xfs: use a separate slab cache for deferred xattr work state

Create a separate slab cache for struct xfs_attr_item objects, since we
can pack the (104-byte) intent items more tightly than we can with the
general slab cache objects.  On x86, this means 39 intents per memory
page instead of 32.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NAllison Henderson <allison.henderson@oracle.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

fs/xfs/libxfs/xfs_attr.c

@@ -29,6 +29,7 @@
 
 struct kmem_cache		*xfs_attri_cache;
 struct kmem_cache		*xfs_attrd_cache;
+struct kmem_cache		*xfs_attr_intent_cache;
 
 /*
  * xfs_attr.c
@@ -902,7 +903,7 @@ xfs_attr_item_init(
 
 	struct xfs_attr_item	*new;
 
-	new = kmem_zalloc(sizeof(struct xfs_attr_item), KM_NOFS);
+	new = kmem_cache_zalloc(xfs_attr_intent_cache, GFP_NOFS | __GFP_NOFAIL);
 	new->xattri_op_flags = op_flags;
 	new->xattri_da_args = args;
 
@@ -1650,3 +1651,20 @@ xfs_attr_namecheck(
 	/* There shouldn't be any nulls here */
 	return !memchr(name, 0, length);
 }
+
+int __init
+xfs_attr_intent_init_cache(void)
+{
+	xfs_attr_intent_cache = kmem_cache_create("xfs_attr_item",
+			sizeof(struct xfs_attr_item),
+			0, 0, NULL);
+
+	return xfs_attr_intent_cache != NULL ? 0 : -ENOMEM;
+}
+
+void
+xfs_attr_intent_destroy_cache(void)
+{
+	kmem_cache_destroy(xfs_attr_intent_cache);
+	xfs_attr_intent_cache = NULL;
+}

fs/xfs/libxfs/xfs_attr.h

@@ -634,4 +634,8 @@ xfs_attr_init_replace_state(struct xfs_da_args *args)
 	return xfs_attr_init_add_state(args);
 }
 
+extern struct kmem_cache *xfs_attr_intent_cache;
+int __init xfs_attr_intent_init_cache(void);
+void xfs_attr_intent_destroy_cache(void);
+
 #endif	/* __XFS_ATTR_H__ */

fs/xfs/libxfs/xfs_defer.c

@@ -877,6 +877,9 @@ xfs_defer_init_item_caches(void)
 	if (error)
 		goto err;
 	error = xfs_attrd_init_cache();
+	if (error)
+		goto err;
+	error = xfs_attr_intent_init_cache();
 	if (error)
 		goto err;
 	return 0;
@@ -889,6 +892,7 @@ xfs_defer_init_item_caches(void)
 void
 xfs_defer_destroy_item_caches(void)
 {
+	xfs_attr_intent_destroy_cache();
 	xfs_attri_destroy_cache();
 	xfs_attrd_destroy_cache();
 	xfs_extfree_intent_destroy_cache();

fs/xfs/xfs_attr_item.c

@@ -404,7 +404,10 @@ xfs_attr_free_item(
 {
 	if (attr->xattri_da_state)
 		xfs_da_state_free(attr->xattri_da_state);
-	kmem_free(attr);
+	if (attr->xattri_da_args->op_flags & XFS_DA_OP_RECOVERY)
+		kmem_free(attr);
+	else
+		kmem_cache_free(xfs_attr_intent_cache, attr);
 }
 
 /* Process an attr. */