svn commit: r269907 - in head/sys: kern vm

[Konstantin Belousov]

Author: kib
Date: Wed Aug 13 05:44:08 2014
New Revision: 269907
URL: http://svnweb.freebsd.org/changeset/base/269907

Log:
  If vm_page_grab() allocates a new page, the page is not inserted into
  page queue even when the allocation is not wired.  It is
  responsibility of the vm_page_grab() caller to ensure that the page
  does not end on the vm_object queue but not on the pagedaemon queue,
  which would effectively create unpageable unwired page.
  
  In exec_map_first_page() and vm_imgact_hold_page(), activate the page
  immediately after unbusying it, to avoid leak.
  
  In the uiomove_object_page(), deactivate page before the object is
  unlocked.  There is no leak, since the page is deactivated after
  uiomove_fromphys() finished.  But allowing non-queued non-wired page
  in the unlocked object queue makes it impossible to assert that leak
  does not happen in other places.
  
  Reviewed by:	alc
  Sponsored by:	The FreeBSD Foundation
  MFC after:	1 week

Modified:
  head/sys/kern/kern_exec.c
  head/sys/kern/uipc_shm.c
  head/sys/vm/vm_glue.c

Modified: head/sys/kern/kern_exec.c
==============================================================================
--- head/sys/kern/kern_exec.c	Wed Aug 13 05:15:28 2014	(r269906)
+++ head/sys/kern/kern_exec.c	Wed Aug 13 05:44:08 2014	(r269907)
@@ -993,6 +993,7 @@ exec_map_first_page(imgp)
 	vm_page_xunbusy(ma[0]);
 	vm_page_lock(ma[0]);
 	vm_page_hold(ma[0]);
+	vm_page_activate(ma[0]);
 	vm_page_unlock(ma[0]);
 	VM_OBJECT_WUNLOCK(object);
 

Modified: head/sys/kern/uipc_shm.c
==============================================================================
--- head/sys/kern/uipc_shm.c	Wed Aug 13 05:15:28 2014	(r269906)
+++ head/sys/kern/uipc_shm.c	Wed Aug 13 05:44:08 2014	(r269907)
@@ -197,6 +197,12 @@ uiomove_object_page(vm_object_t obj, siz
 	vm_page_xunbusy(m);
 	vm_page_lock(m);
 	vm_page_hold(m);
+	if (m->queue == PQ_NONE) {
+		vm_page_deactivate(m);
+	} else {
+		/* Requeue to maintain LRU ordering. */
+		vm_page_requeue(m);
+	}
 	vm_page_unlock(m);
 	VM_OBJECT_WUNLOCK(obj);
 	error = uiomove_fromphys(&m, offset, tlen, uio);
@@ -208,12 +214,6 @@ uiomove_object_page(vm_object_t obj, siz
 	}
 	vm_page_lock(m);
 	vm_page_unhold(m);
-	if (m->queue == PQ_NONE) {
-		vm_page_deactivate(m);
-	} else {
-		/* Requeue to maintain LRU ordering. */
-		vm_page_requeue(m);
-	}
 	vm_page_unlock(m);
 
 	return (error);

Modified: head/sys/vm/vm_glue.c
==============================================================================
--- head/sys/vm/vm_glue.c	Wed Aug 13 05:15:28 2014	(r269906)
+++ head/sys/vm/vm_glue.c	Wed Aug 13 05:44:08 2014	(r269907)
@@ -251,6 +251,7 @@ vm_imgact_hold_page(vm_object_t object, 
 	vm_page_xunbusy(m);
 	vm_page_lock(m);
 	vm_page_hold(m);
+	vm_page_activate(m);
 	vm_page_unlock(m);
 out:
 	VM_OBJECT_WUNLOCK(object);