mesos git commit: Linked against the executor in the agent to ensure ordered message delivery.

[bm...@apache.org]

Repository: mesos
Updated Branches:
  refs/heads/master fdfe2b55e -> 4201c2c3e


Linked against the executor in the agent to ensure ordered message delivery.

Previously, we did not `link` against the executor `PID` while
(re)-registering. This might lead to libprocess creating ephemeral
sockets everytime a `send` was invoked. This was leading to races
where messages might appear on the Executor out of order. This change
does a `link` on the executor PID to ensure ordered message delivery.

Review: https://reviews.apache.org/r/40660


Project: http://git-wip-us.apache.org/repos/asf/mesos/repo
Commit: http://git-wip-us.apache.org/repos/asf/mesos/commit/4201c2c3
Tree: http://git-wip-us.apache.org/repos/asf/mesos/tree/4201c2c3
Diff: http://git-wip-us.apache.org/repos/asf/mesos/diff/4201c2c3

Branch: refs/heads/master
Commit: 4201c2c3e5849a01d0a63769404bad03792ae5de
Parents: fdfe2b5
Author: Anand Mazumdar <ma...@gmail.com>
Authored: Fri Dec 4 14:15:26 2015 -0800
Committer: Benjamin Mahler <be...@gmail.com>
Committed: Fri Dec 4 14:15:27 2015 -0800

----------------------------------------------------------------------
 src/slave/slave.cpp | 2 ++
 1 file changed, 2 insertions(+)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/mesos/blob/4201c2c3/src/slave/slave.cpp
----------------------------------------------------------------------
diff --git a/src/slave/slave.cpp b/src/slave/slave.cpp
index 777f36b..a33187e 100644
--- a/src/slave/slave.cpp
+++ b/src/slave/slave.cpp
@@ -2475,6 +2475,7 @@ void Slave::registerExecutor(
 
       // Save the pid for the executor.
       executor->pid = from;
+      link(from);
 
       if (framework->info.checkpoint()) {
         // TODO(vinod): This checkpointing should be done
@@ -2589,6 +2590,7 @@ void Slave::reregisterExecutor(
       executor->state = Executor::RUNNING;
 
       executor->pid = from; // Update the pid.
+      link(from);
 
       // Send re-registration message to the executor.
       ExecutorReregisteredMessage message;