1 // SPDX-License-Identifier: GPL-2.0
3 * Moving/copying garbage collector
5 * Copyright 2012 Google, Inc.
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"
16 #include "disk_groups.h"
20 #include "eytzinger.h"
29 #include <linux/bsearch.h>
30 #include <linux/freezer.h>
31 #include <linux/kthread.h>
32 #include <linux/math64.h>
33 #include <linux/sched/task.h>
34 #include <linux/sort.h>
35 #include <linux/wait.h>
37 struct buckets_in_flight {
38 struct rhashtable table;
39 struct move_bucket_in_flight *first;
40 struct move_bucket_in_flight *last;
45 static const struct rhashtable_params bch_move_bucket_params = {
46 .head_offset = offsetof(struct move_bucket_in_flight, hash),
47 .key_offset = offsetof(struct move_bucket_in_flight, bucket.k),
48 .key_len = sizeof(struct move_bucket_key),
51 static struct move_bucket_in_flight *
52 move_bucket_in_flight_add(struct buckets_in_flight *list, struct move_bucket b)
54 struct move_bucket_in_flight *new = kzalloc(sizeof(*new), GFP_KERNEL);
58 return ERR_PTR(-ENOMEM);
62 ret = rhashtable_lookup_insert_fast(&list->table, &new->hash,
63 bch_move_bucket_params);
72 list->last->next = new;
76 list->sectors += b.sectors;
80 static int bch2_bucket_is_movable(struct btree_trans *trans,
81 struct move_bucket *b, u64 time)
83 struct btree_iter iter;
85 struct bch_alloc_v4 _a;
86 const struct bch_alloc_v4 *a;
89 if (bch2_bucket_is_open(trans->c,
94 k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_alloc,
95 b->k.bucket, BTREE_ITER_CACHED);
100 a = bch2_alloc_to_v4(k, &_a);
102 b->sectors = a->dirty_sectors;
104 ret = data_type_movable(a->data_type) &&
105 a->fragmentation_lru &&
106 a->fragmentation_lru <= time;
108 bch2_trans_iter_exit(trans, &iter);
112 static void move_buckets_wait(struct btree_trans *trans,
113 struct moving_context *ctxt,
114 struct buckets_in_flight *list,
117 struct move_bucket_in_flight *i;
120 while ((i = list->first)) {
122 move_ctxt_wait_event(ctxt, trans, !atomic_read(&i->count));
124 if (atomic_read(&i->count))
127 list->first = i->next;
132 list->sectors -= i->bucket.sectors;
134 ret = rhashtable_remove_fast(&list->table, &i->hash,
135 bch_move_bucket_params);
140 bch2_trans_unlock(trans);
143 static bool bucket_in_flight(struct buckets_in_flight *list,
144 struct move_bucket_key k)
146 return rhashtable_lookup_fast(&list->table, &k, bch_move_bucket_params);
149 typedef DARRAY(struct move_bucket) move_buckets;
151 static int bch2_copygc_get_buckets(struct btree_trans *trans,
152 struct moving_context *ctxt,
153 struct buckets_in_flight *buckets_in_flight,
154 move_buckets *buckets)
156 struct bch_fs *c = trans->c;
157 struct btree_iter iter;
159 size_t nr_to_get = max(16UL, buckets_in_flight->nr / 4);
160 size_t saw = 0, in_flight = 0, not_movable = 0, sectors = 0;
163 move_buckets_wait(trans, ctxt, buckets_in_flight, false);
165 ret = bch2_btree_write_buffer_flush(trans);
166 if (bch2_fs_fatal_err_on(ret, c, "%s: error %s from bch2_btree_write_buffer_flush()",
167 __func__, bch2_err_str(ret)))
170 ret = for_each_btree_key2_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),
174 struct move_bucket b = { .k.bucket = u64_to_bucket(k.k->p.offset) };
179 if (!bch2_bucket_is_movable(trans, &b, lru_pos_time(k.k->p)))
181 else if (bucket_in_flight(buckets_in_flight, b.k))
184 ret = darray_push(buckets, b) ?: buckets->nr >= nr_to_get;
186 sectors += b.sectors;
191 pr_debug("have: %zu (%zu) saw %zu in flight %zu not movable %zu got %zu (%zu)/%zu buckets ret %i",
192 buckets_in_flight->nr, buckets_in_flight->sectors,
193 saw, in_flight, not_movable, buckets->nr, sectors, nr_to_get, ret);
195 return ret < 0 ? ret : 0;
199 static int bch2_copygc(struct btree_trans *trans,
200 struct moving_context *ctxt,
201 struct buckets_in_flight *buckets_in_flight)
203 struct bch_fs *c = trans->c;
204 struct data_update_opts data_opts = {
205 .btree_insert_flags = BCH_WATERMARK_copygc,
207 move_buckets buckets = { 0 };
208 struct move_bucket_in_flight *f;
209 struct move_bucket *i;
210 u64 moved = atomic64_read(&ctxt->stats->sectors_moved);
213 ret = bch2_copygc_get_buckets(trans, ctxt, buckets_in_flight, &buckets);
217 darray_for_each(buckets, i) {
218 if (unlikely(freezing(current)))
221 f = move_bucket_in_flight_add(buckets_in_flight, *i);
222 ret = PTR_ERR_OR_ZERO(f);
223 if (ret == -EEXIST) /* rare race: copygc_get_buckets returned same bucket more than once */
225 if (ret == -ENOMEM) { /* flush IO, continue later */
230 ret = __bch2_evacuate_bucket(trans, ctxt, f, f->bucket.k.bucket,
231 f->bucket.k.gen, data_opts);
236 darray_exit(&buckets);
238 /* no entries in LRU btree found, or got to end: */
239 if (bch2_err_matches(ret, ENOENT))
242 if (ret < 0 && !bch2_err_matches(ret, EROFS))
243 bch_err(c, "error from bch2_move_data() in copygc: %s", bch2_err_str(ret));
245 moved = atomic64_read(&ctxt->stats->sectors_moved) - moved;
246 trace_and_count(c, copygc, c, moved, 0, 0, 0);
251 * Copygc runs when the amount of fragmented data is above some arbitrary
254 * The threshold at the limit - when the device is full - is the amount of space
255 * we reserved in bch2_recalc_capacity; we can't have more than that amount of
256 * disk space stranded due to fragmentation and store everything we have
259 * But we don't want to be running copygc unnecessarily when the device still
260 * has plenty of free space - rather, we want copygc to smoothly run every so
261 * often and continually reduce the amount of fragmented space as the device
262 * fills up. So, we increase the threshold by half the current free space.
264 unsigned long bch2_copygc_wait_amount(struct bch_fs *c)
268 s64 wait = S64_MAX, fragmented_allowed, fragmented;
271 for_each_rw_member(ca, c, dev_idx) {
272 struct bch_dev_usage usage = bch2_dev_usage_read(ca);
274 fragmented_allowed = ((__dev_buckets_available(ca, usage, BCH_WATERMARK_stripe) *
275 ca->mi.bucket_size) >> 1);
278 for (i = 0; i < BCH_DATA_NR; i++)
279 if (data_type_movable(i))
280 fragmented += usage.d[i].fragmented;
282 wait = min(wait, max(0LL, fragmented_allowed - fragmented));
288 void bch2_copygc_wait_to_text(struct printbuf *out, struct bch_fs *c)
290 prt_printf(out, "Currently waiting for: ");
291 prt_human_readable_u64(out, max(0LL, c->copygc_wait -
292 atomic64_read(&c->io_clock[WRITE].now)) << 9);
295 prt_printf(out, "Currently waiting since: ");
296 prt_human_readable_u64(out, max(0LL,
297 atomic64_read(&c->io_clock[WRITE].now) -
298 c->copygc_wait_at) << 9);
301 prt_printf(out, "Currently calculated wait: ");
302 prt_human_readable_u64(out, bch2_copygc_wait_amount(c));
306 static int bch2_copygc_thread(void *arg)
308 struct bch_fs *c = arg;
309 struct btree_trans trans;
310 struct moving_context ctxt;
311 struct bch_move_stats move_stats;
312 struct io_clock *clock = &c->io_clock[WRITE];
313 struct buckets_in_flight move_buckets;
317 memset(&move_buckets, 0, sizeof(move_buckets));
319 ret = rhashtable_init(&move_buckets.table, &bch_move_bucket_params);
321 bch_err(c, "error allocating copygc buckets in flight: %s",
327 bch2_trans_init(&trans, c, 0, 0);
329 bch2_move_stats_init(&move_stats, "copygc");
330 bch2_moving_ctxt_init(&ctxt, c, NULL, &move_stats,
331 writepoint_ptr(&c->copygc_write_point),
334 while (!ret && !kthread_should_stop()) {
335 bch2_trans_unlock(&trans);
338 if (!c->copy_gc_enabled) {
339 move_buckets_wait(&trans, &ctxt, &move_buckets, true);
340 kthread_wait_freezable(c->copy_gc_enabled);
343 if (unlikely(freezing(current))) {
344 move_buckets_wait(&trans, &ctxt, &move_buckets, true);
345 __refrigerator(false);
349 last = atomic64_read(&clock->now);
350 wait = bch2_copygc_wait_amount(c);
352 if (wait > clock->max_slop) {
353 c->copygc_wait_at = last;
354 c->copygc_wait = last + wait;
355 move_buckets_wait(&trans, &ctxt, &move_buckets, true);
356 trace_and_count(c, copygc_wait, c, wait, last + wait);
357 bch2_kthread_io_clock_wait(clock, last + wait,
358 MAX_SCHEDULE_TIMEOUT);
364 c->copygc_running = true;
365 ret = bch2_copygc(&trans, &ctxt, &move_buckets);
366 c->copygc_running = false;
368 wake_up(&c->copygc_running_wq);
371 move_buckets_wait(&trans, &ctxt, &move_buckets, true);
372 rhashtable_destroy(&move_buckets.table);
373 bch2_trans_exit(&trans);
374 bch2_moving_ctxt_exit(&ctxt);
379 void bch2_copygc_stop(struct bch_fs *c)
381 if (c->copygc_thread) {
382 kthread_stop(c->copygc_thread);
383 put_task_struct(c->copygc_thread);
385 c->copygc_thread = NULL;
388 int bch2_copygc_start(struct bch_fs *c)
390 struct task_struct *t;
393 if (c->copygc_thread)
396 if (c->opts.nochanges)
399 if (bch2_fs_init_fault("copygc_start"))
402 t = kthread_create(bch2_copygc_thread, c, "bch-copygc/%s", c->name);
403 ret = PTR_ERR_OR_ZERO(t);
405 bch_err(c, "error creating copygc thread: %s", bch2_err_str(ret));
411 c->copygc_thread = t;
412 wake_up_process(c->copygc_thread);
417 void bch2_fs_copygc_init(struct bch_fs *c)
419 init_waitqueue_head(&c->copygc_running_wq);
420 c->copygc_running = false;