4 * Copyright (c) 1990 University of Utah.
5 * Copyright (c) 1991 The Regents of the University of California.
7 * Copyright (c) 1993, 1994 John S. Dyson
8 * Copyright (c) 1995, David Greenman
10 * This code is derived from software contributed to Berkeley by
11 * the Systems Programming Group of the University of Utah Computer
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
22 * 3. All advertising materials mentioning features or use of this software
23 * must display the following acknowledgement:
24 * This product includes software developed by the University of
25 * California, Berkeley and its contributors.
26 * 4. Neither the name of the University nor the names of its contributors
27 * may be used to endorse or promote products derived from this software
28 * without specific prior written permission.
30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
42 * from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91
43 * $FreeBSD: src/sys/vm/vnode_pager.c,v 1.116.2.7 2002/12/31 09:34:51 dillon Exp $
44 * $DragonFly: src/sys/vm/vnode_pager.c,v 1.43 2008/06/19 23:27:39 dillon Exp $
48 * Page to/from files (vnodes).
53 * Implement VOP_GETPAGES/PUTPAGES interface for filesystems. Will
54 * greatly re-simplify the vnode_pager.
57 #include <sys/param.h>
58 #include <sys/systm.h>
59 #include <sys/kernel.h>
61 #include <sys/vnode.h>
62 #include <sys/mount.h>
64 #include <sys/vmmeter.h>
67 #include <cpu/lwbuf.h>
70 #include <vm/vm_object.h>
71 #include <vm/vm_page.h>
72 #include <vm/vm_pager.h>
73 #include <vm/vm_map.h>
74 #include <vm/vnode_pager.h>
75 #include <vm/swap_pager.h>
76 #include <vm/vm_extern.h>
78 #include <sys/thread2.h>
79 #include <vm/vm_page2.h>
81 static void vnode_pager_dealloc (vm_object_t);
82 static int vnode_pager_getpage (vm_object_t, vm_page_t *, int);
83 static void vnode_pager_putpages (vm_object_t, vm_page_t *, int, boolean_t, int *);
84 static boolean_t vnode_pager_haspage (vm_object_t, vm_pindex_t);
86 struct pagerops vnodepagerops = {
93 static struct krate vbadrate = { 1 };
94 static struct krate vresrate = { 1 };
96 int vnode_pbuf_freecnt = -1; /* start out unlimited */
99 * Allocate a VM object for a vnode, typically a regular file vnode.
101 * Some additional information is required to generate a properly sized
102 * object which covers the entire buffer cache buffer straddling the file
103 * EOF. Userland does not see the extra pages as the VM fault code tests
104 * against v_filesize.
107 vnode_pager_alloc(void *handle, off_t length, vm_prot_t prot, off_t offset,
108 int blksize, int boff)
116 * Pageout to vnode, no can do yet.
122 * XXX hack - This initialization should be put somewhere else.
124 if (vnode_pbuf_freecnt < 0) {
125 vnode_pbuf_freecnt = nswbuf / 2 + 1;
129 * Serialize potential vnode/object teardowns and interlocks
131 vp = (struct vnode *)handle;
132 lwkt_gettoken(&vp->v_token);
135 * Prevent race condition when allocating the object. This
136 * can happen with NFS vnodes since the nfsnode isn't locked.
138 while (vp->v_flag & VOLOCK) {
139 vsetflags(vp, VOWANT);
140 tsleep(vp, 0, "vnpobj", 0);
142 vsetflags(vp, VOLOCK);
143 lwkt_reltoken(&vp->v_token);
146 * If the object is being terminated, wait for it to
149 while ((object = vp->v_object) != NULL) {
150 vm_object_hold(object);
151 if ((object->flags & OBJ_DEAD) == 0)
153 vm_object_dead_sleep(object, "vadead");
154 vm_object_drop(object);
157 if (vp->v_sysref.refcnt <= 0)
158 panic("vnode_pager_alloc: no vnode reference");
161 * Round up to the *next* block, then destroy the buffers in question.
162 * Since we are only removing some of the buffers we must rely on the
163 * scan count to determine whether a loop is necessary.
165 * Destroy any pages beyond the last buffer.
168 boff = (int)(length % blksize);
170 loffset = length + (blksize - boff);
173 lsize = OFF_TO_IDX(round_page64(loffset));
175 if (object == NULL) {
177 * And an object of the appropriate size
179 object = vm_object_allocate(OBJT_VNODE, lsize);
180 vm_object_hold(object);
182 object->handle = handle;
183 vp->v_object = object;
184 vp->v_filesize = length;
185 if (vp->v_mount && (vp->v_mount->mnt_kern_flag & MNTK_NOMSYNC))
186 vm_object_set_flag(object, OBJ_NOMSYNC);
189 if (object->size != lsize) {
190 kprintf("vnode_pager_alloc: Warning, objsize "
191 "mismatch %jd/%jd vp=%p obj=%p\n",
192 (intmax_t)object->size,
196 if (vp->v_filesize != length) {
197 kprintf("vnode_pager_alloc: Warning, filesize "
198 "mismatch %jd/%jd vp=%p obj=%p\n",
199 (intmax_t)vp->v_filesize,
206 lwkt_gettoken(&vp->v_token);
207 vclrflags(vp, VOLOCK);
208 if (vp->v_flag & VOWANT) {
209 vclrflags(vp, VOWANT);
212 lwkt_reltoken(&vp->v_token);
214 vm_object_drop(object);
220 * Add a ref to a vnode's existing VM object, return the object or
221 * NULL if the vnode did not have one. This does not create the
222 * object (we can't since we don't know what the proper blocksize/boff
223 * is to match the VFS's use of the buffer cache).
226 vnode_pager_reference(struct vnode *vp)
231 * Prevent race condition when allocating the object. This
232 * can happen with NFS vnodes since the nfsnode isn't locked.
234 * Serialize potential vnode/object teardowns and interlocks
236 lwkt_gettoken(&vp->v_token);
237 while (vp->v_flag & VOLOCK) {
238 vsetflags(vp, VOWANT);
239 tsleep(vp, 0, "vnpobj", 0);
241 vsetflags(vp, VOLOCK);
242 lwkt_reltoken(&vp->v_token);
245 * Prevent race conditions against deallocation of the VM
248 while ((object = vp->v_object) != NULL) {
249 vm_object_hold(object);
250 if ((object->flags & OBJ_DEAD) == 0)
252 vm_object_dead_sleep(object, "vadead");
253 vm_object_drop(object);
257 * The object is expected to exist, the caller will handle
258 * NULL returns if it does not.
265 lwkt_gettoken(&vp->v_token);
266 vclrflags(vp, VOLOCK);
267 if (vp->v_flag & VOWANT) {
268 vclrflags(vp, VOWANT);
271 lwkt_reltoken(&vp->v_token);
273 vm_object_drop(object);
279 vnode_pager_dealloc(vm_object_t object)
281 struct vnode *vp = object->handle;
284 panic("vnode_pager_dealloc: pager already dealloced");
286 vm_object_pip_wait(object, "vnpdea");
288 object->handle = NULL;
289 object->type = OBJT_DEAD;
291 vp->v_filesize = NOOFFSET;
292 vclrflags(vp, VTEXT | VOBJBUF);
293 swap_pager_freespace_all(object);
297 * Return whether the vnode pager has the requested page. Return the
298 * number of disk-contiguous pages before and after the requested page,
299 * not including the requested page.
302 vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex)
304 struct vnode *vp = object->handle;
312 * If no vp or vp is doomed or marked transparent to VM, we do not
315 if ((vp == NULL) || (vp->v_flag & VRECLAIMED))
319 * If filesystem no longer mounted or offset beyond end of file we do
322 loffset = IDX_TO_OFF(pindex);
324 if (vp->v_mount == NULL || loffset >= vp->v_filesize)
327 bsize = vp->v_mount->mnt_stat.f_iosize;
328 voff = loffset % bsize;
333 * BMAP returns byte counts before and after, where after
334 * is inclusive of the base page. haspage must return page
335 * counts before and after where after does not include the
338 * BMAP is allowed to return a *after of 0 for backwards
339 * compatibility. The base page is still considered valid if
340 * no error is returned.
342 error = VOP_BMAP(vp, loffset - voff, &doffset, NULL, NULL, 0);
345 if (doffset == NOOFFSET)
351 * Lets the VM system know about a change in size for a file.
352 * We adjust our own internal size and flush any cached pages in
353 * the associated object that are affected by the size change.
355 * NOTE: This routine may be invoked as a result of a pager put
356 * operation (possibly at object termination time), so we must be careful.
358 * NOTE: vp->v_filesize is initialized to NOOFFSET (-1), be sure that
359 * we do not blow up on the case. nsize will always be >= 0, however.
362 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize)
364 vm_pindex_t nobjsize;
365 vm_pindex_t oobjsize;
368 while ((object = vp->v_object) != NULL) {
369 vm_object_hold(object);
370 if (vp->v_object == object)
372 vm_object_drop(object);
378 * Hasn't changed size
380 if (nsize == vp->v_filesize) {
381 vm_object_drop(object);
386 * Has changed size. Adjust the VM object's size and v_filesize
387 * before we start scanning pages to prevent new pages from being
388 * allocated during the scan.
390 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK);
391 oobjsize = object->size;
392 object->size = nobjsize;
395 * File has shrunk. Toss any cached pages beyond the new EOF.
397 if (nsize < vp->v_filesize) {
398 vp->v_filesize = nsize;
399 if (nobjsize < oobjsize) {
400 vm_object_page_remove(object, nobjsize, oobjsize,
404 * This gets rid of garbage at the end of a page that is now
405 * only partially backed by the vnode. Since we are setting
406 * the entire page valid & clean after we are done we have
407 * to be sure that the portion of the page within the file
408 * bounds is already valid. If it isn't then making it
409 * valid would create a corrupt block.
411 if (nsize & PAGE_MASK) {
415 m = vm_page_lookup_busy_wait(object, OFF_TO_IDX(nsize),
419 int base = (int)nsize & PAGE_MASK;
420 int size = PAGE_SIZE - base;
422 struct lwbuf lwb_cache;
425 * Clear out partial-page garbage in case
426 * the page has been mapped.
428 * This is byte aligned.
430 lwb = lwbuf_alloc(m, &lwb_cache);
431 kva = lwbuf_kva(lwb);
432 bzero((caddr_t)kva + base, size);
436 * XXX work around SMP data integrity race
437 * by unmapping the page from user processes.
438 * The garbage we just cleared may be mapped
439 * to a user process running on another cpu
440 * and this code is not running through normal
441 * I/O channels which handle SMP issues for
442 * us, so unmap page to synchronize all cpus.
444 * XXX should vm_pager_unmap_page() have
447 vm_page_protect(m, VM_PROT_NONE);
450 * Clear out partial-page dirty bits. This
451 * has the side effect of setting the valid
452 * bits, but that is ok. There are a bunch
453 * of places in the VM system where we expected
454 * m->dirty == VM_PAGE_BITS_ALL. The file EOF
455 * case is one of them. If the page is still
456 * partially dirty, make it fully dirty.
458 * NOTE: We do not clear out the valid
459 * bits. This would prevent bogus_page
460 * replacement from working properly.
462 * NOTE: We do not want to clear the dirty
463 * bit for a partial DEV_BSIZE'd truncation!
464 * This is DEV_BSIZE aligned!
466 vm_page_clear_dirty_beg_nonincl(m, base, size);
468 m->dirty = VM_PAGE_BITS_ALL;
475 vp->v_filesize = nsize;
477 vm_object_drop(object);
481 * Release a page busied for a getpages operation. The page may have become
482 * wired (typically due to being used by the buffer cache) or otherwise been
483 * soft-busied and cannot be freed in that case. A held page can still be
487 vnode_pager_freepage(vm_page_t m)
489 if (m->busy || m->wire_count) {
498 * EOPNOTSUPP is no longer legal. For local media VFS's that do not
499 * implement their own VOP_GETPAGES, their VOP_GETPAGES should call to
500 * vnode_pager_generic_getpages() to implement the previous behaviour.
502 * All other FS's should use the bypass to get to the local media
503 * backing vp's VOP_GETPAGES.
506 vnode_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess)
512 rtval = VOP_GETPAGES(vp, mpp, PAGE_SIZE, 0, 0, seqaccess);
513 if (rtval == EOPNOTSUPP)
514 panic("vnode_pager: vfs's must implement vop_getpages\n");
519 * This is now called from local media FS's to operate against their
520 * own vnodes if they fail to implement VOP_GETPAGES.
522 * With all the caching local media devices do these days there is really
523 * very little point to attempting to restrict the I/O size to contiguous
524 * blocks on-disk, especially if our caller thinks we need all the specified
525 * pages. Just construct and issue a READ.
528 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *mpp, int bytecount,
529 int reqpage, int seqaccess)
540 * Do not do anything if the vnode is bad.
542 if (vp->v_mount == NULL)
546 * Calculate the number of pages. Since we are paging in whole
547 * pages, adjust bytecount to be an integral multiple of the page
548 * size. It will be clipped to the file EOF later on.
550 bytecount = round_page(bytecount);
551 count = bytecount / PAGE_SIZE;
554 * We could check m[reqpage]->valid here and shortcut the operation,
555 * but doing so breaks read-ahead. Instead assume that the VM
556 * system has already done at least the check, don't worry about
557 * any races, and issue the VOP_READ to allow read-ahead to function.
559 * This keeps the pipeline full for I/O bound sequentially scanned
565 * Discard pages past the file EOF. If the requested page is past
566 * the file EOF we just leave its valid bits set to 0, the caller
567 * expects to maintain ownership of the requested page. If the
568 * entire range is past file EOF discard everything and generate
571 foff = IDX_TO_OFF(mpp[0]->pindex);
572 if (foff >= vp->v_filesize) {
573 for (i = 0; i < count; i++) {
575 vnode_pager_freepage(mpp[i]);
577 return VM_PAGER_ERROR;
580 if (foff + bytecount > vp->v_filesize) {
581 bytecount = vp->v_filesize - foff;
582 i = round_page(bytecount) / PAGE_SIZE;
585 if (count != reqpage)
586 vnode_pager_freepage(mpp[count]);
591 * The size of the transfer is bytecount. bytecount will be an
592 * integral multiple of the page size unless it has been clipped
593 * to the file EOF. The transfer cannot exceed the file EOF.
595 * When dealing with real devices we must round-up to the device
598 if (vp->v_type == VBLK || vp->v_type == VCHR) {
599 int secmask = vp->v_rdev->si_bsize_phys - 1;
600 KASSERT(secmask < PAGE_SIZE, ("vnode_pager_generic_getpages: sector size %d too large\n", secmask + 1));
601 bytecount = (bytecount + secmask) & ~secmask;
605 * Severe hack to avoid deadlocks with the buffer cache
607 for (i = 0; i < count; ++i) {
608 vm_page_t mt = mpp[i];
610 vm_page_io_start(mt);
615 * Issue the I/O with some read-ahead if bytecount > PAGE_SIZE
619 ioflags |= IO_SEQMAX << IO_SEQSHIFT;
621 aiov.iov_base = NULL;
622 aiov.iov_len = bytecount;
623 auio.uio_iov = &aiov;
625 auio.uio_offset = foff;
626 auio.uio_segflg = UIO_NOCOPY;
627 auio.uio_rw = UIO_READ;
628 auio.uio_resid = bytecount;
630 mycpu->gd_cnt.v_vnodein++;
631 mycpu->gd_cnt.v_vnodepgsin += count;
633 error = VOP_READ(vp, &auio, ioflags, proc0.p_ucred);
636 * Severe hack to avoid deadlocks with the buffer cache
638 for (i = 0; i < count; ++i) {
639 vm_page_busy_wait(mpp[i], FALSE, "getpgs");
640 vm_page_io_finish(mpp[i]);
644 * Calculate the actual number of bytes read and clean up the
647 bytecount -= auio.uio_resid;
649 for (i = 0; i < count; ++i) {
650 vm_page_t mt = mpp[i];
653 if (error == 0 && mt->valid) {
654 if (mt->flags & PG_REFERENCED)
655 vm_page_activate(mt);
657 vm_page_deactivate(mt);
660 vnode_pager_freepage(mt);
662 } else if (mt->valid == 0) {
664 kprintf("page failed but no I/O error page "
665 "%p object %p pindex %d\n",
666 mt, mt->object, (int) mt->pindex);
667 /* whoops, something happened */
670 } else if (mt->valid != VM_PAGE_BITS_ALL) {
672 * Zero-extend the requested page if necessary (if
673 * the filesystem is using a small block size).
675 vm_page_zero_invalid(mt, TRUE);
679 kprintf("vnode_pager_getpage: I/O read error\n");
681 return (error ? VM_PAGER_ERROR : VM_PAGER_OK);
685 * EOPNOTSUPP is no longer legal. For local media VFS's that do not
686 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to
687 * vnode_pager_generic_putpages() to implement the previous behaviour.
689 * Caller has already cleared the pmap modified bits, if any.
691 * All other FS's should use the bypass to get to the local media
692 * backing vp's VOP_PUTPAGES.
695 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count,
696 boolean_t sync, int *rtvals)
700 int bytes = count * PAGE_SIZE;
703 * Force synchronous operation if we are extremely low on memory
704 * to prevent a low-memory deadlock. VOP operations often need to
705 * allocate more memory to initiate the I/O ( i.e. do a BMAP
706 * operation ). The swapper handles the case by limiting the amount
707 * of asynchronous I/O, but that sort of solution doesn't scale well
708 * for the vnode pager without a lot of work.
710 * Also, the backing vnode's iodone routine may not wake the pageout
711 * daemon up. This should be probably be addressed XXX.
714 if ((vmstats.v_free_count + vmstats.v_cache_count) <
715 vmstats.v_pageout_free_min) {
720 * Call device-specific putpages function
723 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0);
724 if (rtval == EOPNOTSUPP) {
725 kprintf("vnode_pager: *** WARNING *** stale FS putpages\n");
726 rtval = vnode_pager_generic_putpages( vp, m, bytes, sync, rtvals);
732 * This is now called from local media FS's to operate against their
733 * own vnodes if they fail to implement VOP_PUTPAGES.
735 * This is typically called indirectly via the pageout daemon and
736 * clustering has already typically occured, so in general we ask the
737 * underlying filesystem to write the data out asynchronously rather
741 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *m, int bytecount,
742 int flags, int *rtvals)
746 int maxsize, ncount, count;
747 vm_ooffset_t poffset;
753 object = vp->v_object;
754 count = bytecount / PAGE_SIZE;
756 for (i = 0; i < count; i++)
757 rtvals[i] = VM_PAGER_AGAIN;
759 if ((int) m[0]->pindex < 0) {
760 kprintf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%x)\n",
761 (long)m[0]->pindex, m[0]->dirty);
762 rtvals[0] = VM_PAGER_BAD;
766 maxsize = count * PAGE_SIZE;
769 poffset = IDX_TO_OFF(m[0]->pindex);
772 * If the page-aligned write is larger then the actual file we
773 * have to invalidate pages occuring beyond the file EOF.
775 * If the file EOF resides in the middle of a page we still clear
776 * all of that page's dirty bits later on. If we didn't it would
777 * endlessly re-write.
779 * We do not under any circumstances truncate the valid bits, as
780 * this will screw up bogus page replacement.
782 * The caller has already read-protected the pages. The VFS must
783 * use the buffer cache to wrap the pages. The pages might not
784 * be immediately flushed by the buffer cache but once under its
785 * control the pages themselves can wind up being marked clean
786 * and their covering buffer cache buffer can be marked dirty.
788 if (poffset + maxsize > vp->v_filesize) {
789 if (poffset < vp->v_filesize) {
790 maxsize = vp->v_filesize - poffset;
791 ncount = btoc(maxsize);
796 if (ncount < count) {
797 for (i = ncount; i < count; i++) {
798 rtvals[i] = VM_PAGER_BAD;
804 * pageouts are already clustered, use IO_ASYNC to force a bawrite()
805 * rather then a bdwrite() to prevent paging I/O from saturating
806 * the buffer cache. Dummy-up the sequential heuristic to cause
807 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set,
808 * the system decides how to cluster.
811 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL))
813 else if ((flags & VM_PAGER_CLUSTER_OK) == 0)
815 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0;
816 ioflags |= IO_SEQMAX << IO_SEQSHIFT;
818 aiov.iov_base = (caddr_t) 0;
819 aiov.iov_len = maxsize;
820 auio.uio_iov = &aiov;
822 auio.uio_offset = poffset;
823 auio.uio_segflg = UIO_NOCOPY;
824 auio.uio_rw = UIO_WRITE;
825 auio.uio_resid = maxsize;
827 error = VOP_WRITE(vp, &auio, ioflags, proc0.p_ucred);
828 mycpu->gd_cnt.v_vnodeout++;
829 mycpu->gd_cnt.v_vnodepgsout += ncount;
832 krateprintf(&vbadrate,
833 "vnode_pager_putpages: I/O error %d\n", error);
835 if (auio.uio_resid) {
836 krateprintf(&vresrate,
837 "vnode_pager_putpages: residual I/O %zd at %lu\n",
838 auio.uio_resid, (u_long)m[0]->pindex);
841 for (i = 0; i < ncount; i++) {
842 rtvals[i] = VM_PAGER_OK;
843 vm_page_undirty(m[i]);
850 * Run the chain and if the bottom-most object is a vnode-type lock the
851 * underlying vnode. A locked vnode or NULL is returned.
854 vnode_pager_lock(vm_object_t object)
856 struct vnode *vp = NULL;
864 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object));
867 while (lobject->type != OBJT_VNODE) {
868 if (lobject->flags & OBJ_DEAD)
870 tobject = lobject->backing_object;
873 vm_object_hold(tobject);
874 if (tobject == lobject->backing_object) {
875 if (lobject != object) {
876 vm_object_lock_swap();
877 vm_object_drop(lobject);
881 vm_object_drop(tobject);
884 while (lobject->type == OBJT_VNODE &&
885 (lobject->flags & OBJ_DEAD) == 0) {
889 vp = lobject->handle;
890 error = vget(vp, LK_SHARED | LK_RETRY | LK_CANRECURSE);
892 if (lobject->handle == vp)
896 kprintf("vnode_pager_lock: vp %p error %d "
897 "lockstatus %d, retrying\n",
899 lockstatus(&vp->v_lock, curthread));
900 tsleep(object->handle, 0, "vnpgrl", hz);
904 if (lobject != object)
905 vm_object_drop(lobject);