Date: Fri, 25 Apr 1997 18:36:20 +0200 From: Poul-Henning Kamp <phk@dk.tfs.com> To: fs@freebsd.org Subject: patch to be benchmarked. Message-ID: <230.861986180@critter>
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This patch removes all the ".." entries from the namei cache, and
instead stores the information in the vnode.
This is a "freebie" since we allocate 128 bytes for the vnode and only
use less of it currently.
Benchmark results will be most appreciated !
Poul-Henning
Index: kern/vfs_cache.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/vfs_cache.c,v
retrieving revision 1.24
diff -u -r1.24 vfs_cache.c
--- vfs_cache.c 1997/03/08 15:22:14 1.24
+++ vfs_cache.c 1997/04/25 16:23:28
@@ -78,7 +78,13 @@
(&nchashtbl[((dvp)->v_id + (cnp)->cn_hash) % nchash])
static LIST_HEAD(nchashhead, namecache) *nchashtbl; /* Hash Table */
static u_long nchash; /* size of hash table */
+
static u_long numcache; /* number of cache entries allocated */
+SYSCTL_INT(_debug, OID_AUTO, vfscachesize, CTLFLAG_RD, &numcache, 0, "");
+
+static u_long cachelimit;
+SYSCTL_INT(_debug, OID_AUTO, vfscachelimit, CTLFLAG_RW, &cachelimit, 0, "");
+
static TAILQ_HEAD(, namecache) nclruhead; /* LRU chain */
struct nchstats nchstats; /* cache effectiveness statistics */
@@ -151,6 +157,18 @@
return (0);
}
+ if (cnp->cn_namelen == 2 &&
+ cnp->cn_nameptr[0] == '.' && cnp->cn_nameptr[1] == '.') {
+ if (dvp->v_dd->v_id != dvp->v_ddid)
+ return (0);
+ if ((cnp->cn_flags & MAKEENTRY) == 0) {
+ dvp->v_dd = dvp;
+ return (0);
+ }
+ *vpp = dvp->v_dd;
+ return (-1);
+ }
+
ncpp = NCHHASH(dvp, cnp);
for (ncp = ncpp->lh_first; ncp != 0; ncp = nnp) {
nnp = ncp->nc_hash.le_next;
@@ -230,12 +248,18 @@
return;
}
+ if (cnp->cn_namelen == 2 &&
+ cnp->cn_nameptr[0] == '.' && cnp->cn_nameptr[1] == '.') {
+ dvp->v_dd = vp;
+ dvp->v_ddid = vp->v_id;
+ }
+
/*
* We allocate a new entry if we are less than the maximum
* allowed and the one at the front of the LRU list is in use.
* Otherwise we use the one at the front of the LRU list.
*/
- if (numcache < desiredvnodes &&
+ if (numcache < (cachelimit ? cachelimit : desiredvnodes) &&
((ncp = nclruhead.tqh_first) == NULL ||
ncp->nc_hash.le_prev != 0)) {
/* Add one more entry */
Index: kern/vfs_subr.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/vfs_subr.c,v
retrieving revision 1.82
diff -u -r1.82 vfs_subr.c
--- vfs_subr.c 1997/04/04 17:46:16 1.82
+++ vfs_subr.c 1997/04/25 16:04:31
@@ -361,6 +361,7 @@
vp = (struct vnode *) malloc((u_long) sizeof *vp,
M_VNODE, M_WAITOK);
bzero((char *) vp, sizeof *vp);
+ vp->v_dd = vp; /* Always point to some vnode */
numvnodes++;
} else {
for (vp = vnode_free_list.tqh_first;
Index: sys/vnode.h
===================================================================
RCS file: /home/ncvs/src/sys/sys/vnode.h,v
retrieving revision 1.43
diff -u -r1.43 vnode.h
--- vnode.h 1997/04/04 17:43:32 1.43
+++ vnode.h 1997/04/25 15:55:55
@@ -110,6 +110,8 @@
struct lock *v_vnlock; /* used for non-locking fs's */
enum vtagtype v_tag; /* type of underlying data */
void *v_data; /* private data for fs */
+ struct vnode *v_dd; /* ".." vnode */
+ u_long v_ddid; /* ".." vnode.v_id */
};
#define v_mountedhere v_un.vu_mountedhere
#define v_socket v_un.vu_socket
--
Poul-Henning Kamp | phk@FreeBSD.ORG FreeBSD Core-team.
http://www.freebsd.org/~phk | phk@login.dknet.dk Private mailbox.
whois: [PHK] | phk@tfs.com TRW Financial Systems, Inc.
Future will arrive by its own means, progress not so.
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