Date: Sun, 23 Sep 2001 00:46:22 -0700 (PDT) From: Matt Dillon <dillon@earth.backplane.com> To: David Greenman <dg@root.com> Cc: Poul-Henning Kamp <phk@critter.freebsd.dk>, Seigo Tanimura <tanimura@r.dl.itc.u-tokyo.ac.jp>, bright@wintelcom.net, hackers@FreeBSD.ORG Subject: Re: Conclusions on... was Re: More on the cache_purgeleafdirs() routine Message-ID: <200109230746.f8N7kMM85221@earth.backplane.com> References: <88901.1001191415@critter> <200109222121.f8MLLHe82202@earth.backplane.com> <20010922141934.C28469@nexus.root.com> <200109230642.f8N6gPj84955@earth.backplane.com> <20010922235704.D28469@nexus.root.com>
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:> Well, this has turned into a rather sticky little problem. I've
:> spent all day going through the vnode/name-cache reclaim code, looking
:> both at Seigo's cache_purgeleafdirs() and my own patch.
:
: Can you forward me your patch? I'd like to try it out on some machines in
:the TSI lab.
Absolutely, any and all testing is good.
Here's the patch for stable and current. Stable first:
Index: kern/vfs_subr.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/vfs_subr.c,v
retrieving revision 1.249.2.11
diff -u -r1.249.2.11 vfs_subr.c
--- kern/vfs_subr.c 2001/09/11 09:49:53 1.249.2.11
+++ kern/vfs_subr.c 2001/09/23 07:33:51
@@ -506,10 +506,12 @@
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
TAILQ_INSERT_TAIL(&vnode_tmp_list, vp, v_freelist);
continue;
+#if 0
} else if (LIST_FIRST(&vp->v_cache_src)) {
/* Don't recycle if active in the namecache */
simple_unlock(&vp->v_interlock);
continue;
+#endif
} else {
break;
}
And here is the patch for current:
Index: kern/vfs_cache.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/vfs_cache.c,v
retrieving revision 1.61
diff -u -r1.61 vfs_cache.c
--- kern/vfs_cache.c 2001/09/12 08:37:46 1.61
+++ kern/vfs_cache.c 2001/09/23 07:27:05
@@ -101,8 +101,10 @@
SYSCTL_ULONG(_debug, OID_AUTO, numcache, CTLFLAG_RD, &numcache, 0, "");
static u_long numcachehv; /* number of cache entries with vnodes held */
SYSCTL_ULONG(_debug, OID_AUTO, numcachehv, CTLFLAG_RD, &numcachehv, 0, "");
+#if 0
static u_long numcachepl; /* number of cache purge for leaf entries */
SYSCTL_ULONG(_debug, OID_AUTO, numcachepl, CTLFLAG_RD, &numcachepl, 0, "");
+#endif
struct nchstats nchstats; /* cache effectiveness statistics */
static int doingcache = 1; /* 1 => enable the cache */
@@ -499,6 +501,8 @@
}
}
+#if 0
+
/*
* Flush all dirctory entries with no child directories held in
* the cache.
@@ -554,6 +558,8 @@
}
numcachepl++;
}
+
+#endif
/*
* Perform canonical checks and cache lookup and pass on to filesystem
Index: kern/vfs_subr.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/vfs_subr.c,v
retrieving revision 1.319
diff -u -r1.319 vfs_subr.c
--- kern/vfs_subr.c 2001/09/12 08:37:47 1.319
+++ kern/vfs_subr.c 2001/09/22 20:15:11
@@ -110,6 +110,8 @@
/* Number of vnodes in the free list. */
static u_long freevnodes = 0;
SYSCTL_LONG(_debug, OID_AUTO, freevnodes, CTLFLAG_RD, &freevnodes, 0, "");
+
+#if 0
/* Number of vnode allocation. */
static u_long vnodeallocs = 0;
SYSCTL_LONG(_debug, OID_AUTO, vnodeallocs, CTLFLAG_RD, &vnodeallocs, 0, "");
@@ -125,6 +127,7 @@
/* Number of vnodes attempted to recycle at a time. */
static u_long vnoderecyclenumber = 3000;
SYSCTL_LONG(_debug, OID_AUTO, vnoderecyclenumber, CTLFLAG_RW, &vnoderecyclenumber, 0, "");
+#endif
/*
* Various variables used for debugging the new implementation of
@@ -556,8 +559,13 @@
* Don't recycle if active in the namecache or
* if it still has cached pages or we cannot get
* its interlock.
+ *
+ * XXX the namei cache can hold onto vnodes too long,
+ * causing us to run out of MALLOC space. Instead, we
+ * should make path lookups requeue any vnodes on the free
+ * list.
*/
- if (LIST_FIRST(&vp->v_cache_src) != NULL ||
+ if (/* LIST_FIRST(&vp->v_cache_src) != NULL || */
(VOP_GETVOBJECT(vp, &object) == 0 &&
(object->resident_page_count || object->ref_count)) ||
!mtx_trylock(&vp->v_interlock)) {
@@ -636,6 +644,7 @@
vfs_object_create(vp, td, td->td_proc->p_ucred);
+#if 0
vnodeallocs++;
if (vnodeallocs % vnoderecycleperiod == 0 &&
freevnodes < vnoderecycleminfreevn &&
@@ -643,6 +652,7 @@
/* Recycle vnodes. */
cache_purgeleafdirs(vnoderecyclenumber);
}
+#endif
return (0);
}
Index: sys/vnode.h
===================================================================
RCS file: /home/ncvs/src/sys/sys/vnode.h,v
retrieving revision 1.157
diff -u -r1.157 vnode.h
--- sys/vnode.h 2001/09/13 22:52:42 1.157
+++ sys/vnode.h 2001/09/23 07:26:54
@@ -559,7 +559,6 @@
struct componentname *cnp));
void cache_purge __P((struct vnode *vp));
void cache_purgevfs __P((struct mount *mp));
-void cache_purgeleafdirs __P((int ndir));
void cvtstat __P((struct stat *st, struct ostat *ost));
void cvtnstat __P((struct stat *sb, struct nstat *nsb));
int getnewvnode __P((enum vtagtype tag,
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