ThreadContext: define yield(), and use yield()/start() whenever possible.

[simgrid.git] / src / kernel / context / ContextThread.cpp

diff --git a/src/kernel/context/ContextThread.cpp b/src/kernel/context/ContextThread.cpp
index 67a6418..4eac4a5 100644 (file)
--- a/src/kernel/context/ContextThread.cpp
+++ b/src/kernel/context/ContextThread.cpp
@@ -6,12 +6,12 @@
 #include <utility>
 #include <functional>
 
+#include "src/internal_config.h" /* loads context system definitions */
+#include "src/simix/smx_private.hpp"
+#include "src/xbt_modinter.h" /* prototype of os thread module's init/exit in XBT */
 #include "xbt/function_types.h"
-#include "src/simix/smx_private.h"
-#include "src/internal_config.h"           /* loads context system definitions */
 #include "xbt/swag.h"
 #include "xbt/xbt_os_thread.h"
-#include "src/xbt_modinter.h"       /* prototype of os thread module's init/exit in XBT */
 
 #include "src/kernel/context/ContextThread.hpp"
 
@@ -89,9 +89,9 @@ ThreadContext* ThreadContextFactory::create_maestro(std::function<void()> code,
     return this->new_context<ThreadContext>(std::move(code), nullptr, process, true);
 }
 
-ThreadContext::ThreadContext(std::function<void()> code,
-    void_pfn_smxprocess_t cleanup, smx_actor_t process, bool maestro)
-  : AttachContext(std::move(code), cleanup, process)
+ThreadContext::ThreadContext(std::function<void()> code, void_pfn_smxprocess_t cleanup, smx_actor_t process,
+                             bool maestro)
+    : AttachContext(std::move(code), cleanup, process), is_maestro_(maestro)
 {
   // We do not need the semaphores when maestro is in main,
   // but creating them anyway simplifies things when maestro is externalized
@@ -147,13 +147,22 @@ void *ThreadContext::wrapper(void *param)
   /* Tell the maestro we are starting, and wait for its green light */
   xbt_os_sem_release(context->end_);
 
-  xbt_os_sem_acquire(context->begin_);
-  if (smx_ctx_thread_sem)       /* parallel run */
-    xbt_os_sem_acquire(smx_ctx_thread_sem);
+  context->start();
 
-  (*context)();
-  context->stop();
+  try {
+    (*context)();
+    context->Context::stop();
+  } catch (StopRequest const&) {
+    XBT_DEBUG("Caught a StopRequest");
+  }
 
+  // Signal to the maestro that it has finished:
+  context->yield();
+
+#ifndef WIN32
+  stack.ss_flags = SS_DISABLE;
+  sigaltstack(&stack, nullptr);
+#endif
   return nullptr;
 }
 
@@ -173,42 +182,43 @@ void *ThreadContext::maestro_wrapper(void *param)
   xbt_os_sem_release(context->end_);
 
   // Wait for the caller to give control back to us:
-  xbt_os_sem_acquire(context->begin_);
+  context->start();
   (*context)();
 
   // Tell main that we have finished:
-  xbt_os_sem_release(context->end_);
+  context->yield();
 
+#ifndef WIN32
+  stack.ss_flags = SS_DISABLE;
+  sigaltstack(&stack, nullptr);
+#endif
   return nullptr;
 }
 
 void ThreadContext::start()
 {
   xbt_os_sem_acquire(this->begin_);
-  if (smx_ctx_thread_sem)       /* parallel run */
+  if (not is_maestro_ && smx_ctx_thread_sem) /* parallel run */
     xbt_os_sem_acquire(smx_ctx_thread_sem);
 }
 
-void ThreadContext::stop()
+void ThreadContext::yield()
 {
-  Context::stop();
-  if (smx_ctx_thread_sem)
+  if (not is_maestro_ && smx_ctx_thread_sem) /* parallel run */
     xbt_os_sem_release(smx_ctx_thread_sem);
-
-  // Signal to the maestro that it has finished:
   xbt_os_sem_release(this->end_);
+}
 
-  xbt_os_thread_exit(nullptr);
+void ThreadContext::stop()
+{
+  Context::stop();
+  throw StopRequest();
 }
 
 void ThreadContext::suspend()
 {
-  if (smx_ctx_thread_sem)
-    xbt_os_sem_release(smx_ctx_thread_sem);
-  xbt_os_sem_release(this->end_);
-  xbt_os_sem_acquire(this->begin_);
-  if (smx_ctx_thread_sem)
-    xbt_os_sem_acquire(smx_ctx_thread_sem);
+  this->yield();
+  this->start();
 }
 
 void ThreadContext::attach_start()
@@ -216,14 +226,14 @@ void ThreadContext::attach_start()
   // We're breaking the layers here by depending on the upper layer:
   ThreadContext* maestro = (ThreadContext*) simix_global->maestro_process->context;
   xbt_os_sem_release(maestro->begin_);
+  xbt_assert(not this->is_maestro_);
   this->start();
 }
 
 void ThreadContext::attach_stop()
 {
-  if (smx_ctx_thread_sem)
-    xbt_os_sem_release(smx_ctx_thread_sem);
-  xbt_os_sem_release(this->end_);
+  xbt_assert(not this->is_maestro_);
+  this->yield();
 
   ThreadContext* maestro = (ThreadContext*) simix_global->maestro_process->context;
   xbt_os_sem_acquire(maestro->end_);