Index: uvm.h
===================================================================
RCS file: /cvs/src/sys/uvm/uvm.h,v
retrieving revision 1.57
diff -u -p -r1.57 uvm.h
--- uvm.h	3 Oct 2014 17:41:00 -0000	1.57
+++ uvm.h	22 Apr 2015 04:19:34 -0000
@@ -59,8 +59,6 @@ struct uvm {
 	/* Lock order: pageqlock, then fpageqlock. */
 	struct mutex fpageqlock;	/* lock for free page q  + pdaemon */
 	boolean_t page_init_done;	/* TRUE if uvm_page_init() finished */
-	boolean_t page_idle_zero;	/* TRUE if we should try to zero
-					   pages in the idle loop */
 	struct uvm_pmr_control pmr_control; /* pmemrange data */
 
 		/* page daemon trigger */
Index: uvm_page.c
===================================================================
RCS file: /cvs/src/sys/uvm/uvm_page.c,v
retrieving revision 1.137
diff -u -p -r1.137 uvm_page.c
--- uvm_page.c	14 Mar 2015 03:38:53 -0000	1.137
+++ uvm_page.c	22 Apr 2015 04:19:34 -0000
@@ -100,11 +100,6 @@ int vm_nphysseg = 0;				/* XXXCDC: uvm.n
  * of the things necessary to do idle page zero'ing efficiently.
  * We therefore provide a way to disable it from machdep code here.
  */
-/*
- * XXX disabled until we can find a way to do this without causing
- * problems for either cpu caches or DMA latency.
- */
-boolean_t vm_page_zero_enable = FALSE;
 
 /*
  * local variables
@@ -154,7 +149,6 @@ uvm_pageinsert(struct vm_page *pg)
 static __inline void
 uvm_pageremove(struct vm_page *pg)
 {
-
 	KASSERT(pg->pg_flags & PG_TABLED);
 	RB_REMOVE(uvm_objtree, &pg->uobject->memt, pg);
 
@@ -289,9 +283,6 @@ uvm_page_init(vaddr_t *kvm_startp, vaddr
 	uvmexp.vnodemin = uvmexp.vnodeminpct * 256 / 100;
 	uvmexp.vtextmin = uvmexp.vtextminpct * 256 / 100;
 
-  	/* determine if we should zero pages in the idle loop. */
-	uvm.page_idle_zero = vm_page_zero_enable;
-
 	uvm.page_init_done = TRUE;
 }
 
@@ -1065,9 +1056,6 @@ uvm_pagefree(struct vm_page *pg)
 #endif
 
 	uvm_pmr_freepages(pg, 1);
-
-	if (uvmexp.zeropages < UVM_PAGEZERO_TARGET)
-		uvm.page_idle_zero = vm_page_zero_enable;
 }
 
 /*