[SMPI] Added explanation of what smpi_data_exe_size==0 means

[simgrid.git] / src / smpi / internals / smpi_memory.cpp

diff --git a/src/smpi/internals/smpi_memory.cpp b/src/smpi/internals/smpi_memory.cpp
index a94b870..7b02774 100644 (file)
--- a/src/smpi/internals/smpi_memory.cpp
+++ b/src/smpi/internals/smpi_memory.cpp
@@ -24,15 +24,17 @@
 #include "src/internal_config.h"
 #include "src/xbt/memory_map.hpp"
 
-#include "private.h"
 #include "private.hpp"
 
 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(smpi_memory, smpi, "Memory layout support for SMPI");
 
-int smpi_loaded_page = -1;
+int smpi_loaded_page      = -1;
 char* smpi_data_exe_start = nullptr;
 int smpi_data_exe_size    = 0;
 int smpi_privatize_global_variables;
+static char* smpi_data_exe_copy;
+smpi_privatization_region_t smpi_privatization_regions;
+// static std::set smpi_privatization_regions;
 
 static const int PROT_RWX = (PROT_READ | PROT_WRITE | PROT_EXEC);
 static const int PROT_RW  = (PROT_READ | PROT_WRITE );
@@ -111,10 +113,8 @@ void smpi_really_switch_data_segment(int dest)
     return;
 
 #if HAVE_PRIVATIZATION
-  if(smpi_loaded_page==-1){//initial switch, do the copy from the real page here
-    for (int i=0; i< smpi_process_count(); i++){
-      asan_safe_memcpy(smpi_privatization_regions[i].address, TOPAGE(smpi_data_exe_start), smpi_data_exe_size);
-    }
+  if (smpi_loaded_page == -1) { // initial switch, do the copy from the real page here
+    asan_safe_memcpy(smpi_data_exe_copy, TOPAGE(smpi_data_exe_start), smpi_data_exe_size);
   }
 
   // FIXME, cross-process support (mmap across process when necessary)
@@ -136,19 +136,19 @@ int smpi_is_privatization_file(char* file)
 
 void smpi_initialize_global_memory_segments()
 {
-
 #if HAVE_PRIVATIZATION
   smpi_get_executable_global_size();
 
   XBT_DEBUG("bss+data segment found : size %d starting at %p", smpi_data_exe_size, smpi_data_exe_start);
 
-  if (smpi_data_exe_size == 0) { // no need to switch
+  if (smpi_data_exe_size == 0) { // no need to switch as global variables don't exist
     smpi_privatize_global_variables=false;
     return;
   }
 
-  smpi_privatization_regions = static_cast<smpi_privatization_region_t>(
-      xbt_malloc(smpi_process_count() * sizeof(struct s_smpi_privatization_region)));
+  smpi_data_exe_copy = (char*)malloc(smpi_data_exe_size);
+  asan_safe_memcpy(smpi_data_exe_copy, TOPAGE(smpi_data_exe_start), smpi_data_exe_size);
+  smpi_privatization_regions = new s_smpi_privatization_region_t[smpi_process_count()];
 
   for (int i=0; i< smpi_process_count(); i++){
     // create SIMIX_process_count() mappings of this size with the same data inside
@@ -194,7 +194,7 @@ Ask the Internet about tutorials on how to increase the files limit such as: htt
       xbt_die("Impossible to unlink temporary file for memory mapping");
 
     // initialize the values
-    asan_safe_memcpy(address, TOPAGE(smpi_data_exe_start), smpi_data_exe_size);
+    asan_safe_memcpy(address, smpi_data_exe_copy, smpi_data_exe_size);
 
     // store the address of the mapping for further switches
     smpi_privatization_regions[i].file_descriptor = file_descriptor;
@@ -216,7 +216,7 @@ void smpi_destroy_global_memory_segments(){
       XBT_WARN("Unmapping of fd %d failed: %s", smpi_privatization_regions[i].file_descriptor, strerror(errno));
     close(smpi_privatization_regions[i].file_descriptor);
   }
-  xbt_free(smpi_privatization_regions);
+  delete[] smpi_privatization_regions;
 #endif
 }