache *__kmem_cache_create(c
 
 		if (sysfs_slab_alias(s, name)) {
 			s->refcount--;
-			return NULL;
+			s = NULL;
 		}
-		return s;
 	}
 
+	return s;
+}
+
+struct kmem_cache *__kmem_cache_create(const char *name, size_t size,
+		size_t align, unsigned long flags, void (*ctor)(void *))
+{
+	struct kmem_cache *s;
+
 	s = kmem_cache_alloc(kmem_cache, GFP_KERNEL);
 	if (s) {
 		if (kmem_cache_open(s, name,

Christoph Lameter

author

2012-08-08 21:03 UTC #5 lore raw

Common11 [12/20] Move sysfs_slab_add to common

In reply to Christoph Lameter

Simplify locking by moving the slab_add_sysfs after all locks have been dropped. Eases the upcoming move to provide sysfs support for all allocators.

Signed-off-by Christoph Lameter <[email protected]>

mm/slab.h +3 -0

Index: linux-2.6/mm/slab.h
===================================================================
@@ -39,10 +39,13 @@ struct kmem_cache *__kmem_cache_create(c
 #ifdef CONFIG_SLUB
 struct kmem_cache *__kmem_cache_alias(const char *name, size_t size,
 	size_t align, unsigned long flags, void (*ctor)(void *));
+extern int sysfs_slab_add(struct kmem_cache *s);
 #else
 static inline struct kmem_cache *__kmem_cache_alias(const char *name, size_t size,
 	size_t align, unsigned long flags, void (*ctor)(void *))
 { return NULL; }
+static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
+
 #endif

mm/slab_common.c +3 -0

Index: linux-2.6/mm/slab_common.c
===================================================================
@@ -140,6 +140,9 @@ out:
 		return NULL;
 	}
 
+	if (s->refcount == 1)
+		sysfs_slab_add(s);
+
 	return s;
 }
 EXPORT_SYMBOL(kmem_cache_create);

mm/slub.c +2 ~~-13~~

Index: linux-2.6/mm/slub.c
===================================================================
@@ -202,12 +202,10 @@ struct track {
 enum track_item { TRACK_ALLOC, TRACK_FREE };
 
 #ifdef CONFIG_SYSFS
-static int sysfs_slab_add(struct kmem_cache *);
 static int sysfs_slab_alias(struct kmem_cache *, const char *);
 static void sysfs_slab_remove(struct kmem_cache *);
 
 #else
-static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
 static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
 							{ return 0; }
 static inline void sysfs_slab_remove(struct kmem_cache *s) { }

@@ -3948,16 +3946,7 @@ struct kmem_cache *__kmem_cache_create(c
 	if (s) {
 		if (kmem_cache_open(s, name,
 				size, align, flags, ctor)) {
-			int r;
-
-			mutex_unlock(&slab_mutex);
-			r = sysfs_slab_add(s);
-			mutex_lock(&slab_mutex);
-
-			if (!r)
-				return s;
-
-			kmem_cache_close(s);
+			return s;
 		}
 		kmem_cache_free(kmem_cache, s);
 	}

@@ -5251,7 +5240,7 @@ static char *create_unique_id(struct kme
 	return name;
 }
 
-static int sysfs_slab_add(struct kmem_cache *s)
+int sysfs_slab_add(struct kmem_cache *s)
 {
 	int err;
 	const char *name;

Christoph Lameter

author

2012-08-08 21:03 UTC #6 lore raw

Common11 [13/20] Move kmem_cache allocations into common code.

In reply to Christoph Lameter

Shift the allocations to common code. That way the allocation and freeing of the kmem_cache structures is handled by common code.

V2->V3: Use GFP_KERNEL instead of GFP_NOWAIT (JoonSoo Kim).
V1->V2: Use the return code from setup_cpucache() in slab instead of returning -ENOSPC

Signed-off-by Christoph Lameter <[email protected]>

mm/slab.c +16 ~~-18~~

Index: linux-2.6/mm/slab.c
===================================================================
@@ -1673,7 +1673,8 @@ void __init kmem_cache_init(void)
 	 * bug.
 	 */
 
-	sizes[INDEX_AC].cs_cachep = __kmem_cache_create(names[INDEX_AC].name,
+	sizes[INDEX_AC].cs_cachep = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
+	__kmem_cache_create(sizes[INDEX_AC].cs_cachep, names[INDEX_AC].name,
 					sizes[INDEX_AC].cs_size,
 					ARCH_KMALLOC_MINALIGN,
 					ARCH_KMALLOC_FLAGS|SLAB_PANIC,

@@ -1681,8 +1682,8 @@ void __init kmem_cache_init(void)
 
 	list_add(&sizes[INDEX_AC].cs_cachep->list, &slab_caches);
 	if (INDEX_AC != INDEX_L3) {
-		sizes[INDEX_L3].cs_cachep =
-			__kmem_cache_create(names[INDEX_L3].name,
+		sizes[INDEX_L3].cs_cachep = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
+		__kmem_cache_create(sizes[INDEX_L3].cs_cachep, names[INDEX_L3].name,
 				sizes[INDEX_L3].cs_size,
 				ARCH_KMALLOC_MINALIGN,
 				ARCH_KMALLOC_FLAGS|SLAB_PANIC,

@@ -1701,7 +1702,8 @@ void __init kmem_cache_init(void)
 		 * allow tighter packing of the smaller caches.
 		 */
 		if (!sizes->cs_cachep) {
-			sizes->cs_cachep = __kmem_cache_create(names->name,
+			sizes->cs_cachep = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
+			__kmem_cache_create(sizes->cs_cachep, names->name,
 					sizes->cs_size,
 					ARCH_KMALLOC_MINALIGN,
 					ARCH_KMALLOC_FLAGS|SLAB_PANIC,

@@ -1709,7 +1711,8 @@ void __init kmem_cache_init(void)
 			list_add(&sizes->cs_cachep->list, &slab_caches);
 		}
 #ifdef CONFIG_ZONE_DMA
-		sizes->cs_dmacachep = __kmem_cache_create(
+		sizes->cs_dmacachep = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
+		__kmem_cache_create(sizes->cs_dmacachep,
 					names->name_dma,
 					sizes->cs_size,
 					ARCH_KMALLOC_MINALIGN,

@@ -2353,13 +2356,13 @@ static int __init_refok setup_cpu_cache(
  * cacheline.  This can be beneficial if you're counting cycles as closely
  * as davem.
  */
-struct kmem_cache *
-__kmem_cache_create (const char *name, size_t size, size_t align,
+int
+__kmem_cache_create (struct kmem_cache *cachep, const char *name, size_t size, size_t align,
 	unsigned long flags, void (*ctor)(void *))
 {
 	size_t left_over, slab_size, ralign;
-	struct kmem_cache *cachep = NULL;
 	gfp_t gfp;
+	int err;
 
 #if DEBUG
 #if FORCED_DEBUG

@@ -2447,11 +2450,6 @@ __kmem_cache_create (const char *name, s
 	else
 		gfp = GFP_NOWAIT;
 
-	/* Get cache's description obj. */
-	cachep = kmem_cache_zalloc(kmem_cache, gfp);
-	if (!cachep)
-		return NULL;
-
 	cachep->nodelists = (struct kmem_list3 **)&cachep->array[nr_cpu_ids];
 	cachep->object_size = size;
 	cachep->align = align;

@@ -2506,8 +2504,7 @@ __kmem_cache_create (const char *name, s
 	if (!cachep->num) {
 		printk(KERN_ERR
 		       "kmem_cache_create: couldn't create cache %s.\n", name);
-		kmem_cache_free(kmem_cache, cachep);
-		return NULL;
+		return -E2BIG;
 	}
 	slab_size = ALIGN(cachep->num * sizeof(kmem_bufctl_t)
 			  + sizeof(struct slab), align);

@@ -2564,9 +2561,10 @@ __kmem_cache_create (const char *name, s
 	cachep->name = name;
 	cachep->refcount = 1;
 
-	if (setup_cpu_cache(cachep, gfp)) {
+	err = setup_cpu_cache(cachep, gfp);
+	if (err) {
 		__kmem_cache_shutdown(cachep);
-		return NULL;
+		return err;
 	}
 
 	if (flags & SLAB_DEBUG_OBJECTS) {

@@ -2579,7 +2577,7 @@ __kmem_cache_create (const char *name, s
 		slab_set_debugobj_lock_classes(cachep);
 	}
 
-	return cachep;
+	return 0;
 }
 
 #if DEBUG

mm/slab.h +2 -2

Index: linux-2.6/mm/slab.h
===================================================================
@@ -33,8 +33,8 @@ extern struct list_head slab_caches;
 extern struct kmem_cache *kmem_cache;
 
 /* Functions provided by the slab allocators */
-struct kmem_cache *__kmem_cache_create(const char *name, size_t size,
-	size_t align, unsigned long flags, void (*ctor)(void *));
+extern int __kmem_cache_create(struct kmem_cache *, const char *name,
+	size_t size, size_t align, unsigned long flags, void (*ctor)(void *));
 
 #ifdef CONFIG_SLUB
 struct kmem_cache *__kmem_cache_alias(const char *name, size_t size,

mm/slab_common.c +10 -8

Index: linux-2.6/mm/slab_common.c
===================================================================
@@ -104,19 +104,21 @@ struct kmem_cache *kmem_cache_create(con
 	if (s)
 		goto out_locked;
 
-	s = __kmem_cache_create(n, size, align, flags, ctor);
-
+	s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
 	if (s) {
-		/*
-		 * Check if the slab has actually been created and if it was a
-		 * real instatiation. Aliases do not belong on the list
-		 */
-		if (s->refcount == 1)
+		err = __kmem_cache_create(s, n, size, align, flags, ctor);
+		if (!err)
+
 			list_add(&s->list, &slab_caches);
 
+		else {
+			kfree(n);
+			kmem_cache_free(kmem_cache, s);
+		}
+
 	} else {
 		kfree(n);
-		err = -ENOSYS; /* Until __kmem_cache_create returns code */
+		err = -ENOMEM;
 	}
 
 out_locked:

mm/slob.c +18 ~~-25~~

52 lines not on this page · raw message

mm/slub.c +6 ~~-16~~

Index: linux-2.6/mm/slub.c
===================================================================
@@ -3027,7 +3027,6 @@ static int kmem_cache_open(struct kmem_c
 		size_t align, unsigned long flags,
 		void (*ctor)(void *))
 {
-	memset(s, 0, kmem_size);
 	s->name = name;
 	s->ctor = ctor;
 	s->object_size = size;

@@ -3102,7 +3101,7 @@ static int kmem_cache_open(struct kmem_c
 		goto error;
 
 	if (alloc_kmem_cache_cpus(s))
-		return 1;
+		return 0;
 
 	free_kmem_cache_nodes(s);
 error:

@@ -3111,7 +3110,7 @@ error:
 			"order=%u offset=%u flags=%lx\n",
 			s->name, (unsigned long)size, s->size, oo_order(s->oo),
 			s->offset, flags);
-	return 0;
+	return -EINVAL;
 }
 
 /*

@@ -3259,7 +3258,7 @@ static struct kmem_cache *__init create_
 	 * This function is called with IRQs disabled during early-boot on
 	 * single CPU so there's no need to take slab_mutex here.
 	 */
-	if (!kmem_cache_open(s, name, size, ARCH_KMALLOC_MINALIGN,
+	if (kmem_cache_open(s, name, size, ARCH_KMALLOC_MINALIGN,
 								flags, NULL))
 		goto panic;

@@ -3937,20 +3936,11 @@ struct kmem_cache *__kmem_cache_alias(co
 	return s;
 }
 
-struct kmem_cache *__kmem_cache_create(const char *name, size_t size,
+int __kmem_cache_create(struct kmem_cache *s,
+		const char *name, size_t size,
 		size_t align, unsigned long flags, void (*ctor)(void *))
 {
-	struct kmem_cache *s;
-
-	s = kmem_cache_alloc(kmem_cache, GFP_KERNEL);
-	if (s) {
-		if (kmem_cache_open(s, name,
-				size, align, flags, ctor)) {
-			return s;
-		}
-		kmem_cache_free(kmem_cache, s);
-	}
-	return NULL;
+	return kmem_cache_open(s, name, size, align, flags, ctor);
 }
 
 #ifdef CONFIG_SMP

Christoph Lameter

author

2012-08-08 21:03 UTC #7 lore raw

Common11 [15/20] Move kmem_cache refcounting to common code

In reply to Christoph Lameter

Get rid of the refcount stuff in the allocators and do that part of kmem_cache management in the common code.

Signed-off-by Christoph Lameter <[email protected]>

mm/slab.c +0 -1

Index: linux-2.6/mm/slab.c
===================================================================
@@ -2550,7 +2550,6 @@ __kmem_cache_create (struct kmem_cache *
 		 */
 		BUG_ON(ZERO_OR_NULL_PTR(cachep->slabp_cache));
 	}
-	cachep->refcount = 1;
 
 	err = setup_cpu_cache(cachep, gfp);
 	if (err) {

mm/slab_common.c +3 -2

Index: linux-2.6/mm/slab_common.c
===================================================================
@@ -110,11 +110,12 @@ struct kmem_cache *kmem_cache_create(con
 		}
 
 		err = __kmem_cache_create(s, flags);
-		if (!err)
+		if (!err) {
 
+			s->refcount = 1;
 			list_add(&s->list, &slab_caches);
 
-		else {
+		} else {
 			kfree(s->name);
 			kmem_cache_free(kmem_cache, s);
 		}

mm/slob.c +0 -2

Index: linux-2.6/mm/slob.c
===================================================================
@@ -524,8 +524,6 @@ int __kmem_cache_create(struct kmem_cach
 	if (c->align < align)
 		c->align = align;
 
-	kmemleak_alloc(c, sizeof(struct kmem_cache), 1, GFP_KERNEL);
-	c->refcount = 1;
 	return 0;
 }

mm/slub.c +0 -1

Index: linux-2.6/mm/slub.c
===================================================================
@@ -3086,7 +3086,6 @@ static int kmem_cache_open(struct kmem_c
 	else
 		s->cpu_partial = 30;
 
-	s->refcount = 1;
 #ifdef CONFIG_NUMA
 	s->remote_node_defrag_ratio = 1000;
 #endif

Christoph Lameter

author

2012-08-08 21:03 UTC #8 lore raw

Common11 [16/20] slab: Simplify bootstrap

In reply to Christoph Lameter

The nodelists field in kmem_cache is pointing to the first unused object in the array field when bootstrap is complete.

On boot we use a statically allocated array for that purpose.

A problem with the current approach is that the statically sized kmem_cache structure can only contain NR_CPUS entries. If the number of nodes plus the number of cpus is greater then we would overwrite memory following the kmem_cache_boot definition.

Increase the size of the array field to ensure that also the node pointers fit into the array field.

Once we do that we no longer need the kmem_cache_nodelists array and we can then also simplify bootstrap.

Signed-off-by Christoph Lameter <[email protected]>

include/linux/slab_def.h +1 -1

Index: linux-2.6/include/linux/slab_def.h
===================================================================
@@ -92,7 +92,7 @@ struct kmem_cache {
 	 * is statically defined, so we reserve the max number of cpus.
 	 */
 	struct kmem_list3 **nodelists;
-	struct array_cache *array[NR_CPUS];
+	struct array_cache *array[NR_CPUS + MAX_NUMNODES];
 	/*
 	 * Do not add fields after array[]
 	 */

mm/slab.c +13 -5

Index: linux-2.6/mm/slab.c
===================================================================
@@ -585,9 +585,7 @@ static struct arraycache_init initarray_
     { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
 
 /* internal cache of cache description objs */
-static struct kmem_list3 *kmem_cache_nodelists[MAX_NUMNODES];
 static struct kmem_cache kmem_cache_boot = {
-	.nodelists = kmem_cache_nodelists,
 	.batchcount = 1,
 	.limit = BOOT_CPUCACHE_ENTRIES,
 	.shared = 1,

@@ -1579,6 +1577,15 @@ static void __init set_up_list3s(struct
 }
 
 /*
+ * The memory after the last cpu cache pointer is used for the
+ * the nodelists pointer.
+ */
+static void setup_nodelists_pointer(struct kmem_cache *s)
+{
+	s->nodelists = (struct kmem_list3 **)&s->array[nr_cpu_ids];
+}
+
+/*
  * Initialisation.  Called after the page allocator have been initialised and
  * before smp_init().
  */

@@ -1592,13 +1599,15 @@ void __init kmem_cache_init(void)
 	int node;
 
 	kmem_cache = &kmem_cache_boot;
+	setup_nodelists_pointer(kmem_cache);
 
 	if (num_possible_nodes() == 1)
 		use_alien_caches = 0;
 
+
 	for (i = 0; i < NUM_INIT_LISTS; i++) {
 		kmem_list3_init(&initkmem_list3[i]);
-		if (i < MAX_NUMNODES)
+		if (i < nr_node_ids)
 			kmem_cache->nodelists[i] = NULL;
 	}
 	set_up_list3s(kmem_cache, CACHE_CACHE);

@@ -1638,7 +1647,6 @@ void __init kmem_cache_init(void)
 	list_add(&kmem_cache->list, &slab_caches);
 	kmem_cache->colour_off = cache_line_size();
 	kmem_cache->array[smp_processor_id()] = &initarray_cache.cache;
-	kmem_cache->nodelists[node] = &initkmem_list3[CACHE_CACHE + node];
 
 	/*
 	 * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids

@@ -2448,7 +2456,7 @@ __kmem_cache_create (struct kmem_cache *
 	else
 		gfp = GFP_NOWAIT;
 
-	cachep->nodelists = (struct kmem_list3 **)&cachep->array[nr_cpu_ids];
+	setup_nodelists_pointer(cachep);
 #if DEBUG
 
 	/*

Christoph Lameter

author

2012-08-08 21:03 UTC #9 lore raw

Common11 [17/20] create common functions for boot slab creation

In reply to Christoph Lameter

Use a special function to create kmalloc caches and use that function in SLAB and SLUB.

Signed-off-by Christoph Lameter <[email protected]>

---
 mm/slab.c |   53 +++++++++++++++++++++++------------------------------
 1 file changed, 23 insertions(+), 30 deletions(-)

mm/slab.c +13 ~~-33~~

Index: linux-2.6/mm/slab.c
===================================================================
@@ -1681,23 +1681,13 @@ void __init kmem_cache_init(void)
 	 * bug.
 	 */
 
-	sizes[INDEX_AC].cs_cachep = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
-	sizes[INDEX_AC].cs_cachep->name = names[INDEX_AC].name;
-	sizes[INDEX_AC].cs_cachep->size = sizes[INDEX_AC].cs_size;
-	sizes[INDEX_AC].cs_cachep->object_size = sizes[INDEX_AC].cs_size;
-	sizes[INDEX_AC].cs_cachep->align = ARCH_KMALLOC_MINALIGN;
-	__kmem_cache_create(sizes[INDEX_AC].cs_cachep, ARCH_KMALLOC_FLAGS|SLAB_PANIC);
-	list_add(&sizes[INDEX_AC].cs_cachep->list, &slab_caches);
+	sizes[INDEX_AC].cs_cachep = create_kmalloc_cache(names[INDEX_AC].name,
+					sizes[INDEX_AC].cs_size, ARCH_KMALLOC_FLAGS);
 
-	if (INDEX_AC != INDEX_L3) {
-		sizes[INDEX_L3].cs_cachep = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
-		sizes[INDEX_L3].cs_cachep->name = names[INDEX_L3].name;
-		sizes[INDEX_L3].cs_cachep->size = sizes[INDEX_L3].cs_size;
-		sizes[INDEX_L3].cs_cachep->object_size = sizes[INDEX_L3].cs_size;
-		sizes[INDEX_L3].cs_cachep->align = ARCH_KMALLOC_MINALIGN;
-		__kmem_cache_create(sizes[INDEX_L3].cs_cachep, ARCH_KMALLOC_FLAGS|SLAB_PANIC);
-		list_add(&sizes[INDEX_L3].cs_cachep->list, &slab_caches);
-	}
+	if (INDEX_AC != INDEX_L3)
+		sizes[INDEX_L3].cs_cachep =
+			create_kmalloc_cache(names[INDEX_L3].name,
+				sizes[INDEX_L3].cs_size, ARCH_KMALLOC_FLAGS);
 
 	slab_early_init = 0;

@@ -1709,24 +1699,14 @@ void __init kmem_cache_init(void)
 		 * Note for systems short on memory removing the alignment will
 		 * allow tighter packing of the smaller caches.
 		 */
-		if (!sizes->cs_cachep) {
-			sizes->cs_cachep = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
-			sizes->cs_cachep->name = names->name;
-			sizes->cs_cachep->size = sizes->cs_size;
-			sizes->cs_cachep->object_size = sizes->cs_size;
-			sizes->cs_cachep->align = ARCH_KMALLOC_MINALIGN;
-			__kmem_cache_create(sizes->cs_cachep, ARCH_KMALLOC_FLAGS|SLAB_PANIC);
-			list_add(&sizes->cs_cachep->list, &slab_caches);
-		}
+		if (!sizes->cs_cachep)
+			sizes->cs_cachep = create_kmalloc_cache(names->name,
+					sizes->cs_size, ARCH_KMALLOC_FLAGS);
+
 #ifdef CONFIG_ZONE_DMA
-		sizes->cs_dmacachep = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
-		sizes->cs_dmacachep->name = names->name_dma;
-		sizes->cs_dmacachep->size = sizes->cs_size;
-		sizes->cs_dmacachep->object_size = sizes->cs_size;
-		sizes->cs_dmacachep->align = ARCH_KMALLOC_MINALIGN;
-		__kmem_cache_create(sizes->cs_dmacachep,
-			       ARCH_KMALLOC_FLAGS|SLAB_CACHE_DMA| SLAB_PANIC);
-		list_add(&sizes->cs_dmacachep->list, &slab_caches);
+		sizes->cs_dmacachep = create_kmalloc_cache(
+			names->name_dma, sizes->cs_size,
+			SLAB_CACHE_DMA|ARCH_KMALLOC_FLAGS);
 #endif
 		sizes++;
 		names++;

mm/slab.h +5 -0

Index: linux-2.6/mm/slab.h
===================================================================
@@ -35,6 +35,11 @@ extern struct kmem_cache *kmem_cache;
 /* Functions provided by the slab allocators */
 extern int __kmem_cache_create(struct kmem_cache *, unsigned long flags);
 
+extern struct kmem_cache *create_kmalloc_cache(const char *name, size_t size,
+			unsigned long flags);
+extern void create_boot_cache(struct kmem_cache *, const char *name,
+	       size_t size, unsigned long flags);
+
 #ifdef CONFIG_SLUB
 struct kmem_cache *__kmem_cache_alias(const char *name, size_t size,
 	size_t align, unsigned long flags, void (*ctor)(void *));

mm/slab_common.c +32 -0

Index: linux-2.6/mm/slab_common.c
===================================================================
@@ -185,3 +185,35 @@ int slab_is_available(void)
 {
 	return slab_state >= UP;
 }
+
+/* Create a cache during boot when no slab services are available yet */
+void __init create_boot_cache(struct kmem_cache *s, const char *name, size_t size,
+	       	unsigned long flags)
+{
+	int err;
+
+	s->name = name;
+	s->size = s->object_size = size;
+	s->align = ARCH_KMALLOC_MINALIGN;
+	err = __kmem_cache_create(s, flags);
+
+	if (err)
+		panic("Creation of kmalloc slab %s size=%ld failed. Reason %d\n",
+		       			name, size, err);
+
+	list_add(&s->list, &slab_caches);
+	s->refcount = -1;	/* Exempt from merging for now */
+}
+
+struct kmem_cache *__init create_kmalloc_cache(const char *name, size_t size,
+				unsigned long flags)
+{
+	struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
+
+	if (!s)
+		panic("Out of memory when creating slab %s\n", name);
+
+	create_boot_cache(s, name, size, flags);
+	s->refcount = 1;
+	return s;
+}

mm/slub.c +3 ~~-33~~

Index: linux-2.6/mm/slub.c
===================================================================
@@ -3239,32 +3239,6 @@ static int __init setup_slub_nomerge(cha
 
 __setup("slub_nomerge", setup_slub_nomerge);
 
-static struct kmem_cache *__init create_kmalloc_cache(const char *name,
-						int size, unsigned int flags)
-{
-	struct kmem_cache *s;
-
-	s = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
-
-	s->name = name;
-	s->size = s->object_size = size;
-	s->align = ARCH_KMALLOC_MINALIGN;
-
-	/*
-	 * This function is called with IRQs disabled during early-boot on
-	 * single CPU so there's no need to take slab_mutex here.
-	 */
-	if (kmem_cache_open(s, flags))
-		goto panic;
-
-	list_add(&s->list, &slab_caches);
-	return s;
-
-panic:
-	panic("Creation of kmalloc slab %s size=%d failed.\n", name, size);
-	return NULL;
-}
-
 /*
  * Conversion table for small slabs sizes / 8 to the index in the
  * kmalloc array. This is necessary for slabs < 192 since we have non power

@@ -3707,10 +3681,8 @@ void __init kmem_cache_init(void)
 	 */
 	kmem_cache_node = (void *)kmem_cache + kmalloc_size;
 
-	kmem_cache_node->name = "kmem_cache_node";
-	kmem_cache_node->size = kmem_cache_node->object_size =
-		sizeof(struct kmem_cache_node);
-	kmem_cache_open(kmem_cache_node, SLAB_HWCACHE_ALIGN | SLAB_PANIC);
+	create_boot_cache(kmem_cache_node, "kmem_cache_node",
+		       sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN);
 
 	hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);

@@ -3718,9 +3690,7 @@ void __init kmem_cache_init(void)
 	slab_state = PARTIAL;
 
 	temp_kmem_cache = kmem_cache;
-	kmem_cache->name = "kmem_cache";
-	kmem_cache->size = kmem_cache->object_size = kmem_size;
-	kmem_cache_open(kmem_cache, SLAB_HWCACHE_ALIGN | SLAB_PANIC);
+	create_boot_cache(kmem_cache, "kmem_cache", kmem_size, SLAB_HWCACHE_ALIGN);
 
 	kmem_cache = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
 	memcpy(kmem_cache, temp_kmem_cache, kmem_size);

Christoph Lameter

author

2012-08-08 21:03 UTC #10 lore raw

Common11 [05/20] Move list_add() to slab_common.c

In reply to Christoph Lameter

Move the code to append the new kmem_cache to the list of slab caches to the kmem_cache_create code in the shared code.

This is possible now since the acquisition of the mutex was moved into kmem_cache_create().

V1->V2:
- SLOB: Add code to remove the slab from list
(will be removed a couple of patches down when we also move the list_del to common code).

Acked-by David Rientjes <[email protected]>

Reviewed-by Glauber Costa <[email protected]>

Reviewed-by Joonsoo Kim <[email protected]>

Signed-off-by Christoph Lameter <[email protected]>

---
 mm/slab.c        |    7 +++++--
 mm/slab_common.c |    7 +++++++
 mm/slub.c        |    2 --
 3 files changed, 12 insertions(+), 4 deletions(-)

mm/slab_common.c +7 -0

Index: linux-2.6/mm/slab_common.c
===================================================================
@@ -96,6 +96,13 @@ struct kmem_cache *kmem_cache_create(con
 	if (!s)
 		err = -ENOSYS; /* Until __kmem_cache_create returns code */
 
+	/*
+	 * Check if the slab has actually been created and if it was a
+	 * real instatiation. Aliases do not belong on the list
+	 */
+	if (s && s->refcount == 1)
+		list_add(&s->list, &slab_caches);
+
 #ifdef CONFIG_DEBUG_VM
 out_locked:
 #endif

mm/slab.c +5 -2

Index: linux-2.6/mm/slab.c
===================================================================
@@ -1687,6 +1687,7 @@ void __init kmem_cache_init(void)
 					ARCH_KMALLOC_FLAGS|SLAB_PANIC,
 					NULL);
 
+	list_add(&sizes[INDEX_AC].cs_cachep->list, &slab_caches);
 	if (INDEX_AC != INDEX_L3) {
 		sizes[INDEX_L3].cs_cachep =
 			__kmem_cache_create(names[INDEX_L3].name,

@@ -1694,6 +1695,7 @@ void __init kmem_cache_init(void)
 				ARCH_KMALLOC_MINALIGN,
 				ARCH_KMALLOC_FLAGS|SLAB_PANIC,
 				NULL);
+		list_add(&sizes[INDEX_L3].cs_cachep->list, &slab_caches);
 	}
 
 	slab_early_init = 0;

@@ -1712,6 +1714,7 @@ void __init kmem_cache_init(void)
 					ARCH_KMALLOC_MINALIGN,
 					ARCH_KMALLOC_FLAGS|SLAB_PANIC,
 					NULL);
+			list_add(&sizes->cs_cachep->list, &slab_caches);
 		}
 #ifdef CONFIG_ZONE_DMA
 		sizes->cs_dmacachep = __kmem_cache_create(

@@ -1721,6 +1724,7 @@ void __init kmem_cache_init(void)
 					ARCH_KMALLOC_FLAGS|SLAB_CACHE_DMA|
 						SLAB_PANIC,
 					NULL);
+		list_add(&sizes->cs_dmacachep->list, &slab_caches);
 #endif
 		sizes++;
 		names++;

@@ -2590,6 +2594,7 @@ __kmem_cache_create (const char *name, s
 	}
 	cachep->ctor = ctor;
 	cachep->name = name;
+	cachep->refcount = 1;
 
 	if (setup_cpu_cache(cachep, gfp)) {
 		__kmem_cache_destroy(cachep);

@@ -2606,8 +2611,6 @@ __kmem_cache_create (const char *name, s
 		slab_set_debugobj_lock_classes(cachep);
 	}
 
-	/* cache setup completed, link it into the list */
-	list_add(&cachep->list, &slab_caches);
 	return cachep;
 }

mm/slub.c +0 -2

Index: linux-2.6/mm/slub.c
===================================================================
@@ -3968,7 +3968,6 @@ struct kmem_cache *__kmem_cache_create(c
 				size, align, flags, ctor)) {
 			int r;
 
-			list_add(&s->list, &slab_caches);
 			mutex_unlock(&slab_mutex);
 			r = sysfs_slab_add(s);
 			mutex_lock(&slab_mutex);

@@ -3976,7 +3975,6 @@ struct kmem_cache *__kmem_cache_create(c
 			if (!r)
 				return s;
 
-			list_del(&s->list);
 			kmem_cache_close(s);
 		}
 		kmem_cache_free(kmem_cache, s);

Christoph Lameter

author

2012-08-08 21:03 UTC #11 lore raw

Common11 [09/20] Get rid of __kmem_cache_destroy

In reply to Christoph Lameter

What is done there can be done in __kmem_cache_shutdown.

This affects RCU handling somewhat. On rcu free all slab allocators do not refer to other management structures than the kmem_cache structure. Therefore these other structures can be freed before the rcu deferred free to the page allocator occurs.

Reviewed-by Joonsoo Kim <[email protected]>

Signed-off-by Christoph Lameter <[email protected]>

---
 mm/slab.c        |   43 +++++++++++++++++++++----------------------
 mm/slab.h        |    1 -
 mm/slab_common.c |    1 -
 mm/slob.c        |    4 ----
 mm/slub.c        |   10 +++++-----
 5 files changed, 26 insertions(+), 33 deletions(-)

mm/slob.c +0 -4

Index: linux-2.6/mm/slob.c
===================================================================
@@ -538,10 +538,6 @@
 	return c;
 }
 
-void __kmem_cache_destroy(struct kmem_cache *c)
-{
-}
-
 void *kmem_cache_alloc_node(struct kmem_cache *c, gfp_t flags, int node)
 {
 	void *b;

mm/slub.c +5 -5

Index: linux-2.6/mm/slub.c
===================================================================
@@ -3198,12 +3198,12 @@
 
 int __kmem_cache_shutdown(struct kmem_cache *s)
 {
-	return kmem_cache_close(s);
-}
+	int rc = kmem_cache_close(s);
 
-void __kmem_cache_destroy(struct kmem_cache *s)
-{
-	sysfs_slab_remove(s);
+	if (!rc)
+		sysfs_slab_remove(s);
+
+	return rc;
 }
 
 /********************************************************************

mm/slab.c +21 ~~-22~~

61 lines not on this page · raw message

mm/slab.h +0 -1

Index: linux-2.6/mm/slab.h
===================================================================
@@ -37,6 +37,5 @@
 	size_t align, unsigned long flags, void (*ctor)(void *));
 
 int __kmem_cache_shutdown(struct kmem_cache *);
-void __kmem_cache_destroy(struct kmem_cache *);
 
 #endif

mm/slab_common.c +0 -1

Index: linux-2.6/mm/slab_common.c
===================================================================
@@ -143,7 +143,6 @@
 			if (s->flags & SLAB_DESTROY_BY_RCU)
 				rcu_barrier();
 
-			__kmem_cache_destroy(s);
 			kmem_cache_free(kmem_cache, s);
 		} else {
 			list_add(&s->list, &slab_caches);

Christoph Lameter

author

2012-08-08 21:03 UTC #12 lore raw

Common11 [14/20] Shrink __kmem_cache_create() parameter lists

In reply to Christoph Lameter

Do the initial settings of the fields in common code. This will allow us to push more processing into common code later and improve readability.

Signed-off-by Christoph Lameter <[email protected]>

mm/slab.h +1 -2

Index: linux-2.6/mm/slab.h
===================================================================
@@ -33,8 +33,7 @@ extern struct list_head slab_caches;
 extern struct kmem_cache *kmem_cache;
 
 /* Functions provided by the slab allocators */
-extern int __kmem_cache_create(struct kmem_cache *, const char *name,
-	size_t size, size_t align, unsigned long flags, void (*ctor)(void *));
+extern int __kmem_cache_create(struct kmem_cache *, unsigned long flags);
 
 #ifdef CONFIG_SLUB
 struct kmem_cache *__kmem_cache_alias(const char *name, size_t size,

mm/slab_common.c +13 ~~-13~~

Index: linux-2.6/mm/slab_common.c
===================================================================
@@ -54,7 +54,6 @@ struct kmem_cache *kmem_cache_create(con
 {
 	struct kmem_cache *s;
 	int err = 0;
-	char *n;
 
 #ifdef CONFIG_DEBUG_VM
 	if (!name || in_interrupt() || size < sizeof(void *) ||

@@ -94,32 +93,33 @@ struct kmem_cache *kmem_cache_create(con
 	WARN_ON(strchr(name, ' '));	/* It confuses parsers */
 #endif
 
-	n = kstrdup(name, GFP_KERNEL);
-	if (!n) {
-		err = -ENOMEM;
-		goto out_locked;
-	}
-
 	s = __kmem_cache_alias(name, size, align, flags, ctor);
 	if (s)
 		goto out_locked;
 
 	s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
 	if (s) {
-		err = __kmem_cache_create(s, n, size, align, flags, ctor);
+		s->object_size = s->size = size;
+		s->align = align;
+		s->ctor = ctor;
+		s->name = kstrdup(name, GFP_KERNEL);
+		if (!s->name) {
+			kmem_cache_free(kmem_cache, s);
+			err = -ENOMEM;
+			goto out_locked;
+		}
+
+		err = __kmem_cache_create(s, flags);
 		if (!err)
 
 			list_add(&s->list, &slab_caches);
 
 		else {
-			kfree(n);
+			kfree(s->name);
 			kmem_cache_free(kmem_cache, s);
 		}
-
-	} else {
-		kfree(n);
+	} else
 		err = -ENOMEM;
-	}
 
 out_locked:
 	mutex_unlock(&slab_mutex);

mm/slub.c +18 ~~-21~~

Index: linux-2.6/mm/slub.c
===================================================================
@@ -3022,16 +3022,9 @@ static int calculate_sizes(struct kmem_c
 
 }
 
-static int kmem_cache_open(struct kmem_cache *s,
-		const char *name, size_t size,
-		size_t align, unsigned long flags,
-		void (*ctor)(void *))
+static int kmem_cache_open(struct kmem_cache *s, unsigned long flags)
 {
-	s->name = name;
-	s->ctor = ctor;
-	s->object_size = size;
-	s->align = align;
-	s->flags = kmem_cache_flags(size, flags, name, ctor);
+	s->flags = kmem_cache_flags(s->size, flags, s->name, s->ctor);
 	s->reserved = 0;
 
 	if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU))

@@ -3108,7 +3101,7 @@ error:
 	if (flags & SLAB_PANIC)
 		panic("Cannot create slab %s size=%lu realsize=%u "
 			"order=%u offset=%u flags=%lx\n",
-			s->name, (unsigned long)size, s->size, oo_order(s->oo),
+			s->name, (unsigned long)s->size, s->size, oo_order(s->oo),
 			s->offset, flags);
 	return -EINVAL;
 }

@@ -3254,12 +3247,15 @@ static struct kmem_cache *__init create_
 
 	s = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
 
+	s->name = name;
+	s->size = s->object_size = size;
+	s->align = ARCH_KMALLOC_MINALIGN;
+
 	/*
 	 * This function is called with IRQs disabled during early-boot on
 	 * single CPU so there's no need to take slab_mutex here.
 	 */
-	if (kmem_cache_open(s, name, size, ARCH_KMALLOC_MINALIGN,
-								flags, NULL))
+	if (kmem_cache_open(s, flags))
 		goto panic;
 
 	list_add(&s->list, &slab_caches);

@@ -3712,9 +3708,10 @@ void __init kmem_cache_init(void)
 	 */
 	kmem_cache_node = (void *)kmem_cache + kmalloc_size;
 
-	kmem_cache_open(kmem_cache_node, "kmem_cache_node",
-		sizeof(struct kmem_cache_node),
-		0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
+	kmem_cache_node->name = "kmem_cache_node";
+	kmem_cache_node->size = kmem_cache_node->object_size =
+		sizeof(struct kmem_cache_node);
+	kmem_cache_open(kmem_cache_node, SLAB_HWCACHE_ALIGN | SLAB_PANIC);
 
 	hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);

@@ -3722,8 +3719,10 @@ void __init kmem_cache_init(void)
 	slab_state = PARTIAL;
 
 	temp_kmem_cache = kmem_cache;
-	kmem_cache_open(kmem_cache, "kmem_cache", kmem_size,
-		0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
+	kmem_cache->name = "kmem_cache";
+	kmem_cache->size = kmem_cache->object_size = kmem_size;
+	kmem_cache_open(kmem_cache, SLAB_HWCACHE_ALIGN | SLAB_PANIC);
+
 	kmem_cache = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
 	memcpy(kmem_cache, temp_kmem_cache, kmem_size);

@@ -3936,11 +3935,9 @@ struct kmem_cache *__kmem_cache_alias(co
 	return s;
 }
 
-int __kmem_cache_create(struct kmem_cache *s,
-		const char *name, size_t size,
-		size_t align, unsigned long flags, void (*ctor)(void *))
+int __kmem_cache_create(struct kmem_cache *s, unsigned long flags)
 {
-	return kmem_cache_open(s, name, size, align, flags, ctor);
+	return kmem_cache_open(s, flags);
 }
 
 #ifdef CONFIG_SMP

mm/slab.c +41 ~~-50~~

193 lines not on this page · raw message

mm/slob.c +3 -5

Index: linux-2.6/mm/slob.c
===================================================================
@@ -508,17 +508,15 @@ size_t ksize(const void *block)
 }
 EXPORT_SYMBOL(ksize);
 
-int __kmem_cache_create(struct kmem_cache *c, const char *name, size_t size,
-	size_t align, unsigned long flags, void (*ctor)(void *))
+int __kmem_cache_create(struct kmem_cache *c, unsigned long flags)
 {
-	c->name = name;
-	c->size = size;
+	size_t align = c->size;
+
 	if (flags & SLAB_DESTROY_BY_RCU) {
 		/* leave room for rcu footer at the end of object */
 		c->size += sizeof(struct slob_rcu);
 	}
 	c->flags = flags;
-	c->ctor = ctor;
 	/* ignore alignment unless it's forced */
 	c->align = (flags & SLAB_HWCACHE_ALIGN) ? SLOB_ALIGN : 0;
 	if (c->align < ARCH_SLAB_MINALIGN)

Christoph Lameter

author

2012-08-08 21:03 UTC #13 lore raw

Common11 [18/20] slub: Use a statically allocated kmem_cache boot structure for bootstrap

In reply to Christoph Lameter

Simplify bootstrap by statically allocated two kmem_cache structures. These are freed after bootup is complete. Allows us to no longer worry about calculations of sizes of kmem_cache structures during bootstrap.

Reviewed-by Glauber Costa <[email protected]>

Signed-off-by Christoph Lameter <[email protected]>

---
 mm/slub.c |   32 +++++++++-----------------------
 1 file changed, 9 insertions(+), 23 deletions(-)

mm/slub.c +11 ~~-30~~

Index: linux-2.6/mm/slub.c
===================================================================
@@ -3635,9 +3635,6 @@ static void __init kmem_cache_bootstrap_
 {
 	int node;
 
-	list_add(&s->list, &slab_caches);
-	s->refcount = -1;
-
 	for_each_node_state(node, N_NORMAL_MEMORY) {
 		struct kmem_cache_node *n = get_node(s, node);
 		struct page *p;

@@ -3654,13 +3651,13 @@ static void __init kmem_cache_bootstrap_
 	}
 }
 
+static __initdata struct kmem_cache boot_kmem_cache,
+			boot_kmem_cache_node;
+
 void __init kmem_cache_init(void)
 {
 	int i;
-	int caches = 0;
-	struct kmem_cache *temp_kmem_cache;
-	int order;
-	struct kmem_cache *temp_kmem_cache_node;
+	int caches = 2;
 	unsigned long kmalloc_size;
 
 	if (debug_guardpage_minorder())

@@ -3669,49 +3666,33 @@ void __init kmem_cache_init(void)
 	kmem_size = offsetof(struct kmem_cache, node) +
 			nr_node_ids * sizeof(struct kmem_cache_node *);
 
-	/* Allocate two kmem_caches from the page allocator */
 	kmalloc_size = ALIGN(kmem_size, cache_line_size());
-	order = get_order(2 * kmalloc_size);
-	kmem_cache = (void *)__get_free_pages(GFP_NOWAIT, order);
-
-	/*
-	 * Must first have the slab cache available for the allocations of the
-	 * struct kmem_cache_node's. There is special bootstrap code in
-	 * kmem_cache_open for slab_state == DOWN.
-	 */
-	kmem_cache_node = (void *)kmem_cache + kmalloc_size;
+	kmem_cache_node = &boot_kmem_cache_node;
 
 	create_boot_cache(kmem_cache_node, "kmem_cache_node",
-		       sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN);
+		sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN);
 
 	hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
 
 	/* Able to allocate the per node structures */
 	slab_state = PARTIAL;
 
-	temp_kmem_cache = kmem_cache;
-	create_boot_cache(kmem_cache, "kmem_cache", kmem_size, SLAB_HWCACHE_ALIGN);
+	create_boot_cache(&boot_kmem_cache, "kmem_cache", kmem_size,
+		       SLAB_HWCACHE_ALIGN);
 
-	kmem_cache = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
-	memcpy(kmem_cache, temp_kmem_cache, kmem_size);
+	kmem_cache = kmem_cache_alloc(&boot_kmem_cache, GFP_NOWAIT);
+	memcpy(kmem_cache, &boot_kmem_cache, kmem_size);
 
 	/*
 	 * Allocate kmem_cache_node properly from the kmem_cache slab.
 	 * kmem_cache_node is separately allocated so no need to
 	 * update any list pointers.
 	 */
-	temp_kmem_cache_node = kmem_cache_node;
-
 	kmem_cache_node = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
-	memcpy(kmem_cache_node, temp_kmem_cache_node, kmem_size);
+	memcpy(kmem_cache_node, &boot_kmem_cache_node, kmem_size);
 
 	kmem_cache_bootstrap_fixup(kmem_cache_node);
-
-	caches++;
 	kmem_cache_bootstrap_fixup(kmem_cache);
-	caches++;
-	/* Free temporary boot structure */
-	free_pages((unsigned long)temp_kmem_cache, order);
 
 	/* Now we can use the kmem_cache to allocate kmalloc slabs */

Christoph Lameter

author

2012-08-08 21:03 UTC #14 lore raw

Common11 [19/20] slab: Use the new create_boot_cache function to simplify bootstrap

In reply to Christoph Lameter

Simplify setup and reduce code in kmem_cache_init(). This allows us to get rid of initarray_cache as well as the manual setup code for the kmem_cache and kmem_cache_node arrays during bootstrap.

We introduce a new bootstrap state "PARTIAL" for slab that signals the creation of a kmem_cache boot cache.

V1->V2: Get rid of initarray_cache as well.

Signed-off-by Christoph Lameter <[email protected]>

mm/slab.c +18 ~~-33~~

Index: linux-2.6/mm/slab.c
===================================================================
@@ -579,8 +579,6 @@ static struct cache_names __initdata cac
 #undef CACHE
 };
 
-static struct arraycache_init initarray_cache __initdata =
-    { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
 static struct arraycache_init initarray_generic =
     { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };

@@ -1591,12 +1589,9 @@ static void setup_nodelists_pointer(stru
  */
 void __init kmem_cache_init(void)
 {
-	size_t left_over;
 	struct cache_sizes *sizes;
 	struct cache_names *names;
 	int i;
-	int order;
-	int node;
 
 	kmem_cache = &kmem_cache_boot;
 	setup_nodelists_pointer(kmem_cache);

@@ -1640,36 +1635,17 @@ void __init kmem_cache_init(void)
 	 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
 	 */
 
-	node = numa_mem_id();
-
 	/* 1) create the kmem_cache */
-	INIT_LIST_HEAD(&slab_caches);
-	list_add(&kmem_cache->list, &slab_caches);
-	kmem_cache->colour_off = cache_line_size();
-	kmem_cache->array[smp_processor_id()] = &initarray_cache.cache;
 
 	/*
 	 * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids
 	 */
-	kmem_cache->size = offsetof(struct kmem_cache, array[nr_cpu_ids]) +
-				  nr_node_ids * sizeof(struct kmem_list3 *);
-	kmem_cache->object_size = kmem_cache->size;
-	kmem_cache->size = ALIGN(kmem_cache->object_size,
-					cache_line_size());
-	kmem_cache->reciprocal_buffer_size =
-		reciprocal_value(kmem_cache->size);
-
-	for (order = 0; order < MAX_ORDER; order++) {
-		cache_estimate(order, kmem_cache->size,
-			cache_line_size(), 0, &left_over, &kmem_cache->num);
-		if (kmem_cache->num)
-			break;
-	}
-	BUG_ON(!kmem_cache->num);
-	kmem_cache->gfporder = order;
-	kmem_cache->colour = left_over / kmem_cache->colour_off;
-	kmem_cache->slab_size = ALIGN(kmem_cache->num * sizeof(kmem_bufctl_t) +
-				      sizeof(struct slab), cache_line_size());
+	create_boot_cache(kmem_cache, "kmem_cache",
+		offsetof(struct kmem_cache, array[nr_cpu_ids]) +
+				  nr_node_ids * sizeof(struct kmem_list3 *),
+				  SLAB_HWCACHE_ALIGN);
+
+	slab_state = PARTIAL;
 
 	/* 2+3) create the kmalloc caches */
 	sizes = malloc_sizes;

@@ -1717,7 +1693,6 @@ void __init kmem_cache_init(void)
 
 		ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
 
-		BUG_ON(cpu_cache_get(kmem_cache) != &initarray_cache.cache);
 		memcpy(ptr, cpu_cache_get(kmem_cache),
 		       sizeof(struct arraycache_init));
 		/*

@@ -2272,7 +2247,16 @@ static int __init_refok setup_cpu_cache(
 
 	if (slab_state == DOWN) {
 		/*
-		 * Note: the first kmem_cache_create must create the cache
+		 * Note: Creation of first cache (kmem_cache).
+		 * The setup_list3s is taken care
+		 * of by the caller of __kmem_cache_create
+		 */
+		cachep->array[smp_processor_id()] = &initarray_generic.cache;
+		slab_state = PARTIAL;
+	} else
+	if (slab_state == PARTIAL) {
+		/*
+		 * Note: the second kmem_cache_create must create the cache
 		 * that's used by kmalloc(24), otherwise the creation of
 		 * further caches will BUG().
 		 */

@@ -2280,7 +2264,7 @@ static int __init_refok setup_cpu_cache(
 
 		/*
 		 * If the cache that's used by kmalloc(sizeof(kmem_list3)) is
-		 * the first cache, then we need to set up all its list3s,
+		 * the second cache, then we need to set up all its list3s,
 		 * otherwise the creation of further caches will BUG().
 		 */
 		set_up_list3s(cachep, SIZE_AC);

@@ -2289,6 +2273,7 @@ static int __init_refok setup_cpu_cache(
 		else
 			slab_state = PARTIAL_ARRAYCACHE;
 	} else {
+		/* Remaining boot caches */
 		cachep->array[smp_processor_id()] =
 			kmalloc(sizeof(struct arraycache_init), gfp);

Christoph Lameter

author

2012-08-08 21:03 UTC #15 lore raw

Common11 [20/20] Common alignment code

In reply to Christoph Lameter

Extract the code to do object alignment from the allocators. Do the alignment calculations in slab_common so that the __kmem_cache_create functions of the allocators do not have to deal with alignment.

Signed-off-by Christoph Lameter <[email protected]>

---
 mm/slab.c        |   22 +---------------------
 mm/slab.h        |    3 +++
 mm/slab_common.c |   30 +++++++++++++++++++++++++++++-
 mm/slob.c        |   11 -----------
 mm/slub.c        |   45 ++++++++-------------------------------------
 5 files changed, 41 insertions(+), 70 deletions(-)

mm/slab.c +0 ~~-20~~

Index: linux-2.6/mm/slab.c
===================================================================
@@ -2368,22 +2368,6 @@ __kmem_cache_create (struct kmem_cache *
 		cachep->size &= ~(BYTES_PER_WORD - 1);
 	}
 
-	/* calculate the final buffer alignment: */
-
-	/* 1) arch recommendation: can be overridden for debug */
-	if (flags & SLAB_HWCACHE_ALIGN) {
-		/*
-		 * Default alignment: as specified by the arch code.  Except if
-		 * an object is really small, then squeeze multiple objects into
-		 * one cacheline.
-		 */
-		ralign = cache_line_size();
-		while (cachep->size <= ralign / 2)
-			ralign /= 2;
-	} else {
-		ralign = BYTES_PER_WORD;
-	}
-
 	/*
 	 * Redzoning and user store require word alignment or possibly larger.
 	 * Note this will be overridden by architecture or caller mandated

@@ -2400,10 +2384,6 @@ __kmem_cache_create (struct kmem_cache *
 		cachep->size &= ~(REDZONE_ALIGN - 1);
 	}
 
-	/* 2) arch mandated alignment */
-	if (ralign < ARCH_SLAB_MINALIGN) {
-		ralign = ARCH_SLAB_MINALIGN;
-	}
 	/* 3) caller mandated alignment */
 	if (ralign < cachep->align) {
 		ralign = cachep->align;

mm/slab_common.c +30 -2

Index: linux-2.6/mm/slab_common.c
===================================================================
@@ -25,6 +25,34 @@ DEFINE_MUTEX(slab_mutex);
 struct kmem_cache *kmem_cache;
 
 /*
+ * Figure out what the alignment of the objects will be given a set of
+ * flags, a user specified alignment and the size of the objects.
+ */
+unsigned long calculate_alignment(unsigned long flags,
+		unsigned long align, unsigned long size)
+{
+	/*
+	 * If the user wants hardware cache aligned objects then follow that
+	 * suggestion if the object is sufficiently large.
+	 *
+	 * The hardware cache alignment cannot override the specified
+	 * alignment though. If that is greater then use it.
+	 */
+	if (flags & SLAB_HWCACHE_ALIGN) {
+		unsigned long ralign = cache_line_size();
+		while (size <= ralign / 2)
+			ralign /= 2;
+		align = max(align, ralign);
+	}
+
+	if (align < ARCH_SLAB_MINALIGN)
+		align = ARCH_SLAB_MINALIGN;
+
+	return ALIGN(align, sizeof(void *));
+}
+
+
+/*
  * kmem_cache_create - Create a cache.
  * @name: A string which is used in /proc/slabinfo to identify this cache.
  * @size: The size of objects to be created in this cache.

@@ -100,7 +128,7 @@ struct kmem_cache *kmem_cache_create(con
 	s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
 	if (s) {
 		s->object_size = s->size = size;
-		s->align = align;
+		s->align = calculate_alignment(flags, align, size);
 		s->ctor = ctor;
 		s->name = kstrdup(name, GFP_KERNEL);
 		if (!s->name) {

@@ -194,7 +222,7 @@ void __init create_boot_cache(struct kme
 
 	s->name = name;
 	s->size = s->object_size = size;
-	s->align = ARCH_KMALLOC_MINALIGN;
+	s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size);
 	err = __kmem_cache_create(s, flags);
 
 	if (err)

mm/slob.c +0 ~~-10~~

Index: linux-2.6/mm/slob.c
===================================================================
@@ -124,7 +124,6 @@ static inline void clear_slob_page_free(
 
 #define SLOB_UNIT sizeof(slob_t)
 #define SLOB_UNITS(size) (((size) + SLOB_UNIT - 1)/SLOB_UNIT)
-#define SLOB_ALIGN L1_CACHE_BYTES
 
 /*
  * struct slob_rcu is inserted at the tail of allocated slob blocks, which

@@ -510,20 +509,11 @@ EXPORT_SYMBOL(ksize);
 
 int __kmem_cache_create(struct kmem_cache *c, unsigned long flags)
 {
-	size_t align = c->size;
-
 	if (flags & SLAB_DESTROY_BY_RCU) {
 		/* leave room for rcu footer at the end of object */
 		c->size += sizeof(struct slob_rcu);
 	}
 	c->flags = flags;
-	/* ignore alignment unless it's forced */
-	c->align = (flags & SLAB_HWCACHE_ALIGN) ? SLOB_ALIGN : 0;
-	if (c->align < ARCH_SLAB_MINALIGN)
-		c->align = ARCH_SLAB_MINALIGN;
-	if (c->align < align)
-		c->align = align;
-
 	return 0;
 }

mm/slub.c +1 ~~-37~~

Index: linux-2.6/mm/slub.c
===================================================================
@@ -2747,32 +2747,6 @@ static inline int calculate_order(int si
 	return -ENOSYS;
 }
 
-/*
- * Figure out what the alignment of the objects will be.
- */
-static unsigned long calculate_alignment(unsigned long flags,
-		unsigned long align, unsigned long size)
-{
-	/*
-	 * If the user wants hardware cache aligned objects then follow that
-	 * suggestion if the object is sufficiently large.
-	 *
-	 * The hardware cache alignment cannot override the specified
-	 * alignment though. If that is greater then use it.
-	 */
-	if (flags & SLAB_HWCACHE_ALIGN) {
-		unsigned long ralign = cache_line_size();
-		while (size <= ralign / 2)
-			ralign /= 2;
-		align = max(align, ralign);
-	}
-
-	if (align < ARCH_SLAB_MINALIGN)
-		align = ARCH_SLAB_MINALIGN;
-
-	return ALIGN(align, sizeof(void *));
-}
-
 static void
 init_kmem_cache_node(struct kmem_cache_node *n)
 {

@@ -2906,7 +2880,6 @@ static int calculate_sizes(struct kmem_c
 {
 	unsigned long flags = s->flags;
 	unsigned long size = s->object_size;
-	unsigned long align = s->align;
 	int order;
 
 	/*

@@ -2978,19 +2951,11 @@ static int calculate_sizes(struct kmem_c
 #endif
 
 	/*
-	 * Determine the alignment based on various parameters that the
-	 * user specified and the dynamic determination of cache line size
-	 * on bootup.
-	 */
-	align = calculate_alignment(flags, align, s->object_size);
-	s->align = align;
-
-	/*
 	 * SLUB stores one object immediately after another beginning from
 	 * offset 0. In order to align the objects we have to simply size
 	 * each object to conform to the alignment.
 	 */
-	size = ALIGN(size, align);
+	size = ALIGN(size, s->align);
 	s->size = size;
 	if (forced_order >= 0)
 		order = forced_order;

@@ -3019,7 +2984,6 @@ static int calculate_sizes(struct kmem_c
 		s->max = s->oo;
 
 	return !!oo_objects(s->oo);
-
 }
 
 static int kmem_cache_open(struct kmem_cache *s, unsigned long flags)

mm/slab.h +3 -0

Index: linux-2.6/mm/slab.h
===================================================================
@@ -32,6 +32,9 @@ extern struct list_head slab_caches;
 /* The slab cache that manages slab cache information */
 extern struct kmem_cache *kmem_cache;
 
+unsigned long calculate_alignment(unsigned long flags,
+		unsigned long align, unsigned long size);
+
 /* Functions provided by the slab allocators */
 extern int __kmem_cache_create(struct kmem_cache *, unsigned long flags);

Christoph Lameter

author

2012-08-08 21:04 UTC #16 lore raw

Common11 [07/20] Always use the name "kmem_cache" for the slab cache with the kmem_cache structure.

In reply to Christoph Lameter

Make all allocators use the "kmem_cache" slabname for the "kmem_cache" structure.

Reviewed-by Glauber Costa <[email protected]>

Reviewed-by Joonsoo Kim <[email protected]>

Signed-off-by Christoph Lameter <[email protected]>

---
 mm/slab.c        |   72 ++++++++++++++++++++++++++++---------------------------
 mm/slab.h        |    6 ++++
 mm/slab_common.c |    1 
 mm/slob.c        |    9 ++++++
 mm/slub.c        |    2 -
 5 files changed, 52 insertions(+), 38 deletions(-)

mm/slab.c +37 ~~-35~~

Index: linux-2.6/mm/slab.c
===================================================================
@@ -585,9 +585,9 @@
     { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
 
 /* internal cache of cache description objs */
-static struct kmem_list3 *cache_cache_nodelists[MAX_NUMNODES];
-static struct kmem_cache cache_cache = {
-	.nodelists = cache_cache_nodelists,
+static struct kmem_list3 *kmem_cache_nodelists[MAX_NUMNODES];
+static struct kmem_cache kmem_cache_boot = {
+	.nodelists = kmem_cache_nodelists,
 	.batchcount = 1,
 	.limit = BOOT_CPUCACHE_ENTRIES,
 	.shared = 1,

@@ -1591,15 +1591,17 @@
 	int order;
 	int node;
 
+	kmem_cache = &kmem_cache_boot;
+
 	if (num_possible_nodes() == 1)
 		use_alien_caches = 0;
 
 	for (i = 0; i < NUM_INIT_LISTS; i++) {
 		kmem_list3_init(&initkmem_list3[i]);
 		if (i < MAX_NUMNODES)
-			cache_cache.nodelists[i] = NULL;
+			kmem_cache->nodelists[i] = NULL;
 	}
-	set_up_list3s(&cache_cache, CACHE_CACHE);
+	set_up_list3s(kmem_cache, CACHE_CACHE);
 
 	/*
 	 * Fragmentation resistance on low memory - only use bigger

@@ -1611,9 +1613,9 @@
 
 	/* Bootstrap is tricky, because several objects are allocated
 	 * from caches that do not exist yet:
-	 * 1) initialize the cache_cache cache: it contains the struct
-	 *    kmem_cache structures of all caches, except cache_cache itself:
-	 *    cache_cache is statically allocated.
+	 * 1) initialize the kmem_cache cache: it contains the struct
+	 *    kmem_cache structures of all caches, except kmem_cache itself:
+	 *    kmem_cache is statically allocated.
 	 *    Initially an __init data area is used for the head array and the
 	 *    kmem_list3 structures, it's replaced with a kmalloc allocated
 	 *    array at the end of the bootstrap.

@@ -1622,43 +1624,43 @@
 	 *    An __init data area is used for the head array.
 	 * 3) Create the remaining kmalloc caches, with minimally sized
 	 *    head arrays.
-	 * 4) Replace the __init data head arrays for cache_cache and the first
+	 * 4) Replace the __init data head arrays for kmem_cache and the first
 	 *    kmalloc cache with kmalloc allocated arrays.
-	 * 5) Replace the __init data for kmem_list3 for cache_cache and
+	 * 5) Replace the __init data for kmem_list3 for kmem_cache and
 	 *    the other cache's with kmalloc allocated memory.
 	 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
 	 */
 
 	node = numa_mem_id();
 
-	/* 1) create the cache_cache */
+	/* 1) create the kmem_cache */
 	INIT_LIST_HEAD(&slab_caches);
-	list_add(&cache_cache.list, &slab_caches);
-	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];
+	list_add(&kmem_cache->list, &slab_caches);
+	kmem_cache->colour_off = cache_line_size();
+	kmem_cache->array[smp_processor_id()] = &initarray_cache.cache;
+	kmem_cache->nodelists[node] = &initkmem_list3[CACHE_CACHE + node];
 
 	/*
 	 * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids
 	 */
-	cache_cache.size = offsetof(struct kmem_cache, array[nr_cpu_ids]) +
+	kmem_cache->size = offsetof(struct kmem_cache, array[nr_cpu_ids]) +
 				  nr_node_ids * sizeof(struct kmem_list3 *);
-	cache_cache.object_size = cache_cache.size;
-	cache_cache.size = ALIGN(cache_cache.size,
+	kmem_cache->object_size = kmem_cache->size;
+	kmem_cache->size = ALIGN(kmem_cache->object_size,
 					cache_line_size());
-	cache_cache.reciprocal_buffer_size =
-		reciprocal_value(cache_cache.size);
+	kmem_cache->reciprocal_buffer_size =
+		reciprocal_value(kmem_cache->size);
 
 	for (order = 0; order < MAX_ORDER; order++) {
-		cache_estimate(order, cache_cache.size,
-			cache_line_size(), 0, &left_over, &cache_cache.num);
-		if (cache_cache.num)
+		cache_estimate(order, kmem_cache->size,
+			cache_line_size(), 0, &left_over, &kmem_cache->num);
+		if (kmem_cache->num)
 			break;
 	}
-	BUG_ON(!cache_cache.num);
-	cache_cache.gfporder = order;
-	cache_cache.colour = left_over / cache_cache.colour_off;
-	cache_cache.slab_size = ALIGN(cache_cache.num * sizeof(kmem_bufctl_t) +
+	BUG_ON(!kmem_cache->num);
+	kmem_cache->gfporder = order;
+	kmem_cache->colour = left_over / kmem_cache->colour_off;
+	kmem_cache->slab_size = ALIGN(kmem_cache->num * sizeof(kmem_bufctl_t) +
 				      sizeof(struct slab), cache_line_size());
 
 	/* 2+3) create the kmalloc caches */

@@ -1725,15 +1727,15 @@
 
 		ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
 
-		BUG_ON(cpu_cache_get(&cache_cache) != &initarray_cache.cache);
-		memcpy(ptr, cpu_cache_get(&cache_cache),
+		BUG_ON(cpu_cache_get(kmem_cache) != &initarray_cache.cache);
+		memcpy(ptr, cpu_cache_get(kmem_cache),
 		       sizeof(struct arraycache_init));
 		/*
 		 * Do not assume that spinlocks can be initialized via memcpy:
 		 */
 		spin_lock_init(&ptr->lock);
 
-		cache_cache.array[smp_processor_id()] = ptr;
+		kmem_cache->array[smp_processor_id()] = ptr;
 
 		ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);

@@ -1754,7 +1756,7 @@
 		int nid;
 
 		for_each_online_node(nid) {
-			init_list(&cache_cache, &initkmem_list3[CACHE_CACHE + nid], nid);
+			init_list(kmem_cache, &initkmem_list3[CACHE_CACHE + nid], nid);
 
 			init_list(malloc_sizes[INDEX_AC].cs_cachep,
 				  &initkmem_list3[SIZE_AC + nid], nid);

@@ -2220,7 +2222,7 @@
 			kfree(l3);
 		}
 	}
-	kmem_cache_free(&cache_cache, cachep);
+	kmem_cache_free(kmem_cache, cachep);
 }

@@ -2470,7 +2472,7 @@
 		gfp = GFP_NOWAIT;
 
 	/* Get cache's description obj. */
-	cachep = kmem_cache_zalloc(&cache_cache, gfp);
+	cachep = kmem_cache_zalloc(kmem_cache, gfp);
 	if (!cachep)
 		return NULL;

@@ -2528,7 +2530,7 @@
 	if (!cachep->num) {
 		printk(KERN_ERR
 		       "kmem_cache_create: couldn't create cache %s.\n", name);
-		kmem_cache_free(&cache_cache, cachep);
+		kmem_cache_free(kmem_cache, cachep);
 		return NULL;
 	}
 	slab_size = ALIGN(cachep->num * sizeof(kmem_bufctl_t)

@@ -3296,7 +3298,7 @@
 
 static bool slab_should_failslab(struct kmem_cache *cachep, gfp_t flags)
 {
-	if (cachep == &cache_cache)
+	if (cachep == kmem_cache)
 		return false;
 
 	return should_failslab(cachep->object_size, flags, cachep->flags);

mm/slab.h +6 -0

Index: linux-2.6/mm/slab.h
===================================================================
@@ -25,8 +25,14 @@
 
 /* The slab cache mutex protects the management structures during changes */
 extern struct mutex slab_mutex;
+
+/* The list of all slab caches on the system */
 extern struct list_head slab_caches;
 
+/* The slab cache that manages slab cache information */
+extern struct kmem_cache *kmem_cache;
+
+/* Functions provided by the slab allocators */
 struct kmem_cache *__kmem_cache_create(const char *name, size_t size,
 	size_t align, unsigned long flags, void (*ctor)(void *));

mm/slab_common.c +1 -0

Index: linux-2.6/mm/slab_common.c
===================================================================
@@ -22,6 +22,7 @@
 enum slab_state slab_state;
 LIST_HEAD(slab_caches);
 DEFINE_MUTEX(slab_mutex);
+struct kmem_cache *kmem_cache;
 
 /*
  * kmem_cache_create - Create a cache.

mm/slub.c +0 -2

Index: linux-2.6/mm/slub.c
===================================================================
@@ -3214,8 +3214,6 @@
 struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
 EXPORT_SYMBOL(kmalloc_caches);
 
-static struct kmem_cache *kmem_cache;
-
 #ifdef CONFIG_ZONE_DMA
 static struct kmem_cache *kmalloc_dma_caches[SLUB_PAGE_SHIFT];
 #endif

mm/slob.c +8 -0

Index: linux-2.6/mm/slob.c
===================================================================
@@ -622,8 +622,16 @@
 }
 EXPORT_SYMBOL(kmem_cache_shrink);
 
+struct kmem_cache kmem_cache_boot = {
+	.name = "kmem_cache",
+	.size = sizeof(struct kmem_cache),
+	.flags = SLAB_PANIC,
+	.align = ARCH_KMALLOC_MINALIGN,
+};
+
 void __init kmem_cache_init(void)
 {
+	kmem_cache = &kmem_cache_boot;
 	slab_state = UP;
 }

Christoph Lameter

author

2012-08-08 21:04 UTC #17 lore raw

Common11 [10/20] Move duping of slab name to slab_common.c

In reply to Christoph Lameter

Duping of the slabname has to be done by each slab. Moving this code to slab_common avoids duplicate implementations.

With this patch we have common string handling for all slab allocators. Strings passed to kmem_cache_create() are copied internally. Subsystems can create temporary strings to create slab caches.

Slabs allocated in early states of bootstrap will never be freed (and those can never be freed since they are essential to slab allocator operations). During bootstrap we therefore do not have to worry about duping names.

Signed-off-by Christoph Lameter <[email protected]>

---
 mm/slab_common.c |   24 +++++++++++++++++-------
 mm/slub.c        |    5 -----
 2 files changed, 17 insertions(+), 12 deletions(-)

mm/slab_common.c +21 ~~-11~~

Index: linux-2.6/mm/slab_common.c
===================================================================
@@ -54,6 +54,7 @@ struct kmem_cache *kmem_cache_create(con
 {
 	struct kmem_cache *s;
 	int err = 0;
+	char *n;
 
 #ifdef CONFIG_DEBUG_VM
 	if (!name || in_interrupt() || size < sizeof(void *) ||

@@ -93,20 +94,28 @@ struct kmem_cache *kmem_cache_create(con
 	WARN_ON(strchr(name, ' '));	/* It confuses parsers */
 #endif
 
-	s = __kmem_cache_create(name, size, align, flags, ctor);
-	if (!s)
-		err = -ENOSYS; /* Until __kmem_cache_create returns code */
+	n = kstrdup(name, GFP_KERNEL);
+	if (!n) {
+		err = -ENOMEM;
+		goto out_locked;
+	}
 
-	/*
-	 * Check if the slab has actually been created and if it was a
-	 * real instatiation. Aliases do not belong on the list
-	 */
-	if (s && s->refcount == 1)
-		list_add(&s->list, &slab_caches);
+	s = __kmem_cache_create(n, size, align, flags, ctor);
+
+	if (s) {
+		/*
+		 * Check if the slab has actually been created and if it was a
+		 * real instatiation. Aliases do not belong on the list
+		 */
+		if (s->refcount == 1)
+			list_add(&s->list, &slab_caches);
+
+	} else {
+		kfree(n);
+		err = -ENOSYS; /* Until __kmem_cache_create returns code */
+	}
 
-#ifdef CONFIG_DEBUG_VM
 out_locked:
-#endif
 	mutex_unlock(&slab_mutex);
 	put_online_cpus();

@@ -143,6 +152,7 @@ void kmem_cache_destroy(struct kmem_cach
 			if (s->flags & SLAB_DESTROY_BY_RCU)
 				rcu_barrier();
 
+			kfree(s->name);
 			kmem_cache_free(kmem_cache, s);
 		} else {
 			list_add(&s->list, &slab_caches);

mm/slub.c +2 ~~-19~~

Index: linux-2.6/mm/slub.c
===================================================================
@@ -210,10 +210,7 @@ static void sysfs_slab_remove(struct kme
 static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
 static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
 							{ return 0; }
-static inline void sysfs_slab_remove(struct kmem_cache *s)
-{
-	kfree(s->name);
-}
+static inline void sysfs_slab_remove(struct kmem_cache *s) { }
 
 #endif

@@ -3922,7 +3919,6 @@ struct kmem_cache *__kmem_cache_create(c
 		size_t align, unsigned long flags, void (*ctor)(void *))
 {
 	struct kmem_cache *s;
-	char *n;
 
 	s = find_mergeable(size, align, flags, name, ctor);
 	if (s) {

@@ -3941,13 +3937,9 @@ struct kmem_cache *__kmem_cache_create(c
 		return s;
 	}
 
-	n = kstrdup(name, GFP_KERNEL);
-	if (!n)
-		return NULL;
-
 	s = kmem_cache_alloc(kmem_cache, GFP_KERNEL);
 	if (s) {
-		if (kmem_cache_open(s, n,
+		if (kmem_cache_open(s, name,
 				size, align, flags, ctor)) {
 			int r;

@@ -3962,7 +3954,6 @@ struct kmem_cache *__kmem_cache_create(c
 		}
 		kmem_cache_free(kmem_cache, s);
 	}
-	kfree(n);
 	return NULL;
 }

@@ -5193,13 +5184,6 @@ static ssize_t slab_attr_store(struct ko
 	return err;
 }
 
-static void kmem_cache_release(struct kobject *kobj)
-{
-	struct kmem_cache *s = to_slab(kobj);
-
-	kfree(s->name);
-}
-
 static const struct sysfs_ops slab_sysfs_ops = {
 	.show = slab_attr_show,
 	.store = slab_attr_store,

@@ -5207,7 +5191,6 @@ static const struct sysfs_ops slab_sysfs
 
 static struct kobj_type slab_ktype = {
 	.sysfs_ops = &slab_sysfs_ops,
-	.release = kmem_cache_release
 };
 
 static int uevent_filter(struct kset *kset, struct kobject *kobj)

Christoph Lameter

author

2012-08-08 21:04 UTC #18 lore raw

Common11 [02/20] slub: Use kmem_cache for the kmem_cache structure

In reply to Christoph Lameter

Do not use kmalloc() but kmem_cache_alloc() for the allocation of the kmem_cache structures in slub.

Acked-by David Rientjes <[email protected]>

Signed-off-by Christoph Lameter <[email protected]>

mm/slub.c +4 -4

Index: linux-2.6/mm/slub.c
===================================================================
@@ -213,7 +213,7 @@ static inline int sysfs_slab_alias(struc
 static inline void sysfs_slab_remove(struct kmem_cache *s)
 {
 	kfree(s->name);
-	kfree(s);
+	kmem_cache_free(kmem_cache, s);
 }
 
 #endif

@@ -3962,7 +3962,7 @@ struct kmem_cache *__kmem_cache_create(c
 	if (!n)
 		return NULL;
 
-	s = kmalloc(kmem_size, GFP_KERNEL);
+	s = kmem_cache_alloc(kmem_cache, GFP_KERNEL);
 	if (s) {
 		if (kmem_cache_open(s, n,
 				size, align, flags, ctor)) {

@@ -3979,7 +3979,7 @@ struct kmem_cache *__kmem_cache_create(c
 			list_del(&s->list);
 			kmem_cache_close(s);
 		}
-		kfree(s);
+		kmem_cache_free(kmem_cache, s);
 	}
 	kfree(n);
 	return NULL;

@@ -5217,7 +5217,7 @@ static void kmem_cache_release(struct ko
 	struct kmem_cache *s = to_slab(kobj);
 
 	kfree(s->name);
-	kfree(s);
+	kmem_cache_free(kmem_cache, s);
 }
 
 static const struct sysfs_ops slab_sysfs_ops = {

Christoph Lameter

author

2012-08-08 21:04 UTC #19 lore raw

Common11 [06/20] Extract a common function for kmem_cache_destroy

In reply to Christoph Lameter

kmem_cache_destroy does basically the same in all allocators.

Extract common code which is easy since we already have common mutex handling.

V1-V2:
- Move percpu freeing to later so that we fail cleaner if objects are left in the cache [JoonSoo Kim]

Signed-off-by Christoph Lameter <[email protected]>

---
 mm/slab.c        |   55 +++----------------------------------------------------
 mm/slab.h        |    3 +++
 mm/slab_common.c |   25 +++++++++++++++++++++++++
 mm/slob.c        |   11 +++++++----
 mm/slub.c        |   35 +++++++++++------------------------
 5 files changed, 49 insertions(+), 80 deletions(-)

mm/slab_common.c +25 -0

Index: linux-2.6/mm/slab_common.c
===================================================================
@@ -130,6 +130,31 @@ out:
 }
 EXPORT_SYMBOL(kmem_cache_create);
 
+void kmem_cache_destroy(struct kmem_cache *s)
+{
+	get_online_cpus();
+	mutex_lock(&slab_mutex);
+	s->refcount--;
+	if (!s->refcount) {
+		list_del(&s->list);
+
+		if (!__kmem_cache_shutdown(s)) {
+			if (s->flags & SLAB_DESTROY_BY_RCU)
+				rcu_barrier();
+
+			__kmem_cache_destroy(s);
+		} else {
+			list_add(&s->list, &slab_caches);
+			printk(KERN_ERR "kmem_cache_destroy %s: Slab cache still has objects\n",
+				s->name);
+			dump_stack();
+		}
+	}
+	mutex_unlock(&slab_mutex);
+	put_online_cpus();
+}
+EXPORT_SYMBOL(kmem_cache_destroy);
+
 int slab_is_available(void)
 {
 	return slab_state >= UP;

mm/slab.c +3 ~~-52~~

75 lines not on this page · raw message

mm/slab.h +3 -0

Index: linux-2.6/mm/slab.h
===================================================================
@@ -30,4 +30,7 @@ extern struct list_head slab_caches;
 struct kmem_cache *__kmem_cache_create(const char *name, size_t size,
 	size_t align, unsigned long flags, void (*ctor)(void *));
 
+int __kmem_cache_shutdown(struct kmem_cache *);
+void __kmem_cache_destroy(struct kmem_cache *);
+
 #endif

mm/slob.c +7 -7

Index: linux-2.6/mm/slob.c
===================================================================
@@ -538,17 +538,11 @@ struct kmem_cache *__kmem_cache_create(c
 	return c;
 }
 
-void kmem_cache_destroy(struct kmem_cache *c)
+void __kmem_cache_destroy(struct kmem_cache *c)
 {
-	mutex_lock(&slab_mutex);
-	list_del(&c->list);
-	mutex_unlock(&slab_mutex);
 	kmemleak_free(c);
-	if (c->flags & SLAB_DESTROY_BY_RCU)
-		rcu_barrier();
 	slob_free(c, sizeof(struct kmem_cache));
 }
-EXPORT_SYMBOL(kmem_cache_destroy);
 
 void *kmem_cache_alloc_node(struct kmem_cache *c, gfp_t flags, int node)
 {

@@ -616,6 +610,12 @@ unsigned int kmem_cache_size(struct kmem
 }
 EXPORT_SYMBOL(kmem_cache_size);
 
+int __kmem_cache_shutdown(struct kmem_cache *c)
+{
+	/* No way to check for remaining objects */
+	return 0;
+}
+
 int kmem_cache_shrink(struct kmem_cache *d)
 {
 	return 0;

mm/slub.c +10 ~~-24~~

Index: linux-2.6/mm/slub.c
===================================================================
@@ -624,7 +624,7 @@ static void object_err(struct kmem_cache
 	print_trailer(s, page, object);
 }
 
-static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...)
+static void slab_err(struct kmem_cache *s, struct page *page, const char *fmt, ...)
 {
 	va_list args;
 	char buf[100];

@@ -3139,7 +3139,7 @@ static void list_slab_objects(struct kme
 				     sizeof(long), GFP_ATOMIC);
 	if (!map)
 		return;
-	slab_err(s, page, "%s", text);
+	slab_err(s, page, text, s->name);
 	slab_lock(page);
 
 	get_map(s, page, map);

@@ -3171,7 +3171,7 @@ static void free_partial(struct kmem_cac
 			discard_slab(s, page);
 		} else {
 			list_slab_objects(s, page,
-				"Objects remaining on kmem_cache_close()");
+			"Objects remaining in %s on kmem_cache_close()");
 		}
 	}
 }

@@ -3197,29 +3197,15 @@ static inline int kmem_cache_close(struc
 	return 0;
 }
 
-/*
- * Close a cache and release the kmem_cache structure
- * (must be used for caches created using kmem_cache_create)
- */
-void kmem_cache_destroy(struct kmem_cache *s)
+int __kmem_cache_shutdown(struct kmem_cache *s)
 {
-	mutex_lock(&slab_mutex);
-	s->refcount--;
-	if (!s->refcount) {
-		list_del(&s->list);
-		mutex_unlock(&slab_mutex);
-		if (kmem_cache_close(s)) {
-			printk(KERN_ERR "SLUB %s: %s called for cache that "
-				"still has objects.\n", s->name, __func__);
-			dump_stack();
-		}
-		if (s->flags & SLAB_DESTROY_BY_RCU)
-			rcu_barrier();
-		sysfs_slab_remove(s);
-	} else
-		mutex_unlock(&slab_mutex);
+	return kmem_cache_close(s);
+}
+
+void __kmem_cache_destroy(struct kmem_cache *s)
+{
+	sysfs_slab_remove(s);
 }
-EXPORT_SYMBOL(kmem_cache_destroy);
 
 /********************************************************************
  *		Kmalloc subsystem

Glauber Costa

2012-08-09 09:59 UTC #20 lore raw

Re: Common11 [06/20] Extract a common function for kmem_cache_destroy

mm/slob.c struct kmem_cache *__kmem_cache_create(c · line 547

Quoted 8 lines · Christoph Lameter

mm/slob.c +1 -5

-void kmem_cache_destroy(struct kmem_cache *c)
+void __kmem_cache_destroy(struct kmem_cache *c)
 {
-	mutex_lock(&slab_mutex);
-	list_del(&c->list);
-	mutex_unlock(&slab_mutex);
 	kmemleak_free(c);
-	if (c->flags & SLAB_DESTROY_BY_RCU)

which tree are you based on?

These lines you are removing doesn't seem to exist on Pekka's, and are certainly not added in the previous patches. The patch fails to apply because of that.

As a matter of fact, this removal was not present in your earlier series.

For now I'll manually edit it.

Christoph Lameter (Open Source)

author

2012-08-09 13:57 UTC #21 lore raw

Re: Common11 [06/20] Extract a common function for kmem_cache_destroy

Quoted 3 lines · Glauber Costa

These lines you are removing doesn't seem to exist on Pekka's, and are certainly not added in the previous patches. The patch fails to apply because of that.

These lines were added by the previous patch as per Joonsoo's request.

Unrefreshed patches again. Sorry but there are numerous other things that require my attention at this point.

Christoph Lameter

author

2012-08-08 21:04 UTC #22 lore raw

Common11 [03/20] Rename oops label

In reply to Christoph Lameter

The label is actually used for successful exits so change the name. Easy to do now before more users of this label surface.

Signed-off-by Christoph Lameter <[email protected]>

mm/slab_common.c +2 -2

Index: linux-2.6/mm/slab_common.c
===================================================================
@@ -89,7 +89,7 @@
 				name);
 			dump_stack();
 			s = NULL;
-			goto oops;
+			goto out_locked;
 		}
 	}

@@ -99,7 +99,7 @@
 	s = __kmem_cache_create(name, size, align, flags, ctor);
 
 #ifdef CONFIG_DEBUG_VM
-oops:
+out_locked:
 #endif
 	mutex_unlock(&slab_mutex);
 	put_online_cpus();