1 /* 2 * Dirtyrate implement code 3 * 4 * Copyright (c) 2020 HUAWEI TECHNOLOGIES CO.,LTD. 5 * 6 * Authors: 7 * Chuan Zheng <zhengchuan@huawei.com> 8 * 9 * This work is licensed under the terms of the GNU GPL, version 2 or later. 10 * See the COPYING file in the top-level directory. 11 */ 12 13 #include "qemu/osdep.h" 14 #include <zlib.h> 15 #include "qapi/error.h" 16 #include "cpu.h" 17 #include "exec/ramblock.h" 18 #include "qemu/rcu_queue.h" 19 #include "qapi/qapi-commands-migration.h" 20 #include "ram.h" 21 #include "trace.h" 22 #include "dirtyrate.h" 23 24 static int CalculatingState = DIRTY_RATE_STATUS_UNSTARTED; 25 static struct DirtyRateStat DirtyStat; 26 27 static int64_t set_sample_page_period(int64_t msec, int64_t initial_time) 28 { 29 int64_t current_time; 30 31 current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); 32 if ((current_time - initial_time) >= msec) { 33 msec = current_time - initial_time; 34 } else { 35 g_usleep((msec + initial_time - current_time) * 1000); 36 } 37 38 return msec; 39 } 40 41 static bool is_sample_period_valid(int64_t sec) 42 { 43 if (sec < MIN_FETCH_DIRTYRATE_TIME_SEC || 44 sec > MAX_FETCH_DIRTYRATE_TIME_SEC) { 45 return false; 46 } 47 48 return true; 49 } 50 51 static bool is_sample_pages_valid(int64_t pages) 52 { 53 return pages >= MIN_SAMPLE_PAGE_COUNT && 54 pages <= MAX_SAMPLE_PAGE_COUNT; 55 } 56 57 static int dirtyrate_set_state(int *state, int old_state, int new_state) 58 { 59 assert(new_state < DIRTY_RATE_STATUS__MAX); 60 trace_dirtyrate_set_state(DirtyRateStatus_str(new_state)); 61 if (qatomic_cmpxchg(state, old_state, new_state) == old_state) { 62 return 0; 63 } else { 64 return -1; 65 } 66 } 67 68 static struct DirtyRateInfo *query_dirty_rate_info(void) 69 { 70 int64_t dirty_rate = DirtyStat.dirty_rate; 71 struct DirtyRateInfo *info = g_malloc0(sizeof(DirtyRateInfo)); 72 73 if (qatomic_read(&CalculatingState) == DIRTY_RATE_STATUS_MEASURED) { 74 info->has_dirty_rate = true; 75 info->dirty_rate = dirty_rate; 76 } 77 78 info->status = CalculatingState; 79 info->start_time = DirtyStat.start_time; 80 info->calc_time = DirtyStat.calc_time; 81 info->sample_pages = DirtyStat.sample_pages; 82 83 trace_query_dirty_rate_info(DirtyRateStatus_str(CalculatingState)); 84 85 return info; 86 } 87 88 static void init_dirtyrate_stat(int64_t start_time, int64_t calc_time, 89 uint64_t sample_pages) 90 { 91 DirtyStat.total_dirty_samples = 0; 92 DirtyStat.total_sample_count = 0; 93 DirtyStat.total_block_mem_MB = 0; 94 DirtyStat.dirty_rate = -1; 95 DirtyStat.start_time = start_time; 96 DirtyStat.calc_time = calc_time; 97 DirtyStat.sample_pages = sample_pages; 98 } 99 100 static void update_dirtyrate_stat(struct RamblockDirtyInfo *info) 101 { 102 DirtyStat.total_dirty_samples += info->sample_dirty_count; 103 DirtyStat.total_sample_count += info->sample_pages_count; 104 /* size of total pages in MB */ 105 DirtyStat.total_block_mem_MB += (info->ramblock_pages * 106 TARGET_PAGE_SIZE) >> 20; 107 } 108 109 static void update_dirtyrate(uint64_t msec) 110 { 111 uint64_t dirtyrate; 112 uint64_t total_dirty_samples = DirtyStat.total_dirty_samples; 113 uint64_t total_sample_count = DirtyStat.total_sample_count; 114 uint64_t total_block_mem_MB = DirtyStat.total_block_mem_MB; 115 116 dirtyrate = total_dirty_samples * total_block_mem_MB * 117 1000 / (total_sample_count * msec); 118 119 DirtyStat.dirty_rate = dirtyrate; 120 } 121 122 /* 123 * get hash result for the sampled memory with length of TARGET_PAGE_SIZE 124 * in ramblock, which starts from ramblock base address. 125 */ 126 static uint32_t get_ramblock_vfn_hash(struct RamblockDirtyInfo *info, 127 uint64_t vfn) 128 { 129 uint32_t crc; 130 131 crc = crc32(0, (info->ramblock_addr + 132 vfn * TARGET_PAGE_SIZE), TARGET_PAGE_SIZE); 133 134 trace_get_ramblock_vfn_hash(info->idstr, vfn, crc); 135 return crc; 136 } 137 138 static bool save_ramblock_hash(struct RamblockDirtyInfo *info) 139 { 140 unsigned int sample_pages_count; 141 int i; 142 GRand *rand; 143 144 sample_pages_count = info->sample_pages_count; 145 146 /* ramblock size less than one page, return success to skip this ramblock */ 147 if (unlikely(info->ramblock_pages == 0 || sample_pages_count == 0)) { 148 return true; 149 } 150 151 info->hash_result = g_try_malloc0_n(sample_pages_count, 152 sizeof(uint32_t)); 153 if (!info->hash_result) { 154 return false; 155 } 156 157 info->sample_page_vfn = g_try_malloc0_n(sample_pages_count, 158 sizeof(uint64_t)); 159 if (!info->sample_page_vfn) { 160 g_free(info->hash_result); 161 return false; 162 } 163 164 rand = g_rand_new(); 165 for (i = 0; i < sample_pages_count; i++) { 166 info->sample_page_vfn[i] = g_rand_int_range(rand, 0, 167 info->ramblock_pages - 1); 168 info->hash_result[i] = get_ramblock_vfn_hash(info, 169 info->sample_page_vfn[i]); 170 } 171 g_rand_free(rand); 172 173 return true; 174 } 175 176 static void get_ramblock_dirty_info(RAMBlock *block, 177 struct RamblockDirtyInfo *info, 178 struct DirtyRateConfig *config) 179 { 180 uint64_t sample_pages_per_gigabytes = config->sample_pages_per_gigabytes; 181 182 /* Right shift 30 bits to calc ramblock size in GB */ 183 info->sample_pages_count = (qemu_ram_get_used_length(block) * 184 sample_pages_per_gigabytes) >> 30; 185 /* Right shift TARGET_PAGE_BITS to calc page count */ 186 info->ramblock_pages = qemu_ram_get_used_length(block) >> 187 TARGET_PAGE_BITS; 188 info->ramblock_addr = qemu_ram_get_host_addr(block); 189 strcpy(info->idstr, qemu_ram_get_idstr(block)); 190 } 191 192 static void free_ramblock_dirty_info(struct RamblockDirtyInfo *infos, int count) 193 { 194 int i; 195 196 if (!infos) { 197 return; 198 } 199 200 for (i = 0; i < count; i++) { 201 g_free(infos[i].sample_page_vfn); 202 g_free(infos[i].hash_result); 203 } 204 g_free(infos); 205 } 206 207 static bool skip_sample_ramblock(RAMBlock *block) 208 { 209 /* 210 * Sample only blocks larger than MIN_RAMBLOCK_SIZE. 211 */ 212 if (qemu_ram_get_used_length(block) < (MIN_RAMBLOCK_SIZE << 10)) { 213 trace_skip_sample_ramblock(block->idstr, 214 qemu_ram_get_used_length(block)); 215 return true; 216 } 217 218 return false; 219 } 220 221 static bool record_ramblock_hash_info(struct RamblockDirtyInfo **block_dinfo, 222 struct DirtyRateConfig config, 223 int *block_count) 224 { 225 struct RamblockDirtyInfo *info = NULL; 226 struct RamblockDirtyInfo *dinfo = NULL; 227 RAMBlock *block = NULL; 228 int total_count = 0; 229 int index = 0; 230 bool ret = false; 231 232 RAMBLOCK_FOREACH_MIGRATABLE(block) { 233 if (skip_sample_ramblock(block)) { 234 continue; 235 } 236 total_count++; 237 } 238 239 dinfo = g_try_malloc0_n(total_count, sizeof(struct RamblockDirtyInfo)); 240 if (dinfo == NULL) { 241 goto out; 242 } 243 244 RAMBLOCK_FOREACH_MIGRATABLE(block) { 245 if (skip_sample_ramblock(block)) { 246 continue; 247 } 248 if (index >= total_count) { 249 break; 250 } 251 info = &dinfo[index]; 252 get_ramblock_dirty_info(block, info, &config); 253 if (!save_ramblock_hash(info)) { 254 goto out; 255 } 256 index++; 257 } 258 ret = true; 259 260 out: 261 *block_count = index; 262 *block_dinfo = dinfo; 263 return ret; 264 } 265 266 static void calc_page_dirty_rate(struct RamblockDirtyInfo *info) 267 { 268 uint32_t crc; 269 int i; 270 271 for (i = 0; i < info->sample_pages_count; i++) { 272 crc = get_ramblock_vfn_hash(info, info->sample_page_vfn[i]); 273 if (crc != info->hash_result[i]) { 274 trace_calc_page_dirty_rate(info->idstr, crc, info->hash_result[i]); 275 info->sample_dirty_count++; 276 } 277 } 278 } 279 280 static struct RamblockDirtyInfo * 281 find_block_matched(RAMBlock *block, int count, 282 struct RamblockDirtyInfo *infos) 283 { 284 int i; 285 struct RamblockDirtyInfo *matched; 286 287 for (i = 0; i < count; i++) { 288 if (!strcmp(infos[i].idstr, qemu_ram_get_idstr(block))) { 289 break; 290 } 291 } 292 293 if (i == count) { 294 return NULL; 295 } 296 297 if (infos[i].ramblock_addr != qemu_ram_get_host_addr(block) || 298 infos[i].ramblock_pages != 299 (qemu_ram_get_used_length(block) >> TARGET_PAGE_BITS)) { 300 trace_find_page_matched(block->idstr); 301 return NULL; 302 } 303 304 matched = &infos[i]; 305 306 return matched; 307 } 308 309 static bool compare_page_hash_info(struct RamblockDirtyInfo *info, 310 int block_count) 311 { 312 struct RamblockDirtyInfo *block_dinfo = NULL; 313 RAMBlock *block = NULL; 314 315 RAMBLOCK_FOREACH_MIGRATABLE(block) { 316 if (skip_sample_ramblock(block)) { 317 continue; 318 } 319 block_dinfo = find_block_matched(block, block_count, info); 320 if (block_dinfo == NULL) { 321 continue; 322 } 323 calc_page_dirty_rate(block_dinfo); 324 update_dirtyrate_stat(block_dinfo); 325 } 326 327 if (DirtyStat.total_sample_count == 0) { 328 return false; 329 } 330 331 return true; 332 } 333 334 static void calculate_dirtyrate(struct DirtyRateConfig config) 335 { 336 struct RamblockDirtyInfo *block_dinfo = NULL; 337 int block_count = 0; 338 int64_t msec = 0; 339 int64_t initial_time; 340 341 rcu_register_thread(); 342 rcu_read_lock(); 343 initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); 344 if (!record_ramblock_hash_info(&block_dinfo, config, &block_count)) { 345 goto out; 346 } 347 rcu_read_unlock(); 348 349 msec = config.sample_period_seconds * 1000; 350 msec = set_sample_page_period(msec, initial_time); 351 DirtyStat.start_time = initial_time / 1000; 352 DirtyStat.calc_time = msec / 1000; 353 354 rcu_read_lock(); 355 if (!compare_page_hash_info(block_dinfo, block_count)) { 356 goto out; 357 } 358 359 update_dirtyrate(msec); 360 361 out: 362 rcu_read_unlock(); 363 free_ramblock_dirty_info(block_dinfo, block_count); 364 rcu_unregister_thread(); 365 } 366 367 void *get_dirtyrate_thread(void *arg) 368 { 369 struct DirtyRateConfig config = *(struct DirtyRateConfig *)arg; 370 int ret; 371 int64_t start_time; 372 int64_t calc_time; 373 uint64_t sample_pages; 374 375 ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_UNSTARTED, 376 DIRTY_RATE_STATUS_MEASURING); 377 if (ret == -1) { 378 error_report("change dirtyrate state failed."); 379 return NULL; 380 } 381 382 start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000; 383 calc_time = config.sample_period_seconds; 384 sample_pages = config.sample_pages_per_gigabytes; 385 init_dirtyrate_stat(start_time, calc_time, sample_pages); 386 387 calculate_dirtyrate(config); 388 389 ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_MEASURING, 390 DIRTY_RATE_STATUS_MEASURED); 391 if (ret == -1) { 392 error_report("change dirtyrate state failed."); 393 } 394 return NULL; 395 } 396 397 void qmp_calc_dirty_rate(int64_t calc_time, bool has_sample_pages, 398 int64_t sample_pages, Error **errp) 399 { 400 static struct DirtyRateConfig config; 401 QemuThread thread; 402 int ret; 403 404 /* 405 * If the dirty rate is already being measured, don't attempt to start. 406 */ 407 if (qatomic_read(&CalculatingState) == DIRTY_RATE_STATUS_MEASURING) { 408 error_setg(errp, "the dirty rate is already being measured."); 409 return; 410 } 411 412 if (!is_sample_period_valid(calc_time)) { 413 error_setg(errp, "calc-time is out of range[%d, %d].", 414 MIN_FETCH_DIRTYRATE_TIME_SEC, 415 MAX_FETCH_DIRTYRATE_TIME_SEC); 416 return; 417 } 418 419 if (has_sample_pages) { 420 if (!is_sample_pages_valid(sample_pages)) { 421 error_setg(errp, "sample-pages is out of range[%d, %d].", 422 MIN_SAMPLE_PAGE_COUNT, 423 MAX_SAMPLE_PAGE_COUNT); 424 return; 425 } 426 } else { 427 sample_pages = DIRTYRATE_DEFAULT_SAMPLE_PAGES; 428 } 429 430 /* 431 * Init calculation state as unstarted. 432 */ 433 ret = dirtyrate_set_state(&CalculatingState, CalculatingState, 434 DIRTY_RATE_STATUS_UNSTARTED); 435 if (ret == -1) { 436 error_setg(errp, "init dirty rate calculation state failed."); 437 return; 438 } 439 440 config.sample_period_seconds = calc_time; 441 config.sample_pages_per_gigabytes = sample_pages; 442 qemu_thread_create(&thread, "get_dirtyrate", get_dirtyrate_thread, 443 (void *)&config, QEMU_THREAD_DETACHED); 444 } 445 446 struct DirtyRateInfo *qmp_query_dirty_rate(Error **errp) 447 { 448 return query_dirty_rate_info(); 449 } 450