Module Name: src
Committed By: rmind
Date: Fri Oct 12 21:10:56 UTC 2012
Modified Files:
src/sys/kern: vfs_vnode.c
Log Message:
Update comment on vnode life-cycle a little.
To generate a diff of this commit:
cvs rdiff -u -r1.15 -r1.16 src/sys/kern/vfs_vnode.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/vfs_vnode.c
diff -u src/sys/kern/vfs_vnode.c:1.15 src/sys/kern/vfs_vnode.c:1.16
--- src/sys/kern/vfs_vnode.c:1.15 Tue Dec 20 16:49:37 2011
+++ src/sys/kern/vfs_vnode.c Fri Oct 12 21:10:55 2012
@@ -1,4 +1,4 @@
-/* $NetBSD: vfs_vnode.c,v 1.15 2011/12/20 16:49:37 hannken Exp $ */
+/* $NetBSD: vfs_vnode.c,v 1.16 2012/10/12 21:10:55 rmind Exp $ */
/*-
* Copyright (c) 1997-2011 The NetBSD Foundation, Inc.
@@ -78,11 +78,15 @@
* - Allocation, via getnewvnode(9) and/or vnalloc(9).
* - Reclamation of inactive vnode, via vget(9).
*
+ * Recycle from a free list, via getnewvnode(9) -> getcleanvnode(9)
+ * was another, traditional way. Currently, only the draining thread
+ * recycles the vnodes. This behaviour might be revisited.
+ *
* The life-cycle ends when the last reference is dropped, usually
* in VOP_REMOVE(9). In such case, VOP_INACTIVE(9) is called to inform
* the file system that vnode is inactive. Via this call, file system
- * indicates whether vnode should be recycled (usually, count of links
- * is checked i.e. whether file was removed).
+ * indicates whether vnode can be recycled (usually, it checks its own
+ * references, e.g. count of links, whether the file was removed).
*
* Depending on indication, vnode can be put into a free list (cache),
* or cleaned via vclean(9), which calls VOP_RECLAIM(9) to disassociate
@@ -120,7 +124,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.15 2011/12/20 16:49:37 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.16 2012/10/12 21:10:55 rmind Exp $");
#include <sys/param.h>
#include <sys/kernel.h>
@@ -147,18 +151,23 @@ __KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,
u_int numvnodes __cacheline_aligned;
static pool_cache_t vnode_cache __read_mostly;
-static kmutex_t vnode_free_list_lock __cacheline_aligned;
+/*
+ * There are two free lists: one is for vnodes which have no buffer/page
+ * references and one for those which do (i.e. v_holdcnt is non-zero).
+ * Vnode recycling mechanism first attempts to look into the former list.
+ */
+static kmutex_t vnode_free_list_lock __cacheline_aligned;
static vnodelst_t vnode_free_list __cacheline_aligned;
static vnodelst_t vnode_hold_list __cacheline_aligned;
-static vnodelst_t vrele_list __cacheline_aligned;
+static kcondvar_t vdrain_cv __cacheline_aligned;
+static vnodelst_t vrele_list __cacheline_aligned;
static kmutex_t vrele_lock __cacheline_aligned;
static kcondvar_t vrele_cv __cacheline_aligned;
static lwp_t * vrele_lwp __cacheline_aligned;
static int vrele_pending __cacheline_aligned;
static int vrele_gen __cacheline_aligned;
-static kcondvar_t vdrain_cv __cacheline_aligned;
static int cleanvnode(void);
static void vdrain_thread(void *);
