Implement per-cpu local caches. This seems to have bough me another

factor of 10x improvement on SMP system due to reduced lock contention.
This may put me in the ballpark of what is needed.  We can still further
improve things on NUMA systems by creating an additional L3 cache per 
memory node instead of the current global pool.  With luck this won't
be needed.  I should also take another look at the locking now that
everything is working.  There's a good chance I can tighten it up a
little bit and improve things a little more.

   kmem_lock: time (sec)        slabs           objs            hash
   kmem_lock:                   tot/max/calc    tot/max/calc    size/depth
   kmem_lock:  0.000999926      6/6/1           192/192/32      32768/0
   kmem_lock:  0.000999926      4/4/2           128/128/64      32768/0
   kmem_lock:  0.000999926      4/4/4           128/128/128     32768/0
   kmem_lock:  0.000999926      4/4/8           128/128/256     32768/0
   kmem_lock:  0.000999926      4/4/16          128/128/512     32768/0
   kmem_lock:  0.000999926      4/4/32          128/128/1024    32768/0
   kmem_lock:  0.000999926      4/4/64          128/128/2048    32768/0
   kmem_lock:  0.000999926      8/8/128         256/256/4096    32768/0
   kmem_lock:  0.003999704      24/23/256       768/736/8192    32768/1
   kmem_lock:  0.012999038      44/41/512       1408/1312/16384 32768/1
   kmem_lock:  0.051996153      96/93/1024      3072/2976/32768 32768/2
   kmem_lock:  0.181986536      187/184/2048    5984/5888/65536 32768/3
   kmem_lock:  0.655951469      342/339/4096    10944/10848/131072 32768/4



git-svn-id: https://outreach.scidac.gov/svn/spl/trunk@136 7e1ea52c-4ff2-0310-8f11-9dd32ca42a1c

5 files changed, 404 insertions, 146 deletions

diff --git a/include/sys/kmem.h b/include/sys/kmem.h
index fb0c22e3a..25269335d 100644
--- a/include/sys/kmem.h
+++ b/include/sys/kmem.h
@@ -360,6 +360,7 @@ kmem_debugging(void)
 extern int kmem_set_warning(int flag);
 
 
+#define SKM_MAGIC			0x2e2e2e2e
 #define SKO_MAGIC			0x20202020
 #define SKS_MAGIC			0x22222222
 #define SKC_MAGIC			0x2c2c2c2c
@@ -376,6 +377,15 @@ typedef int (*spl_kmem_ctor_t)(void *, void *, int);
 typedef void (*spl_kmem_dtor_t)(void *, void *);
 typedef void (*spl_kmem_reclaim_t)(void *);
 
+typedef struct spl_kmem_magazine {
+        uint32_t		skm_magic;	/* Sanity magic */
+	uint32_t		skm_avail;	/* Available objects */
+	uint32_t		skm_size;	/* Magazine size */
+	uint32_t		skm_refill;	/* Batch refill size */
+	unsigned long		skm_age;	/* Last cache access */
+	void			*skm_objs[0];	/* Object pointers */
+} spl_kmem_magazine_t;
+
 typedef struct spl_kmem_obj {
         uint32_t		sko_magic;	/* Sanity magic */
 	uint32_t		sko_flags;	/* Per object flags */
@@ -392,13 +402,16 @@ typedef struct spl_kmem_slab {
 	struct list_head	sks_list;	/* Slab list linkage */
 	struct list_head	sks_free_list;	/* Free object list */
 	unsigned long		sks_age;	/* Last modify jiffie */
-	atomic_t		sks_ref;	/* Ref count used objects */
+	uint32_t		sks_ref;	/* Ref count used objects */
 } spl_kmem_slab_t;
 
 typedef struct spl_kmem_cache {
         uint32_t		skc_magic;	/* Sanity magic */
         uint32_t		skc_name_size;	/* Name length */
         char			*skc_name;	/* Name string */
+	spl_kmem_magazine_t	*skc_mag[NR_CPUS]; /* Per-CPU warm cache */
+	uint32_t		skc_mag_size;	/* Magazine size */
+	uint32_t		skc_mag_refill;	/* Magazine refill count */
         spl_kmem_ctor_t		skc_ctor;	/* Constructor */
         spl_kmem_dtor_t		skc_dtor;	/* Destructor */
         spl_kmem_reclaim_t      skc_reclaim;	/* Reclaimator */
@@ -427,8 +440,8 @@ typedef struct spl_kmem_cache {
 	uint64_t		skc_obj_total;	/* Obj total current */
 	uint64_t		skc_obj_alloc;	/* Obj alloc current */
 	uint64_t		skc_obj_max;	/* Obj max historic */
-	uint64_t		skc_hash_depth;	/* Hash depth */
-	uint64_t		skc_hash_max;	/* Hash depth max */
+	uint64_t		skc_hash_depth;	/* Lazy hash depth */
+	uint64_t		skc_hash_count;	/* Hash entries current */
 } spl_kmem_cache_t;
 
 extern spl_kmem_cache_t *
diff --git a/modules/spl/spl-kmem.c b/modules/spl/spl-kmem.c
index ec12aca21..708b01cc5 100644
--- a/modules/spl/spl-kmem.c
+++ b/modules/spl/spl-kmem.c
@@ -109,13 +109,10 @@ EXPORT_SYMBOL(kmem_set_warning);
  * small virtual address space on 32bit arches.  This will seriously
  * constrain the size of the slab caches and their performance.
  *
- * XXX: Refactor the below code in to smaller functions.  This works
- *      for a first pass but each function is doing to much.
- *
  * XXX: Implement SPL proc interface to export full per cache stats.
  *
  * XXX: Implement work requests to keep an eye on each cache and
- *      shrink them via slab_reclaim() when they are wasting lots
+ *      shrink them via spl_slab_reclaim() when they are wasting lots
  *      of space.  Currently this process is driven by the reapers.
  *
  * XXX: Implement proper small cache object support by embedding
@@ -138,6 +135,8 @@ EXPORT_SYMBOL(kmem_set_warning);
  *
  * XXX: Slab coloring may also yield performance improvements and would
  *      be desirable to implement.
+ *
+ * XXX: Proper hardware cache alignment would be good too.
  */
 
 /* Ensure the __kmem_cache_create/__kmem_cache_destroy macros are
@@ -155,18 +154,22 @@ static struct rw_semaphore spl_kmem_cache_sem;	/* Cache list lock */
 static kmem_cache_t *spl_slab_cache;		/* Cache for slab structs */
 static kmem_cache_t *spl_obj_cache;		/* Cache for obj structs */
 
+static int spl_cache_flush(spl_kmem_cache_t *skc,
+			   spl_kmem_magazine_t *skm, int flush);
+
 #ifdef HAVE_SET_SHRINKER
 static struct shrinker *spl_kmem_cache_shrinker;
 #else
-static int kmem_cache_generic_shrinker(int nr_to_scan, unsigned int gfp_mask);
+static int spl_kmem_cache_generic_shrinker(int nr_to_scan,
+					   unsigned int gfp_mask);
 static struct shrinker spl_kmem_cache_shrinker = {
-	.shrink = kmem_cache_generic_shrinker,
+	.shrink = spl_kmem_cache_generic_shrinker,
 	.seeks = KMC_DEFAULT_SEEKS,
 };
 #endif
 
 static spl_kmem_slab_t *
-slab_alloc(spl_kmem_cache_t *skc, int flags) {
+spl_slab_alloc(spl_kmem_cache_t *skc, int flags) {
 	spl_kmem_slab_t *sks;
 	spl_kmem_obj_t *sko, *n;
 	int i;
@@ -182,7 +185,7 @@ slab_alloc(spl_kmem_cache_t *skc, int flags) {
 	sks->sks_cache = skc;
 	INIT_LIST_HEAD(&sks->sks_list);
 	INIT_LIST_HEAD(&sks->sks_free_list);
-	atomic_set(&sks->sks_ref, 0);
+	sks->sks_ref = 0;
 
 	for (i = 0; i < sks->sks_objs; i++) {
 		sko = kmem_cache_alloc(spl_obj_cache, flags);
@@ -224,21 +227,19 @@ out:
  * be called with the 'skc->skc_lock' held.
  *                         */
 static void
-slab_free(spl_kmem_slab_t *sks) {
+spl_slab_free(spl_kmem_slab_t *sks) {
 	spl_kmem_cache_t *skc;
 	spl_kmem_obj_t *sko, *n;
 	int i = 0;
 	ENTRY;
 
 	ASSERT(sks->sks_magic == SKS_MAGIC);
-	ASSERT(atomic_read(&sks->sks_ref) == 0);
+	ASSERT(sks->sks_ref == 0);
 	skc = sks->sks_cache;
 	skc->skc_obj_total -= sks->sks_objs;
 	skc->skc_slab_total--;
 
-//#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
 	ASSERT(spin_is_locked(&skc->skc_lock));
-//#endif
 
 	list_for_each_entry_safe(sko, n, &sks->sks_free_list, sko_list) {
 		ASSERT(sko->sko_magic == SKO_MAGIC);
@@ -261,15 +262,13 @@ slab_free(spl_kmem_slab_t *sks) {
 }
 
 static int
-__slab_reclaim(spl_kmem_cache_t *skc)
+__spl_slab_reclaim(spl_kmem_cache_t *skc)
 {
 	spl_kmem_slab_t *sks, *m;
 	int rc = 0;
 	ENTRY;
 
-//#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
 	ASSERT(spin_is_locked(&skc->skc_lock));
-//#endif
 	/*
 	 * Free empty slabs which have not been touched in skc_delay
 	 * seconds.  This delay time is important to avoid thrashing.
@@ -277,11 +276,11 @@ __slab_reclaim(spl_kmem_cache_t *skc)
 	 */
         list_for_each_entry_safe_reverse(sks, m, &skc->skc_partial_list,
 					 sks_list) {
-		if (atomic_read(&sks->sks_ref) > 0)
+		if (sks->sks_ref > 0)
 		       break;
 
 		if (time_after(jiffies, sks->sks_age + skc->skc_delay * HZ)) {
-			slab_free(sks);
+			spl_slab_free(sks);
 			rc++;
 		}
 	}
@@ -291,18 +290,110 @@ __slab_reclaim(spl_kmem_cache_t *skc)
 }
 
 static int
-slab_reclaim(spl_kmem_cache_t *skc)
+spl_slab_reclaim(spl_kmem_cache_t *skc)
 {
 	int rc;
 	ENTRY;
 
 	spin_lock(&skc->skc_lock);
-	rc = __slab_reclaim(skc);
+	rc = __spl_slab_reclaim(skc);
 	spin_unlock(&skc->skc_lock);
 
 	RETURN(rc);
 }
 
+static int
+spl_magazine_size(spl_kmem_cache_t *skc)
+{
+	int size;
+	ENTRY;
+
+	/* Guesses for reasonable magazine sizes, they
+	 * should really adapt based on observed usage. */
+	if (skc->skc_obj_size > (PAGE_SIZE * 256))
+		size = 1;
+	else if (skc->skc_obj_size > (PAGE_SIZE * 32))
+		size = 4;
+	else if (skc->skc_obj_size > (PAGE_SIZE))
+		size = 16;
+	else if (skc->skc_obj_size > (PAGE_SIZE / 4))
+		size = 32;
+	else if (skc->skc_obj_size > (PAGE_SIZE / 16))
+		size = 64;
+	else
+		size = 128;
+
+	RETURN(size);
+}
+
+static spl_kmem_magazine_t *
+spl_magazine_alloc(spl_kmem_cache_t *skc, int node)
+{
+	spl_kmem_magazine_t *skm;
+	int size = sizeof(spl_kmem_magazine_t) +
+	           sizeof(void *) * skc->skc_mag_size;
+	ENTRY;
+
+	skm = kmalloc_node(size, GFP_KERNEL, node);
+	if (skm) {
+		skm->skm_magic = SKM_MAGIC;
+		skm->skm_avail = 0;
+		skm->skm_size = skc->skc_mag_size;
+		skm->skm_refill = skc->skc_mag_refill;
+		skm->skm_age = jiffies;
+	}
+
+	RETURN(skm);
+}
+
+static void
+spl_magazine_free(spl_kmem_magazine_t *skm)
+{
+	ENTRY;
+	ASSERT(skm->skm_magic == SKM_MAGIC);
+	ASSERT(skm->skm_avail == 0);
+	kfree(skm);
+	EXIT;
+}
+
+static int
+spl_magazine_create(spl_kmem_cache_t *skc)
+{
+	int i;
+	ENTRY;
+
+	skc->skc_mag_size = spl_magazine_size(skc);
+	skc->skc_mag_refill = (skc->skc_mag_size + 1)  / 2;
+
+	for_each_online_cpu(i) {
+		skc->skc_mag[i] = spl_magazine_alloc(skc, cpu_to_node(i));
+		if (!skc->skc_mag[i]) {
+			for (i--; i >= 0; i--)
+				spl_magazine_free(skc->skc_mag[i]);
+
+			RETURN(-ENOMEM);
+		}
+	}
+
+	RETURN(0);
+}
+
+static void
+spl_magazine_destroy(spl_kmem_cache_t *skc)
+{
+        spl_kmem_magazine_t *skm;
+	int i;
+	ENTRY;
+
+	for_each_online_cpu(i) {
+		skm = skc->skc_mag[i];
+		(void)spl_cache_flush(skc, skm, skm->skm_avail);
+		spl_magazine_free(skm);
+	}
+
+	EXIT;
+}
+
 spl_kmem_cache_t *
 spl_kmem_cache_create(char *name, size_t size, size_t align,
                       spl_kmem_ctor_t ctor,
@@ -311,7 +402,7 @@ spl_kmem_cache_create(char *name, size_t size, size_t align,
                       void *priv, void *vmp, int flags)
 {
         spl_kmem_cache_t *skc;
-	int i, kmem_flags = KM_SLEEP;
+	int i, rc, kmem_flags = KM_SLEEP;
 	ENTRY;
 
         /* We may be called when there is a non-zero preempt_count or
@@ -326,7 +417,6 @@ spl_kmem_cache_create(char *name, size_t size, size_t align,
 		RETURN(NULL);
 
 	skc->skc_magic = SKC_MAGIC;
-
 	skc->skc_name_size = strlen(name) + 1;
 	skc->skc_name = (char *)kmem_alloc(skc->skc_name_size, kmem_flags);
 	if (skc->skc_name == NULL) {
@@ -355,6 +445,7 @@ spl_kmem_cache_create(char *name, size_t size, size_t align,
 	if (skc->skc_hash == NULL) {
 		kmem_free(skc->skc_name, skc->skc_name_size);
 		kmem_free(skc, sizeof(*skc));
+		RETURN(NULL);
 	}
 
 	for (i = 0; i < skc->skc_hash_elts; i++)
@@ -374,7 +465,15 @@ spl_kmem_cache_create(char *name, size_t size, size_t align,
 	skc->skc_obj_alloc = 0;
 	skc->skc_obj_max = 0;
 	skc->skc_hash_depth = 0;
-	skc->skc_hash_max = 0;
+	skc->skc_hash_count = 0;
+
+	rc = spl_magazine_create(skc);
+	if (rc) {
+		kmem_free(skc->skc_hash, skc->skc_hash_size);
+		kmem_free(skc->skc_name, skc->skc_name_size);
+		kmem_free(skc, sizeof(*skc));
+		RETURN(NULL);
+	}
 
 	down_write(&spl_kmem_cache_sem);
         list_add_tail(&skc->skc_list, &spl_kmem_cache_list);
@@ -385,8 +484,7 @@ spl_kmem_cache_create(char *name, size_t size, size_t align,
 EXPORT_SYMBOL(spl_kmem_cache_create);
 
 /* The caller must ensure there are no racing calls to
- * spl_kmem_cache_alloc() for this spl_kmem_cache_t when
- * it is being destroyed.
+ * spl_kmem_cache_alloc() for this spl_kmem_cache_t.
  */
 void
 spl_kmem_cache_destroy(spl_kmem_cache_t *skc)
@@ -398,20 +496,22 @@ spl_kmem_cache_destroy(spl_kmem_cache_t *skc)
         list_del_init(&skc->skc_list);
         up_write(&spl_kmem_cache_sem);
 
+	spl_magazine_destroy(skc);
 	spin_lock(&skc->skc_lock);
 
 	/* Validate there are no objects in use and free all the
-	 * spl_kmem_slab_t, spl_kmem_obj_t, and object buffers.
-	 */
+	 * spl_kmem_slab_t, spl_kmem_obj_t, and object buffers. */
 	ASSERT(list_empty(&skc->skc_complete_list));
+	ASSERTF(skc->skc_hash_count == 0, "skc->skc_hash_count=%d\n",
+		skc->skc_hash_count);
 
         list_for_each_entry_safe(sks, m, &skc->skc_partial_list, sks_list)
-		slab_free(sks);
+		spl_slab_free(sks);
 
 	kmem_free(skc->skc_hash, skc->skc_hash_size);
 	kmem_free(skc->skc_name, skc->skc_name_size);
-	kmem_free(skc, sizeof(*skc));
 	spin_unlock(&skc->skc_lock);
+	kmem_free(skc, sizeof(*skc));
 
 	EXIT;
 }
@@ -427,88 +527,92 @@ spl_hash_ptr(void *ptr, unsigned int bits)
 	return hash_long((unsigned long)ptr >> PAGE_SHIFT, bits);
 }
 
-#ifndef list_first_entry
-#define list_first_entry(ptr, type, member) \
-	        list_entry((ptr)->next, type, member)
-#endif
+static spl_kmem_obj_t *
+spl_hash_obj(spl_kmem_cache_t *skc, void *obj)
+{
+        struct hlist_node *node;
+	spl_kmem_obj_t *sko = NULL;
+	unsigned long key = spl_hash_ptr(obj, skc->skc_hash_bits);
+	int i = 0;
 
-void *
-spl_kmem_cache_alloc(spl_kmem_cache_t *skc, int flags)
+	ASSERT(spin_is_locked(&skc->skc_lock));
+
+        hlist_for_each_entry(sko, node, &skc->skc_hash[key], sko_hlist) {
+
+		if (unlikely((++i) > skc->skc_hash_depth))
+			skc->skc_hash_depth = i;
+
+                if (sko->sko_addr == obj) {
+			ASSERT(sko->sko_magic == SKO_MAGIC);
+			RETURN(sko);
+		}
+	}
+
+	RETURN(NULL);
+}
+
+static void *
+spl_cache_obj(spl_kmem_cache_t *skc, spl_kmem_slab_t *sks)
 {
-        spl_kmem_slab_t *sks;
 	spl_kmem_obj_t *sko;
-	void *obj;
 	unsigned long key;
-	ENTRY;
 
-	spin_lock(&skc->skc_lock);
-restart:
-	/* Check for available objects from the partial slabs */
-	if (!list_empty(&skc->skc_partial_list)) {
-		sks = list_first_entry(&skc->skc_partial_list,
-		                       spl_kmem_slab_t, sks_list);
-		ASSERT(sks->sks_magic == SKS_MAGIC);
-		ASSERT(atomic_read(&sks->sks_ref) < sks->sks_objs);
-		ASSERT(!list_empty(&sks->sks_free_list));
-
-		sko = list_first_entry(&sks->sks_free_list,
-		                       spl_kmem_obj_t, sko_list);
-		ASSERT(sko->sko_magic == SKO_MAGIC);
-		ASSERT(sko->sko_addr != NULL);
+	ASSERT(spin_is_locked(&skc->skc_lock));
 
-		/* Remove from sks_free_list, add to used hash */
-		list_del_init(&sko->sko_list);
-		key = spl_hash_ptr(sko->sko_addr, skc->skc_hash_bits);
-		hlist_add_head(&sko->sko_hlist, &skc->skc_hash[key]);
+	sko = list_entry((&sks->sks_free_list)->next,spl_kmem_obj_t,sko_list);
+	ASSERT(sko->sko_magic == SKO_MAGIC);
+	ASSERT(sko->sko_addr != NULL);
 
-		sks->sks_age = jiffies;
-		atomic_inc(&sks->sks_ref);
-		skc->skc_obj_alloc++;
+	/* Remove from sks_free_list and add to used hash */
+	list_del_init(&sko->sko_list);
+	key = spl_hash_ptr(sko->sko_addr, skc->skc_hash_bits);
+	hlist_add_head(&sko->sko_hlist, &skc->skc_hash[key]);
 
-		if (skc->skc_obj_alloc > skc->skc_obj_max)
-			skc->skc_obj_max = skc->skc_obj_alloc;
+	sks->sks_age = jiffies;
+	sks->sks_ref++;
+	skc->skc_obj_alloc++;
+	skc->skc_hash_count++;
 
-		if (atomic_read(&sks->sks_ref) == 1) {
-			skc->skc_slab_alloc++;
+	/* Track max obj usage statistics */
+	if (skc->skc_obj_alloc > skc->skc_obj_max)
+		skc->skc_obj_max = skc->skc_obj_alloc;
 
-			if (skc->skc_slab_alloc > skc->skc_slab_max)
-				skc->skc_slab_max = skc->skc_slab_alloc;
-		}
+	/* Track max slab usage statistics */
+	if (sks->sks_ref == 1) {
+		skc->skc_slab_alloc++;
 
-		/* Move slab to skc_complete_list when full */
-		if (atomic_read(&sks->sks_ref) == sks->sks_objs) {
-			list_del(&sks->sks_list);
-			list_add(&sks->sks_list, &skc->skc_complete_list);
-		}
-
-		GOTO(out_lock, obj = sko->sko_addr);
+		if (skc->skc_slab_alloc > skc->skc_slab_max)
+			skc->skc_slab_max = skc->skc_slab_alloc;
 	}
 
-	spin_unlock(&skc->skc_lock);
-
-	/* No available objects create a new slab.  Since this is an
-	 * expensive operation we do it without holding the semaphore
-	 * and only briefly aquire it when we link in the fully
-	 * allocated and constructed slab.
-	 */
+	return sko->sko_addr;
+}
 
-	/* Under Solaris if the KM_SLEEP flag is passed we may never
-	 * fail, so sleep as long as needed.  Additionally, since we are
-	 * using vmem_alloc() KM_NOSLEEP is not an option and we must
-	 * fail.  Shifting to allocating our own pages and mapping the
-	 * virtual address space may allow us to bypass this issue.
-	 */
-	if (!flags)
-		flags |= KM_SLEEP;
+/* No available objects create a new slab.  Since this is an
+ * expensive operation we do it without holding the spinlock
+ * and only briefly aquire it when we link in the fully
+ * allocated and constructed slab.
+ */
+static spl_kmem_slab_t *
+spl_cache_grow(spl_kmem_cache_t *skc, int flags)
+{
+        spl_kmem_slab_t *sks;
+	spl_kmem_obj_t *sko;
+	ENTRY;
 
-	if (flags & KM_SLEEP)
+        if (flags & __GFP_WAIT) {
 		flags |= __GFP_NOFAIL;
-	else
-		GOTO(out, obj = NULL);
+		might_sleep();
+		local_irq_enable();
+	}
 
-	sks = slab_alloc(skc, flags);
-	if (sks == NULL)
-		GOTO(out, obj = NULL);
+	sks = spl_slab_alloc(skc, flags);
+	if (sks == NULL) {
+	        if (flags & __GFP_WAIT)
+			local_irq_disable();
+
+		RETURN(NULL);
+	}
 
 	/* Run all the constructors now that the slab is fully allocated */
 	list_for_each_entry(sko, &sks->sks_free_list, sko_list) {
@@ -518,81 +622,205 @@ restart:
 			skc->skc_ctor(sko->sko_addr, skc->skc_private, flags);
 	}
 
-	/* Link the newly created slab in to the skc_partial_list,
-	 * and retry the allocation which will now succeed.
-	 */
+        if (flags & __GFP_WAIT)
+		local_irq_disable();
+
+	/* Link the new empty slab in to the end of skc_partial_list */
 	spin_lock(&skc->skc_lock);
 	skc->skc_slab_total++;
 	skc->skc_obj_total += sks->sks_objs;
 	list_add_tail(&sks->sks_list, &skc->skc_partial_list);
-	GOTO(restart, obj = NULL);
-
-out_lock:
 	spin_unlock(&skc->skc_lock);
-out:
-	RETURN(obj);
+
+	RETURN(sks);
 }
-EXPORT_SYMBOL(spl_kmem_cache_alloc);
 
-void
-spl_kmem_cache_free(spl_kmem_cache_t *skc, void *obj)
+static int
+spl_cache_refill(spl_kmem_cache_t *skc, spl_kmem_magazine_t *skm, int flags)
 {
-        struct hlist_node *node;
-        spl_kmem_slab_t *sks = NULL;
-	spl_kmem_obj_t *sko = NULL;
-	unsigned long key = spl_hash_ptr(obj, skc->skc_hash_bits);
-	int i = 0;
+        spl_kmem_slab_t *sks;
+	int refill = skm->skm_refill;
 	ENTRY;
 
+	/* XXX: Check for refill bouncing by age perhaps */
+
 	spin_lock(&skc->skc_lock);
+	while (refill > 0) {
+		/* No slabs available we must grow the cache */
+		if (list_empty(&skc->skc_partial_list)) {
+			spin_unlock(&skc->skc_lock);
+			sks = spl_cache_grow(skc, flags);
+			if (!sks)
+				GOTO(out, refill);
+
+			/* Rescheduled to different CPU skm is not local */
+			if (skm != skc->skc_mag[smp_processor_id()])
+				GOTO(out, refill);
+
+			spin_lock(&skc->skc_lock);
+			continue;
+		}
 
-        hlist_for_each_entry(sko, node, &skc->skc_hash[key], sko_hlist) {
+		/* Grab the next available slab */
+		sks = list_entry((&skc->skc_partial_list)->next,
+		                 spl_kmem_slab_t, sks_list);
+		ASSERT(sks->sks_magic == SKS_MAGIC);
+		ASSERT(sks->sks_ref < sks->sks_objs);
+		ASSERT(!list_empty(&sks->sks_free_list));
 
-		if (unlikely((++i) > skc->skc_hash_depth))
-			skc->skc_hash_depth = i;
+		/* Consume as many objects as needed to refill the requested
+		 * cache.  We must be careful to lock here because our local
+		 * magazine may not be local anymore due to spl_cache_grow. */
+		while ((sks->sks_ref < sks->sks_objs) && (refill-- > 0))
+			skm->skm_objs[skm->skm_avail++]=spl_cache_obj(skc,sks);
 
-                if (sko->sko_addr == obj) {
-			ASSERT(sko->sko_magic == SKO_MAGIC);
-			sks = sko->sko_slab;
-			break;
+		/* Move slab to skc_complete_list when full */
+		if (sks->sks_ref == sks->sks_objs) {
+			list_del(&sks->sks_list);
+			list_add(&sks->sks_list, &skc->skc_complete_list);
 		}
 	}
 
-	ASSERT(sko != NULL); /* Obj must be in hash */
-	ASSERT(sks != NULL); /* Obj must reference slab */
+	spin_unlock(&skc->skc_lock);
+out:
+	/* Returns the number of entries added to cache */
+	RETURN(skm->skm_refill - refill);
+}
+
+static void
+spl_cache_shrink(spl_kmem_cache_t *skc, void *obj)
+{
+        spl_kmem_slab_t *sks = NULL;
+	spl_kmem_obj_t *sko = NULL;
+	ENTRY;
+
+	ASSERT(spin_is_locked(&skc->skc_lock));
+
+	sko = spl_hash_obj(skc, obj);
+	ASSERTF(sko, "Obj %p missing from in-use hash (%d) for cache %s\n",
+	        obj, skc->skc_hash_count, skc->skc_name);
+
+	sks = sko->sko_slab;
+	ASSERTF(sks, "Obj %p/%p linked to invalid slab for cache %s\n",
+		obj, sko, skc->skc_name);
+
 	ASSERT(sks->sks_cache == skc);
 	hlist_del_init(&sko->sko_hlist);
 	list_add(&sko->sko_list, &sks->sks_free_list);
 
 	sks->sks_age = jiffies;
-	atomic_dec(&sks->sks_ref);
+	sks->sks_ref--;
 	skc->skc_obj_alloc--;
+	skc->skc_hash_count--;
 
 	/* Move slab to skc_partial_list when no longer full.  Slabs
-	 * are added to the kead to keep the partial list is quasi
-	 * full sorted order.  Fuller at the head, emptier at the tail.
-	 */
-	if (atomic_read(&sks->sks_ref) == (sks->sks_objs - 1)) {
+	 * are added to the head to keep the partial list is quasi-full
+	 * sorted order.  Fuller at the head, emptier at the tail. */
+	if (sks->sks_ref == (sks->sks_objs - 1)) {
 		list_del(&sks->sks_list);
 		list_add(&sks->sks_list, &skc->skc_partial_list);
 	}
 
 	/* Move emply slabs to the end of the partial list so
-	 * they can be easily found and freed during reclamation.
-	 */
-	if (atomic_read(&sks->sks_ref) == 0) {
+	 * they can be easily found and freed during reclamation. */
+	if (sks->sks_ref == 0) {
 		list_del(&sks->sks_list);
 		list_add_tail(&sks->sks_list, &skc->skc_partial_list);
 		skc->skc_slab_alloc--;
 	}
 
-	__slab_reclaim(skc);
+	EXIT;
+}
+
+static int
+spl_cache_flush(spl_kmem_cache_t *skc, spl_kmem_magazine_t *skm, int flush)
+{
+	int i, count = MIN(flush, skm->skm_avail);
+	ENTRY;
+
+
+	spin_lock(&skc->skc_lock);
+	for (i = 0; i < count; i++)
+		spl_cache_shrink(skc, skm->skm_objs[i]);
+
+	__spl_slab_reclaim(skc);
+        skm->skm_avail -= count;
+        memmove(skm->skm_objs, &(skm->skm_objs[count]),
+	        sizeof(void *) * skm->skm_avail);
+
 	spin_unlock(&skc->skc_lock);
+
+	RETURN(count);
+}
+
+void *
+spl_kmem_cache_alloc(spl_kmem_cache_t *skc, int flags)
+{
+	spl_kmem_magazine_t *skm;
+	unsigned long irq_flags;
+	void *obj = NULL;
+	ENTRY;
+
+	ASSERT(flags & KM_SLEEP);
+	local_irq_save(irq_flags);
+
+restart:
+	/* Safe to update per-cpu structure without lock, but
+	 * in the restart case we must be careful to reaquire
+	 * the local magazine since this may have changed
+	 * when we need to grow the cache. */
+	skm = skc->skc_mag[smp_processor_id()];
+
+	if (likely(skm->skm_avail)) {
+		/* Object available in CPU cache, use it */
+		obj = skm->skm_objs[--skm->skm_avail];
+		skm->skm_age = jiffies;
+	} else {
+		/* Per-CPU cache empty, directly allocate from
+		 * the slab and refill the per-CPU cache. */
+		(void)spl_cache_refill(skc, skm, flags);
+		GOTO(restart, obj = NULL);
+	}
+
+	local_irq_restore(irq_flags);
+
+	/* Pre-emptively migrate object to CPU L1 cache */
+	prefetchw(obj);
+
+	RETURN(obj);
+}
+EXPORT_SYMBOL(spl_kmem_cache_alloc);
+
+void
+spl_kmem_cache_free(spl_kmem_cache_t *skc, void *obj)
+{
+	spl_kmem_magazine_t *skm;
+	unsigned long flags;
+	ENTRY;
+
+	local_irq_save(flags);
+
+	/* Safe to update per-cpu structure without lock, but
+	 * no remote memory allocation tracking is being performed
+	 * it is entirely possible to allocate an object from one
+	 * CPU cache and return it to another. */
+	skm = skc->skc_mag[smp_processor_id()];
+
+	/* Per-CPU cache full, flush it to make space */
+	if (unlikely(skm->skm_avail >= skm->skm_size))
+		(void)spl_cache_flush(skc, skm, skm->skm_refill);
+
+	/* Available space in cache, use it */
+	skm->skm_objs[skm->skm_avail++] = obj;
+
+	local_irq_restore(flags);
+
+	EXIT;
 }
 EXPORT_SYMBOL(spl_kmem_cache_free);
 
 static int
-kmem_cache_generic_shrinker(int nr_to_scan, unsigned int gfp_mask)
+spl_kmem_cache_generic_shrinker(int nr_to_scan, unsigned int gfp_mask)
 {
         spl_kmem_cache_t *skc;
 
@@ -619,13 +847,24 @@ kmem_cache_generic_shrinker(int nr_to_scan, unsigned int gfp_mask)
 void
 spl_kmem_cache_reap_now(spl_kmem_cache_t *skc)
 {
+	spl_kmem_magazine_t *skm;
+	int i;
 	ENTRY;
         ASSERT(skc && skc->skc_magic == SKC_MAGIC);
 
 	if (skc->skc_reclaim)
 		skc->skc_reclaim(skc->skc_private);
 
-	slab_reclaim(skc);
+	/* Ensure per-CPU caches which are idle gradually flush */
+	for_each_online_cpu(i) {
+		skm = skc->skc_mag[i];
+
+		if (time_after(jiffies, skm->skm_age + skc->skc_delay * HZ))
+			(void)spl_cache_flush(skc, skm, skm->skm_refill);
+	}
+
+	spl_slab_reclaim(skc);
+
 	EXIT;
 }
 EXPORT_SYMBOL(spl_kmem_cache_reap_now);
@@ -633,7 +872,7 @@ EXPORT_SYMBOL(spl_kmem_cache_reap_now);
 void
 spl_kmem_reap(void)
 {
-	kmem_cache_generic_shrinker(KMC_REAP_CHUNK, GFP_KERNEL);
+	spl_kmem_cache_generic_shrinker(KMC_REAP_CHUNK, GFP_KERNEL);
 }
 EXPORT_SYMBOL(spl_kmem_reap);
 
@@ -663,7 +902,7 @@ spl_kmem_init(void)
 
 #ifdef HAVE_SET_SHRINKER
 	spl_kmem_cache_shrinker = set_shrinker(KMC_DEFAULT_SEEKS,
-					       kmem_cache_generic_shrinker);
+					       spl_kmem_cache_generic_shrinker);
 	if (spl_kmem_cache_shrinker == NULL)
 		GOTO(out_cache, rc = -ENOMEM);
 #else
@@ -703,7 +942,7 @@ out_cache:
 
 #ifdef DEBUG_KMEM
 static char *
-sprintf_addr(kmem_debug_t *kd, char *str, int len, int min)
+spl_sprintf_addr(kmem_debug_t *kd, char *str, int len, int min)
 {
         int size = ((len - 1) < kd->kd_size) ? (len - 1) : kd->kd_size;
 	int i, flag = 1;
@@ -769,7 +1008,7 @@ spl_kmem_fini(void)
 	list_for_each_entry(kd, &kmem_list, kd_list)
 		CDEBUG(D_WARNING, "%p %-5d %-16s %s:%d\n",
 		       kd->kd_addr, kd->kd_size,
-		       sprintf_addr(kd, str, 17, 8),
+		       spl_sprintf_addr(kd, str, 17, 8),
 		       kd->kd_func, kd->kd_line);
 
 	spin_unlock_irqrestore(&kmem_lock, flags);
@@ -786,7 +1025,7 @@ spl_kmem_fini(void)
 	list_for_each_entry(kd, &vmem_list, kd_list)
 		CDEBUG(D_WARNING, "%p %-5d %-16s %s:%d\n",
 		       kd->kd_addr, kd->kd_size,
-		       sprintf_addr(kd, str, 17, 8),
+		       spl_sprintf_addr(kd, str, 17, 8),
 		       kd->kd_func, kd->kd_line);
 
 	spin_unlock_irqrestore(&vmem_lock, flags);
diff --git a/modules/spl/spl-proc.c b/modules/spl/spl-proc.c
index 927fe86d3..8ef1698dc 100644
--- a/modules/spl/spl-proc.c
+++ b/modules/spl/spl-proc.c
@@ -913,7 +913,9 @@ out:
 	if (rc) {
 		remove_proc_entry("kstat", proc_spl);
 		remove_proc_entry("kmem", proc_spl);
+#ifdef DEBUG_MUTEX
 	        remove_proc_entry("stats_per", proc_spl_mutex);
+#endif
 		remove_proc_entry("mutex", proc_spl);
 		remove_proc_entry("spl", NULL);
 #ifdef CONFIG_SYSCTL
@@ -933,7 +935,9 @@ proc_fini(void)
 #if defined(DEBUG_MUTEX) || defined(DEBUG_KMEM) || defined(DEBUG_KSTAT)
 	remove_proc_entry("kstat", proc_spl);
 	remove_proc_entry("kmem", proc_spl);
+#ifdef DEBUG_MUTEX
         remove_proc_entry("stats_per", proc_spl_mutex);
+#endif
 	remove_proc_entry("mutex", proc_spl);
 	remove_proc_entry("spl", NULL);
 #endif /* DEBUG_MUTEX || DEBUG_KMEM || DEBUG_KSTAT */
diff --git a/modules/spl/spl-vnode.c b/modules/spl/spl-vnode.c
index f6dbc00c3..678d94682 100644
--- a/modules/spl/spl-vnode.c
+++ b/modules/spl/spl-vnode.c
@@ -486,7 +486,7 @@ vn_getf(int fd)
 	spin_unlock(&vn_file_lock);
 
 	/* File was not yet opened create the object and setup */
-	fp = kmem_cache_alloc(vn_file_cache, 0);
+	fp = kmem_cache_alloc(vn_file_cache, KM_SLEEP);
 	if (fp == NULL)
 		GOTO(out, rc);
 
diff --git a/modules/splat/splat-kmem.c b/modules/splat/splat-kmem.c
index 51fa6f0ef..3f059aa22 100644
--- a/modules/splat/splat-kmem.c
+++ b/modules/splat/splat-kmem.c
@@ -525,6 +525,9 @@ splat_kmem_test8_thread(void *arg)
 
 	objs = vmem_zalloc(count * sizeof(void *), KM_SLEEP);
 	if (!objs) {
+		splat_vprint(kcp->kcp_file, SPLAT_KMEM_TEST8_NAME,
+	                     "Unable to alloc objp array for cache '%s'\n",
+		             kcp->kcp_cache->skc_name);
 		rc = -ENOMEM;
 		goto out;
 	}
@@ -533,14 +536,13 @@ splat_kmem_test8_thread(void *arg)
 		objs[i] = kmem_cache_alloc(kcp->kcp_cache, KM_SLEEP);
 		if (!objs[i]) {
 			splat_vprint(kcp->kcp_file, SPLAT_KMEM_TEST8_NAME,
-		                     "Unable to allocate from '%s'\n",
-			             SPLAT_KMEM_CACHE_NAME);
+		                     "Unable to allocate from cache '%s'\n",
+			             kcp->kcp_cache->skc_name);
 			rc = -ENOMEM;
-			goto out_free;
+			break;
 		}
 	}
 
-out_free:
 	for (i = 0; i < count; i++)
 		if (objs[i])
 			kmem_cache_free(kcp->kcp_cache, objs[i]);
@@ -578,6 +580,7 @@ splat_kmem_test8(struct file *file, void *arg)
 	kmem_cache_priv_t kcp;
 	kthread_t *thr;
 	struct timespec start, stop, delta;
+	char cache_name[16];
 	int alloc, i;
 
 	kcp.kcp_magic = SPLAT_KMEM_TEST_MAGIC;
@@ -588,7 +591,7 @@ splat_kmem_test8(struct file *file, void *arg)
         splat_vprint(file, SPLAT_KMEM_TEST8_NAME, "%s",
 	             "          \ttot/max/calc\ttot/max/calc\tsize/depth\n");
 
-	for (alloc = 64; alloc <= 4096; alloc *= 2) {
+	for (alloc = 1; alloc <= 4096; alloc *= 2) {
 		kcp.kcp_size = 256;
 		kcp.kcp_count = 0;
 		kcp.kcp_threads = 0;
@@ -597,9 +600,8 @@ splat_kmem_test8(struct file *file, void *arg)
 	        spin_lock_init(&kcp.kcp_lock);
 	        init_waitqueue_head(&kcp.kcp_waitq);
 
-
-		kcp.kcp_cache = kmem_cache_create(SPLAT_KMEM_CACHE_NAME,
-		                                  kcp.kcp_size, 0,
+		sprintf(cache_name, "%s-%d", SPLAT_KMEM_CACHE_NAME, alloc);
+		kcp.kcp_cache = kmem_cache_create(cache_name, kcp.kcp_size, 0,
 		                                  splat_kmem_cache_test_constructor,
 		                                  splat_kmem_cache_test_destructor,
 						  NULL, &kcp, NULL, 0);