[RFC v2 66/83] Super: Add file write item cache.

[Andiry Xu]

From: Andiry Xu <jix...@cs.ucsd.edu>

nova_file_write_item combines a file write item with a list head.
NOVA uses a linked list of file write items to describe a write operation.

Signed-off-by: Andiry Xu <jix...@cs.ucsd.edu>
---
 fs/nova/super.c | 43 ++++++++++++++++++++++++++++++++++++++++++-
 fs/nova/super.h |  3 +++
 2 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/fs/nova/super.c b/fs/nova/super.c
index 0847e57..9710be8 100644
--- a/fs/nova/super.c
+++ b/fs/nova/super.c
@@ -55,6 +55,7 @@ static const struct export_operations nova_export_ops;
 
 static struct kmem_cache *nova_inode_cachep;
 static struct kmem_cache *nova_range_node_cachep;
+static struct kmem_cache *nova_file_write_item_cachep;
 
 
 /* FIXME: should the following variable be one per NOVA instance? */
@@ -791,6 +792,21 @@ inline void nova_free_inode_node(struct super_block *sb,
        nova_free_range_node(node);
 }
 
+inline void nova_free_file_write_item(struct nova_file_write_item *item)
+{
+       kmem_cache_free(nova_file_write_item_cachep, item);
+}
+
+inline struct nova_file_write_item *
+nova_alloc_file_write_item(struct super_block *sb)
+{
+       struct nova_file_write_item *p;
+
+       p = (struct nova_file_write_item *)
+               kmem_cache_alloc(nova_file_write_item_cachep, GFP_NOFS);
+       return p;
+}
+
 inline struct nova_range_node *nova_alloc_range_node(struct super_block *sb)
 {
        struct nova_range_node *p;
@@ -849,6 +865,18 @@ static int __init init_rangenode_cache(void)
        return 0;
 }
 
+static int __init init_file_write_item_cache(void)
+{
+       nova_file_write_item_cachep = kmem_cache_create(
+                                       "nova_file_write_item_cache",
+                                       sizeof(struct nova_file_write_item),
+                                       0, (SLAB_RECLAIM_ACCOUNT |
+                                       SLAB_MEM_SPREAD), NULL);
+       if (nova_file_write_item_cachep == NULL)
+               return -ENOMEM;
+       return 0;
+}
+
 static int __init init_inodecache(void)
 {
        nova_inode_cachep = kmem_cache_create("nova_inode_cache",
@@ -875,6 +903,11 @@ static void destroy_rangenode_cache(void)
        kmem_cache_destroy(nova_range_node_cachep);
 }
 
+static void destroy_file_write_item_cache(void)
+{
+       kmem_cache_destroy(nova_file_write_item_cachep);
+}
+
 
 /*
  * the super block writes are all done "on the fly", so the
@@ -974,14 +1007,21 @@ static int __init init_nova_fs(void)
        if (rc)
                goto out1;
 
-       rc = register_filesystem(&nova_fs_type);
+       rc = init_file_write_item_cache();
        if (rc)
                goto out2;
 
+       rc = register_filesystem(&nova_fs_type);
+       if (rc)
+               goto out3;
+
 out:
        NOVA_END_TIMING(init_t, init_time);
        return rc;
 
+out3:
+       destroy_file_write_item_cache();
+
 out2:
        destroy_inodecache();
 
@@ -993,6 +1033,7 @@ static int __init init_nova_fs(void)
 static void __exit exit_nova_fs(void)
 {
        unregister_filesystem(&nova_fs_type);
+       destroy_file_write_item_cache();
        destroy_inodecache();
        destroy_rangenode_cache();
 }
diff --git a/fs/nova/super.h b/fs/nova/super.h
index 56a840e..bcf9548 100644
--- a/fs/nova/super.h
+++ b/fs/nova/super.h
@@ -160,8 +160,11 @@ static inline struct nova_super_block 
*nova_get_super(struct super_block *sb)
 extern void nova_error_mng(struct super_block *sb, const char *fmt, ...);
 extern struct nova_range_node *nova_alloc_range_node(struct super_block *sb);
 extern inline struct nova_range_node *nova_alloc_inode_node(struct super_block 
*sb);
+extern struct nova_file_write_item *
+nova_alloc_file_write_item(struct super_block *sb);
 extern void nova_free_range_node(struct nova_range_node *node);
 extern inline void nova_free_inode_node(struct super_block *sb,
        struct nova_range_node *node);
+void nova_free_file_write_item(struct nova_file_write_item *item);
 
 #endif
-- 
2.7.4