When tmpfs and POSIX shm pagein a page for the sole purpose of performing

truncation, immediately queue the page for asynchronous laundering rather
than making the page pass through inactive queue first.

Reviewed by:	kib, markj

sys/fs/tmpfs/tmpfs_subr.c

@@ -1376,7 +1376,15 @@ tmpfs_reg_resize(struct vnode *vp, off_t newsize, boolean_t ignerr)
 				    NULL);
 				vm_page_lock(m);
 				if (rv == VM_PAGER_OK) {
-					vm_page_deactivate(m);
+					/*
+					 * Since the page was not resident,
+					 * and therefore not recently
+					 * accessed, immediately enqueue it
+					 * for asynchronous laundering.  The
+					 * current operation is not regarded
+					 * as an access.
+					 */
+					vm_page_launder(m);
 					vm_page_unlock(m);
 					vm_page_xunbusy(m);
 				} else {

sys/kern/uipc_shm.c

@@ -460,7 +460,15 @@ shm_dotruncate(struct shmfd *shmfd, off_t length)
 				    NULL);
 				vm_page_lock(m);
 				if (rv == VM_PAGER_OK) {
-					vm_page_deactivate(m);
+					/*
+					 * Since the page was not resident,
+					 * and therefore not recently
+					 * accessed, immediately enqueue it
+					 * for asynchronous laundering.  The
+					 * current operation is not regarded
+					 * as an access.
+					 */
+					vm_page_launder(m);
 					vm_page_unlock(m);
 					vm_page_xunbusy(m);
 				} else {