+// SPDX-License-Identifier: GPL-2.0
/*
* Moving/copying garbage collector
*
*/
#include "bcachefs.h"
+#include "alloc_background.h"
+#include "alloc_foreground.h"
#include "btree_iter.h"
#include "btree_update.h"
#include "buckets.h"
#include "clock.h"
+#include "disk_groups.h"
+#include "error.h"
#include "extents.h"
#include "eytzinger.h"
#include "io.h"
#include <linux/sort.h>
#include <linux/wait.h>
-/*
- * We can't use the entire copygc reserve in one iteration of copygc: we may
- * need the buckets we're freeing up to go back into the copygc reserve to make
- * forward progress, but if the copygc reserve is full they'll be available for
- * any allocation - and it's possible that in a given iteration, we free up most
- * of the buckets we're going to free before we allocate most of the buckets
- * we're going to allocate.
- *
- * If we only use half of the reserve per iteration, then in steady state we'll
- * always have room in the reserve for the buckets we're going to need in the
- * next iteration:
- */
-#define COPYGC_BUCKETS_PER_ITER(ca) \
- ((ca)->free[RESERVE_MOVINGGC].size / 2)
+static int bucket_offset_cmp(const void *_l, const void *_r, size_t size)
+{
+ const struct copygc_heap_entry *l = _l;
+ const struct copygc_heap_entry *r = _r;
-/*
- * Max sectors to move per iteration: Have to take into account internal
- * fragmentation from the multiple write points for each generation:
- */
-#define COPYGC_SECTORS_PER_ITER(ca) \
- ((ca)->mi.bucket_size * COPYGC_BUCKETS_PER_ITER(ca))
+ return cmp_int(l->dev, r->dev) ?:
+ cmp_int(l->offset, r->offset);
+}
-static inline int sectors_used_cmp(copygc_heap *heap,
+static enum data_cmd copygc_pred(struct bch_fs *c, void *arg,
+ struct bkey_s_c k,
+ struct bch_io_opts *io_opts,
+ struct data_opts *data_opts)
+{
+ copygc_heap *h = &c->copygc_heap;
+ struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+ const union bch_extent_entry *entry;
+ struct extent_ptr_decoded p = { 0 };
+
+ bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
+ struct bch_dev *ca = bch_dev_bkey_exists(c, p.ptr.dev);
+ struct copygc_heap_entry search = {
+ .dev = p.ptr.dev,
+ .offset = p.ptr.offset,
+ };
+ ssize_t i;
+
+ if (p.ptr.cached)
+ continue;
+
+ i = eytzinger0_find_le(h->data, h->used,
+ sizeof(h->data[0]),
+ bucket_offset_cmp, &search);
+#if 0
+ /* eytzinger search verify code: */
+ ssize_t j = -1, k;
+
+ for (k = 0; k < h->used; k++)
+ if (h->data[k].offset <= ptr->offset &&
+ (j < 0 || h->data[k].offset > h->data[j].offset))
+ j = k;
+
+ BUG_ON(i != j);
+#endif
+ if (i >= 0 &&
+ p.ptr.dev == h->data[i].dev &&
+ p.ptr.offset < h->data[i].offset + ca->mi.bucket_size &&
+ p.ptr.gen == h->data[i].gen) {
+ /*
+ * We need to use the journal reserve here, because
+ * - journal reclaim depends on btree key cache
+ * flushing to make forward progress,
+ * - which has to make forward progress when the
+ * journal is pre-reservation full,
+ * - and depends on allocation - meaning allocator and
+ * copygc
+ */
+
+ data_opts->target = io_opts->background_target;
+ data_opts->nr_replicas = 1;
+ data_opts->btree_insert_flags = BTREE_INSERT_USE_RESERVE|
+ JOURNAL_WATERMARK_copygc;
+ data_opts->rewrite_dev = p.ptr.dev;
+
+ if (p.has_ec)
+ data_opts->nr_replicas += p.ec.redundancy;
+
+ return DATA_REWRITE;
+ }
+ }
+
+ return DATA_SKIP;
+}
+
+static inline int fragmentation_cmp(copygc_heap *heap,
struct copygc_heap_entry l,
struct copygc_heap_entry r)
{
- return bucket_sectors_used(l.mark) - bucket_sectors_used(r.mark);
+ return cmp_int(l.fragmentation, r.fragmentation);
}
-static int bucket_offset_cmp(const void *_l, const void *_r, size_t size)
+static int walk_buckets_to_copygc(struct bch_fs *c)
{
- const struct copygc_heap_entry *l = _l;
- const struct copygc_heap_entry *r = _r;
+ copygc_heap *h = &c->copygc_heap;
+ struct btree_trans trans;
+ struct btree_iter iter;
+ struct bkey_s_c k;
+ struct bch_alloc_v4 a;
+ int ret;
- return (l->offset > r->offset) - (l->offset < r->offset);
-}
+ bch2_trans_init(&trans, c, 0, 0);
-static bool __copygc_pred(struct bch_dev *ca,
- struct bkey_s_c_extent e)
-{
- copygc_heap *h = &ca->copygc_heap;
- const struct bch_extent_ptr *ptr =
- bch2_extent_has_device(e, ca->dev_idx);
+ for_each_btree_key(&trans, iter, BTREE_ID_alloc, POS_MIN,
+ BTREE_ITER_PREFETCH, k, ret) {
+ struct bch_dev *ca = bch_dev_bkey_exists(c, iter.pos.inode);
+ struct copygc_heap_entry e;
+
+ bch2_alloc_to_v4(k, &a);
- if (ptr) {
- struct copygc_heap_entry search = { .offset = ptr->offset };
+ if (a.data_type != BCH_DATA_user ||
+ a.dirty_sectors >= ca->mi.bucket_size ||
+ bch2_bucket_is_open(c, iter.pos.inode, iter.pos.offset))
+ continue;
- ssize_t i = eytzinger0_find_le(h->data, h->used,
- sizeof(h->data[0]),
- bucket_offset_cmp, &search);
+ e = (struct copygc_heap_entry) {
+ .dev = iter.pos.inode,
+ .gen = a.gen,
+ .replicas = 1 + a.stripe_redundancy,
+ .fragmentation = (u64) a.dirty_sectors * (1ULL << 31)
+ / ca->mi.bucket_size,
+ .sectors = a.dirty_sectors,
+ .offset = bucket_to_sector(ca, iter.pos.offset),
+ };
+ heap_add_or_replace(h, e, -fragmentation_cmp, NULL);
- return (i >= 0 &&
- ptr->offset < h->data[i].offset + ca->mi.bucket_size &&
- ptr->gen == h->data[i].mark.gen);
}
+ bch2_trans_iter_exit(&trans, &iter);
- return false;
+ bch2_trans_exit(&trans);
+ return ret;
}
-static enum data_cmd copygc_pred(struct bch_fs *c, void *arg,
- enum bkey_type type,
- struct bkey_s_c_extent e,
- struct bch_io_opts *io_opts,
- struct data_opts *data_opts)
+static int bucket_inorder_cmp(const void *_l, const void *_r)
{
- struct bch_dev *ca = arg;
-
- if (!__copygc_pred(ca, e))
- return DATA_SKIP;
+ const struct copygc_heap_entry *l = _l;
+ const struct copygc_heap_entry *r = _r;
- data_opts->target = dev_to_target(ca->dev_idx);
- data_opts->btree_insert_flags = BTREE_INSERT_USE_RESERVE;
- data_opts->rewrite_dev = ca->dev_idx;
- return DATA_REWRITE;
+ return cmp_int(l->dev, r->dev) ?: cmp_int(l->offset, r->offset);
}
-static bool have_copygc_reserve(struct bch_dev *ca)
+static int check_copygc_was_done(struct bch_fs *c,
+ u64 *sectors_not_moved,
+ u64 *buckets_not_moved)
{
- bool ret;
+ copygc_heap *h = &c->copygc_heap;
+ struct btree_trans trans;
+ struct btree_iter iter;
+ struct bkey_s_c k;
+ struct bch_alloc_v4 a;
+ struct copygc_heap_entry *i;
+ int ret = 0;
+
+ sort(h->data, h->used, sizeof(h->data[0]), bucket_inorder_cmp, NULL);
+
+ bch2_trans_init(&trans, c, 0, 0);
+ bch2_trans_iter_init(&trans, &iter, BTREE_ID_alloc, POS_MIN, 0);
+
+ for (i = h->data; i < h->data + h->used; i++) {
+ struct bch_dev *ca = bch_dev_bkey_exists(c, i->dev);
+
+ bch2_btree_iter_set_pos(&iter, POS(i->dev, sector_to_bucket(ca, i->offset)));
+
+ ret = lockrestart_do(&trans,
+ bkey_err(k = bch2_btree_iter_peek_slot(&iter)));
+ if (ret)
+ break;
+
+ bch2_alloc_to_v4(k, &a);
- spin_lock(&ca->freelist_lock);
- ret = fifo_full(&ca->free[RESERVE_MOVINGGC]) ||
- ca->allocator_blocked;
- spin_unlock(&ca->freelist_lock);
+ if (a.gen == i->gen && a.dirty_sectors) {
+ *sectors_not_moved += a.dirty_sectors;
+ *buckets_not_moved += 1;
+ }
+ }
+ bch2_trans_iter_exit(&trans, &iter);
+ bch2_trans_exit(&trans);
return ret;
}
-static void bch2_copygc(struct bch_fs *c, struct bch_dev *ca)
+static int bch2_copygc(struct bch_fs *c)
{
- copygc_heap *h = &ca->copygc_heap;
+ copygc_heap *h = &c->copygc_heap;
struct copygc_heap_entry e, *i;
- struct bucket_array *buckets;
struct bch_move_stats move_stats;
- u64 sectors_to_move = 0, sectors_not_moved = 0;
+ u64 sectors_to_move = 0, sectors_to_write = 0, sectors_not_moved = 0;
+ u64 sectors_reserved = 0;
u64 buckets_to_move, buckets_not_moved = 0;
- size_t b;
+ struct bch_dev *ca;
+ unsigned dev_idx;
+ size_t heap_size = 0;
int ret;
- memset(&move_stats, 0, sizeof(move_stats));
- closure_wait_event(&c->freelist_wait, have_copygc_reserve(ca));
+ bch_move_stats_init(&move_stats, "copygc");
/*
* Find buckets with lowest sector counts, skipping completely
*/
h->used = 0;
- /*
- * We need bucket marks to be up to date - gc can't be recalculating
- * them:
- */
- down_read(&c->gc_lock);
- down_read(&ca->bucket_lock);
- buckets = bucket_array(ca);
+ for_each_rw_member(ca, c, dev_idx)
+ heap_size += ca->mi.nbuckets >> 7;
- for (b = buckets->first_bucket; b < buckets->nbuckets; b++) {
- struct bucket_mark m = READ_ONCE(buckets->b[b].mark);
- struct copygc_heap_entry e;
+ if (h->size < heap_size) {
+ free_heap(&c->copygc_heap);
+ if (!init_heap(&c->copygc_heap, heap_size, GFP_KERNEL)) {
+ bch_err(c, "error allocating copygc heap");
+ return 0;
+ }
+ }
- if (m.owned_by_allocator ||
- m.data_type != BCH_DATA_USER ||
- !bucket_sectors_used(m) ||
- bucket_sectors_used(m) >= ca->mi.bucket_size)
- continue;
+ for_each_rw_member(ca, c, dev_idx) {
+ s64 avail = min(dev_buckets_available(ca, RESERVE_movinggc),
+ ca->mi.nbuckets >> 6);
- e = (struct copygc_heap_entry) {
- .offset = bucket_to_sector(ca, b),
- .mark = m
- };
- heap_add_or_replace(h, e, -sectors_used_cmp);
+ sectors_reserved += avail * ca->mi.bucket_size;
}
- up_read(&ca->bucket_lock);
- up_read(&c->gc_lock);
- for (i = h->data; i < h->data + h->used; i++)
- sectors_to_move += bucket_sectors_used(i->mark);
+ ret = walk_buckets_to_copygc(c);
+ if (ret) {
+ bch2_fs_fatal_error(c, "error walking buckets to copygc!");
+ return ret;
+ }
- while (sectors_to_move > COPYGC_SECTORS_PER_ITER(ca)) {
- BUG_ON(!heap_pop(h, e, -sectors_used_cmp));
- sectors_to_move -= bucket_sectors_used(e.mark);
+ if (!h->used) {
+ bch_err_ratelimited(c, "copygc requested to run but found no buckets to move!");
+ return 0;
+ }
+
+ /*
+ * Our btree node allocations also come out of RESERVE_movingc:
+ */
+ sectors_reserved = (sectors_reserved * 3) / 4;
+ if (!sectors_reserved) {
+ bch2_fs_fatal_error(c, "stuck, ran out of copygc reserve!");
+ return -1;
+ }
+
+ for (i = h->data; i < h->data + h->used; i++) {
+ sectors_to_move += i->sectors;
+ sectors_to_write += i->sectors * i->replicas;
+ }
+
+ while (sectors_to_write > sectors_reserved) {
+ BUG_ON(!heap_pop(h, e, -fragmentation_cmp, NULL));
+ sectors_to_write -= e.sectors * e.replicas;
}
buckets_to_move = h->used;
- if (!buckets_to_move)
- return;
+ if (!buckets_to_move) {
+ bch_err_ratelimited(c, "copygc cannot run - sectors_reserved %llu!",
+ sectors_reserved);
+ return 0;
+ }
eytzinger0_sort(h->data, h->used,
sizeof(h->data[0]),
bucket_offset_cmp, NULL);
- ret = bch2_move_data(c, &ca->copygc_pd.rate,
- writepoint_ptr(&ca->copygc_write_point),
- POS_MIN, POS_MAX,
- copygc_pred, ca,
+ ret = bch2_move_data(c,
+ 0, POS_MIN,
+ BTREE_ID_NR, POS_MAX,
+ NULL,
+ writepoint_ptr(&c->copygc_write_point),
+ copygc_pred, NULL,
&move_stats);
+ if (ret) {
+ bch_err(c, "error %i from bch2_move_data() in copygc", ret);
+ return ret;
+ }
- down_read(&ca->bucket_lock);
- buckets = bucket_array(ca);
- for (i = h->data; i < h->data + h->used; i++) {
- size_t b = sector_to_bucket(ca, i->offset);
- struct bucket_mark m = READ_ONCE(buckets->b[b].mark);
-
- if (i->mark.gen == m.gen && bucket_sectors_used(m)) {
- sectors_not_moved += bucket_sectors_used(m);
- buckets_not_moved++;
- }
+ ret = check_copygc_was_done(c, §ors_not_moved, &buckets_not_moved);
+ if (ret) {
+ bch_err(c, "error %i from check_copygc_was_done()", ret);
+ return ret;
}
- up_read(&ca->bucket_lock);
- if (sectors_not_moved && !ret)
- bch_warn(c, "copygc finished but %llu/%llu sectors, %llu/%llu buckets not moved",
+ if (sectors_not_moved)
+ bch_warn_ratelimited(c,
+ "copygc finished but %llu/%llu sectors, %llu/%llu buckets not moved (move stats: moved %llu sectors, raced %llu keys, %llu sectors)",
sectors_not_moved, sectors_to_move,
- buckets_not_moved, buckets_to_move);
+ buckets_not_moved, buckets_to_move,
+ atomic64_read(&move_stats.sectors_moved),
+ atomic64_read(&move_stats.keys_raced),
+ atomic64_read(&move_stats.sectors_raced));
- trace_copygc(ca,
+ trace_copygc(c,
atomic64_read(&move_stats.sectors_moved), sectors_not_moved,
buckets_to_move, buckets_not_moved);
+ return 0;
+}
+
+/*
+ * Copygc runs when the amount of fragmented data is above some arbitrary
+ * threshold:
+ *
+ * The threshold at the limit - when the device is full - is the amount of space
+ * we reserved in bch2_recalc_capacity; we can't have more than that amount of
+ * disk space stranded due to fragmentation and store everything we have
+ * promised to store.
+ *
+ * But we don't want to be running copygc unnecessarily when the device still
+ * has plenty of free space - rather, we want copygc to smoothly run every so
+ * often and continually reduce the amount of fragmented space as the device
+ * fills up. So, we increase the threshold by half the current free space.
+ */
+unsigned long bch2_copygc_wait_amount(struct bch_fs *c)
+{
+ struct bch_dev *ca;
+ unsigned dev_idx;
+ s64 wait = S64_MAX, fragmented_allowed, fragmented;
+
+ for_each_rw_member(ca, c, dev_idx) {
+ struct bch_dev_usage usage = bch2_dev_usage_read(ca);
+
+ fragmented_allowed = ((__dev_buckets_available(ca, usage, RESERVE_none) *
+ ca->mi.bucket_size) >> 1);
+ fragmented = usage.d[BCH_DATA_user].fragmented;
+
+ wait = min(wait, max(0LL, fragmented_allowed - fragmented));
+ }
+
+ return wait;
}
static int bch2_copygc_thread(void *arg)
{
- struct bch_dev *ca = arg;
- struct bch_fs *c = ca->fs;
+ struct bch_fs *c = arg;
struct io_clock *clock = &c->io_clock[WRITE];
- struct bch_dev_usage usage;
- unsigned long last;
- u64 available, fragmented, reserve, next;
+ u64 last, wait;
set_freezable();
while (!kthread_should_stop()) {
+ cond_resched();
+
if (kthread_wait_freezable(c->copy_gc_enabled))
break;
- last = atomic_long_read(&clock->now);
-
- reserve = div64_u64((ca->mi.nbuckets - ca->mi.first_bucket) *
- ca->mi.bucket_size *
- c->opts.gc_reserve_percent, 200);
-
- usage = bch2_dev_usage_read(c, ca);
+ last = atomic64_read(&clock->now);
+ wait = bch2_copygc_wait_amount(c);
- /*
- * don't start copygc until less than half the gc reserve is
- * available:
- */
- available = __dev_buckets_available(ca, usage) *
- ca->mi.bucket_size;
- if (available > reserve) {
- next = last + available - reserve;
- bch2_kthread_io_clock_wait(clock, next);
+ if (wait > clock->max_slop) {
+ trace_copygc_wait(c, wait, last + wait);
+ c->copygc_wait = last + wait;
+ bch2_kthread_io_clock_wait(clock, last + wait,
+ MAX_SCHEDULE_TIMEOUT);
continue;
}
- /*
- * don't start copygc until there's more than half the copygc
- * reserve of fragmented space:
- */
- fragmented = usage.sectors_fragmented;
- if (fragmented < reserve) {
- next = last + reserve - fragmented;
- bch2_kthread_io_clock_wait(clock, next);
- continue;
- }
+ c->copygc_wait = 0;
- bch2_copygc(c, ca);
+ if (bch2_copygc(c))
+ break;
}
return 0;
}
-void bch2_copygc_stop(struct bch_dev *ca)
+void bch2_copygc_stop(struct bch_fs *c)
{
- ca->copygc_pd.rate.rate = UINT_MAX;
- bch2_ratelimit_reset(&ca->copygc_pd.rate);
-
- if (ca->copygc_thread) {
- kthread_stop(ca->copygc_thread);
- put_task_struct(ca->copygc_thread);
+ if (c->copygc_thread) {
+ kthread_stop(c->copygc_thread);
+ put_task_struct(c->copygc_thread);
}
- ca->copygc_thread = NULL;
+ c->copygc_thread = NULL;
}
-int bch2_copygc_start(struct bch_fs *c, struct bch_dev *ca)
+int bch2_copygc_start(struct bch_fs *c)
{
struct task_struct *t;
- BUG_ON(ca->copygc_thread);
+ if (c->copygc_thread)
+ return 0;
if (c->opts.nochanges)
return 0;
if (bch2_fs_init_fault("copygc_start"))
return -ENOMEM;
- t = kthread_create(bch2_copygc_thread, ca, "bch_copygc");
- if (IS_ERR(t))
+ t = kthread_create(bch2_copygc_thread, c, "bch-copygc/%s", c->name);
+ if (IS_ERR(t)) {
+ bch_err(c, "error creating copygc thread: %li", PTR_ERR(t));
return PTR_ERR(t);
+ }
get_task_struct(t);
- ca->copygc_thread = t;
- wake_up_process(ca->copygc_thread);
+ c->copygc_thread = t;
+ wake_up_process(c->copygc_thread);
return 0;
}
-void bch2_dev_copygc_init(struct bch_dev *ca)
+void bch2_fs_copygc_init(struct bch_fs *c)
{
- bch2_pd_controller_init(&ca->copygc_pd);
- ca->copygc_pd.d_term = 0;
}
projects / bcachefs-tools-debian / blobdiff