1 /* Copyright (c) 2007, 2009-2017. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
6 /* Shared allocations are handled through shared memory segments.
7 * Associated data and metadata are used as follows:
10 * `allocs' dict ---- -.
11 * ---------- shared_data_t shared_metadata_t / | | |
12 * .->| <name> | ---> -------------------- <--. ----------------- | | | |
13 * | ---------- | fd of <name> | | | size of mmap | --| | | |
14 * | | count (2) | |-- | data | \ | | |
15 * `----------------- | <name> | | ----------------- ---- |
16 * -------------------- | ^ |
18 * | | `allocs_metadata' dict |
19 * | | ---------------------- |
20 * | `-- | <addr of mmap #1> |<-'
21 * | .-- | <addr of mmap #2> |<-.
22 * | | ---------------------- |
28 * | shared_metadata_t / | |
29 * | ----------------- | | |
30 * | | size of mmap | --| | |
32 * ----------------- | | |
39 #include "private.hpp"
43 #include <sys/types.h>
53 #define MAP_ANONYMOUS MAP_ANON
57 #define MAP_POPULATE 0
60 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(smpi_shared, smpi, "Logging specific to SMPI (shared memory macros)");
62 #define PTR_STRLEN (2 + 2 * sizeof(void*) + 1)
65 /** Some location in the source code
67 * This information is used by SMPI_SHARED_MALLOC to allocate some shared memory for all simulated processes.
70 class smpi_source_location {
72 smpi_source_location(const char* filename, int line)
73 : filename(xbt_strdup(filename)), filename_length(strlen(filename)), line(line)
77 /** Pointer to a static string containing the file name */
78 char* filename = nullptr;
79 int filename_length = 0;
82 bool operator==(smpi_source_location const& that) const
84 return filename_length == that.filename_length && line == that.line &&
85 std::memcmp(filename, that.filename, filename_length) == 0;
87 bool operator!=(smpi_source_location const& that) const { return !(*this == that); }
93 template <> class hash<smpi_source_location> {
95 typedef smpi_source_location argument_type;
96 typedef std::size_t result_type;
97 result_type operator()(smpi_source_location const& loc) const
99 return xbt_str_hash_ext(loc.filename, loc.filename_length) ^
100 xbt_str_hash_ext((const char*)&loc.line, sizeof(loc.line));
112 std::unordered_map<smpi_source_location, shared_data_t> allocs;
113 typedef std::unordered_map<smpi_source_location, shared_data_t>::value_type shared_data_key_type;
117 shared_data_key_type* data;
120 std::map<void*, shared_metadata_t> allocs_metadata;
121 xbt_dict_t calls = nullptr; /* Allocated on first use */
123 static int smpi_shared_malloc_bogusfile = -1;
124 static unsigned long smpi_shared_malloc_blocksize = 1UL << 20;
129 void smpi_shared_destroy()
132 allocs_metadata.clear();
133 xbt_dict_free(&calls);
136 static size_t shm_size(int fd) {
139 if(fstat(fd, &st) < 0) {
140 xbt_die("Could not stat fd %d: %s", fd, strerror(errno));
142 return static_cast<size_t>(st.st_size);
146 static void* shm_map(int fd, size_t size, shared_data_key_type* data) {
147 char loc[PTR_STRLEN];
148 shared_metadata_t meta;
150 if(size > shm_size(fd) && (ftruncate(fd, static_cast<off_t>(size)) < 0)) {
151 xbt_die("Could not truncate fd %d to %zu: %s", fd, size, strerror(errno));
154 void* mem = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
155 if(mem == MAP_FAILED) {
157 "Failed to map fd %d with size %zu: %s\n"
158 "If you are running a lot of ranks, you may be exceeding the amount of mappings allowed per process.\n"
159 "On Linux systems, change this value with sudo sysctl -w vm.max_map_count=newvalue (default value: 65536)\n"
160 "Please see http://simgrid.gforge.inria.fr/simgrid/latest/doc/html/options.html#options_virt for more info.",
161 fd, size, strerror(errno));
163 snprintf(loc, PTR_STRLEN, "%p", mem);
166 allocs_metadata[mem] = meta;
167 XBT_DEBUG("MMAP %zu to %p", size, mem);
171 void *smpi_shared_malloc_local(size_t size, const char *file, int line)
174 smpi_source_location loc(file, line);
175 auto res = allocs.insert(std::make_pair(loc, shared_data_t()));
176 auto data = res.first;
178 // The insertion did not take place.
179 // Generate a shared memory name from the address of the shared_data:
180 char shmname[32]; // cannot be longer than PSHMNAMLEN = 31 on Mac OS X (shm_open raises ENAMETOOLONG otherwise)
181 snprintf(shmname, 31, "/shmalloc%p", &*data);
182 int fd = shm_open(shmname, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
185 xbt_die("Please cleanup /dev/shm/%s", shmname);
187 xbt_die("An unhandled error occurred while opening %s. shm_open: %s", shmname, strerror(errno));
189 data->second.fd = fd;
190 data->second.count = 1;
191 mem = shm_map(fd, size, &*data);
192 if (shm_unlink(shmname) < 0) {
193 XBT_WARN("Could not early unlink %s. shm_unlink: %s", shmname, strerror(errno));
195 XBT_DEBUG("Mapping %s at %p through %d", shmname, mem, fd);
197 mem = shm_map(data->second.fd, size, &*data);
198 data->second.count++;
200 XBT_DEBUG("Shared malloc %zu in %p (metadata at %p)", size, mem, &*data);
204 // Align functions, from http://stackoverflow.com/questions/4840410/how-to-align-a-pointer-in-c
205 #define ALIGN_UP(n, align) (((n) + (align)-1) & -(align))
206 #define ALIGN_DOWN(n, align) ((n) & -(align))
208 void *smpi_shared_malloc_global__(size_t size, const char *file, int line, int *shared_block_offsets, int nb_shared_blocks) {
210 /* First reserve memory area */
211 mem = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
213 xbt_assert(mem != MAP_FAILED, "Failed to allocate %luMiB of memory. Run \"sysctl vm.overcommit_memory=1\" as root "
214 "to allow big allocations.\n",
215 (unsigned long)(size >> 20));
217 /* Create bogus file if not done already */
218 if (smpi_shared_malloc_bogusfile == -1) {
219 /* Create a fd to a new file on disk, make it smpi_shared_malloc_blocksize big, and unlink it.
220 * It still exists in memory but not in the file system (thus it cannot be leaked). */
221 smpi_shared_malloc_blocksize = static_cast<unsigned long>(xbt_cfg_get_double("smpi/shared-malloc-blocksize"));
222 XBT_DEBUG("global shared allocation. Blocksize %lu", smpi_shared_malloc_blocksize);
223 char* name = xbt_strdup("/tmp/simgrid-shmalloc-XXXXXX");
224 smpi_shared_malloc_bogusfile = mkstemp(name);
227 char* dumb = (char*)calloc(1, smpi_shared_malloc_blocksize);
228 ssize_t err = write(smpi_shared_malloc_bogusfile, dumb, smpi_shared_malloc_blocksize);
230 xbt_die("Could not write bogus file for shared malloc");
234 /* Map the bogus file in place of the anonymous memory */
235 for(int i_block = 0; i_block < nb_shared_blocks; i_block ++) {
236 int start_offset = ALIGN_UP(shared_block_offsets[2*i_block], smpi_shared_malloc_blocksize);
237 int stop_offset = ALIGN_DOWN(shared_block_offsets[2*i_block+1], smpi_shared_malloc_blocksize);
239 for (i = start_offset; i < stop_offset / smpi_shared_malloc_blocksize; i++) {
240 void* pos = (void*)((unsigned long)mem + i * smpi_shared_malloc_blocksize);
241 void* res = mmap(pos, smpi_shared_malloc_blocksize, PROT_READ | PROT_WRITE, MAP_FIXED | MAP_SHARED | MAP_POPULATE,
242 smpi_shared_malloc_bogusfile, 0);
243 xbt_assert(res == pos, "Could not map folded virtual memory (%s). Do you perhaps need to increase the "
244 "size of the mapped file using --cfg=smpi/shared-malloc-blocksize=newvalue (default 1048576) ?"
245 "You can also try using the sysctl vm.max_map_count",
250 if(nb_shared_blocks == 1 && shared_block_offsets[0] == 0 && shared_block_offsets[1] == size) {
251 shared_metadata_t newmeta;
252 //register metadata for memcpy avoidance
253 shared_data_key_type* data = (shared_data_key_type*)xbt_malloc(sizeof(shared_data_key_type));
254 data->second.fd = -1;
255 data->second.count = 1;
258 allocs_metadata[mem] = newmeta;
265 * When nb_shared_blocks == -1, default behavior of smpi_shared_malloc: everything is shared.
266 * Otherwise, only the blocks described by shared_block_offsets are shared.
267 * This array contains the offsets (in bytes) of the block to share.
268 * Even indices are the start offsets (included), odd indices are the stop offsets (excluded).
269 * For instance, if shared_block_offsets == {27, 42}, then the elements mem[27], mem[28], ..., mem[41] are shared. The others are not.
271 void *smpi_shared_malloc_global(size_t size, const char *file, int line, int *shared_block_offsets=NULL, int nb_shared_blocks=-1) {
272 int tmp_shared_block_offsets[2];
273 if(nb_shared_blocks == -1) {
274 nb_shared_blocks = 1;
275 shared_block_offsets = tmp_shared_block_offsets;
276 shared_block_offsets[0] = 0;
277 shared_block_offsets[1] = size;
279 return smpi_shared_malloc_global__(size, file, line, shared_block_offsets, nb_shared_blocks);
282 void *smpi_shared_malloc(size_t size, const char *file, int line) {
284 if (size > 0 && smpi_cfg_shared_malloc == shmalloc_local) {
285 mem = smpi_shared_malloc_local(size, file, line);
286 } else if (smpi_cfg_shared_malloc == shmalloc_global) {
287 mem = smpi_shared_malloc_global(size, file, line);
289 mem = xbt_malloc(size);
290 XBT_DEBUG("Classic malloc %zu in %p", size, mem);
295 int smpi_is_shared(void* ptr){
296 if (allocs_metadata.empty())
298 if ( smpi_cfg_shared_malloc == shmalloc_local || smpi_cfg_shared_malloc == shmalloc_global) {
299 auto low = allocs_metadata.lower_bound(ptr);
302 if (low == allocs_metadata.begin())
305 if (ptr < (char*)low->first + low->second.size)
313 void smpi_shared_free(void *ptr)
315 if (smpi_cfg_shared_malloc == shmalloc_local) {
316 char loc[PTR_STRLEN];
317 snprintf(loc, PTR_STRLEN, "%p", ptr);
318 auto meta = allocs_metadata.find(ptr);
319 if (meta == allocs_metadata.end()) {
320 XBT_WARN("Cannot free: %p was not shared-allocated by SMPI - maybe its size was 0?", ptr);
323 shared_data_t* data = &meta->second.data->second;
324 if (munmap(ptr, meta->second.size) < 0) {
325 XBT_WARN("Unmapping of fd %d failed: %s", data->fd, strerror(errno));
328 if (data->count <= 0) {
330 allocs.erase(allocs.find(meta->second.data->first));
331 allocs_metadata.erase(ptr);
332 XBT_DEBUG("Shared free - with removal - of %p", ptr);
334 XBT_DEBUG("Shared free - no removal - of %p, count = %d", ptr, data->count);
337 } else if (smpi_cfg_shared_malloc == shmalloc_global) {
338 auto meta = allocs_metadata.find(ptr);
339 if (meta != allocs_metadata.end()){
340 meta->second.data->second.count--;
341 if(meta->second.data->second.count==0)
342 xbt_free(meta->second.data);
345 munmap(ptr, 0); // the POSIX says that I should not give 0 as a length, but it seems to work OK
347 XBT_DEBUG("Classic free of %p", ptr);
353 int smpi_shared_known_call(const char* func, const char* input)
355 char* loc = bprintf("%s:%s", func, input);
358 if (calls==nullptr) {
359 calls = xbt_dict_new_homogeneous(nullptr);
362 xbt_dict_get(calls, loc); /* Succeed or throw */
368 if (ex.category != not_found_error)
378 void* smpi_shared_get_call(const char* func, const char* input) {
379 char* loc = bprintf("%s:%s", func, input);
381 if (calls == nullptr)
382 calls = xbt_dict_new_homogeneous(nullptr);
383 void* data = xbt_dict_get(calls, loc);
388 void* smpi_shared_set_call(const char* func, const char* input, void* data) {
389 char* loc = bprintf("%s:%s", func, input);
391 if (calls == nullptr)
392 calls = xbt_dict_new_homogeneous(nullptr);
393 xbt_dict_set(calls, loc, data, nullptr);