[Openmosix-devel] [Patch] Do not crash upon remote-remote migration

[Ansgar E. <an...@th...>]

When asking an already migrated process to move to another (remote)
node, bring it back home first. The current implementation leads to a
crash. A direct remote->remote migration would be better, but is not
implemented yet.

---

 hpc/migctrl.c |   84 +++++++++++++++++++++++++++++++----------------------=
----
 1 files changed, 46 insertions(+), 38 deletions(-)

2a7d618eb6d2ae0942349f16e7a46d13351d7dc2
diff --git a/hpc/migctrl.c b/hpc/migctrl.c
index 18a798a..dee9adb 100644
--- a/hpc/migctrl.c
+++ b/hpc/migctrl.c
@@ -79,6 +79,44 @@ int task_remote_wait_expel(task_t *p)
 	return task_remote_expel(p);
 }
=20
+
+/**
+ * task_local_bring - Receive task back in the deputy stub
+ * @p:		deputy task to receive
+ * @reason:	reason to send (if any)
+ **/
+static int task_local_bring(task_t *p, int reason)
+{
+	int error;
+	om_link_t *link;
+
+	if (obtain_mm(p)) {
+		printk(KERN_ERR "unable to obtain mm\n");
+		goto failed;
+	}
+
+	/* send remote request */
+	comm_send_req(p->om.contact, DEP_COMING_HOME);
+
+	/* see if other part is with on this */
+	if (mig_recv_hshake(p->om.contact))
+		goto failed;
+=09
+	/* receive the process back */
+	error =3D mig_do_receive(p);
+	if (error)
+		goto failed;
+
+	task_clear_dflags(p, DDEPUTY);
+	link =3D task_set_comm(p, NULL);
+	comm_close(link);
+
+	return 0;
+failed:
+	OMBUG("failed\n");
+	return -1;
+}
+
 /**
  * task_local_send - Send a local task to remote
  * @p:		task to send
@@ -90,6 +128,14 @@ static int task_local_send(task_t *p, st
 	om_link_t *mlink;
 	int error =3D 0;
=20
+	/* if this is a stub, bring it back first */
+	if (p->om.contact)
+	{
+		error =3D task_local_bring(p, reason);
+		if (error)
+			goto failed;
+	}
+
 	sockaddr_setup_port(whereto, REMOTE_DAEMON_PORT);
 	mlink =3D comm_setup_connect(whereto, 0);
 	if (!mlink) {
@@ -123,44 +169,6 @@ failed:
 }
=20
=20
-
-/**
- * task_local_bring - Receive task back in the deputy stub
- * @p:		deputy task to receive
- * @reason:	reason to send (if any)
- **/
-static int task_local_bring(task_t *p, int reason)
-{
-	int error;
-	om_link_t *link;
-
-	if (obtain_mm(p)) {
-		printk(KERN_ERR "unable to obtain mm\n");
-		goto failed;
-	}
-
-	/* send remote request */
-	comm_send_req(p->om.contact, DEP_COMING_HOME);
-
-	/* see if other part is with on this */
-	if (mig_recv_hshake(p->om.contact))
-		goto failed;
-
-	/* receive the process back */
-	error =3D mig_do_receive(p);
-	if (error)
-		goto failed;
-
-	task_clear_dflags(p, DDEPUTY);
-	link =3D task_set_comm(p, NULL);
-	comm_close(link);
-
-	return 0;
-failed:
-	OMBUG("failed\n");
-	return -1;
-}
-
 /**
  * task_move_remote2remote - migrate a task from remote to remote
  * @p:		task to send
--=20
1.2.4

--=20
Ansgar Esztermann
Researcher & Sysadmin
http://www2.thphy.uni-duesseldorf.de/~ansgar