-
- // FIXME, cross-process support (mmap across process when necessary)
- int current = smpi_privatisation_regions[dest].file_descriptor;
- XBT_DEBUG("Switching data frame to the one of process %d", dest);
- void* tmp = mmap (TOPAGE(smpi_start_data_exe), smpi_size_data_exe,
- PROT_READ | PROT_WRITE, MAP_FIXED | MAP_SHARED, current, 0);
- if (tmp != TOPAGE(smpi_start_data_exe))
- xbt_die("Couldn't map the new region");
- smpi_loaded_page = dest;
-#endif
-}
-
-int smpi_is_privatisation_file(char* file)
-{
- return strncmp("/dev/shm/my-buffer-", file, 19) == 0;
-}
-
-void smpi_initialize_global_memory_segments(){
-
-#if !HAVE_PRIVATIZATION
- smpi_privatize_global_variables=0;
- xbt_die("You are trying to use privatization on a system that does not support it. Don't.");
- return;
-#else
-
- smpi_get_executable_global_size();
-
- XBT_DEBUG ("bss+data segment found : size %d starting at %p", smpi_size_data_exe, smpi_start_data_exe );
-
- if (smpi_size_data_exe == 0){//no need to switch
- smpi_privatize_global_variables=0;
- return;
- }
-
- smpi_privatisation_regions =
- (smpi_privatisation_region_t) malloc(smpi_process_count() * sizeof(struct s_smpi_privatisation_region));
-
- for (int i=0; i< smpi_process_count(); i++){
- //create SIMIX_process_count() mappings of this size with the same data inside
- void *address = NULL;
- char path[] = "/dev/shm/my-buffer-XXXXXX";
- int status;
-
- int file_descriptor= mkstemp (path);
- if (file_descriptor < 0) {
- if (errno==EMFILE) {
- xbt_die("Impossible to create temporary file for memory mapping: %s\n\
-The open() system call failed with the EMFILE error code (too many files). \n\n\
-This means that you reached the system limits concerning the amount of files per process. \
-This is not a surprise if you are trying to virtualize many processes on top of SMPI. \
-Don't panic -- you should simply increase your system limits and try again. \n\n\
-First, check what your limits are:\n\
- cat /proc/sys/fs/file-max # Gives you the system-wide limit\n\
- ulimit -Hn # Gives you the per process hard limit\n\
- ulimit -Sn # Gives you the per process soft limit\n\
- cat /proc/self/limits # Displays any per-process limitation (including the one given above)\n\n\
-If one of these values is less than the amount of MPI processes that you try to run, then you got the explanation of this error. \
-Ask the Internet about tutorials on how to increase the files limit such as: https://rtcamp.com/tutorials/linux/increase-open-files-limit/",
- strerror(errno));
- }
- xbt_die("Impossible to create temporary file for memory mapping: %s",
- strerror(errno));
- }
-
- status = unlink (path);
- if (status)
- xbt_die("Impossible to unlink temporary file for memory mapping");
-
- status = ftruncate(file_descriptor, smpi_size_data_exe);
- if(status)
- xbt_die("Impossible to set the size of the temporary file for memory mapping");
-
- /* Ask for a free region */
- address = mmap (NULL, smpi_size_data_exe, PROT_READ | PROT_WRITE, MAP_SHARED, file_descriptor, 0);
- if (address == MAP_FAILED)
- xbt_die("Couldn't find a free region for memory mapping");
-
- //initialize the values
- memcpy(address, TOPAGE(smpi_start_data_exe), smpi_size_data_exe);
-
- //store the address of the mapping for further switches
- smpi_privatisation_regions[i].file_descriptor = file_descriptor;
- smpi_privatisation_regions[i].address = address;
- }
-#endif
-}
-
-void smpi_destroy_global_memory_segments(){
- if (smpi_size_data_exe == 0)//no need to switch
- return;
-#if HAVE_PRIVATIZATION
- int i;
- for (i=0; i< smpi_process_count(); i++){
- if(munmap(smpi_privatisation_regions[i].address, smpi_size_data_exe) < 0) {
- XBT_WARN("Unmapping of fd %d failed: %s", smpi_privatisation_regions[i].file_descriptor, strerror(errno));
- }
- close(smpi_privatisation_regions[i].file_descriptor);
- }
- xbt_free(smpi_privatisation_regions);
-#endif