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Fix a problem with the vfs vnode caching that it doesn't grow quickly

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enough and can cause some strange performance problems.  Specifically, at
or near startup time is when the problem is worst.  To reproduce
the problem, run "lat_syscall stat" from the alpha lmbench code right
after bootup.  A positive side effect of this mod is that the name
cache can be set to grow again by sysctl.  A noticable positive
performance impact is realized due to a larger namecache being available
as needed (or tuned.)
This commit is contained in:
dyson 1997-08-04 07:43:28 +00:00
parent 14e530a9e3
commit 4811e46aa5
2 changed files with 42 additions and 32 deletions
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37
sys/kern/vfs_export.c
View File

@ -36,7 +36,7 @@
* SUCH DAMAGE.
*
* @(#)vfs_subr.c 8.31 (Berkeley) 5/26/95
* $Id: vfs_subr.c,v 1.88 1997/06/22 03:00:21 dyson Exp $
* $Id: vfs_subr.c,v 1.89 1997/07/17 07:17:31 dfr Exp $
*/
/*
@ -354,24 +354,29 @@ getnewvnode(tag, mp, vops, vpp)
simple_lock(&vnode_free_list_slock);
TAILQ_FOREACH(vp, &vnode_free_list, v_freelist) {
if (!simple_lock_try(&vp->v_interlock))
continue;
if (vp->v_usecount)
panic("free vnode isn't");
if (freevnodes >= desiredvnodes) {
TAILQ_FOREACH(vp, &vnode_free_list, v_freelist) {
if (!simple_lock_try(&vp->v_interlock))
continue;
if (vp->v_usecount)
panic("free vnode isn't");
if (vp->v_object && vp->v_object->resident_page_count) {
/* Don't recycle if it's caching some pages */
simple_unlock(&vp->v_interlock);
continue;
} else if (LIST_FIRST(&vp->v_cache_src)) {
/* Don't recycle if active in the namecache */
simple_unlock(&vp->v_interlock);
continue;
} else {
break;
if (vp->v_object && vp->v_object->resident_page_count) {
/* Don't recycle if it's caching some pages */
simple_unlock(&vp->v_interlock);
continue;
} else if (LIST_FIRST(&vp->v_cache_src)) {
/* Don't recycle if active in the namecache */
simple_unlock(&vp->v_interlock);
continue;
} else {
break;
}
}
} else {
vp = NULL;
}
if (vp) {
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
freevnodes--;

37
sys/kern/vfs_subr.c
View File

@ -36,7 +36,7 @@
* SUCH DAMAGE.
*
* @(#)vfs_subr.c 8.31 (Berkeley) 5/26/95
* $Id: vfs_subr.c,v 1.88 1997/06/22 03:00:21 dyson Exp $
* $Id: vfs_subr.c,v 1.89 1997/07/17 07:17:31 dfr Exp $
*/
/*
@ -354,24 +354,29 @@ getnewvnode(tag, mp, vops, vpp)
simple_lock(&vnode_free_list_slock);
TAILQ_FOREACH(vp, &vnode_free_list, v_freelist) {
if (!simple_lock_try(&vp->v_interlock))
continue;
if (vp->v_usecount)
panic("free vnode isn't");
if (freevnodes >= desiredvnodes) {
TAILQ_FOREACH(vp, &vnode_free_list, v_freelist) {
if (!simple_lock_try(&vp->v_interlock))
continue;
if (vp->v_usecount)
panic("free vnode isn't");
if (vp->v_object && vp->v_object->resident_page_count) {
/* Don't recycle if it's caching some pages */
simple_unlock(&vp->v_interlock);
continue;
} else if (LIST_FIRST(&vp->v_cache_src)) {
/* Don't recycle if active in the namecache */
simple_unlock(&vp->v_interlock);
continue;
} else {
break;
if (vp->v_object && vp->v_object->resident_page_count) {
/* Don't recycle if it's caching some pages */
simple_unlock(&vp->v_interlock);
continue;
} else if (LIST_FIRST(&vp->v_cache_src)) {
/* Don't recycle if active in the namecache */
simple_unlock(&vp->v_interlock);
continue;
} else {
break;
}
}
} else {
vp = NULL;
}
if (vp) {
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
freevnodes--;