[src/trunk]: src Add vrele_async routine which asynchronously release vnodes ...

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

details:   https://anonhg.NetBSD.org/src/rev/4fe21602c31d
branches:  trunk
changeset: 752043:4fe21602c31d
user:      haad <haad%NetBSD.org@localhost>
date:      Thu Feb 11 23:16:35 2010 +0000

description:
Add vrele_async routine which asynchronously release vnodes in different contex
and in some time in the future.

Ok: ad@.

diffstat:

 share/man/man9/vnode.9 |   8 +++++++-
 sys/kern/vfs_subr.c    |  27 ++++++++++++++++++++++++---
 sys/sys/vnode.h        |   4 +++-
 3 files changed, 34 insertions(+), 5 deletions(-)

diffs (124 lines):

diff -r 3fa85313a89a -r 4fe21602c31d share/man/man9/vnode.9
--- a/share/man/man9/vnode.9    Thu Feb 11 23:13:46 2010 +0000
+++ b/share/man/man9/vnode.9    Thu Feb 11 23:16:35 2010 +0000
@@ -1,4 +1,4 @@
-.\"     $NetBSD: vnode.9,v 1.44 2010/01/08 13:15:46 pooka Exp $
+.\"     $NetBSD: vnode.9,v 1.45 2010/02/11 23:16:35 haad Exp $
 .\"
 .\" Copyright (c) 2001, 2005, 2006 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -34,6 +34,7 @@
 .Nm vnode ,
 .Nm vref ,
 .Nm vrele ,
+.Nm vrele_async ,
 .Nm vget ,
 .Nm vput ,
 .Nm vhold ,
@@ -62,6 +63,8 @@
 .Fn vref "struct vnode *vp"
 .Ft void
 .Fn vrele "struct vnode *vp"
+.Ft void
+.Fn vrele_async "struct vnode *vp"
 .Ft int
 .Fn vget "struct vnode *vp" "int lockflag"
 .Ft void
@@ -246,6 +249,7 @@
 This count is maintained by
 .Fn vref ,
 .Fn vrele ,
+.Fn vrele_async ,
 and
 .Fn vput .
 The second is the number of active references within the kernel to the
@@ -531,6 +535,8 @@
 .Em v_holdcnt
 are zero, the vnode is placed on the freelist.
 .It Fn vget "vp" "lockflags"
+.It Fn vrele_async "vp"
+Will asychronously release vnode in different context than caller, sometime in future. 
 Reclaim vnode
 .Fa vp
 from the freelist, increment its reference count and lock it.
diff -r 3fa85313a89a -r 4fe21602c31d sys/kern/vfs_subr.c
--- a/sys/kern/vfs_subr.c       Thu Feb 11 23:13:46 2010 +0000
+++ b/sys/kern/vfs_subr.c       Thu Feb 11 23:16:35 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_subr.c,v 1.397 2010/01/15 19:28:26 bouyer Exp $    */
+/*     $NetBSD: vfs_subr.c,v 1.398 2010/02/11 23:16:35 haad Exp $      */
 
 /*-
  * Copyright (c) 1997, 1998, 2004, 2005, 2007, 2008 The NetBSD Foundation, Inc.
@@ -91,7 +91,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_subr.c,v 1.397 2010/01/15 19:28:26 bouyer Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_subr.c,v 1.398 2010/02/11 23:16:35 haad Exp $");
 
 #include "opt_ddb.h"
 #include "opt_compat_netbsd.h"
@@ -1424,8 +1424,12 @@
                /*
                 * XXX This ugly block can be largely eliminated if
                 * locking is pushed down into the file systems.
+                *
+                * Defer vnode release to vrele_thread if caller
+                * requests it explicitly.
                 */
-               if (curlwp == uvm.pagedaemon_lwp) {
+               if ((curlwp == uvm.pagedaemon_lwp) ||
+                   (flags & VRELEL_ASYNC_RELE) != 0) {
                        /* The pagedaemon can't wait around; defer. */
                        defer = true;
                } else if (curlwp == vrele_lwp) {
@@ -1599,6 +1603,23 @@
        vrelel(vp, 0);
 }
 
+/*
+ * Asynchronous vnode release, vnode is released in different context.
+ */
+void
+vrele_async(vnode_t *vp)
+{
+
+       KASSERT((vp->v_iflag & VI_MARKER) == 0);
+
+       if ((vp->v_iflag & VI_INACTNOW) == 0 && vtryrele(vp)) {
+               return;
+       }
+       
+       mutex_enter(&vp->v_interlock);
+       vrelel(vp, VRELEL_ASYNC_RELE);
+}
+
 static void
 vrele_thread(void *cookie)
 {
diff -r 3fa85313a89a -r 4fe21602c31d sys/sys/vnode.h
--- a/sys/sys/vnode.h   Thu Feb 11 23:13:46 2010 +0000
+++ b/sys/sys/vnode.h   Thu Feb 11 23:16:35 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vnode.h,v 1.213 2010/01/27 15:34:08 uebayasi Exp $     */
+/*     $NetBSD: vnode.h,v 1.214 2010/02/11 23:16:35 haad Exp $ */
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -601,6 +601,7 @@
 void   vput(struct vnode *);
 int    vrecycle(struct vnode *, kmutex_t *, struct lwp *);
 void   vrele(struct vnode *);
+void   vrele_async(struct vnode *);
 int    vtruncbuf(struct vnode *, daddr_t, bool, int);
 void   vwakeup(struct buf *);
 void   vwait(struct vnode *, int);
@@ -609,6 +610,7 @@
 void   vrelel(struct vnode *, int);
 #define VRELEL_NOINACTIVE      0x01
 #define VRELEL_ONHEAD          0x02
+#define VRELEL_ASYNC_RELE      0x03
 struct vnode *
        vnalloc(struct mount *);
 void   vnfree(struct vnode *);