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1// SPDX-License-Identifier: GPL-2.02/*3 * Moving/copying garbage collector4 *5 * Copyright 2012 Google, Inc.6 */7 8#include "bcachefs.h"9#include "alloc_background.h"10#include "alloc_foreground.h"11#include "btree_iter.h"12#include "btree_update.h"13#include "btree_write_buffer.h"14#include "buckets.h"15#include "clock.h"16#include "errcode.h"17#include "error.h"18#include "lru.h"19#include "move.h"20#include "movinggc.h"21#include "trace.h"22 23#include <linux/freezer.h>24#include <linux/kthread.h>25#include <linux/math64.h>26#include <linux/sched/task.h>27#include <linux/wait.h>28 29struct buckets_in_flight {30 struct rhashtable table;31 struct move_bucket_in_flight *first;32 struct move_bucket_in_flight *last;33 size_t nr;34 size_t sectors;35};36 37static const struct rhashtable_params bch_move_bucket_params = {38 .head_offset = offsetof(struct move_bucket_in_flight, hash),39 .key_offset = offsetof(struct move_bucket_in_flight, bucket.k),40 .key_len = sizeof(struct move_bucket_key),41 .automatic_shrinking = true,42};43 44static struct move_bucket_in_flight *45move_bucket_in_flight_add(struct buckets_in_flight *list, struct move_bucket b)46{47 struct move_bucket_in_flight *new = kzalloc(sizeof(*new), GFP_KERNEL);48 int ret;49 50 if (!new)51 return ERR_PTR(-ENOMEM);52 53 new->bucket = b;54 55 ret = rhashtable_lookup_insert_fast(&list->table, &new->hash,56 bch_move_bucket_params);57 if (ret) {58 kfree(new);59 return ERR_PTR(ret);60 }61 62 if (!list->first)63 list->first = new;64 else65 list->last->next = new;66 67 list->last = new;68 list->nr++;69 list->sectors += b.sectors;70 return new;71}72 73static int bch2_bucket_is_movable(struct btree_trans *trans,74 struct move_bucket *b, u64 time)75{76 struct bch_fs *c = trans->c;77 struct btree_iter iter;78 struct bkey_s_c k;79 struct bch_alloc_v4 _a;80 const struct bch_alloc_v4 *a;81 int ret;82 83 if (bch2_bucket_is_open(trans->c,84 b->k.bucket.inode,85 b->k.bucket.offset))86 return 0;87 88 k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_alloc,89 b->k.bucket, BTREE_ITER_cached);90 ret = bkey_err(k);91 if (ret)92 return ret;93 94 struct bch_dev *ca = bch2_dev_tryget(c, k.k->p.inode);95 if (!ca)96 goto out;97 98 a = bch2_alloc_to_v4(k, &_a);99 b->k.gen = a->gen;100 b->sectors = bch2_bucket_sectors_dirty(*a);101 u64 lru_idx = alloc_lru_idx_fragmentation(*a, ca);102 103 ret = lru_idx && lru_idx <= time;104 105 bch2_dev_put(ca);106out:107 bch2_trans_iter_exit(trans, &iter);108 return ret;109}110 111static void move_buckets_wait(struct moving_context *ctxt,112 struct buckets_in_flight *list,113 bool flush)114{115 struct move_bucket_in_flight *i;116 int ret;117 118 while ((i = list->first)) {119 if (flush)120 move_ctxt_wait_event(ctxt, !atomic_read(&i->count));121 122 if (atomic_read(&i->count))123 break;124 125 list->first = i->next;126 if (!list->first)127 list->last = NULL;128 129 list->nr--;130 list->sectors -= i->bucket.sectors;131 132 ret = rhashtable_remove_fast(&list->table, &i->hash,133 bch_move_bucket_params);134 BUG_ON(ret);135 kfree(i);136 }137 138 bch2_trans_unlock_long(ctxt->trans);139}140 141static bool bucket_in_flight(struct buckets_in_flight *list,142 struct move_bucket_key k)143{144 return rhashtable_lookup_fast(&list->table, &k, bch_move_bucket_params);145}146 147typedef DARRAY(struct move_bucket) move_buckets;148 149static int bch2_copygc_get_buckets(struct moving_context *ctxt,150 struct buckets_in_flight *buckets_in_flight,151 move_buckets *buckets)152{153 struct btree_trans *trans = ctxt->trans;154 struct bch_fs *c = trans->c;155 size_t nr_to_get = max_t(size_t, 16U, buckets_in_flight->nr / 4);156 size_t saw = 0, in_flight = 0, not_movable = 0, sectors = 0;157 int ret;158 159 move_buckets_wait(ctxt, buckets_in_flight, false);160 161 ret = bch2_btree_write_buffer_tryflush(trans);162 if (bch2_err_matches(ret, EROFS))163 return ret;164 165 if (bch2_fs_fatal_err_on(ret, c, "%s: from bch2_btree_write_buffer_tryflush()", bch2_err_str(ret)))166 return ret;167 168 bch2_trans_begin(trans);169 170 ret = for_each_btree_key_upto(trans, iter, BTREE_ID_lru,171 lru_pos(BCH_LRU_FRAGMENTATION_START, 0, 0),172 lru_pos(BCH_LRU_FRAGMENTATION_START, U64_MAX, LRU_TIME_MAX),173 0, k, ({174 struct move_bucket b = { .k.bucket = u64_to_bucket(k.k->p.offset) };175 int ret2 = 0;176 177 saw++;178 179 ret2 = bch2_bucket_is_movable(trans, &b, lru_pos_time(k.k->p));180 if (ret2 < 0)181 goto err;182 183 if (!ret2)184 not_movable++;185 else if (bucket_in_flight(buckets_in_flight, b.k))186 in_flight++;187 else {188 ret2 = darray_push(buckets, b);189 if (ret2)190 goto err;191 sectors += b.sectors;192 }193 194 ret2 = buckets->nr >= nr_to_get;195err:196 ret2;197 }));198 199 pr_debug("have: %zu (%zu) saw %zu in flight %zu not movable %zu got %zu (%zu)/%zu buckets ret %i",200 buckets_in_flight->nr, buckets_in_flight->sectors,201 saw, in_flight, not_movable, buckets->nr, sectors, nr_to_get, ret);202 203 return ret < 0 ? ret : 0;204}205 206noinline207static int bch2_copygc(struct moving_context *ctxt,208 struct buckets_in_flight *buckets_in_flight,209 bool *did_work)210{211 struct btree_trans *trans = ctxt->trans;212 struct bch_fs *c = trans->c;213 struct data_update_opts data_opts = {214 .btree_insert_flags = BCH_WATERMARK_copygc,215 };216 move_buckets buckets = { 0 };217 struct move_bucket_in_flight *f;218 u64 moved = atomic64_read(&ctxt->stats->sectors_moved);219 int ret = 0;220 221 ret = bch2_copygc_get_buckets(ctxt, buckets_in_flight, &buckets);222 if (ret)223 goto err;224 225 darray_for_each(buckets, i) {226 if (kthread_should_stop() || freezing(current))227 break;228 229 f = move_bucket_in_flight_add(buckets_in_flight, *i);230 ret = PTR_ERR_OR_ZERO(f);231 if (ret == -EEXIST) { /* rare race: copygc_get_buckets returned same bucket more than once */232 ret = 0;233 continue;234 }235 if (ret == -ENOMEM) { /* flush IO, continue later */236 ret = 0;237 break;238 }239 240 ret = bch2_evacuate_bucket(ctxt, f, f->bucket.k.bucket,241 f->bucket.k.gen, data_opts);242 if (ret)243 goto err;244 245 *did_work = true;246 }247err:248 darray_exit(&buckets);249 250 /* no entries in LRU btree found, or got to end: */251 if (bch2_err_matches(ret, ENOENT))252 ret = 0;253 254 if (ret < 0 && !bch2_err_matches(ret, EROFS))255 bch_err_msg(c, ret, "from bch2_move_data()");256 257 moved = atomic64_read(&ctxt->stats->sectors_moved) - moved;258 trace_and_count(c, copygc, c, moved, 0, 0, 0);259 return ret;260}261 262/*263 * Copygc runs when the amount of fragmented data is above some arbitrary264 * threshold:265 *266 * The threshold at the limit - when the device is full - is the amount of space267 * we reserved in bch2_recalc_capacity; we can't have more than that amount of268 * disk space stranded due to fragmentation and store everything we have269 * promised to store.270 *271 * But we don't want to be running copygc unnecessarily when the device still272 * has plenty of free space - rather, we want copygc to smoothly run every so273 * often and continually reduce the amount of fragmented space as the device274 * fills up. So, we increase the threshold by half the current free space.275 */276unsigned long bch2_copygc_wait_amount(struct bch_fs *c)277{278 s64 wait = S64_MAX, fragmented_allowed, fragmented;279 280 for_each_rw_member(c, ca) {281 struct bch_dev_usage usage = bch2_dev_usage_read(ca);282 283 fragmented_allowed = ((__dev_buckets_available(ca, usage, BCH_WATERMARK_stripe) *284 ca->mi.bucket_size) >> 1);285 fragmented = 0;286 287 for (unsigned i = 0; i < BCH_DATA_NR; i++)288 if (data_type_movable(i))289 fragmented += usage.d[i].fragmented;290 291 wait = min(wait, max(0LL, fragmented_allowed - fragmented));292 }293 294 return wait;295}296 297void bch2_copygc_wait_to_text(struct printbuf *out, struct bch_fs *c)298{299 printbuf_tabstop_push(out, 32);300 prt_printf(out, "running:\t%u\n", c->copygc_running);301 prt_printf(out, "copygc_wait:\t%llu\n", c->copygc_wait);302 prt_printf(out, "copygc_wait_at:\t%llu\n", c->copygc_wait_at);303 304 prt_printf(out, "Currently waiting for:\t");305 prt_human_readable_u64(out, max(0LL, c->copygc_wait -306 atomic64_read(&c->io_clock[WRITE].now)) << 9);307 prt_newline(out);308 309 prt_printf(out, "Currently waiting since:\t");310 prt_human_readable_u64(out, max(0LL,311 atomic64_read(&c->io_clock[WRITE].now) -312 c->copygc_wait_at) << 9);313 prt_newline(out);314 315 prt_printf(out, "Currently calculated wait:\t");316 prt_human_readable_u64(out, bch2_copygc_wait_amount(c));317 prt_newline(out);318}319 320static int bch2_copygc_thread(void *arg)321{322 struct bch_fs *c = arg;323 struct moving_context ctxt;324 struct bch_move_stats move_stats;325 struct io_clock *clock = &c->io_clock[WRITE];326 struct buckets_in_flight *buckets;327 u64 last, wait;328 int ret = 0;329 330 buckets = kzalloc(sizeof(struct buckets_in_flight), GFP_KERNEL);331 if (!buckets)332 return -ENOMEM;333 ret = rhashtable_init(&buckets->table, &bch_move_bucket_params);334 bch_err_msg(c, ret, "allocating copygc buckets in flight");335 if (ret) {336 kfree(buckets);337 return ret;338 }339 340 set_freezable();341 342 bch2_move_stats_init(&move_stats, "copygc");343 bch2_moving_ctxt_init(&ctxt, c, NULL, &move_stats,344 writepoint_ptr(&c->copygc_write_point),345 false);346 347 while (!ret && !kthread_should_stop()) {348 bool did_work = false;349 350 bch2_trans_unlock_long(ctxt.trans);351 cond_resched();352 353 if (!c->copy_gc_enabled) {354 move_buckets_wait(&ctxt, buckets, true);355 kthread_wait_freezable(c->copy_gc_enabled ||356 kthread_should_stop());357 }358 359 if (unlikely(freezing(current))) {360 move_buckets_wait(&ctxt, buckets, true);361 __refrigerator(false);362 continue;363 }364 365 last = atomic64_read(&clock->now);366 wait = bch2_copygc_wait_amount(c);367 368 if (wait > clock->max_slop) {369 c->copygc_wait_at = last;370 c->copygc_wait = last + wait;371 move_buckets_wait(&ctxt, buckets, true);372 trace_and_count(c, copygc_wait, c, wait, last + wait);373 bch2_kthread_io_clock_wait(clock, last + wait,374 MAX_SCHEDULE_TIMEOUT);375 continue;376 }377 378 c->copygc_wait = 0;379 380 c->copygc_running = true;381 ret = bch2_copygc(&ctxt, buckets, &did_work);382 c->copygc_running = false;383 384 wake_up(&c->copygc_running_wq);385 386 if (!wait && !did_work) {387 u64 min_member_capacity = bch2_min_rw_member_capacity(c);388 389 if (min_member_capacity == U64_MAX)390 min_member_capacity = 128 * 2048;391 392 move_buckets_wait(&ctxt, buckets, true);393 bch2_kthread_io_clock_wait(clock, last + (min_member_capacity >> 6),394 MAX_SCHEDULE_TIMEOUT);395 }396 }397 398 move_buckets_wait(&ctxt, buckets, true);399 400 rhashtable_destroy(&buckets->table);401 kfree(buckets);402 bch2_moving_ctxt_exit(&ctxt);403 bch2_move_stats_exit(&move_stats, c);404 405 return 0;406}407 408void bch2_copygc_stop(struct bch_fs *c)409{410 if (c->copygc_thread) {411 kthread_stop(c->copygc_thread);412 put_task_struct(c->copygc_thread);413 }414 c->copygc_thread = NULL;415}416 417int bch2_copygc_start(struct bch_fs *c)418{419 struct task_struct *t;420 int ret;421 422 if (c->copygc_thread)423 return 0;424 425 if (c->opts.nochanges)426 return 0;427 428 if (bch2_fs_init_fault("copygc_start"))429 return -ENOMEM;430 431 t = kthread_create(bch2_copygc_thread, c, "bch-copygc/%s", c->name);432 ret = PTR_ERR_OR_ZERO(t);433 bch_err_msg(c, ret, "creating copygc thread");434 if (ret)435 return ret;436 437 get_task_struct(t);438 439 c->copygc_thread = t;440 wake_up_process(c->copygc_thread);441 442 return 0;443}444 445void bch2_fs_copygc_init(struct bch_fs *c)446{447 init_waitqueue_head(&c->copygc_running_wq);448 c->copygc_running = false;449}450