[Openmp-commits] [PATCH] D44754: [OpenMP][libomptarget] Initialize global memory stack only once.

[Gheorghe-Teodor Bercea via Phabricator via Openmp-commits]

gtbercea created this revision.
gtbercea added reviewers: grokos, carlo.bertolli, ABataev, caomhin.
Herald added subscribers: openmp-commits, guansong.

The global stack initialization function may be called multiple times. The initialization of the shared memory slots should only happen when the function is called for the first time for a given warp master thread.


Repository:
  rOMP OpenMP

https://reviews.llvm.org/D44754

Files:
  libomptarget/deviceRTLs/nvptx/src/data_sharing.cu
  libomptarget/deviceRTLs/nvptx/src/omptarget-nvptx.h


Index: libomptarget/deviceRTLs/nvptx/src/omptarget-nvptx.h
===================================================================
--- libomptarget/deviceRTLs/nvptx/src/omptarget-nvptx.h
+++ libomptarget/deviceRTLs/nvptx/src/omptarget-nvptx.h
@@ -263,6 +263,9 @@
     // If this is invoked by the master thread of the master warp then intialize
     // it with a smaller slot.
     if (IsMasterThread) {
+      // Do not initalize this slot again if it has already been initalized.
+      if (master_rootS[0].DataEnd == &master_rootS[0].Data[0] + DS_Slot_Size)
+        return 0;
       // Initialize the pointer to the end of the slot given the size of the
       // data section. DataEnd is non-inclusive.
       master_rootS[0].DataEnd = &master_rootS[0].Data[0] + DS_Slot_Size;
@@ -272,6 +275,10 @@
       master_rootS[0].PrevSlotStackPtr = 0;
       return (__kmpc_data_sharing_slot *)&master_rootS[0];
     }
+    // Do not initalize this slot again if it has already been initalized.
+    if (worker_rootS[wid].DataEnd ==
+        &worker_rootS[wid].Data[0] + DS_Worker_Warp_Slot_Size)
+      return 0;
     // Initialize the pointer to the end of the slot given the size of the data
     // section. DataEnd is non-inclusive.
     worker_rootS[wid].DataEnd =
Index: libomptarget/deviceRTLs/nvptx/src/data_sharing.cu
===================================================================
--- libomptarget/deviceRTLs/nvptx/src/data_sharing.cu
+++ libomptarget/deviceRTLs/nvptx/src/data_sharing.cu
@@ -346,9 +346,14 @@
         &omptarget_nvptx_threadPrivateContext->TeamContext();
     __kmpc_data_sharing_slot *RootS = teamDescr->RootS(WID, IsMasterThread());
 
-    DataSharingState.SlotPtr[WID] = RootS;
-    DataSharingState.TailPtr[WID] = RootS;
-    DataSharingState.StackPtr[WID] = (void *)&RootS->Data[0];
+    // If a valid address has been returned then proceed with the initalization.
+    // Otherwise the initialization of the slot has already happened in a
+    // previous call to this function.
+    if (RootS) {
+      DataSharingState.SlotPtr[WID] = RootS;
+      DataSharingState.TailPtr[WID] = RootS;
+      DataSharingState.StackPtr[WID] = (void *)&RootS->Data[0];
+    }
   }
 
   // Currently we only support the sharing of variables between master and


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