avoid "can't be called from trap context" errors in ThreadLocalVar

Author: pitr-ch

lib/concurrent/atomic/ruby_thread_local_var.rb

@@ -29,8 +29,8 @@ class RubyThreadLocalVar < AbstractThreadLocalVar
     #   array, so we don't leak memory
 
     # @!visibility private
-    FREE = []
-    LOCK = Mutex.new
+    FREE   = []
+    LOCK   = Mutex.new
     ARRAYS = {} # used as a hash set
     @@next = 0
     private_constant :FREE, :LOCK, :ARRAYS
@@ -72,9 +72,9 @@ def value=(value)
     def allocate_storage
       @index = LOCK.synchronize do
         FREE.pop || begin
-        result = @@next
-        @@next += 1
-        result
+          result = @@next
+          @@next += 1
+          result
         end
       end
       ObjectSpace.define_finalizer(self, self.class.threadlocal_finalizer(@index))
@@ -83,13 +83,15 @@ def allocate_storage
     # @!visibility private
     def self.threadlocal_finalizer(index)
       proc do
-        LOCK.synchronize do
-          FREE.push(index)
-          # The cost of GC'ing a TLV is linear in the number of threads using TLVs
-          # But that is natural! More threads means more storage is used per TLV
-          # So naturally more CPU time is required to free more storage
-          ARRAYS.each_value do |array|
-            array[index] = nil
+        Thread.new do # avoid error: can't be called from trap context
+          LOCK.synchronize do
+            FREE.push(index)
+            # The cost of GC'ing a TLV is linear in the number of threads using TLVs
+            # But that is natural! More threads means more storage is used per TLV
+            # So naturally more CPU time is required to free more storage
+            ARRAYS.each_value do |array|
+              array[index] = nil
+            end
           end
         end
       end
@@ -98,10 +100,12 @@ def self.threadlocal_finalizer(index)
     # @!visibility private
     def self.thread_finalizer(array)
       proc do
-        LOCK.synchronize do
-          # The thread which used this thread-local array is now gone
-          # So don't hold onto a reference to the array (thus blocking GC)
-          ARRAYS.delete(array.object_id)
+        Thread.new do # avoid error: can't be called from trap context
+          LOCK.synchronize do
+            # The thread which used this thread-local array is now gone
+            # So don't hold onto a reference to the array (thus blocking GC)
+            ARRAYS.delete(array.object_id)
+          end
         end
       end
     end