[src/ad-namecache]: src/sys/kern Comments.

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

details:   https://anonhg.NetBSD.org/src/rev/9f75920ee130
branches:  ad-namecache
changeset: 744915:9f75920ee130
user:      ad <ad%NetBSD.org@localhost>
date:      Sun Feb 16 22:00:53 2020 +0000

description:
Comments.

diffstat:

 sys/kern/vfs_cache.c |  22 +++++++++++-----------
 1 files changed, 11 insertions(+), 11 deletions(-)

diffs (64 lines):

diff -r 7b8c35b5f63b -r 9f75920ee130 sys/kern/vfs_cache.c
--- a/sys/kern/vfs_cache.c      Sat Jan 25 22:38:36 2020 +0000
+++ b/sys/kern/vfs_cache.c      Sun Feb 16 22:00:53 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_cache.c,v 1.126.2.11 2020/01/24 16:48:59 ad Exp $  */
+/*     $NetBSD: vfs_cache.c,v 1.126.2.12 2020/02/16 22:00:53 ad Exp $  */
 
 /*-
  * Copyright (c) 2008, 2019, 2020 The NetBSD Foundation, Inc.
@@ -67,8 +67,9 @@
  *     reference.  It is managed LRU, so frequently used names will hang
  *     around.  The cache is indexed by hash value obtained from the name.
  *
- *     The name cache (or directory name lookup cache) is the brainchild of
- *     Robert Elz and made its first appearance in 4.3BSD.
+ *     The name cache is the brainchild of Robert Elz and was introduced in
+ *     4.3BSD.  See "Using gprof to Tune the 4.2BSD Kernel", Marshall Kirk
+ *     McKusick, May 21 1984.
  *
  * Data structures:
  *
@@ -81,7 +82,7 @@
  *     The index is a red-black tree.  There are no special concurrency
  *     requirements placed on it, because it's per-directory and protected
  *     by the namecache's per-directory locks.  It should therefore not be
- *     difficult to experiment with other data structures.
+ *     difficult to experiment with other types of index.
  *
  *     Each cached name is stored in a struct namecache, along with a
  *     pointer to the associated vnode (nc_vp).  Names longer than a
@@ -170,7 +171,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_cache.c,v 1.126.2.11 2020/01/24 16:48:59 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_cache.c,v 1.126.2.12 2020/02/16 22:00:53 ad Exp $");
 
 #define __NAMECACHE_PRIVATE
 #ifdef _KERNEL_OPT
@@ -393,7 +394,7 @@
 }
 
 /*
- * Find a single cache entry and return it.  The vnode lock must be held.
+ * Find a single cache entry and return it.  vi_nc_lock must be held.
  */
 static struct namecache * __noinline
 cache_lookup_entry(struct vnode *dvp, const char *name, size_t namelen,
@@ -1239,11 +1240,10 @@
        }
 
        /*
-        * Aim for a 1:1 ratio of active to inactive.  It's a bit wet finger
-        * in the air here, but this is to allow each potential victim a
-        * reasonable amount of time to cycle through the inactive list in
-        * order to score a hit and be reactivated, while trying not to
-        * cause reactivations too frequently.
+        * Aim for a 1:1 ratio of active to inactive.  This is to allow each
+        * potential victim a reasonable amount of time to cycle through the
+        * inactive list in order to score a hit and be reactivated, while
+        * trying not to cause reactivations too frequently.
         */
        if (cache_lru.count[LRU_ACTIVE] < cache_lru.count[LRU_INACTIVE]) {
                return;