[vmkit-commits] [vmkit] r109982 - in /vmkit/trunk: include/mvm/Threads/Thread.h lib/Mvm/CommonThread/CollectionRV.cpp

[Nicolas Geoffray]

Author: geoffray
Date: Sun Aug  1 11:01:21 2010
New Revision: 109982

URL: http://llvm.org/viewvc/llvm-project?rev=109982&view=rev
Log:
Emit atomic operations when changing states in thread.


Modified:
    vmkit/trunk/include/mvm/Threads/Thread.h
    vmkit/trunk/lib/Mvm/CommonThread/CollectionRV.cpp

Modified: vmkit/trunk/include/mvm/Threads/Thread.h
URL: http://llvm.org/viewvc/llvm-project/vmkit/trunk/include/mvm/Threads/Thread.h?rev=109982&r1=109981&r2=109982&view=diff
==============================================================================
--- vmkit/trunk/include/mvm/Threads/Thread.h (original)
+++ vmkit/trunk/include/mvm/Threads/Thread.h Sun Aug  1 11:01:21 2010
@@ -251,7 +251,8 @@
         ++level;
         void* temp = __builtin_frame_address(0);
         while (level--) temp = ((void**)temp)[0];
-        lastSP = temp;
+        // The cas is not necessary, but it does a memory barrier.
+        __sync_bool_compare_and_swap(&lastSP, 0, temp);
         if (doYield) joinRVBeforeEnter();
         assert(lastSP && "No last SP when entering uncooperative code");
       }
@@ -262,7 +263,8 @@
     if (isMvmThread()) {
       if (!inRV) {
         assert(!lastSP && "SP already set when entering uncooperative code");
-        lastSP = SP;
+        // The cas is not necessary, but it does a memory barrier.
+        __sync_bool_compare_and_swap(&lastSP, 0, SP);
         if (doYield) joinRVBeforeEnter();
         assert(lastSP && "No last SP when entering uncooperative code");
       }
@@ -273,7 +275,8 @@
     if (isMvmThread()) {
       if (!inRV) {
         assert(lastSP && "No last SP when leaving uncooperative code");
-        lastSP = 0;
+        // The cas is not necessary, but it does a memory barrier.
+        __sync_bool_compare_and_swap(&lastSP, lastSP, 0);
         // A rendezvous has just been initiated, join it.
         if (doYield) joinRVAfterLeave();
         assert(!lastSP && "SP has a value after leaving uncooperative code");

Modified: vmkit/trunk/lib/Mvm/CommonThread/CollectionRV.cpp
URL: http://llvm.org/viewvc/llvm-project/vmkit/trunk/lib/Mvm/CommonThread/CollectionRV.cpp?rev=109982&r1=109981&r2=109982&view=diff
==============================================================================
--- vmkit/trunk/lib/Mvm/CommonThread/CollectionRV.cpp (original)
+++ vmkit/trunk/lib/Mvm/CommonThread/CollectionRV.cpp Sun Aug  1 11:01:21 2010
@@ -59,8 +59,10 @@
     assert(!cur->joinedRV);
     cur = (mvm::Thread*)cur->next();
   } while (cur != self);
+ 
+  // The CAS is not necessary but it does a memory barrier. 
+  __sync_bool_compare_and_swap(&(self->joinedRV), false, true);
 
-  self->joinedRV = true; 
   // Lookup currently blocked threads.
   for (cur = (mvm::Thread*)self->next(); cur != self; 
        cur = (mvm::Thread*)cur->next()) {