diff options
Diffstat (limited to 'sys/kern/vfs_subr.c')
| -rw-r--r-- | sys/kern/vfs_subr.c | 93 |
1 files changed, 56 insertions, 37 deletions
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c index 1650576c0e0..0a5ce5265dd 100644 --- a/sys/kern/vfs_subr.c +++ b/sys/kern/vfs_subr.c @@ -1,4 +1,4 @@ -/* $OpenBSD: vfs_subr.c,v 1.149 2007/05/28 21:05:21 thib Exp $ */ +/* $OpenBSD: vfs_subr.c,v 1.150 2007/05/29 05:28:54 beck Exp $ */ /* $NetBSD: vfs_subr.c,v 1.53 1996/04/22 01:39:13 christos Exp $ */ /* @@ -339,47 +339,50 @@ getnewvnode(enum vtagtype tag, struct mount *mp, int (**vops)(void *), { struct proc *p = curproc; struct freelst *listhd; - static int toggle; struct vnode *vp; int s; /* - * We must choose whether to allocate a new vnode or recycle an - * existing one. The criterion for allocating a new one is that - * the total number of vnodes is less than the number desired or - * there are no vnodes on either free list. Generally we only + * Allocate a new vnode if we have less than the desired + * number allocated, otherwise, recycle one. Generally we only * want to recycle vnodes that have no buffers associated with - * them, so we look first on the vnode_free_list. If it is empty, - * we next consider vnodes with referencing buffers on the - * vnode_hold_list. The toggle ensures that half the time we - * will use a buffer from the vnode_hold_list, and half the time - * we will allocate a new one unless the list has grown to twice - * the desired size. We are reticent to recycle vnodes from the - * vnode_hold_list because we will lose the identity of all its - * referencing buffers. + * them, so we look first on the vnode_free_list. If it is + * empty, we next consider vnodes with referencing buffers on + * the vnode_hold_list. We are reticent to recycle vnodes from + * the vnode_hold_list because we will lose the identity of + * all its referencing buffers. */ - toggle ^= 1; - if (numvnodes > 2 * desiredvnodes) - toggle = 0; - + simple_lock(&vnode_free_list_slock); s = splbio(); - if ((numvnodes < desiredvnodes) || - ((TAILQ_FIRST(listhd = &vnode_free_list) == NULL) && - ((TAILQ_FIRST(listhd = &vnode_hold_list) == NULL) || toggle))) { + if (numvnodes < desiredvnodes) { splx(s); vp = pool_get(&vnode_pool, PR_WAITOK); bzero((char *)vp, sizeof *vp); + LIST_INIT(&vp->v_cache_src); + TAILQ_INIT(&vp->v_cache_dst); numvnodes++; } else { - for (vp = TAILQ_FIRST(listhd); vp != NULLVP; + for (vp = TAILQ_FIRST(listhd = &vnode_free_list); vp != NULLVP; vp = TAILQ_NEXT(vp, v_freelist)) { if (VOP_ISLOCKED(vp) == 0) break; } + /* + * There is nothing on the free list, so we have to try to + * recycle one off the hold list + */ + if (vp == NULL) { + for (vp = TAILQ_FIRST(listhd = &vnode_hold_list); + vp != NULLVP; + vp = TAILQ_NEXT(vp, v_freelist)) { + if ((VOP_ISLOCKED(vp) == 0) && (vp->v_holdcnt == 0)) + break; + } + } /* - * Unless this is a bad time of the month, at most - * the first NCPUS items on the free list are - * locked, so this is close enough to being empty. + * We have made a pass through both the free and hold list + * and not encountered an unlocked entry. So this is close + * enough to being empty. */ if (vp == NULL) { splx(s); @@ -393,6 +396,11 @@ getnewvnode(enum vtagtype tag, struct mount *mp, int (**vops)(void *), vprint("free vnode", vp); panic("free vnode isn't"); } + + if (vp->v_holdcnt) { + vprint("held vnode", vp); + panic("unheld vnode being held!"); + } #endif TAILQ_REMOVE(listhd, vp, v_freelist); @@ -758,7 +766,7 @@ vrele(struct vnode *vp) void vhold(struct vnode *vp); /* - * Page or buffer structure gets a reference. + * declare interest in a vnode. */ void vhold(struct vnode *vp) @@ -775,6 +783,27 @@ vhold(struct vnode *vp) vp->v_holdcnt++; } +void vdrop(struct vnode *vp); + +/* + * lose interest in a vnode + */ +void +vdrop(struct vnode *vp) +{ + vp->v_holdcnt--; + + /* + * If it is on the holdlist and the hold count drops to + * zero, move it to the free list. + */ + if ((vp->v_bioflag & VBIOONFREELIST) && + vp->v_holdcnt == 0 && vp->v_usecount == 0) { + TAILQ_REMOVE(&vnode_hold_list, vp, v_freelist); + TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist); + } +} + /* * Remove any vnodes in the vnode table belonging to mount point mp. * @@ -1993,17 +2022,7 @@ brelvp(struct buf *bp) if (vp->v_holdcnt == 0) panic("brelvp: holdcnt"); #endif - vp->v_holdcnt--; - - /* - * If it is on the holdlist and the hold count drops to - * zero, move it to the free list. - */ - if ((vp->v_bioflag & VBIOONFREELIST) && - vp->v_holdcnt == 0 && vp->v_usecount == 0) { - TAILQ_REMOVE(&vnode_hold_list, vp, v_freelist); - TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist); - } + vdrop(vp); } /* |