Each actor is located on a simulated |API_s4u_Host|_. Each host is located
itself in a |API_s4u_NetZone|_, that knows the networking path between one
resource to another. Each NetZone is included in another one, forming
-a tree of NetZones which root zone contains the whole platform.
+a tree of NetZones which root zone contains the whole platform. The
+actors can also be located on a |API_s4U_VirtualMachine|_ that may
+restrict the activities it contains to a limited amount of cores.
+Virtual machines can also be migrated between hosts.
The :ref:`simgrid::s4u::this_actor <API_s4u_this_actor>` namespace
provides many helper functions to simplify the code of actors.
.. |API_s4u_Storages| replace:: **Storages**
.. _API_s4u_Storages: #s4u-storage
-.. |API_s4u_VirtualMachines| replace:: **VirtualMachines**
-.. _API_s4u_VirtualMachines: #s4u-virtualmachine
+.. |API_s4u_VirtualMachine| replace:: **VirtualMachines**
.. |API_s4u_Host| replace:: **Host**
will already be there on the receiver host when the receiver actor
posts its :cpp:func:`get() <simgrid::s4u::Mailbox::get()>`
+Note that being permanent receivers of a mailbox prevents actors to be
+garbage-collected. If your simulation creates many short-lived actors
+that marked as permanent receiver, you should call
+``mailbox->set_receiver(nullptr)`` by the end of the actors so that their
+memory gets properly reclaimed. This call should be at the end of the
+actor's function, not in a on_exit callback.
+
Memory Management
*****************
