On Fri, Oct 29, 2010 at 07:06:03PM +0300, Andriy Gapon wrote: > Probably yes, but have to be careful there. > First, do vm_page_grab only for UIO_NOCOPY case. > Second, the first page is already "shared busy" after vm_page_io_start() call > in > kern_sendfile; so you might need VM_ALLOC_IGN_SBUSY for that page to avoid a > deadlock.
RELENG_8 doesn`t have VM_ALLOC_IGN_SBUSY, it appeared only in HEAD. Can you review this patch, Whether correctly I have understood? (didnt test it yet) --- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c.orig 2010-10-29 18:18:23.921078337 +0200 +++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c 2010-10-29 19:23:48.142513084 +0200 @@ -449,7 +449,7 @@ int bytes = MIN(PAGESIZE - off, len); again: - if ((m = vm_page_lookup(obj, OFF_TO_IDX(start))) != NULL && + if (uio->uio_segflg != UIO_NOCOPY && (m = vm_page_lookup(obj, OFF_TO_IDX(start))) != NULL && vm_page_is_valid(m, off, bytes)) { if (vm_page_sleep_if_busy(m, FALSE, "zfsmrb")) goto again; @@ -464,7 +464,7 @@ uiomove_fromphys(&m, off, bytes, uio); VM_OBJECT_LOCK(obj); vm_page_wakeup(m); - } else if (m != NULL && uio->uio_segflg == UIO_NOCOPY) { + } else if (uio->uio_segflg == UIO_NOCOPY) { /* * The code below is here to make sendfile(2) work * correctly with ZFS. As pointed out by ups@ @@ -472,11 +472,9 @@ * but it pessimize performance of sendfile/UFS, that's * why I handle this special case in ZFS code. */ - KASSERT(off == 0, - ("unexpected offset in mappedread for sendfile")); - if (vm_page_sleep_if_busy(m, FALSE, "zfsmrb")) - goto again; - vm_page_busy(m); + if((m = vm_page_lookup(obj, OFF_TO_IDX(start))) == NULL || !vm_page_is_valid(m, off, bytes)) + m = vm_page_grab(obj, OFF_TO_IDX(start), VM_ALLOC_NORMAL|VM_ALLOC_RETRY); + VM_OBJECT_UNLOCK(obj); if (dirbytes > 0) { error = dmu_read_uio(os, zp->z_id, uio, _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"