Replace manyinstances of VM_WAIT with blocking page allocation flags

similar to the kernel memory allocator.

This simplifies NUMA allocation because the domain will be known at wait
time and races between failure and sleeping are eliminated.  This also
reduces boilerplate code and simplifies callers.

A wait primitive is supplied for uma zones for similar reasons.  This
eliminates some non-specific VM_WAIT calls in favor of more explicit
sleeps that may be satisfied without new pages.

Reviewed by:	alc, kib, markj
Tested by:	pho
Sponsored by:	Netflix, Dell/EMC Isilon

1 files changed, 3 insertions, 6 deletions

diff --git a/sys/kern/uipc_shm.c b/sys/kern/uipc_shm.c
index a4fdb85a95c3..c8e5f0d1ccd9 100644
--- a/sys/kern/uipc_shm.c
+++ b/sys/kern/uipc_shm.c
@@ -454,13 +454,10 @@ retry:
 				if (vm_page_sleep_if_busy(m, "shmtrc"))
 					goto retry;
 			} else if (vm_pager_has_page(object, idx, NULL, NULL)) {
-				m = vm_page_alloc(object, idx, VM_ALLOC_NORMAL);
-				if (m == NULL) {
-					VM_OBJECT_WUNLOCK(object);
-					VM_WAIT;
-					VM_OBJECT_WLOCK(object);
+				m = vm_page_alloc(object, idx,
+				    VM_ALLOC_NORMAL | VM_ALLOC_WAITFAIL);
+				if (m == NULL)
 					goto retry;
-				}
 				rv = vm_pager_get_pages(object, &m, 1, NULL,
 				    NULL);
 				vm_page_lock(m);