Reduce scope for variables.

[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 02d93cf..d2d121e 100644 (file)
--- a/src/smpi/internals/smpi_memory.cpp
+++ b/src/smpi/internals/smpi_memory.cpp
@@ -1,8 +1,14 @@
-/* Copyright (c) 2015-2021. The SimGrid Team. All rights reserved.          */
+/* Copyright (c) 2015-2023. The SimGrid Team. All rights reserved.          */
 
 /* This program is free software; you can redistribute it and/or modify it
  * under the terms of the license (GNU LGPL) which comes with this package. */
 
+#include "private.hpp"
+#include "src/internal_config.h"
+#include "src/smpi/include/smpi_actor.hpp"
+#include "src/xbt/memory_map.hpp"
+#include "xbt/virtu.h"
+
 #include <algorithm>
 #include <cerrno>
 #include <climits>
@@ -12,26 +18,17 @@
 #include <cstring>
 #include <deque>
 #include <fcntl.h>
+#include <sys/mman.h>
 #include <sys/stat.h>
 #include <sys/types.h>
-#include <vector>
-
-#ifndef WIN32
-#include <sys/mman.h>
 #include <unistd.h>
-
-#include "src/internal_config.h"
-#include "src/xbt/memory_map.hpp"
-
-#include "private.hpp"
-#include "src/smpi/include/smpi_actor.hpp"
+#include <vector>
 
 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(smpi_memory, smpi, "Memory layout support for SMPI");
 
-int smpi_loaded_page      = -1;
-char* smpi_data_exe_start = nullptr;
-int smpi_data_exe_size    = 0;
-SmpiPrivStrategies smpi_privatize_global_variables;
+static char* smpi_data_exe_start = nullptr; // start of the data+bss segment of the executable
+static size_t smpi_data_exe_size = 0;       // size of the data+bss segment of the executable
+static SmpiPrivStrategies smpi_privatize_global_variables;
 static void* smpi_data_exe_copy;
 
 // Initialized by smpi_prepare_global_memory_segment().
@@ -72,9 +69,8 @@ static void smpi_get_executable_global_size()
       /* Here we are making the assumption that a suitable empty region
          following the rw- area is the end of the data segment. It would
          be better to check with the size of the data segment. */
-      auto j = i + 1;
-      if (j != map.end() && j->pathname.empty() && (j->prot & PROT_RWX) == PROT_RW &&
-          (char*)j->start_addr == smpi_data_exe_start + smpi_data_exe_size) {
+      if (auto j = i + 1; j != map.end() && j->pathname.empty() && (j->prot & PROT_RWX) == PROT_RW &&
+                          (char*)j->start_addr == smpi_data_exe_start + smpi_data_exe_size) {
         // Only count the portion of this region not present in the initial map.
         auto found    = std::find_if(initial_vm_map.begin(), initial_vm_map.end(), [&j](const simgrid::xbt::VmMap& m) {
           return j->start_addr <= m.start_addr && m.start_addr < j->end_addr;
@@ -87,7 +83,6 @@ static void smpi_get_executable_global_size()
   }
   xbt_die("Did not find my data segment.");
 }
-#endif
 
 #if HAVE_SANITIZER_ADDRESS
 #include <sanitizer/asan_interface.h>
@@ -176,15 +171,25 @@ void* smpi_temp_shm_mmap(int fd, size_t size)
 /** Map a given SMPI privatization segment (make an SMPI process active)
  *
  *  When doing a state restoration, the state of the restored variables  might not be consistent with the state of the
- *  virtual memory. In this case, we to change the data segment.
+ *  virtual memory. In this case, we have to change the data segment.
+ *
+ *  If 'addr' is not null, only switch if it's an address from the data segment.
+ *
+ *  Returns 'true' if the segment has to be switched (mmap privatization and 'addr' in data segment).
  */
-void smpi_switch_data_segment(simgrid::s4u::ActorPtr actor)
+bool smpi_switch_data_segment(simgrid::s4u::ActorPtr actor, const void* addr)
 {
-  if (smpi_loaded_page == actor->get_pid()) // no need to switch, we've already loaded the one we want
-    return;
+  if (smpi_cfg_privatization() != SmpiPrivStrategies::MMAP || smpi_data_exe_size == 0)
+    return false; // no need to switch
 
-  if (smpi_data_exe_size == 0) // no need to switch
-    return;
+  if (addr != nullptr &&
+      not(static_cast<const char*>(addr) >= smpi_data_exe_start &&
+          static_cast<const char*>(addr) < smpi_data_exe_start + smpi_data_exe_size))
+    return false; // no need to switch, addr is not concerned
+
+  static aid_t smpi_loaded_page = -1;
+  if (smpi_loaded_page == actor->get_pid()) // no need to switch, we've already loaded the one we want
+    return true;                            // return 'true' anyway
 
 #if HAVE_PRIVATIZATION
   // FIXME, cross-process support (mmap across process when necessary)
@@ -196,6 +201,8 @@ void smpi_switch_data_segment(simgrid::s4u::ActorPtr actor)
              "Couldn't map the new region (errno %d): %s", errno, strerror(errno));
   smpi_loaded_page = actor->get_pid();
 #endif
+
+  return true;
 }
 
 /**
@@ -210,7 +217,7 @@ void smpi_backup_global_memory_segment()
   initial_vm_map.clear();
   initial_vm_map.shrink_to_fit();
 
-  XBT_DEBUG("bss+data segment found : size %d starting at %p", smpi_data_exe_size, smpi_data_exe_start);
+  XBT_DEBUG("bss+data segment found : size %zu starting at %p", smpi_data_exe_size, smpi_data_exe_start);
 
   if (smpi_data_exe_size == 0) { // no need to do anything as global variables don't exist
     smpi_privatize_global_variables = SmpiPrivStrategies::NONE;