From: Frederic Suter <frederic.suter@cc.in2p3.fr>
Date: Tue, 26 Dec 2017 09:57:08 +0000 (+0100)
Subject: allow zero-cost migration (a.k.a. setPm)
X-Git-Tag: v3.19~404
X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/commitdiff_plain/98a7e16b0620dead1ef3f21792ce9f917b4ece58

allow zero-cost migration (a.k.a. setPm)

remove assert in suspend related to migration to be able to use it
during the migration (was a crappy hack before). This implies that we
assume that migration is a blocking operation (which is it) and that
nobody will try to let another process do a suspend.
---

diff --git a/include/simgrid/s4u/VirtualMachine.hpp b/include/simgrid/s4u/VirtualMachine.hpp
index a655e4905e..3510e78ce2 100644
--- a/include/simgrid/s4u/VirtualMachine.hpp
+++ b/include/simgrid/s4u/VirtualMachine.hpp
@@ -55,6 +55,7 @@ public:
   void getParameters(vm_params_t params);
   void setParameters(vm_params_t params);
   simgrid::s4u::Host* getPm();
+  void setPm(simgrid::s4u::Host * pm);
   size_t getRamsize();
   void setRamsize(size_t ramsize);
   void setBound(double bound);
diff --git a/src/plugins/vm/VirtualMachineImpl.cpp b/src/plugins/vm/VirtualMachineImpl.cpp
index 8b5f1c8502..9ba6c33151 100644
--- a/src/plugins/vm/VirtualMachineImpl.cpp
+++ b/src/plugins/vm/VirtualMachineImpl.cpp
@@ -151,10 +151,9 @@ void VirtualMachineImpl::setState(e_surf_vm_state_t state)
 {
   vmState_ = state;
 }
+
 void VirtualMachineImpl::suspend(smx_actor_t issuer)
 {
-  if (isMigrating)
-    THROWF(vm_error, 0, "Cannot suspend VM '%s': it is migrating", piface_->getCname());
   if (getState() != SURF_VM_STATE_RUNNING)
     THROWF(vm_error, 0, "Cannot suspend VM %s: it is not running.", piface_->getCname());
   if (issuer->host == piface_)
diff --git a/src/plugins/vm/VmLiveMigration.cpp b/src/plugins/vm/VmLiveMigration.cpp
index 46286f94d7..7d8c3b12b6 100644
--- a/src/plugins/vm/VmLiveMigration.cpp
+++ b/src/plugins/vm/VmLiveMigration.cpp
@@ -36,25 +36,16 @@ void MigrationRx::operator()()
   // Here Stage 1, 2  and 3 have been performed.
   // Hence complete the migration
 
-  // Copy the reference to the vm (if SRC crashes now, do_migration will free ms)
-  // This is clearly ugly but I (Adrien) need more time to do something cleaner (actually we should copy the whole ms
-  // structure at the beginning and free it at the end of each function)
-  simgrid::s4u::VirtualMachine* vm = vm_;
-  simgrid::s4u::Host* dst_pm       = dst_pm_;
-
-  // Make sure that we cannot get interrupted between the migrate and the resume to not end in an inconsistent state
-  simgrid::simix::kernelImmediate([vm, dst_pm]() {
-    /* Update the vm location */
-    /* precopy migration makes the VM temporally paused */
-    xbt_assert(vm->getState() == SURF_VM_STATE_SUSPENDED);
-
-    /* Update the vm location and resume it */
-    vm->pimpl_vm_->setPm(dst_pm);
-    vm->resume();
-  });
+  /* Update the vm location */
+  /* precopy migration makes the VM temporally paused */
+  xbt_assert(vm_->getState() == SURF_VM_STATE_SUSPENDED);
+
+  /* Update the vm location and resume it */
+  vm_->setPm(dst_pm_);
+  vm_->resume();
 
   // Now the VM is running on the new host (the migration is completed) (even if the SRC crash)
-  vm->pimpl_vm_->isMigrating = false;
+  vm_->pimpl_vm_->isMigrating = false;
   XBT_DEBUG("VM(%s) moved from PM(%s) to PM(%s)", vm_->getCname(), src_pm_->getCname(), dst_pm_->getCname());
 
   if (TRACE_msg_vm_is_enabled()) {
@@ -63,19 +54,19 @@ void MigrationRx::operator()()
     counter++;
 
     // start link
-    container_t msg = simgrid::instr::Container::byName(vm->getName());
+    container_t msg = simgrid::instr::Container::byName(vm_->getName());
     simgrid::instr::Container::getRoot()->getLink("MSG_VM_LINK")->startEvent(msg, "M", key);
 
     // destroy existing container of this vm
-    container_t existing_container = simgrid::instr::Container::byName(vm->getName());
+    container_t existing_container = simgrid::instr::Container::byName(vm_->getName());
     existing_container->removeFromParent();
     delete existing_container;
 
     // create new container on the new_host location
-    new simgrid::instr::Container(vm->getCname(), "MSG_VM", simgrid::instr::Container::byName(dst_pm_->getName()));
+    new simgrid::instr::Container(vm_->getCname(), "MSG_VM", simgrid::instr::Container::byName(dst_pm_->getName()));
 
     // end link
-    msg = simgrid::instr::Container::byName(vm->getName());
+    msg = simgrid::instr::Container::byName(vm_->getName());
     simgrid::instr::Container::getRoot()->getLink("MSG_VM_LINK")->endEvent(msg, "M", key);
   }
   // Inform the SRC that the migration has been correctly performed
@@ -303,6 +294,8 @@ void sg_vm_migrate(simgrid::s4u::VirtualMachine* vm, simgrid::s4u::Host* dst_pm)
   if (vm->isMigrating())
     THROWF(vm_error, 0, "Cannot migrate VM '%s' that is already migrating.", vm->getCname());
 
+  vm->pimpl_vm_->isMigrating = true;
+
   std::string rx_name =
       std::string("__pr_mig_rx:") + vm->getCname() + "(" + src_pm->getCname() + "-" + dst_pm->getCname() + ")";
   std::string tx_name =
diff --git a/src/plugins/vm/s4u_VirtualMachine.cpp b/src/plugins/vm/s4u_VirtualMachine.cpp
index 153625cd68..197e4dd71b 100644
--- a/src/plugins/vm/s4u_VirtualMachine.cpp
+++ b/src/plugins/vm/s4u_VirtualMachine.cpp
@@ -122,6 +122,11 @@ simgrid::s4u::Host* VirtualMachine::getPm()
   return pimpl_vm_->getPm();
 }
 
+void VirtualMachine::setPm(simgrid::s4u::Host* pm)
+{
+  simgrid::simix::kernelImmediate([this, pm]() { pimpl_vm_->setPm(pm); });
+}
+
 e_surf_vm_state_t VirtualMachine::getState()
 {
   return pimpl_vm_->getState();