| 1 | #define USE_THE_REPOSITORY_VARIABLE |
| 2 | #define DISABLE_SIGN_COMPARE_WARNINGS |
| 3 | |
| 4 | #include "git-compat-util.h" |
| 5 | #include "config.h" |
| 6 | #include "entry.h" |
| 7 | #include "gettext.h" |
| 8 | #include "hash.h" |
| 9 | #include "hex.h" |
| 10 | #include "parallel-checkout.h" |
| 11 | #include "pkt-line.h" |
| 12 | #include "progress.h" |
| 13 | #include "read-cache-ll.h" |
| 14 | #include "run-command.h" |
| 15 | #include "sigchain.h" |
| 16 | #include "odb/streaming.h" |
| 17 | #include "symlinks.h" |
| 18 | #include "thread-utils.h" |
| 19 | #include "trace2.h" |
| 20 | |
| 21 | struct pc_worker { |
| 22 | struct child_process cp; |
| 23 | size_t next_item_to_complete, nr_items_to_complete; |
| 24 | }; |
| 25 | |
| 26 | struct parallel_checkout { |
| 27 | enum pc_status status; |
| 28 | struct parallel_checkout_item *items; /* The parallel checkout queue. */ |
| 29 | size_t nr, alloc; |
| 30 | struct progress *progress; |
| 31 | unsigned int *progress_cnt; |
| 32 | }; |
| 33 | |
| 34 | static struct parallel_checkout parallel_checkout; |
| 35 | |
| 36 | enum pc_status parallel_checkout_status(void) |
| 37 | { |
| 38 | return parallel_checkout.status; |
| 39 | } |
| 40 | |
| 41 | static const int DEFAULT_THRESHOLD_FOR_PARALLELISM = 100; |
| 42 | static const int DEFAULT_NUM_WORKERS = 1; |
| 43 | |
| 44 | void get_parallel_checkout_configs(int *num_workers, int *threshold) |
| 45 | { |
| 46 | char *env_workers = getenv("GIT_TEST_CHECKOUT_WORKERS"); |
| 47 | |
| 48 | if (env_workers && *env_workers) { |
| 49 | if (strtol_i(env_workers, 10, num_workers)) { |
| 50 | die(_("invalid value for '%s': '%s'"), |
| 51 | "GIT_TEST_CHECKOUT_WORKERS", env_workers); |
| 52 | } |
| 53 | if (*num_workers < 1) |
| 54 | *num_workers = online_cpus(); |
| 55 | |
| 56 | *threshold = 0; |
| 57 | return; |
| 58 | } |
| 59 | |
| 60 | if (repo_config_get_int(the_repository, "checkout.workers", num_workers)) |
| 61 | *num_workers = DEFAULT_NUM_WORKERS; |
| 62 | else if (*num_workers < 1) |
| 63 | *num_workers = online_cpus(); |
| 64 | |
| 65 | if (repo_config_get_int(the_repository, "checkout.thresholdForParallelism", threshold)) |
| 66 | *threshold = DEFAULT_THRESHOLD_FOR_PARALLELISM; |
| 67 | } |
| 68 | |
| 69 | void init_parallel_checkout(void) |
| 70 | { |
| 71 | if (parallel_checkout.status != PC_UNINITIALIZED) |
| 72 | BUG("parallel checkout already initialized"); |
| 73 | |
| 74 | parallel_checkout.status = PC_ACCEPTING_ENTRIES; |
| 75 | } |
| 76 | |
| 77 | static void finish_parallel_checkout(void) |
| 78 | { |
| 79 | if (parallel_checkout.status == PC_UNINITIALIZED) |
| 80 | BUG("cannot finish parallel checkout: not initialized yet"); |
| 81 | |
| 82 | free(parallel_checkout.items); |
| 83 | memset(¶llel_checkout, 0, sizeof(parallel_checkout)); |
| 84 | } |
| 85 | |
| 86 | static int is_eligible_for_parallel_checkout(const struct cache_entry *ce, |
| 87 | const struct conv_attrs *ca) |
| 88 | { |
| 89 | enum conv_attrs_classification c; |
| 90 | size_t packed_item_size; |
| 91 | |
| 92 | /* |
| 93 | * Symlinks cannot be checked out in parallel as, in case of path |
| 94 | * collision, they could racily replace leading directories of other |
| 95 | * entries being checked out. Submodules are checked out in child |
| 96 | * processes, which have their own parallel checkout queues. |
| 97 | */ |
| 98 | if (!S_ISREG(ce->ce_mode)) |
| 99 | return 0; |
| 100 | |
| 101 | packed_item_size = sizeof(struct pc_item_fixed_portion) + ce->ce_namelen + |
| 102 | (ca->working_tree_encoding ? strlen(ca->working_tree_encoding) : 0); |
| 103 | |
| 104 | /* |
| 105 | * The amount of data we send to the workers per checkout item is |
| 106 | * typically small (75~300B). So unless we find an insanely huge path |
| 107 | * of 64KB, we should never reach the 65KB limit of one pkt-line. If |
| 108 | * that does happen, we let the sequential code handle the item. |
| 109 | */ |
| 110 | if (packed_item_size > LARGE_PACKET_DATA_MAX) |
| 111 | return 0; |
| 112 | |
| 113 | c = classify_conv_attrs(ca); |
| 114 | switch (c) { |
| 115 | case CA_CLASS_INCORE: |
| 116 | return 1; |
| 117 | |
| 118 | case CA_CLASS_INCORE_FILTER: |
| 119 | /* |
| 120 | * It would be safe to allow concurrent instances of |
| 121 | * single-file smudge filters, like rot13, but we should not |
| 122 | * assume that all filters are parallel-process safe. So we |
| 123 | * don't allow this. |
| 124 | */ |
| 125 | return 0; |
| 126 | |
| 127 | case CA_CLASS_INCORE_PROCESS: |
| 128 | /* |
| 129 | * The parallel queue and the delayed queue are not compatible, |
| 130 | * so they must be kept completely separated. And we can't tell |
| 131 | * if a long-running process will delay its response without |
| 132 | * actually asking it to perform the filtering. Therefore, this |
| 133 | * type of filter is not allowed in parallel checkout. |
| 134 | * |
| 135 | * Furthermore, there should only be one instance of the |
| 136 | * long-running process filter as we don't know how it is |
| 137 | * managing its own concurrency. So, spreading the entries that |
| 138 | * requisite such a filter among the parallel workers would |
| 139 | * require a lot more inter-process communication. We would |
| 140 | * probably have to designate a single process to interact with |
| 141 | * the filter and send all the necessary data to it, for each |
| 142 | * entry. |
| 143 | */ |
| 144 | return 0; |
| 145 | |
| 146 | case CA_CLASS_STREAMABLE: |
| 147 | return 1; |
| 148 | |
| 149 | default: |
| 150 | BUG("unsupported conv_attrs classification '%d'", c); |
| 151 | } |
| 152 | } |
| 153 | |
| 154 | int enqueue_checkout(struct cache_entry *ce, struct conv_attrs *ca, |
| 155 | int *checkout_counter) |
| 156 | { |
| 157 | struct parallel_checkout_item *pc_item; |
| 158 | |
| 159 | if (parallel_checkout.status != PC_ACCEPTING_ENTRIES || |
| 160 | !is_eligible_for_parallel_checkout(ce, ca)) |
| 161 | return -1; |
| 162 | |
| 163 | ALLOC_GROW(parallel_checkout.items, parallel_checkout.nr + 1, |
| 164 | parallel_checkout.alloc); |
| 165 | |
| 166 | pc_item = ¶llel_checkout.items[parallel_checkout.nr]; |
| 167 | pc_item->ce = ce; |
| 168 | memcpy(&pc_item->ca, ca, sizeof(pc_item->ca)); |
| 169 | pc_item->status = PC_ITEM_PENDING; |
| 170 | pc_item->id = parallel_checkout.nr; |
| 171 | pc_item->checkout_counter = checkout_counter; |
| 172 | parallel_checkout.nr++; |
| 173 | |
| 174 | return 0; |
| 175 | } |
| 176 | |
| 177 | size_t pc_queue_size(void) |
| 178 | { |
| 179 | return parallel_checkout.nr; |
| 180 | } |
| 181 | |
| 182 | static void advance_progress_meter(void) |
| 183 | { |
| 184 | if (parallel_checkout.progress) { |
| 185 | (*parallel_checkout.progress_cnt)++; |
| 186 | display_progress(parallel_checkout.progress, |
| 187 | *parallel_checkout.progress_cnt); |
| 188 | } |
| 189 | } |
| 190 | |
| 191 | static int handle_results(struct checkout *state) |
| 192 | { |
| 193 | int ret = 0; |
| 194 | size_t i; |
| 195 | int have_pending = 0; |
| 196 | |
| 197 | /* |
| 198 | * We first update the successfully written entries with the collected |
| 199 | * stat() data, so that they can be found by mark_colliding_entries(), |
| 200 | * in the next loop, when necessary. |
| 201 | */ |
| 202 | for (i = 0; i < parallel_checkout.nr; i++) { |
| 203 | struct parallel_checkout_item *pc_item = ¶llel_checkout.items[i]; |
| 204 | if (pc_item->status == PC_ITEM_WRITTEN) |
| 205 | update_ce_after_write(state, pc_item->ce, &pc_item->st); |
| 206 | } |
| 207 | |
| 208 | for (i = 0; i < parallel_checkout.nr; i++) { |
| 209 | struct parallel_checkout_item *pc_item = ¶llel_checkout.items[i]; |
| 210 | |
| 211 | switch(pc_item->status) { |
| 212 | case PC_ITEM_WRITTEN: |
| 213 | if (pc_item->checkout_counter) |
| 214 | (*pc_item->checkout_counter)++; |
| 215 | break; |
| 216 | case PC_ITEM_COLLIDED: |
| 217 | /* |
| 218 | * The entry could not be checked out due to a path |
| 219 | * collision with another entry. Since there can only |
| 220 | * be one entry of each colliding group on the disk, we |
| 221 | * could skip trying to check out this one and move on. |
| 222 | * However, this would leave the unwritten entries with |
| 223 | * null stat() fields on the index, which could |
| 224 | * potentially slow down subsequent operations that |
| 225 | * require refreshing it: git would not be able to |
| 226 | * trust st_size and would have to go to the filesystem |
| 227 | * to see if the contents match (see ie_modified()). |
| 228 | * |
| 229 | * Instead, let's pay the overhead only once, now, and |
| 230 | * call checkout_entry_ca() again for this file, to |
| 231 | * have its stat() data stored in the index. This also |
| 232 | * has the benefit of adding this entry and its |
| 233 | * colliding pair to the collision report message. |
| 234 | * Additionally, this overwriting behavior is consistent |
| 235 | * with what the sequential checkout does, so it doesn't |
| 236 | * add any extra overhead. |
| 237 | */ |
| 238 | ret |= checkout_entry_ca(pc_item->ce, &pc_item->ca, |
| 239 | state, NULL, |
| 240 | pc_item->checkout_counter); |
| 241 | advance_progress_meter(); |
| 242 | break; |
| 243 | case PC_ITEM_PENDING: |
| 244 | have_pending = 1; |
| 245 | /* fall through */ |
| 246 | case PC_ITEM_FAILED: |
| 247 | ret = -1; |
| 248 | break; |
| 249 | default: |
| 250 | BUG("unknown checkout item status in parallel checkout"); |
| 251 | } |
| 252 | } |
| 253 | |
| 254 | if (have_pending) |
| 255 | error("parallel checkout finished with pending entries"); |
| 256 | |
| 257 | return ret; |
| 258 | } |
| 259 | |
| 260 | static int reset_fd(int fd, const char *path) |
| 261 | { |
| 262 | if (lseek(fd, 0, SEEK_SET) != 0) |
| 263 | return error_errno("failed to rewind descriptor of '%s'", path); |
| 264 | if (ftruncate(fd, 0)) |
| 265 | return error_errno("failed to truncate file '%s'", path); |
| 266 | return 0; |
| 267 | } |
| 268 | |
| 269 | static int write_pc_item_to_fd(struct parallel_checkout_item *pc_item, int fd, |
| 270 | const char *path) |
| 271 | { |
| 272 | int ret; |
| 273 | struct stream_filter *filter; |
| 274 | struct strbuf buf = STRBUF_INIT; |
| 275 | char *blob; |
| 276 | size_t size; |
| 277 | ssize_t wrote; |
| 278 | |
| 279 | /* Sanity check */ |
| 280 | ASSERT(is_eligible_for_parallel_checkout(pc_item->ce, &pc_item->ca)); |
| 281 | |
| 282 | filter = get_stream_filter_ca(&pc_item->ca, &pc_item->ce->oid); |
| 283 | if (filter) { |
| 284 | if (odb_stream_blob_to_fd(the_repository->objects, fd, |
| 285 | &pc_item->ce->oid, filter, 1)) { |
| 286 | /* On error, reset fd to try writing without streaming */ |
| 287 | if (reset_fd(fd, path)) |
| 288 | return -1; |
| 289 | } else { |
| 290 | return 0; |
| 291 | } |
| 292 | } |
| 293 | |
| 294 | blob = read_blob_entry(pc_item->ce, &size); |
| 295 | if (!blob) |
| 296 | return error("cannot read object %s '%s'", |
| 297 | oid_to_hex(&pc_item->ce->oid), pc_item->ce->name); |
| 298 | |
| 299 | /* |
| 300 | * checkout metadata is used to give context for external process |
| 301 | * filters. Files requiring such filters are not eligible for parallel |
| 302 | * checkout, so pass NULL. Note: if that changes, the metadata must also |
| 303 | * be passed from the main process to the workers. |
| 304 | */ |
| 305 | ret = convert_to_working_tree_ca(&pc_item->ca, pc_item->ce->name, |
| 306 | blob, size, &buf, NULL); |
| 307 | |
| 308 | if (ret) { |
| 309 | size_t newsize; |
| 310 | free(blob); |
| 311 | blob = strbuf_detach(&buf, &newsize); |
| 312 | size = newsize; |
| 313 | } |
| 314 | |
| 315 | wrote = write_in_full(fd, blob, size); |
| 316 | free(blob); |
| 317 | if (wrote < 0) |
| 318 | return error("unable to write file '%s'", path); |
| 319 | |
| 320 | return 0; |
| 321 | } |
| 322 | |
| 323 | static int close_and_clear(int *fd) |
| 324 | { |
| 325 | int ret = 0; |
| 326 | |
| 327 | if (*fd >= 0) { |
| 328 | ret = close(*fd); |
| 329 | *fd = -1; |
| 330 | } |
| 331 | |
| 332 | return ret; |
| 333 | } |
| 334 | |
| 335 | void write_pc_item(struct parallel_checkout_item *pc_item, |
| 336 | struct checkout *state) |
| 337 | { |
| 338 | unsigned int mode = (pc_item->ce->ce_mode & 0100) ? 0777 : 0666; |
| 339 | int fd = -1, fstat_done = 0; |
| 340 | struct strbuf path = STRBUF_INIT; |
| 341 | const char *dir_sep; |
| 342 | |
| 343 | strbuf_add(&path, state->base_dir, state->base_dir_len); |
| 344 | strbuf_add(&path, pc_item->ce->name, pc_item->ce->ce_namelen); |
| 345 | |
| 346 | dir_sep = find_last_dir_sep(path.buf); |
| 347 | |
| 348 | /* |
| 349 | * The leading dirs should have been already created by now. But, in |
| 350 | * case of path collisions, one of the dirs could have been replaced by |
| 351 | * a symlink (checked out after we enqueued this entry for parallel |
| 352 | * checkout). Thus, we must check the leading dirs again. |
| 353 | */ |
| 354 | if (dir_sep && !has_dirs_only_path(path.buf, dir_sep - path.buf, |
| 355 | state->base_dir_len)) { |
| 356 | pc_item->status = PC_ITEM_COLLIDED; |
| 357 | trace2_data_string("pcheckout", NULL, "collision/dirname", path.buf); |
| 358 | goto out; |
| 359 | } |
| 360 | |
| 361 | fd = open(path.buf, O_WRONLY | O_CREAT | O_EXCL, mode); |
| 362 | |
| 363 | if (fd < 0) { |
| 364 | if (errno == EEXIST || errno == EISDIR) { |
| 365 | /* |
| 366 | * Errors which probably represent a path collision. |
| 367 | * Suppress the error message and mark the item to be |
| 368 | * retried later, sequentially. ENOTDIR and ENOENT are |
| 369 | * also interesting, but the above has_dirs_only_path() |
| 370 | * call should have already caught these cases. |
| 371 | */ |
| 372 | pc_item->status = PC_ITEM_COLLIDED; |
| 373 | trace2_data_string("pcheckout", NULL, |
| 374 | "collision/basename", path.buf); |
| 375 | } else { |
| 376 | error_errno("failed to open file '%s'", path.buf); |
| 377 | pc_item->status = PC_ITEM_FAILED; |
| 378 | } |
| 379 | goto out; |
| 380 | } |
| 381 | |
| 382 | if (write_pc_item_to_fd(pc_item, fd, path.buf)) { |
| 383 | /* Error was already reported. */ |
| 384 | pc_item->status = PC_ITEM_FAILED; |
| 385 | close_and_clear(&fd); |
| 386 | unlink(path.buf); |
| 387 | goto out; |
| 388 | } |
| 389 | |
| 390 | fstat_done = fstat_checkout_output(fd, state, &pc_item->st); |
| 391 | |
| 392 | if (close_and_clear(&fd)) { |
| 393 | error_errno("unable to close file '%s'", path.buf); |
| 394 | pc_item->status = PC_ITEM_FAILED; |
| 395 | goto out; |
| 396 | } |
| 397 | |
| 398 | if (state->refresh_cache && !fstat_done && lstat(path.buf, &pc_item->st) < 0) { |
| 399 | error_errno("unable to stat just-written file '%s'", path.buf); |
| 400 | pc_item->status = PC_ITEM_FAILED; |
| 401 | goto out; |
| 402 | } |
| 403 | |
| 404 | pc_item->status = PC_ITEM_WRITTEN; |
| 405 | |
| 406 | out: |
| 407 | strbuf_release(&path); |
| 408 | } |
| 409 | |
| 410 | static void send_one_item(int fd, struct parallel_checkout_item *pc_item) |
| 411 | { |
| 412 | size_t len_data; |
| 413 | char *data, *variant; |
| 414 | struct pc_item_fixed_portion *fixed_portion; |
| 415 | const char *working_tree_encoding = pc_item->ca.working_tree_encoding; |
| 416 | size_t name_len = pc_item->ce->ce_namelen; |
| 417 | size_t working_tree_encoding_len = working_tree_encoding ? |
| 418 | strlen(working_tree_encoding) : 0; |
| 419 | |
| 420 | /* |
| 421 | * Any changes in the calculation of the message size must also be made |
| 422 | * in is_eligible_for_parallel_checkout(). |
| 423 | */ |
| 424 | len_data = sizeof(struct pc_item_fixed_portion) + name_len + |
| 425 | working_tree_encoding_len; |
| 426 | |
| 427 | data = xmalloc(len_data); |
| 428 | |
| 429 | fixed_portion = (struct pc_item_fixed_portion *)data; |
| 430 | fixed_portion->id = pc_item->id; |
| 431 | fixed_portion->ce_mode = pc_item->ce->ce_mode; |
| 432 | fixed_portion->crlf_action = pc_item->ca.crlf_action; |
| 433 | fixed_portion->ident = pc_item->ca.ident; |
| 434 | fixed_portion->name_len = name_len; |
| 435 | fixed_portion->working_tree_encoding_len = working_tree_encoding_len; |
| 436 | oidcpy(&fixed_portion->oid, &pc_item->ce->oid); |
| 437 | |
| 438 | variant = data + sizeof(*fixed_portion); |
| 439 | if (working_tree_encoding_len) { |
| 440 | memcpy(variant, working_tree_encoding, working_tree_encoding_len); |
| 441 | variant += working_tree_encoding_len; |
| 442 | } |
| 443 | memcpy(variant, pc_item->ce->name, name_len); |
| 444 | |
| 445 | packet_write(fd, data, len_data); |
| 446 | |
| 447 | free(data); |
| 448 | } |
| 449 | |
| 450 | static void send_batch(int fd, size_t start, size_t nr) |
| 451 | { |
| 452 | size_t i; |
| 453 | sigchain_push(SIGPIPE, SIG_IGN); |
| 454 | for (i = 0; i < nr; i++) |
| 455 | send_one_item(fd, ¶llel_checkout.items[start + i]); |
| 456 | packet_flush(fd); |
| 457 | sigchain_pop(SIGPIPE); |
| 458 | } |
| 459 | |
| 460 | static struct pc_worker *setup_workers(struct checkout *state, int num_workers) |
| 461 | { |
| 462 | struct pc_worker *workers; |
| 463 | int i, workers_with_one_extra_item; |
| 464 | size_t base_batch_size, batch_beginning = 0; |
| 465 | |
| 466 | ALLOC_ARRAY(workers, num_workers); |
| 467 | |
| 468 | for (i = 0; i < num_workers; i++) { |
| 469 | struct child_process *cp = &workers[i].cp; |
| 470 | |
| 471 | child_process_init(cp); |
| 472 | cp->git_cmd = 1; |
| 473 | cp->in = -1; |
| 474 | cp->out = -1; |
| 475 | cp->clean_on_exit = 1; |
| 476 | strvec_push(&cp->args, "checkout--worker"); |
| 477 | if (state->base_dir_len) |
| 478 | strvec_pushf(&cp->args, "--prefix=%s", state->base_dir); |
| 479 | if (start_command(cp)) |
| 480 | die("failed to spawn checkout worker"); |
| 481 | } |
| 482 | |
| 483 | base_batch_size = parallel_checkout.nr / num_workers; |
| 484 | workers_with_one_extra_item = parallel_checkout.nr % num_workers; |
| 485 | |
| 486 | for (i = 0; i < num_workers; i++) { |
| 487 | struct pc_worker *worker = &workers[i]; |
| 488 | size_t batch_size = base_batch_size; |
| 489 | |
| 490 | /* distribute the extra work evenly */ |
| 491 | if (i < workers_with_one_extra_item) |
| 492 | batch_size++; |
| 493 | |
| 494 | send_batch(worker->cp.in, batch_beginning, batch_size); |
| 495 | worker->next_item_to_complete = batch_beginning; |
| 496 | worker->nr_items_to_complete = batch_size; |
| 497 | |
| 498 | batch_beginning += batch_size; |
| 499 | } |
| 500 | |
| 501 | return workers; |
| 502 | } |
| 503 | |
| 504 | static void finish_workers(struct pc_worker *workers, int num_workers) |
| 505 | { |
| 506 | int i; |
| 507 | |
| 508 | /* |
| 509 | * Close pipes before calling finish_command() to let the workers |
| 510 | * exit asynchronously and avoid spending extra time on wait(). |
| 511 | */ |
| 512 | for (i = 0; i < num_workers; i++) { |
| 513 | struct child_process *cp = &workers[i].cp; |
| 514 | if (cp->in >= 0) |
| 515 | close(cp->in); |
| 516 | if (cp->out >= 0) |
| 517 | close(cp->out); |
| 518 | } |
| 519 | |
| 520 | for (i = 0; i < num_workers; i++) { |
| 521 | int rc = finish_command(&workers[i].cp); |
| 522 | if (rc > 128) { |
| 523 | /* |
| 524 | * For a normal non-zero exit, the worker should have |
| 525 | * already printed something useful to stderr. But a |
| 526 | * death by signal should be mentioned to the user. |
| 527 | */ |
| 528 | error("checkout worker %d died of signal %d", i, rc - 128); |
| 529 | } |
| 530 | } |
| 531 | |
| 532 | free(workers); |
| 533 | } |
| 534 | |
| 535 | static inline void assert_pc_item_result_size(int got, int exp) |
| 536 | { |
| 537 | if (got != exp) |
| 538 | BUG("wrong result size from checkout worker (got %dB, exp %dB)", |
| 539 | got, exp); |
| 540 | } |
| 541 | |
| 542 | static void parse_and_save_result(const char *buffer, int len, |
| 543 | struct pc_worker *worker) |
| 544 | { |
| 545 | struct pc_item_result *res; |
| 546 | struct parallel_checkout_item *pc_item; |
| 547 | struct stat *st = NULL; |
| 548 | |
| 549 | if (len < PC_ITEM_RESULT_BASE_SIZE) |
| 550 | BUG("too short result from checkout worker (got %dB, exp >=%dB)", |
| 551 | len, (int)PC_ITEM_RESULT_BASE_SIZE); |
| 552 | |
| 553 | res = (struct pc_item_result *)buffer; |
| 554 | |
| 555 | /* |
| 556 | * Worker should send either the full result struct on success, or |
| 557 | * just the base (i.e. no stat data), otherwise. |
| 558 | */ |
| 559 | if (res->status == PC_ITEM_WRITTEN) { |
| 560 | assert_pc_item_result_size(len, (int)sizeof(struct pc_item_result)); |
| 561 | st = &res->st; |
| 562 | } else { |
| 563 | assert_pc_item_result_size(len, (int)PC_ITEM_RESULT_BASE_SIZE); |
| 564 | } |
| 565 | |
| 566 | if (!worker->nr_items_to_complete) |
| 567 | BUG("received result from supposedly finished checkout worker"); |
| 568 | if (res->id != worker->next_item_to_complete) |
| 569 | BUG("unexpected item id from checkout worker (got %"PRIuMAX", exp %"PRIuMAX")", |
| 570 | (uintmax_t)res->id, (uintmax_t)worker->next_item_to_complete); |
| 571 | |
| 572 | worker->next_item_to_complete++; |
| 573 | worker->nr_items_to_complete--; |
| 574 | |
| 575 | pc_item = ¶llel_checkout.items[res->id]; |
| 576 | pc_item->status = res->status; |
| 577 | if (st) |
| 578 | pc_item->st = *st; |
| 579 | |
| 580 | if (res->status != PC_ITEM_COLLIDED) |
| 581 | advance_progress_meter(); |
| 582 | } |
| 583 | |
| 584 | static void gather_results_from_workers(struct pc_worker *workers, |
| 585 | int num_workers) |
| 586 | { |
| 587 | int i, active_workers = num_workers; |
| 588 | struct pollfd *pfds; |
| 589 | |
| 590 | CALLOC_ARRAY(pfds, num_workers); |
| 591 | for (i = 0; i < num_workers; i++) { |
| 592 | pfds[i].fd = workers[i].cp.out; |
| 593 | pfds[i].events = POLLIN; |
| 594 | } |
| 595 | |
| 596 | while (active_workers) { |
| 597 | int nr = poll(pfds, num_workers, -1); |
| 598 | |
| 599 | if (nr < 0) { |
| 600 | if (errno == EINTR) |
| 601 | continue; |
| 602 | die_errno("failed to poll checkout workers"); |
| 603 | } |
| 604 | |
| 605 | for (i = 0; i < num_workers && nr > 0; i++) { |
| 606 | struct pc_worker *worker = &workers[i]; |
| 607 | struct pollfd *pfd = &pfds[i]; |
| 608 | |
| 609 | if (!pfd->revents) |
| 610 | continue; |
| 611 | |
| 612 | if (pfd->revents & POLLIN) { |
| 613 | int len = packet_read(pfd->fd, packet_buffer, |
| 614 | sizeof(packet_buffer), 0); |
| 615 | |
| 616 | if (len < 0) { |
| 617 | BUG("packet_read() returned negative value"); |
| 618 | } else if (!len) { |
| 619 | pfd->fd = -1; |
| 620 | active_workers--; |
| 621 | } else { |
| 622 | parse_and_save_result(packet_buffer, |
| 623 | len, worker); |
| 624 | } |
| 625 | } else if (pfd->revents & POLLHUP) { |
| 626 | pfd->fd = -1; |
| 627 | active_workers--; |
| 628 | } else if (pfd->revents & (POLLNVAL | POLLERR)) { |
| 629 | die("error polling from checkout worker"); |
| 630 | } |
| 631 | |
| 632 | nr--; |
| 633 | } |
| 634 | } |
| 635 | |
| 636 | free(pfds); |
| 637 | } |
| 638 | |
| 639 | static void write_items_sequentially(struct checkout *state) |
| 640 | { |
| 641 | size_t i; |
| 642 | |
| 643 | for (i = 0; i < parallel_checkout.nr; i++) { |
| 644 | struct parallel_checkout_item *pc_item = ¶llel_checkout.items[i]; |
| 645 | write_pc_item(pc_item, state); |
| 646 | if (pc_item->status != PC_ITEM_COLLIDED) |
| 647 | advance_progress_meter(); |
| 648 | } |
| 649 | } |
| 650 | |
| 651 | int run_parallel_checkout(struct checkout *state, int num_workers, int threshold, |
| 652 | struct progress *progress, unsigned int *progress_cnt) |
| 653 | { |
| 654 | int ret; |
| 655 | |
| 656 | if (parallel_checkout.status != PC_ACCEPTING_ENTRIES) |
| 657 | BUG("cannot run parallel checkout: uninitialized or already running"); |
| 658 | |
| 659 | parallel_checkout.status = PC_RUNNING; |
| 660 | parallel_checkout.progress = progress; |
| 661 | parallel_checkout.progress_cnt = progress_cnt; |
| 662 | |
| 663 | if (parallel_checkout.nr < num_workers) |
| 664 | num_workers = parallel_checkout.nr; |
| 665 | |
| 666 | if (num_workers <= 1 || parallel_checkout.nr < threshold) { |
| 667 | write_items_sequentially(state); |
| 668 | } else { |
| 669 | struct pc_worker *workers = setup_workers(state, num_workers); |
| 670 | gather_results_from_workers(workers, num_workers); |
| 671 | finish_workers(workers, num_workers); |
| 672 | } |
| 673 | |
| 674 | ret = handle_results(state); |
| 675 | |
| 676 | finish_parallel_checkout(); |
| 677 | return ret; |
| 678 | } |