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- make this a bit MP friendly. 

(although no actual changes under the kernel lock)
- remove a test that isn't meaningful anymore.
This commit is contained in:
yamt 2003-08-08 20:19:56 +00:00
parent 1f08924c29
commit a01f6f4ea5
1 changed files with 21 additions and 11 deletions
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32
sys/kern/vfs_cache.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: vfs_cache.c,v 1.52 2003/08/08 20:18:19 yamt Exp $ */
/* $NetBSD: vfs_cache.c,v 1.53 2003/08/08 20:19:56 yamt Exp $ */
/*
* Copyright (c) 1989, 1993
@ -32,7 +32,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vfs_cache.c,v 1.52 2003/08/08 20:18:19 yamt Exp $");
__KERNEL_RCSID(0, "$NetBSD: vfs_cache.c,v 1.53 2003/08/08 20:19:56 yamt Exp $");
#include "opt_ddb.h"
#include "opt_revcache.h"
@ -163,13 +163,14 @@ cache_lookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp)
return (-1);
}
simple_lock(&namecache_slock);
if (cnp->cn_namelen > NCHNAMLEN) {
/* XXXSMP - updating stats without lock; do we care? */
nchstats.ncs_long++;
cnp->cn_flags &= ~MAKEENTRY;
goto fail_wlock;
goto fail;
}
ncpp = &nchashtbl[NCHASH(cnp, dvp)];
simple_lock(&namecache_slock);
LIST_FOREACH(ncp, ncpp, nc_hash) {
if (ncp->nc_dvp == dvp &&
ncp->nc_nlen == cnp->cn_namelen &&
@ -217,6 +218,9 @@ cache_lookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp)
TAILQ_INSERT_TAIL(&nclruhead, ncp, nc_lru);
}
if (vp != dvp)
simple_lock(&vp->v_interlock);
/* Release the name cache mutex while we acquire vnode locks */
simple_unlock(&namecache_slock);
@ -228,13 +232,22 @@ cache_lookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp)
ncp = NULL;
#endif /* DEBUG */
if (vp != dvp && __predict_false(vp->v_flag & VXLOCK)) {
/*
* this vnode is being cleaned out.
*/
simple_unlock(&vp->v_interlock);
nchstats.ncs_falsehits++; /* XXX badhits? */
goto fail;
}
if (vp == dvp) { /* lookup on "." */
VREF(dvp);
error = 0;
} else if (cnp->cn_flags & ISDOTDOT) {
VOP_UNLOCK(dvp, 0);
cnp->cn_flags |= PDIRUNLOCK;
error = vget(vp, LK_EXCLUSIVE);
error = vget(vp, LK_EXCLUSIVE | LK_INTERLOCK);
/*
* If the above vget() succeeded and both LOCKPARENT and
* ISLASTCN is set, lock the directory vnode as well.
@ -247,7 +260,7 @@ cache_lookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp)
cnp->cn_flags &= ~PDIRUNLOCK;
}
} else {
error = vget(vp, LK_EXCLUSIVE);
error = vget(vp, LK_EXCLUSIVE | LK_INTERLOCK);
/*
* If the above vget() failed or either of LOCKPARENT or
* ISLASTCN is set, unlock the directory vnode.
@ -264,11 +277,7 @@ cache_lookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp)
*/
if (error) {
/* XXXSMP - updating stats without lock; do we care? */
if (!error) {
vput(vp);
nchstats.ncs_falsehits++;
} else
nchstats.ncs_badhits++;
nchstats.ncs_badhits++;
/*
* The parent needs to be locked when we return to VOP_LOOKUP().
@ -307,6 +316,7 @@ remove:
fail_wlock:
simple_unlock(&namecache_slock);
fail:
*vpp = NULL;
return (-1);
}