#include <stdlib.h>
#include <sys/types.h>
+#include <string.h>
+#include <stdio.h>
+#include "simgrid/sg_config.h"
+#include <fcntl.h>
#ifndef WIN32
#include <sys/mman.h>
XBT_LOG_NEW_DEFAULT_SUBCATEGORY(smpi_memory, smpi, "Memory layout support for SMPI");
+int smpi_loaded_page = -1;
+char* smpi_start_data_exe = nullptr;
+int smpi_size_data_exe = 0;
+bool smpi_privatize_global_variables;
+
static const int PROT_RWX = (PROT_READ | PROT_WRITE | PROT_EXEC);
static const int PROT_RW = (PROT_READ | PROT_WRITE );
XBT_ATTRIB_UNUSED static const int PROT_RX = (PROT_READ | PROT_EXEC );
xbt_die("Did not find my data segment.");
}
#endif
+
+
+/** Map a given SMPI privatization segment (make a SMPI process active) */
+void smpi_switch_data_segment(int dest) {
+ if (smpi_loaded_page == dest)//no need to switch, we've already loaded the one we want
+ return;
+
+ // So the job:
+ smpi_really_switch_data_segment(dest);
+}
+
+/** Map a given SMPI privatization segment (make a SMPI process active) even if SMPI thinks it is already 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.
+ */
+void smpi_really_switch_data_segment(int dest)
+{
+ if(smpi_size_data_exe == 0)//no need to switch
+ 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++){
+ memcpy(smpi_privatisation_regions[i].address, TOPAGE(smpi_start_data_exe), smpi_size_data_exe);
+ }
+ }
+
+ // 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, std::strlen("/dev/shm/my-buffer-")) == 0;
+}
+
+void smpi_initialize_global_memory_segments()
+{
+
+#if !HAVE_PRIVATIZATION
+ smpi_privatize_global_variables=false;
+ 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=false;
+ return;
+ }
+
+ smpi_privatisation_regions = static_cast<smpi_privatisation_region_t>(
+ xbt_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
+ int file_descriptor;
+ void* address = nullptr;
+ char path[24];
+ int status;
+
+ do {
+ snprintf(path, sizeof(path), "/smpi-buffer-%06x", rand() % 0xffffff);
+ file_descriptor = shm_open(path, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
+ } while (file_descriptor == -1 && errno == EEXIST);
+ 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 = 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(nullptr, 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");
+
+ status = shm_unlink(path);
+ if (status)
+ xbt_die("Impossible to unlink temporary file 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
+ for (int 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
+}
+
