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