svn commit: r213937 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs

[Andriy Gapon]

Author: avg
Date: Sat Oct 16 20:43:05 2010
New Revision: 213937
URL: http://svn.freebsd.org/changeset/base/213937

Log:
  zfs: add vop_getpages method implementation
  
  This should make vnode_pager_getpages path a bit shorter and clearer.
  Also this should eliminate problems with partially valid pages.
  Having this method opens room for future optimizations.
  
  To do: try to satisfy other pages besides the required one taking into
  account tradeofs between number of page faults, read throughput and read
  latency.  Also, eventually vop_putpages should be added too.
  
  Reviewed by:	kib, mm, pjd
  MFC after:	3 weeks

Modified:
  head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c

Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c	Sat Oct 16 20:13:15 2010	(r213936)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c	Sat Oct 16 20:43:05 2010	(r213937)
@@ -4199,6 +4199,96 @@ ioflags(int ioflags)
 }
 
 static int
+zfs_getpages(struct vnode *vp, vm_page_t *m, int count, int reqpage)
+{
+	znode_t *zp = VTOZ(vp);
+	zfsvfs_t *zfsvfs = zp->z_zfsvfs;
+	objset_t *os = zp->z_zfsvfs->z_os;
+	vm_page_t mreq;
+	vm_object_t object;
+	caddr_t va;
+	struct sf_buf *sf;
+	int i, error;
+	int pcount, size;
+
+	ZFS_ENTER(zfsvfs);
+	ZFS_VERIFY_ZP(zp);
+
+	pcount = round_page(count) / PAGE_SIZE;
+	mreq = m[reqpage];
+	object = mreq->object;
+	error = 0;
+
+	KASSERT(vp->v_object == object, ("mismatching object"));
+
+	VM_OBJECT_LOCK(object);
+
+	for (i = 0; i < pcount; i++) {
+		if (i != reqpage) {
+			vm_page_lock(m[i]);
+			vm_page_free(m[i]);
+			vm_page_unlock(m[i]);
+		}
+	}
+
+	if (mreq->valid) {
+		if (mreq->valid != VM_PAGE_BITS_ALL)
+			vm_page_zero_invalid(mreq, TRUE);
+		VM_OBJECT_UNLOCK(object);
+		ZFS_EXIT(zfsvfs);
+		return (VM_PAGER_OK);
+	}
+
+	PCPU_INC(cnt.v_vnodein);
+	PCPU_INC(cnt.v_vnodepgsin);
+
+	if (IDX_TO_OFF(mreq->pindex) >= object->un_pager.vnp.vnp_size) {
+		VM_OBJECT_UNLOCK(object);
+		ZFS_EXIT(zfsvfs);
+		return (VM_PAGER_BAD);
+	}
+
+	size = PAGE_SIZE;
+	if (IDX_TO_OFF(mreq->pindex) + size > object->un_pager.vnp.vnp_size)
+		size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(mreq->pindex);
+
+	VM_OBJECT_UNLOCK(object);
+
+	va = zfs_map_page(mreq, &sf);
+	error = dmu_read(os, zp->z_id, IDX_TO_OFF(mreq->pindex),
+	    size, va, DMU_READ_PREFETCH);
+	if (size != PAGE_SIZE)
+		bzero(va + size, PAGE_SIZE - size);
+	zfs_unmap_page(sf);
+
+	VM_OBJECT_LOCK(object);
+
+	if (!error)
+		mreq->valid = VM_PAGE_BITS_ALL;
+	KASSERT(mreq->dirty == 0, ("zfs_getpages: page %p is dirty", mreq));
+
+	VM_OBJECT_UNLOCK(object);
+
+	ZFS_ACCESSTIME_STAMP(zfsvfs, zp);
+	ZFS_EXIT(zfsvfs);
+	return (error ? VM_PAGER_ERROR : VM_PAGER_OK);
+}
+
+static int
+zfs_freebsd_getpages(ap)
+	struct vop_getpages_args /* {
+		struct vnode *a_vp;
+		vm_page_t *a_m;
+		int a_count;
+		int a_reqpage;
+		vm_ooffset_t a_offset;
+	} */ *ap;
+{
+
+	return (zfs_getpages(ap->a_vp, ap->a_m, ap->a_count, ap->a_reqpage));
+}
+
+static int
 zfs_freebsd_open(ap)
 	struct vop_open_args /* {
 		struct vnode *a_vp;
@@ -5314,6 +5404,7 @@ struct vop_vector zfs_vnodeops = {
 	.vop_getacl =		zfs_freebsd_getacl,
 	.vop_setacl =		zfs_freebsd_setacl,
 	.vop_aclcheck =		zfs_freebsd_aclcheck,
+	.vop_getpages =		zfs_freebsd_getpages,
 };
 
 struct vop_vector zfs_fifoops = {