Index: head/sys/kern/vfs_subr.c =================================================================== --- head/sys/kern/vfs_subr.c +++ head/sys/kern/vfs_subr.c @@ -5299,12 +5299,18 @@ kern_yield(PRI_USER); MNT_ILOCK(mp); KASSERT((*mvp)->v_mount == mp, ("marker vnode mount list mismatch")); - vp = TAILQ_NEXT(*mvp, v_nmntvnodes); - while (vp != NULL && (vp->v_type == VMARKER || - (vp->v_iflag & VI_DOOMED) != 0)) - vp = TAILQ_NEXT(vp, v_nmntvnodes); - - /* Check if we are done */ + for (vp = TAILQ_NEXT(*mvp, v_nmntvnodes); vp != NULL; + vp = TAILQ_NEXT(vp, v_nmntvnodes)) { + /* Allow a racy peek at VI_DOOMED to save a lock acquisition. */ + if (vp->v_type == VMARKER || (vp->v_iflag & VI_DOOMED) != 0) + continue; + VI_LOCK(vp); + if ((vp->v_iflag & VI_DOOMED) != 0) { + VI_UNLOCK(vp); + continue; + } + break; + } if (vp == NULL) { __mnt_vnode_markerfree_all(mvp, mp); /* MNT_IUNLOCK(mp); -- done in above function */ @@ -5313,7 +5319,6 @@ } TAILQ_REMOVE(&mp->mnt_nvnodelist, *mvp, v_nmntvnodes); TAILQ_INSERT_AFTER(&mp->mnt_nvnodelist, vp, *mvp, v_nmntvnodes); - VI_LOCK(vp); MNT_IUNLOCK(mp); return (vp); } @@ -5326,14 +5331,20 @@ *mvp = malloc(sizeof(struct vnode), M_VNODE_MARKER, M_WAITOK | M_ZERO); MNT_ILOCK(mp); MNT_REF(mp); + (*mvp)->v_mount = mp; (*mvp)->v_type = VMARKER; - vp = TAILQ_FIRST(&mp->mnt_nvnodelist); - while (vp != NULL && (vp->v_type == VMARKER || - (vp->v_iflag & VI_DOOMED) != 0)) - vp = TAILQ_NEXT(vp, v_nmntvnodes); - - /* Check if we are done */ + TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) { + /* Allow a racy peek at VI_DOOMED to save a lock acquisition. */ + if (vp->v_type == VMARKER || (vp->v_iflag & VI_DOOMED) != 0) + continue; + VI_LOCK(vp); + if ((vp->v_iflag & VI_DOOMED) != 0) { + VI_UNLOCK(vp); + continue; + } + break; + } if (vp == NULL) { MNT_REL(mp); MNT_IUNLOCK(mp); @@ -5341,13 +5352,10 @@ *mvp = NULL; return (NULL); } - (*mvp)->v_mount = mp; TAILQ_INSERT_AFTER(&mp->mnt_nvnodelist, vp, *mvp, v_nmntvnodes); - VI_LOCK(vp); MNT_IUNLOCK(mp); return (vp); } - void __mnt_vnode_markerfree_all(struct vnode **mvp, struct mount *mp)