- Introduce a cache-miss optimization for consistency with other

  accesses of the cache member of vm_object objects.
- Use novel vm_page_is_cached() for checks outside of the vm subsystem.

Reviewed by:	alc
MFC after:	2 weeks
X-MFC:		r234039

3 files changed, 3 insertions, 4 deletions

diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
index e22e552..2f3f2a7 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
@@ -345,10 +345,9 @@ page_lookup(vnode_t *vp, int64_t start, int64_t off, int64_t nbytes)
 			vm_page_busy(pp);
 			vm_page_undirty(pp);
 		} else {
-			if (__predict_false(obj->cache != NULL)) {
+			if (vm_page_is_cached(obj, OFF_TO_IDX(start)))
 				vm_page_cache_free(obj, OFF_TO_IDX(start),
 				    OFF_TO_IDX(start) + 1);
-			}
 			pp = NULL;
 		}
 		break;
diff --git a/sys/fs/tmpfs/tmpfs_vnops.c b/sys/fs/tmpfs/tmpfs_vnops.c
index 5c86c36..be42f9a 100644
--- a/sys/fs/tmpfs/tmpfs_vnops.c
+++ b/sys/fs/tmpfs/tmpfs_vnops.c
@@ -662,7 +662,7 @@ lookupvpg:
 		VM_OBJECT_UNLOCK(vobj);
 		error = uiomove_fromphys(&vpg, offset, tlen, uio);
 	} else {
-		if (__predict_false(vobj->cache != NULL))
+		if (vm_page_is_cached(vobj, idx))
 			vm_page_cache_free(vobj, idx, idx + 1);
 		VM_OBJECT_UNLOCK(vobj);
 		vpg = NULL;
diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
index 565ac99..65bb701 100644
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
@@ -1303,7 +1303,7 @@ vm_page_is_cached(vm_object_t object, vm_pindex_t pindex)
 	 * exist.
 	 */
 	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
-	if (object->cache == NULL)
+	if (__predict_true(object->cache == NULL))
 		return (FALSE);
 	mtx_lock(&vm_page_queue_free_mtx);
 	m = vm_page_cache_lookup(object, pindex);