drivers/lightnvm/pblk-gc.c

   1 /*
   2  * Copyright (C) 2016 CNEX Labs
   3  * Initial release: Javier Gonzalez <[email protected]>
   4  *                  Matias Bjorling <[email protected]>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License version
   8  * 2 as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * pblk-gc.c - pblk's garbage collector
  16  */
  17
  18 #include "pblk.h"
  19 #include <linux/delay.h>
  20
  21 static void pblk_gc_free_gc_rq(struct pblk_gc_rq *gc_rq)
  22 {
  23         kfree(gc_rq->data);
  24         kfree(gc_rq->lba_list);
  25         kfree(gc_rq);
  26 }
  27
  28 static int pblk_gc_write(struct pblk *pblk)
  29 {
  30         struct pblk_gc *gc = &pblk->gc;
  31         struct pblk_gc_rq *gc_rq, *tgc_rq;
  32         LIST_HEAD(w_list);
  33
  34         spin_lock(&gc->w_lock);
  35         if (list_empty(&gc->w_list)) {
  36                 spin_unlock(&gc->w_lock);
  37                 return 1;
  38         }
  39
  40         list_for_each_entry_safe(gc_rq, tgc_rq, &gc->w_list, list) {
  41                 list_move_tail(&gc_rq->list, &w_list);
  42                 gc->w_entries--;
  43         }
  44         spin_unlock(&gc->w_lock);
  45
  46         list_for_each_entry_safe(gc_rq, tgc_rq, &w_list, list) {
  47                 pblk_write_gc_to_cache(pblk, gc_rq->data, gc_rq->lba_list,
  48                                 gc_rq->nr_secs, gc_rq->secs_to_gc,
  49                                 gc_rq->line, PBLK_IOTYPE_GC);
  50
  51                 kref_put(&gc_rq->line->ref, pblk_line_put);
  52
  53                 list_del(&gc_rq->list);
  54                 pblk_gc_free_gc_rq(gc_rq);
  55         }
  56
  57         return 0;
  58 }
  59
  60 static void pblk_gc_writer_kick(struct pblk_gc *gc)
  61 {
  62         wake_up_process(gc->gc_writer_ts);
  63 }
  64
  65 /*
  66  * Responsible for managing all memory related to a gc request. Also in case of
  67  * failure
  68  */
  69 static int pblk_gc_move_valid_secs(struct pblk *pblk, struct pblk_line *line,
  70                                    u64 *lba_list, unsigned int nr_secs)
  71 {
  72         struct nvm_tgt_dev *dev = pblk->dev;
  73         struct nvm_geo *geo = &dev->geo;
  74         struct pblk_gc *gc = &pblk->gc;
  75         struct pblk_gc_rq *gc_rq;
  76         void *data;
  77         unsigned int secs_to_gc;
  78         int ret = NVM_IO_OK;
  79
  80         data = kmalloc(nr_secs * geo->sec_size, GFP_KERNEL);
  81         if (!data) {
  82                 ret = NVM_IO_ERR;
  83                 goto free_lba_list;
  84         }
  85
  86         /* Read from GC victim block */
  87         if (pblk_submit_read_gc(pblk, lba_list, data, nr_secs,
  88                                                         &secs_to_gc, line)) {
  89                 ret = NVM_IO_ERR;
  90                 goto free_data;
  91         }
  92
  93         if (!secs_to_gc)
  94                 goto free_data;
  95
  96         gc_rq = kmalloc(sizeof(struct pblk_gc_rq), GFP_KERNEL);
  97         if (!gc_rq) {
  98                 ret = NVM_IO_ERR;
  99                 goto free_data;
 100         }
 101
 102         gc_rq->line = line;
 103         gc_rq->data = data;
 104         gc_rq->lba_list = lba_list;
 105         gc_rq->nr_secs = nr_secs;
 106         gc_rq->secs_to_gc = secs_to_gc;
 107
 108         kref_get(&line->ref);
 109
 110 retry:
 111         spin_lock(&gc->w_lock);
 112         if (gc->w_entries > 256) {
 113                 spin_unlock(&gc->w_lock);
 114                 usleep_range(256, 1024);
 115                 goto retry;
 116         }
 117         gc->w_entries++;
 118         list_add_tail(&gc_rq->list, &gc->w_list);
 119         spin_unlock(&gc->w_lock);
 120
 121         pblk_gc_writer_kick(&pblk->gc);
 122
 123         return NVM_IO_OK;
 124
 125 free_data:
 126         kfree(data);
 127 free_lba_list:
 128         kfree(lba_list);
 129
 130         return ret;
 131 }
 132
 133 static void pblk_put_line_back(struct pblk *pblk, struct pblk_line *line)
 134 {
 135         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 136         struct list_head *move_list;
 137
 138         spin_lock(&line->lock);
 139         WARN_ON(line->state != PBLK_LINESTATE_GC);
 140         line->state = PBLK_LINESTATE_CLOSED;
 141         move_list = pblk_line_gc_list(pblk, line);
 142         spin_unlock(&line->lock);
 143
 144         if (move_list) {
 145                 spin_lock(&l_mg->gc_lock);
 146                 list_add_tail(&line->list, move_list);
 147                 spin_unlock(&l_mg->gc_lock);
 148         }
 149 }
 150
 151 static void pblk_gc_line_ws(struct work_struct *work)
 152 {
 153         struct pblk_line_ws *line_ws = container_of(work, struct pblk_line_ws,
 154                                                                         ws);
 155         struct pblk *pblk = line_ws->pblk;
 156         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 157         struct pblk_line *line = line_ws->line;
 158         struct pblk_line_meta *lm = &pblk->lm;
 159         __le64 *lba_list = line_ws->priv;
 160         u64 *gc_list;
 161         int sec_left;
 162         int nr_ppas, bit;
 163         int put_line = 1;
 164
 165         pr_debug("pblk: line '%d' being reclaimed for GC\n", line->id);
 166
 167         spin_lock(&line->lock);
 168         sec_left = line->vsc;
 169         if (!sec_left) {
 170                 /* Lines are erased before being used (l_mg->data_/log_next) */
 171                 spin_unlock(&line->lock);
 172                 goto out;
 173         }
 174         spin_unlock(&line->lock);
 175
 176         if (sec_left < 0) {
 177                 pr_err("pblk: corrupted GC line (%d)\n", line->id);
 178                 put_line = 0;
 179                 pblk_put_line_back(pblk, line);
 180                 goto out;
 181         }
 182
 183         bit = -1;
 184 next_rq:
 185         gc_list = kmalloc_array(pblk->max_write_pgs, sizeof(u64), GFP_KERNEL);
 186         if (!gc_list) {
 187                 put_line = 0;
 188                 pblk_put_line_back(pblk, line);
 189                 goto out;
 190         }
 191
 192         nr_ppas = 0;
 193         do {
 194                 bit = find_next_zero_bit(line->invalid_bitmap, lm->sec_per_line,
 195                                                                 bit + 1);
 196                 if (bit > line->emeta_ssec)
 197                         break;
 198
 199                 gc_list[nr_ppas++] = le64_to_cpu(lba_list[bit]);
 200         } while (nr_ppas < pblk->max_write_pgs);
 201
 202         if (unlikely(!nr_ppas)) {
 203                 kfree(gc_list);
 204                 goto out;
 205         }
 206
 207         if (pblk_gc_move_valid_secs(pblk, line, gc_list, nr_ppas)) {
 208                 pr_err("pblk: could not GC all sectors: line:%d (%d/%d/%d)\n",
 209                                                 line->id, line->vsc,
 210                                                 nr_ppas, nr_ppas);
 211                 put_line = 0;
 212                 pblk_put_line_back(pblk, line);
 213                 goto out;
 214         }
 215
 216         sec_left -= nr_ppas;
 217         if (sec_left > 0)
 218                 goto next_rq;
 219
 220 out:
 221         pblk_mfree(line->emeta, l_mg->emeta_alloc_type);
 222         mempool_free(line_ws, pblk->line_ws_pool);
 223         atomic_dec(&pblk->gc.inflight_gc);
 224         if (put_line)
 225                 kref_put(&line->ref, pblk_line_put);
 226 }
 227
 228 static int pblk_gc_line(struct pblk *pblk, struct pblk_line *line)
 229 {
 230         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 231         struct pblk_line_meta *lm = &pblk->lm;
 232         struct pblk_line_ws *line_ws;
 233         __le64 *lba_list;
 234         int ret;
 235
 236         line_ws = mempool_alloc(pblk->line_ws_pool, GFP_KERNEL);
 237         line->emeta = pblk_malloc(lm->emeta_len, l_mg->emeta_alloc_type,
 238                                                                 GFP_KERNEL);
 239         if (!line->emeta) {
 240                 pr_err("pblk: cannot use GC emeta\n");
 241                 goto fail_free_ws;
 242         }
 243
 244         ret = pblk_line_read_emeta(pblk, line);
 245         if (ret) {
 246                 pr_err("pblk: line %d read emeta failed (%d)\n", line->id, ret);
 247                 goto fail_free_emeta;
 248         }
 249
 250         /* If this read fails, it means that emeta is corrupted. For now, leave
 251          * the line untouched. TODO: Implement a recovery routine that scans and
 252          * moves all sectors on the line.
 253          */
 254         lba_list = pblk_recov_get_lba_list(pblk, line->emeta);
 255         if (!lba_list) {
 256                 pr_err("pblk: could not interpret emeta (line %d)\n", line->id);
 257                 goto fail_free_emeta;
 258         }
 259
 260         line_ws->pblk = pblk;
 261         line_ws->line = line;
 262         line_ws->priv = lba_list;
 263
 264         INIT_WORK(&line_ws->ws, pblk_gc_line_ws);
 265         queue_work(pblk->gc.gc_reader_wq, &line_ws->ws);
 266
 267         return 0;
 268
 269 fail_free_emeta:
 270         pblk_mfree(line->emeta, l_mg->emeta_alloc_type);
 271 fail_free_ws:
 272         mempool_free(line_ws, pblk->line_ws_pool);
 273         pblk_put_line_back(pblk, line);
 274
 275         return 1;
 276 }
 277
 278 static void pblk_gc_lines(struct pblk *pblk, struct list_head *gc_list)
 279 {
 280         struct pblk_line *line, *tline;
 281
 282         list_for_each_entry_safe(line, tline, gc_list, list) {
 283                 if (pblk_gc_line(pblk, line))
 284                         pr_err("pblk: failed to GC line %d\n", line->id);
 285                 list_del(&line->list);
 286         }
 287 }
 288
 289 /*
 290  * Lines with no valid sectors will be returned to the free list immediately. If
 291  * GC is activated - either because the free block count is under the determined
 292  * threshold, or because it is being forced from user space - only lines with a
 293  * high count of invalid sectors will be recycled.
 294  */
 295 static void pblk_gc_run(struct pblk *pblk)
 296 {
 297         struct pblk_line_mgmt *l_mg = &pblk->l_mg;
 298         struct pblk_gc *gc = &pblk->gc;
 299         struct pblk_line *line, *tline;
 300         unsigned int nr_blocks_free, nr_blocks_need;
 301         struct list_head *group_list;
 302         int run_gc, gc_group = 0;
 303         int prev_gc = 0;
 304         int inflight_gc = atomic_read(&gc->inflight_gc);
 305         LIST_HEAD(gc_list);
 306
 307         spin_lock(&l_mg->gc_lock);
 308         list_for_each_entry_safe(line, tline, &l_mg->gc_full_list, list) {
 309                 spin_lock(&line->lock);
 310                 WARN_ON(line->state != PBLK_LINESTATE_CLOSED);
 311                 line->state = PBLK_LINESTATE_GC;
 312                 spin_unlock(&line->lock);
 313
 314                 list_del(&line->list);
 315                 kref_put(&line->ref, pblk_line_put);
 316         }
 317         spin_unlock(&l_mg->gc_lock);
 318
 319         nr_blocks_need = pblk_rl_gc_thrs(&pblk->rl);
 320         nr_blocks_free = pblk_rl_nr_free_blks(&pblk->rl);
 321         run_gc = (nr_blocks_need > nr_blocks_free || gc->gc_forced);
 322
 323 next_gc_group:
 324         group_list = l_mg->gc_lists[gc_group++];
 325         spin_lock(&l_mg->gc_lock);
 326         while (run_gc && !list_empty(group_list)) {
 327                 /* No need to queue up more GC lines than we can handle */
 328                 if (!run_gc || inflight_gc > gc->gc_jobs_active) {
 329                         spin_unlock(&l_mg->gc_lock);
 330                         pblk_gc_lines(pblk, &gc_list);
 331                         return;
 332                 }
 333
 334                 line = list_first_entry(group_list, struct pblk_line, list);
 335                 nr_blocks_free += atomic_read(&line->blk_in_line);
 336
 337                 spin_lock(&line->lock);
 338                 WARN_ON(line->state != PBLK_LINESTATE_CLOSED);
 339                 line->state = PBLK_LINESTATE_GC;
 340                 list_move_tail(&line->list, &gc_list);
 341                 atomic_inc(&gc->inflight_gc);
 342                 inflight_gc++;
 343                 spin_unlock(&line->lock);
 344
 345                 prev_gc = 1;
 346                 run_gc = (nr_blocks_need > nr_blocks_free || gc->gc_forced);
 347         }
 348         spin_unlock(&l_mg->gc_lock);
 349
 350         pblk_gc_lines(pblk, &gc_list);
 351
 352         if (!prev_gc && pblk->rl.rb_state > gc_group &&
 353                                                 gc_group < PBLK_NR_GC_LISTS)
 354                 goto next_gc_group;
 355 }
 356
 357
 358 static void pblk_gc_kick(struct pblk *pblk)
 359 {
 360         struct pblk_gc *gc = &pblk->gc;
 361
 362         wake_up_process(gc->gc_ts);
 363         pblk_gc_writer_kick(gc);
 364         mod_timer(&gc->gc_timer, jiffies + msecs_to_jiffies(GC_TIME_MSECS));
 365 }
 366
 367 static void pblk_gc_timer(unsigned long data)
 368 {
 369         struct pblk *pblk = (struct pblk *)data;
 370
 371         pblk_gc_kick(pblk);
 372 }
 373
 374 static int pblk_gc_ts(void *data)
 375 {
 376         struct pblk *pblk = data;
 377
 378         while (!kthread_should_stop()) {
 379                 pblk_gc_run(pblk);
 380                 set_current_state(TASK_INTERRUPTIBLE);
 381                 io_schedule();
 382         }
 383
 384         return 0;
 385 }
 386
 387 static int pblk_gc_writer_ts(void *data)
 388 {
 389         struct pblk *pblk = data;
 390
 391         while (!kthread_should_stop()) {
 392                 if (!pblk_gc_write(pblk))
 393                         continue;
 394                 set_current_state(TASK_INTERRUPTIBLE);
 395                 io_schedule();
 396         }
 397
 398         return 0;
 399 }
 400
 401 static void pblk_gc_start(struct pblk *pblk)
 402 {
 403         pblk->gc.gc_active = 1;
 404
 405         pr_debug("pblk: gc start\n");
 406 }
 407
 408 int pblk_gc_status(struct pblk *pblk)
 409 {
 410         struct pblk_gc *gc = &pblk->gc;
 411         int ret;
 412
 413         spin_lock(&gc->lock);
 414         ret = gc->gc_active;
 415         spin_unlock(&gc->lock);
 416
 417         return ret;
 418 }
 419
 420 static void __pblk_gc_should_start(struct pblk *pblk)
 421 {
 422         struct pblk_gc *gc = &pblk->gc;
 423
 424         lockdep_assert_held(&gc->lock);
 425
 426         if (gc->gc_enabled && !gc->gc_active)
 427                 pblk_gc_start(pblk);
 428 }
 429
 430 void pblk_gc_should_start(struct pblk *pblk)
 431 {
 432         struct pblk_gc *gc = &pblk->gc;
 433
 434         spin_lock(&gc->lock);
 435         __pblk_gc_should_start(pblk);
 436         spin_unlock(&gc->lock);
 437 }
 438
 439 /*
 440  * If flush_wq == 1 then no lock should be held by the caller since
 441  * flush_workqueue can sleep
 442  */
 443 static void pblk_gc_stop(struct pblk *pblk, int flush_wq)
 444 {
 445         spin_lock(&pblk->gc.lock);
 446         pblk->gc.gc_active = 0;
 447         spin_unlock(&pblk->gc.lock);
 448
 449         pr_debug("pblk: gc stop\n");
 450 }
 451
 452 void pblk_gc_should_stop(struct pblk *pblk)
 453 {
 454         struct pblk_gc *gc = &pblk->gc;
 455
 456         if (gc->gc_active && !gc->gc_forced)
 457                 pblk_gc_stop(pblk, 0);
 458 }
 459
 460 void pblk_gc_sysfs_state_show(struct pblk *pblk, int *gc_enabled,
 461                               int *gc_active)
 462 {
 463         struct pblk_gc *gc = &pblk->gc;
 464
 465         spin_lock(&gc->lock);
 466         *gc_enabled = gc->gc_enabled;
 467         *gc_active = gc->gc_active;
 468         spin_unlock(&gc->lock);
 469 }
 470
 471 void pblk_gc_sysfs_force(struct pblk *pblk, int force)
 472 {
 473         struct pblk_gc *gc = &pblk->gc;
 474         int rsv = 0;
 475
 476         spin_lock(&gc->lock);
 477         if (force) {
 478                 gc->gc_enabled = 1;
 479                 rsv = 64;
 480         }
 481         pblk_rl_set_gc_rsc(&pblk->rl, rsv);
 482         gc->gc_forced = force;
 483         __pblk_gc_should_start(pblk);
 484         spin_unlock(&gc->lock);
 485 }
 486
 487 int pblk_gc_init(struct pblk *pblk)
 488 {
 489         struct pblk_gc *gc = &pblk->gc;
 490         int ret;
 491
 492         gc->gc_ts = kthread_create(pblk_gc_ts, pblk, "pblk-gc-ts");
 493         if (IS_ERR(gc->gc_ts)) {
 494                 pr_err("pblk: could not allocate GC main kthread\n");
 495                 return PTR_ERR(gc->gc_ts);
 496         }
 497
 498         gc->gc_writer_ts = kthread_create(pblk_gc_writer_ts, pblk,
 499                                                         "pblk-gc-writer-ts");
 500         if (IS_ERR(gc->gc_writer_ts)) {
 501                 pr_err("pblk: could not allocate GC writer kthread\n");
 502                 ret = PTR_ERR(gc->gc_writer_ts);
 503                 goto fail_free_main_kthread;
 504         }
 505
 506         setup_timer(&gc->gc_timer, pblk_gc_timer, (unsigned long)pblk);
 507         mod_timer(&gc->gc_timer, jiffies + msecs_to_jiffies(GC_TIME_MSECS));
 508
 509         gc->gc_active = 0;
 510         gc->gc_forced = 0;
 511         gc->gc_enabled = 1;
 512         gc->gc_jobs_active = 8;
 513         gc->w_entries = 0;
 514         atomic_set(&gc->inflight_gc, 0);
 515
 516         gc->gc_reader_wq = alloc_workqueue("pblk-gc-reader-wq",
 517                         WQ_MEM_RECLAIM | WQ_UNBOUND, gc->gc_jobs_active);
 518         if (!gc->gc_reader_wq) {
 519                 pr_err("pblk: could not allocate GC reader workqueue\n");
 520                 ret = -ENOMEM;
 521                 goto fail_free_writer_kthread;
 522         }
 523
 524         spin_lock_init(&gc->lock);
 525         spin_lock_init(&gc->w_lock);
 526         INIT_LIST_HEAD(&gc->w_list);
 527
 528         return 0;
 529
 530 fail_free_writer_kthread:
 531         kthread_stop(gc->gc_writer_ts);
 532 fail_free_main_kthread:
 533         kthread_stop(gc->gc_ts);
 534
 535         return ret;
 536 }
 537
 538 void pblk_gc_exit(struct pblk *pblk)
 539 {
 540         struct pblk_gc *gc = &pblk->gc;
 541
 542         flush_workqueue(gc->gc_reader_wq);
 543
 544         del_timer(&gc->gc_timer);
 545         pblk_gc_stop(pblk, 1);
 546
 547         if (gc->gc_ts)
 548                 kthread_stop(gc->gc_ts);
 549
 550         if (pblk->gc.gc_reader_wq)
 551                 destroy_workqueue(pblk->gc.gc_reader_wq);
 552
 553         if (gc->gc_writer_ts)
 554                 kthread_stop(gc->gc_writer_ts);
 555 }