-/* Copyright (c) 2015-2019. 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 <sys/mman.h>
#include <unistd.h>
-#include "src/internal_config.h"
-#include "src/xbt/memory_map.hpp"
-
#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"
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;
+size_t smpi_data_exe_size = 0;
SmpiPrivStrategies smpi_privatize_global_variables;
static void* smpi_data_exe_copy;
static void smpi_get_executable_global_size()
{
- char buffer[PATH_MAX];
- const char* full_name = realpath(simgrid::xbt::binary_name.c_str(), buffer);
- xbt_assert(full_name != nullptr, "Could not resolve real path of binary file '%s'",
- simgrid::xbt::binary_name.c_str());
+ char* buffer = realpath(simgrid::xbt::binary_name.c_str(), nullptr);
+ xbt_assert(buffer != nullptr, "Could not resolve real path of binary file '%s'", simgrid::xbt::binary_name.c_str());
+ std::string full_name = buffer;
+ free(buffer);
std::vector<simgrid::xbt::VmMap> map = simgrid::xbt::get_memory_map(getpid());
for (auto i = map.begin(); i != map.end() ; ++i) {
/* 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. */
- ++i;
- if (i != map.end() && i->pathname.empty() && (i->prot & PROT_RWX) == PROT_RW &&
- (char*)i->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(), [&i](const simgrid::xbt::VmMap& m) {
- return i->start_addr <= m.start_addr && m.start_addr < i->end_addr;
+ 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;
});
- auto end_addr = (found == initial_vm_map.end() ? i->end_addr : found->start_addr);
+ auto end_addr = (found == initial_vm_map.end() ? j->end_addr : found->start_addr);
smpi_data_exe_size = (char*)end_addr - smpi_data_exe_start;
}
return;
*/
int smpi_temp_shm_get()
{
- constexpr unsigned VAL_MASK = 0xffffffffUL;
- static unsigned prev_val = VAL_MASK;
+ constexpr unsigned INDEX_MASK = 0xffffffffUL;
+ static unsigned index = INDEX_MASK;
char shmname[32]; // cannot be longer than PSHMNAMLEN = 31 on macOS (shm_open raises ENAMETOOLONG otherwise)
int fd;
- for (unsigned i = (prev_val + 1) & VAL_MASK; i != prev_val; i = (i + 1) & VAL_MASK) {
- snprintf(shmname, sizeof(shmname), "/smpi-buffer-%016x", i);
+ unsigned limit = index;
+ do {
+ index = (index + 1) & INDEX_MASK;
+ snprintf(shmname, sizeof(shmname), "/smpi-buffer-%016x", index);
fd = shm_open(shmname, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
- if (fd != -1 || errno != EEXIST) {
- prev_val = i;
- break;
- }
- }
+ } while (fd == -1 && errno == EEXIST && index != limit);
+
if (fd < 0) {
if (errno == EMFILE) {
xbt_die("Impossible to create temporary file for memory mapping: %s\n\
void* smpi_temp_shm_mmap(int fd, size_t size)
{
struct stat st;
- if (fstat(fd, &st) != 0)
- xbt_die("Could not stat fd %d: %s", fd, strerror(errno));
- if (static_cast<off_t>(size) > st.st_size && ftruncate(fd, static_cast<off_t>(size)) != 0)
- xbt_die("Could not truncate fd %d to %zu: %s", fd, size, strerror(errno));
+ xbt_assert(fstat(fd, &st) == 0, "Could not stat fd %d: %s", fd, strerror(errno));
+ xbt_assert(static_cast<off_t>(size) <= st.st_size || ftruncate(fd, static_cast<off_t>(size)) == 0,
+ "Could not truncate fd %d to %zu: %s", fd, size, strerror(errno));
void* mem = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
- if (mem == MAP_FAILED) {
- xbt_die("Failed to map fd %d with size %zu: %s\n"
- "If you are running a lot of ranks, you may be exceeding the amount of mappings allowed per process.\n"
- "On Linux systems, change this value with sudo sysctl -w vm.max_map_count=newvalue (default value: 65536)\n"
- "Please see "
- "https://simgrid.org/doc/latest/Configuring_SimGrid.html#configuring-the-user-code-virtualization for more "
- "information.",
- fd, size, strerror(errno));
- }
+ xbt_assert(
+ mem != MAP_FAILED,
+ "Failed to map fd %d with size %zu: %s\n"
+ "If you are running a lot of ranks, you may be exceeding the amount of mappings allowed per process.\n"
+ "On Linux systems, change this value with sudo sysctl -w vm.max_map_count=newvalue (default value: 65536)\n"
+ "Please see https://simgrid.org/doc/latest/Configuring_SimGrid.html#configuring-the-user-code-virtualization for "
+ "more information.",
+ fd, size, strerror(errno));
return mem;
}
-/** Map a given SMPI privatization segment (make a SMPI process active)
+/** 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)
XBT_DEBUG("Switching data frame to the one of process %ld", actor->get_pid());
- simgrid::smpi::ActorExt* process = smpi_process_remote(actor);
+ const simgrid::smpi::ActorExt* process = smpi_process_remote(actor);
int current = process->privatized_region()->file_descriptor;
- const void* tmp = mmap(TOPAGE(smpi_data_exe_start), smpi_data_exe_size, PROT_RW, MAP_FIXED | MAP_SHARED, current, 0);
- if (tmp != TOPAGE(smpi_data_exe_start))
- xbt_die("Couldn't map the new region (errno %d): %s", errno, strerror(errno));
+ xbt_assert(mmap(TOPAGE(smpi_data_exe_start), smpi_data_exe_size, PROT_RW, MAP_FIXED | MAP_SHARED, current, 0) ==
+ TOPAGE(smpi_data_exe_start),
+ "Couldn't map the new region (errno %d): %s", errno, strerror(errno));
smpi_loaded_page = actor->get_pid();
#endif
+
+ return true;
}
/**
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;
