ipc: replace the IPC table with a radix tree

Currently, the port names are mapped to an IPC object (e.g. a port)
using a table.  This, however, requires large chunks of continuous
memory, and leads to scalability problems as virtual kernel memory is
a scarce resource.  To avoid excessive overhead, non-contiguous port
names are spilled into a splay tree.

Replace the IPC table with a radix tree.  As the radix tree is able to
store non-contiguous names with reasonable overhead, we can drop the
splay tree as well.

* ipc/ipc_entry.c (ipc_entry_tree_collision): Remove function.
(ipc_entry_cache): New variable.
(ipc_entry_lookup): Replace with a radix tree lookup.
(ipc_entry_get): The free list handling is changed a little.  Adopt
accordingly.
(ipc_entry_free_name): New function.
(ipc_entry_alloc): Adopt accordingly.
(ipc_entry_alloc_name): Likewise.
(ipc_entry_dealloc): Likewise.
(ipc_entry_grow_table): Remove function.
* ipc/ipc_entry.h (struct ipc_entry): Update comment, add field for
name and free list, remove unused fields.
(ipc_entry_cache, ie_alloc, ie_free): New declarations.
(struct ipc_tree_entry): Remove.  Also remove any related declarations.
(ipc_entry_grow_table): Remove declaration.
* ipc/ipc_init.c (ipc_bootstrap): Adopt initialization.
* ipc/ipc_kmsg.c (ipc_kmsg_copyout_header): Use `ipc_entry_alloc'
instead of re-coding it.  Adopt free list handling.
(ipc_kmsg_copyout_object): Adopt free list handling, store the name.
* ipc/ipc_object.c (ipc_object_copyout): Likewise.
(ipc_object_copyout_multiname): Likewise.
* ipc/ipc_space.c (ipc_space_create): Initialize radix tree and free list.
Drop table and splay tree initialization.
(ipc_space_destroy): Free ipc entries and radix tree, remove table and
splay tree cleanup.
* ipc/ipc_space.h (struct ipc_space): Add radix tree, free list, and size.
Remove all fields related to the table and splay tree.
* ddb/db_print.c (db_port_iterate): Adopt iteration.
(db_lookup_port): Adopt lookup.
* include/mach_debug/ipc_info.h: Remove unused parts of the debug interface.
* include/mach_debug/mach_debug.defs: Likewise.
* include/mach_debug/mach_debug_types.defs: Likewise.
* ipc/mach_debug.c: Likewise.
* ipc/ipc_right.c (ipc_right_reverse): Adopt lookup, store name.
(ipc_right_check): Adopt removal.
(ipc_right_destroy): Likewise.
(ipc_right_dealloc): Likewise.
(ipc_right_delta): Likewise.
(ipc_right_copyin): Adopt insertion, adopt removal.
(ipc_right_copyin_two): Adopt removal.
(ipc_right_copyout): Adopt insertion, adopt removal.
(ipc_right_rename): Likewise, also update comment.
* ipc/mach_port.c (mach_port_names): Adopt iteration.
(mach_port_get_set_status): Likewise.
* ipc/port.h: Update comment.
* ipc/ipc_hash.c: Delete file.
* ipc/ipc_hash.h: Likewise.
* ipc/ipc_splay.c: Likewise.
* ipc/ipc_splay.h: Likewise.
* Makefrag.am (libkernel_a_SOURCES): Remove these files.

1 files changed, 8 insertions, 10 deletions

diff --git a/ipc/ipc_space.h b/ipc/ipc_space.h
index f41c64c..20b9d57 100644
--- a/ipc/ipc_space.h
+++ b/ipc/ipc_space.h
@@ -47,7 +47,7 @@
 #include <kern/lock.h>
 #include <kern/rdxtree.h>
 #include <kern/slab.h>
-#include <ipc/ipc_splay.h>
+#include <ipc/ipc_entry.h>
 #include <ipc/ipc_types.h>
 
 /*
@@ -73,18 +73,16 @@ struct ipc_space {
 
 	decl_simple_lock_data(,is_lock_data)
 	boolean_t is_active;		/* is the space alive? */
-	boolean_t is_growing;		/* is the space growing? */
-	ipc_entry_t is_table;		/* an array of entries */
-	ipc_entry_num_t is_table_size;	/* current size of table */
-	struct ipc_table_size *is_table_next; /* info for larger table */
-	struct ipc_splay_tree is_tree;	/* a splay tree of entries */
-	ipc_entry_num_t is_tree_total;	/* number of entries in the tree */
-	ipc_entry_num_t is_tree_small;	/* # of small entries in the tree */
-	ipc_entry_num_t is_tree_hash;	/* # of hashed entries in the tree */
+	struct rdxtree is_map;		/* a map of entries */
+	size_t is_size;			/* number of entries */
 	struct rdxtree is_reverse_map;	/* maps objects to entries */
-
+	ipc_entry_t is_free_list;	/* a linked list of free entries */
+	size_t is_free_list_size;	/* number of free entries */
+#define IS_FREE_LIST_SIZE_LIMIT	64	/* maximum number of entries
+					   in the free list */
 };
 
+
 #define	IS_NULL			((ipc_space_t) 0)
 
 extern struct kmem_cache ipc_space_cache;