use atomic field

stdlib/Distributed/src/cluster.jl

@@ -99,7 +99,7 @@ mutable struct Worker
     del_msgs::Array{Any,1} # XXX: Could del_msgs and add_msgs be Channels?
     add_msgs::Array{Any,1}
     @atomic gcflag::Bool
-    state::WorkerState
+    @atomic state::WorkerState
     c_state::Threads.Condition # wait for state changes, lock for state
     ct_time::Float64           # creation time
     conn_func::Any             # used to setup connections lazily
@@ -145,15 +145,13 @@ end
 
 function set_worker_state(w, state)
     lock(w.c_state) do
-        w.state = state
+        @atomic w.state = state
         notify(w.c_state; all=true)
     end
 end
 
 function check_worker_state(w::Worker)
-    lock(w.c_state)
     if w.state === W_CREATED
-        unlock(w.c_state)
         if !isclusterlazy()
             if PGRP.topology === :all_to_all
                 # Since higher pids connect with lower pids, the remote worker
@@ -173,9 +171,8 @@ function check_worker_state(w::Worker)
             errormonitor(t)
             wait_for_conn(w)
         end
-    else
-        unlock(w.c_state)
     end
+    return nothing
 end
 
 exec_conn_func(id::Int) = exec_conn_func(worker_from_id(id)::Worker)
@@ -193,9 +190,7 @@ function exec_conn_func(w::Worker)
 end
 
 function wait_for_conn(w)
-    lock(w.c_state)
     if w.state === W_CREATED
-        unlock(w.c_state)
         timeout =  worker_timeout() - (time() - w.ct_time)
         timeout <= 0 && error("peer $(w.id) has not connected to $(myid())")
 
@@ -210,8 +205,6 @@ function wait_for_conn(w)
             wait(w.c_state)
             w.state === W_CREATED && error("peer $(w.id) didn't connect to $(myid()) within $timeout seconds")
         end
-    else
-        unlock(w.c_state)
     end
     nothing
 end
@@ -663,8 +656,8 @@ function create_worker(manager, wconfig)
         for jw in PGRP.workers
             if (jw.id != 1) && (jw.id < w.id)
                 # wait for wl to join
-                lock(jw.c_state) do
-                    if jw.state === W_CREATED
+                if jw.state === W_CREATED
+                    lock(jw.c_state) do
                         wait(jw.c_state)
                     end
                 end