Switched fork/exec lock to SpinLock.

Since a SpinLock is a simple integer on which CAS operations are performed, there is no way to go afoul of 'ownership' during fork(). This appears to solve a spordic issue where the child was not able to reset the fork_exec_lock_ inherited from the parent process.
rubinius · Mar 19, 2016 · 154bde3 · 154bde3
1 parent 9524ae1
commit 154bde3
Show file tree

Hide file tree

Showing 3 changed files with 7 additions and 7 deletions.
diff --git a/machine/builtin/system.cpp b/machine/builtin/system.cpp
@@ -382,7 +382,7 @@ namespace rubinius {
   }
 
   static int fork_exec(STATE, int errors_fd) {
-    utilities::thread::Mutex::LockGuard guard(state->shared().fork_exec_lock());
+    utilities::thread::SpinLock::LockGuard guard(state->shared().fork_exec_lock());
 
     state->shared().internal_threads()->before_fork_exec(state);
 
@@ -675,7 +675,7 @@ namespace rubinius {
   }
 
   Object* System::vm_exec(STATE, String* path, Array* args) {
-    utilities::thread::Mutex::LockGuard guard(state->shared().fork_exec_lock());
+    utilities::thread::SpinLock::LockGuard guard(state->shared().fork_exec_lock());
 
     /* Setting up the command and arguments may raise an exception so do it
      * before everything else.
@@ -817,7 +817,7 @@ namespace rubinius {
     int pid = -1;
 
     {
-      utilities::thread::Mutex::LockGuard guard(state->shared().fork_exec_lock());
+      utilities::thread::SpinLock::LockGuard guard(state->shared().fork_exec_lock());
 
       state->shared().internal_threads()->before_fork(state);
 

diff --git a/machine/shared_state.cpp b/machine/shared_state.cpp
@@ -46,8 +46,8 @@ namespace rubinius {
     , root_vm_(0)
     , env_(env)
     , tool_broker_(new tooling::ToolBroker)
-    , fork_exec_lock_()
     , codedb_lock_(true)
+    , fork_exec_lock_()
     , capi_ds_lock_()
     , capi_locks_lock_()
     , capi_constant_lock_()
@@ -160,8 +160,8 @@ namespace rubinius {
 
     // Reinit the locks for this object
     global_cache->reset();
-    fork_exec_lock_.init();
     codedb_lock_.init(true);
+    fork_exec_lock_.init();
     capi_ds_lock_.init();
     capi_locks_lock_.init();
     capi_constant_lock_.init();

diff --git a/machine/shared_state.hpp b/machine/shared_state.hpp
@@ -106,9 +106,9 @@ namespace rubinius {
     Environment* env_;
     tooling::ToolBroker* tool_broker_;
 
-    utilities::thread::Mutex fork_exec_lock_;
     utilities::thread::Mutex codedb_lock_;
 
+    utilities::thread::SpinLock fork_exec_lock_;
     utilities::thread::SpinLock capi_ds_lock_;
     utilities::thread::SpinLock capi_locks_lock_;
     utilities::thread::SpinLock capi_constant_lock_;
@@ -268,7 +268,7 @@ namespace rubinius {
 
     const unsigned int* object_memory_mark_address() const;
 
-    utilities::thread::Mutex& fork_exec_lock() {
+    utilities::thread::SpinLock& fork_exec_lock() {
       return fork_exec_lock_;
     }