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Index: share/man/man9/vm_page_alloc.9
===================================================================
--- share/man/man9/vm_page_alloc.9
+++ share/man/man9/vm_page_alloc.9
@@ -26,7 +26,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd November 16, 2016
+.Dd February 19, 2021
.Dt VM_PAGE_ALLOC 9
.Os
.Sh NAME
@@ -103,11 +103,7 @@
.It Dv VM_ALLOC_WIRED
The returned page will be wired.
.It Dv VM_ALLOC_ZERO
-Indicate a preference for a pre-zeroed page.
-There is no guarantee that the returned page will be zeroed, but it
-will have the
-.Dv PG_ZERO
-flag set if it is zeroed.
+Zero-fill the contents of the page.
.El
.El
.Sh RETURN VALUES
Index: sys/vm/vm_page.c
===================================================================
--- sys/vm/vm_page.c
+++ sys/vm/vm_page.c
@@ -1949,6 +1949,19 @@
return (0);
}
+static void
+vm_page_alloc_zero(vm_page_t m, int req)
+{
+ if ((req & VM_ALLOC_ZERO) != 0) {
+ if ((m->flags & PG_ZERO) != 0) {
+ VM_CNT_INC(v_ozfod);
+ } else {
+ pmap_zero_page(m);
+ VM_CNT_INC(v_zfod);
+ }
+ }
+}
+
/*
* vm_page_alloc:
*
@@ -1969,9 +1982,10 @@
* VM_ALLOC_NODUMP do not include the page in a kernel core dump
* VM_ALLOC_NOOBJ page is not associated with an object and
* should not be exclusive busy
+ *
* VM_ALLOC_SBUSY shared busy the allocated page
* VM_ALLOC_WIRED wire the allocated page
- * VM_ALLOC_ZERO prefer a zeroed page
+ * VM_ALLOC_ZERO return a zeroed page
*/
vm_page_t
vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int req)
@@ -2144,10 +2158,9 @@
vm_page_alloc_check(m);
/*
- * Initialize the page. Only the PG_ZERO flag is inherited.
+ * Initialize the page. Zero its contents if so requested.
*/
- if ((req & VM_ALLOC_ZERO) != 0)
- flags |= (m->flags & PG_ZERO);
+ vm_page_alloc_zero(m, req);
if ((req & VM_ALLOC_NODUMP) != 0)
flags |= PG_NODUMP;
m->flags = flags;
@@ -2175,7 +2188,8 @@
KASSERT(m->object == NULL, ("page %p has object", m));
m->oflags = VPO_UNMANAGED;
m->busy_lock = VPB_UNBUSIED;
- /* Don't change PG_ZERO. */
+ if ((req & VM_ALLOC_ZERO) != 0)
+ m->flags |= PG_ZERO;
vm_page_free_toq(m);
if (req & VM_ALLOC_WAITFAIL) {
VM_OBJECT_WUNLOCK(object);
@@ -2232,7 +2246,7 @@
* should not be exclusive busy
* VM_ALLOC_SBUSY shared busy the allocated page
* VM_ALLOC_WIRED wire the allocated page
- * VM_ALLOC_ZERO prefer a zeroed page
+ * VM_ALLOC_ZERO return a zeroed page
*/
vm_page_t
vm_page_alloc_contig(vm_object_t object, vm_pindex_t pindex, int req,
@@ -2334,11 +2348,9 @@
}
/*
- * Initialize the pages. Only the PG_ZERO flag is inherited.
+ * Initialize the pages. Zero their contents if so requested.
*/
flags = 0;
- if ((req & VM_ALLOC_ZERO) != 0)
- flags = PG_ZERO;
if ((req & VM_ALLOC_NODUMP) != 0)
flags |= PG_NODUMP;
oflags = object == NULL || (object->flags & OBJ_UNMANAGED) != 0 ?
@@ -2357,8 +2369,9 @@
memattr = object->memattr;
}
for (m = m_ret; m < &m_ret[npages]; m++) {
+ vm_page_alloc_zero(m, req);
+ m->flags = flags;
m->a.flags = 0;
- m->flags = (m->flags | PG_NODUMP) & flags;
m->busy_lock = busy_lock;
if ((req & VM_ALLOC_WIRED) != 0)
m->ref_count = 1;
@@ -2377,7 +2390,8 @@
m->ref_count = 0;
m->oflags = VPO_UNMANAGED;
m->busy_lock = VPB_UNBUSIED;
- /* Don't change PG_ZERO. */
+ if ((req & VM_ALLOC_ZERO) != 0)
+ m->flags |= PG_ZERO;
vm_page_free_toq(m);
}
if (req & VM_ALLOC_WAITFAIL) {
@@ -2434,7 +2448,7 @@
* VM_ALLOC_COUNT(number) the number of additional pages that the caller
* intends to allocate
* VM_ALLOC_WIRED wire the allocated page
- * VM_ALLOC_ZERO prefer a zeroed page
+ * VM_ALLOC_ZERO return a zeroed page
*/
vm_page_t
vm_page_alloc_freelist(int freelist, int req)
@@ -2458,7 +2472,6 @@
{
struct vm_domain *vmd;
vm_page_t m;
- u_int flags;
m = NULL;
vmd = VM_DOMAIN(domain);
@@ -2480,13 +2493,11 @@
vm_page_alloc_check(m);
/*
- * Initialize the page. Only the PG_ZERO flag is inherited.
+ * Initialize the pages. Zero their contents if so requested.
*/
+ vm_page_alloc_zero(m, req);
+ m->flags = 0;
m->a.flags = 0;
- flags = 0;
- if ((req & VM_ALLOC_ZERO) != 0)
- flags = PG_ZERO;
- m->flags &= flags;
if ((req & VM_ALLOC_WIRED) != 0) {
vm_wire_add(1);
m->ref_count = 1;

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