[src/yamt-pagecache]: src/common/lib/libc/gen comment

[yamt <yamt%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/bddc832ff86f
branches:  yamt-pagecache
changeset: 770882:bddc832ff86f
user:      yamt <yamt%NetBSD.org@localhost>
date:      Wed Jun 13 14:18:49 2012 +0000

description:
comment

diffstat:

 common/lib/libc/gen/radixtree.c |  11 ++++++++---
 1 files changed, 8 insertions(+), 3 deletions(-)

diffs (39 lines):

diff -r 844887a183db -r bddc832ff86f common/lib/libc/gen/radixtree.c
--- a/common/lib/libc/gen/radixtree.c   Tue Jun 12 17:12:01 2012 +0000
+++ b/common/lib/libc/gen/radixtree.c   Wed Jun 13 14:18:49 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: radixtree.c,v 1.17.2.2 2012/02/17 08:16:55 yamt Exp $  */
+/*     $NetBSD: radixtree.c,v 1.17.2.3 2012/06/13 14:18:49 yamt Exp $  */
 
 /*-
  * Copyright (c)2011,2012 YAMAMOTO Takashi,
@@ -56,6 +56,11 @@
  *  - the best case: about RADIX_TREE_PTR_PER_NODE items per intermediate node.
  *  - the worst case: RADIX_TREE_MAX_HEIGHT intermediate nodes per item.
  *
+ * The height of tree is dynamic.  It's smaller if only small index values are
+ * used.  As an extreme case, if only index 0 is used, the corresponding value
+ * is directly stored in the root of the tree (struct radix_tree) without
+ * allocating any intermediate nodes.
+ *
  * Gang lookup:
  *
  * This implementation provides a way to scan many nodes quickly via
@@ -75,7 +80,7 @@
 #include <sys/cdefs.h>
 
 #if defined(_KERNEL) || defined(_STANDALONE)
-__KERNEL_RCSID(0, "$NetBSD: radixtree.c,v 1.17.2.2 2012/02/17 08:16:55 yamt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: radixtree.c,v 1.17.2.3 2012/06/13 14:18:49 yamt Exp $");
 #include <sys/param.h>
 #include <sys/errno.h>
 #include <sys/pool.h>
@@ -85,7 +90,7 @@
 #include <lib/libsa/stand.h>
 #endif /* defined(_STANDALONE) */
 #else /* defined(_KERNEL) || defined(_STANDALONE) */
-__RCSID("$NetBSD: radixtree.c,v 1.17.2.2 2012/02/17 08:16:55 yamt Exp $");
+__RCSID("$NetBSD: radixtree.c,v 1.17.2.3 2012/06/13 14:18:49 yamt Exp $");
 #include <assert.h>
 #include <errno.h>
 #include <stdbool.h>