// SPDX-License-Identifier: GPL-2.0
/*
* Moving/copying garbage collector
*
* Copyright 2012 Google, Inc.
*/
#include "bcachefs.h"
#include "alloc_background.h"
#include "alloc_foreground.h"
#include "btree_iter.h"
#include "btree_update.h"
#include "btree_write_buffer.h"
#include "buckets.h"
#include "clock.h"
#include "errcode.h"
#include "error.h"
#include "lru.h"
#include "move.h"
#include "movinggc.h"
#include "trace.h"
#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/math64.h>
#include <linux/sched/task.h>
#include <linux/wait.h>
struct buckets_in_flight {
struct rhashtable table;
struct move_bucket_in_flight *first;
struct move_bucket_in_flight *last;
size_t nr;
size_t sectors;
};
static const struct rhashtable_params bch_move_bucket_params = {
.head_offset = offsetof(struct move_bucket_in_flight, hash),
.key_offset = offsetof(struct move_bucket_in_flight, bucket.k),
.key_len = sizeof(struct move_bucket_key),
.automatic_shrinking = true,
};
static struct move_bucket_in_flight *
move_bucket_in_flight_add(struct buckets_in_flight *list, struct move_bucket b)
{
struct move_bucket_in_flight *new = kzalloc(sizeof(*new), GFP_KERNEL);
int ret;
if (!new)
return ERR_PTR(-ENOMEM);
new->bucket = b;
ret = rhashtable_lookup_insert_fast(&list->table, &new->hash,
bch_move_bucket_params);
if (ret) {
kfree(new);
return ERR_PTR(ret);
}
if (!list->first)
list->first = new;
else
list->last->next = new;
list->last = new;
list->nr++;
list->sectors += b.sectors;
return new;
}
static int bch2_bucket_is_movable(struct btree_trans *trans,
struct move_bucket *b, u64 time)
{
struct btree_iter iter;
struct bkey_s_c k;
struct bch_alloc_v4 _a;
const struct bch_alloc_v4 *a;
int ret;
if (bch2_bucket_is_open(trans->c,
b->k.bucket.inode,
b->k.bucket.offset))
return 0;
k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_alloc,
b->k.bucket, BTREE_ITER_cached);
ret = bkey_err(k);
if (ret)
return ret;
a = bch2_alloc_to_v4(k, &_a);
b->k.gen = a->gen;
b->sectors = bch2_bucket_sectors_dirty(*a);
ret = data_type_movable(a->data_type) &&
a->fragmentation_lru &&
a->fragmentation_lru <= time;
bch2_trans_iter_exit(trans, &iter);
return ret;
}
static void move_buckets_wait(struct moving_context *ctxt,
struct buckets_in_flight *list,
bool flush)
{
struct move_bucket_in_flight *i;
int ret;
while ((i = list->first)) {
if (flush)
move_ctxt_wait_event(ctxt, !atomic_read(&i->count));
if (atomic_read(&i->count))
break;
list->first = i->next;
if (!list->first)
list->last = NULL;
list->nr--;
list->sectors -= i->bucket.sectors;
ret = rhashtable_remove_fast(&list->table, &i->hash,
bch_move_bucket_params);
BUG_ON(ret);
kfree(i);
}
bch2_trans_unlock_long(ctxt->trans);
}
static bool bucket_in_flight(struct buckets_in_flight *list,
struct move_bucket_key k)
{
return rhashtable_lookup_fast(&list->table, &k, bch_move_bucket_params);
}
typedef DARRAY(struct move_bucket) move_buckets;
static int bch2_copygc_get_buckets(struct moving_context *ctxt,
struct buckets_in_flight *buckets_in_flight,
move_buckets *buckets)
{
struct btree_trans *trans = ctxt->trans;
struct bch_fs *c = trans->c;
size_t nr_to_get = max_t(size_t, 16U, buckets_in_flight->nr / 4);
size_t saw = 0, in_flight = 0, not_movable = 0, sectors = 0;
int ret;
move_buckets_wait(ctxt, buckets_in_flight, false);
ret = bch2_btree_write_buffer_tryflush(trans);
if (bch2_err_matches(ret, EROFS))
return ret;
if (bch2_fs_fatal_err_on(ret, c, "%s: from bch2_btree_write_buffer_tryflush()", bch2_err_str(ret)))
return ret;
bch2_trans_begin(trans);
ret = for_each_btree_key_upto(trans, iter, BTREE_ID_lru,
lru_pos(BCH_LRU_FRAGMENTATION_START, 0, 0),
lru_pos(BCH_LRU_FRAGMENTATION_START, U64_MAX, LRU_TIME_MAX),
0, k, ({
struct move_bucket b = { .k.bucket = u64_to_bucket(k.k->p.offset) };
int ret2 = 0;
saw++;
ret2 = bch2_bucket_is_movable(trans, &b, lru_pos_time(k.k->p));
if (ret2 < 0)
goto err;
if (!ret2)
not_movable++;
else if (bucket_in_flight(buckets_in_flight, b.k))
in_flight++;
else {
ret2 = darray_push(buckets, b);
if (ret2)
goto err;
sectors += b.sectors;
}
ret2 = buckets->nr >= nr_to_get;
err:
ret2;
}));
pr_debug("have: %zu (%zu) saw %zu in flight %zu not movable %zu got %zu (%zu)/%zu buckets ret %i",
buckets_in_flight->nr, buckets_in_flight->sectors,
saw, in_flight, not_movable, buckets->nr, sectors, nr_to_get, ret);
return ret < 0 ? ret : 0;
}
noinline
static int bch2_copygc(struct moving_context *ctxt,
struct buckets_in_flight *buckets_in_flight,
bool *did_work)
{
struct btree_trans *trans = ctxt->trans;
struct bch_fs *c = trans->c;
struct data_update_opts data_opts = {
.btree_insert_flags = BCH_WATERMARK_copygc,
};
move_buckets buckets = { 0 };
struct move_bucket_in_flight *f;
u64 moved = atomic64_read(&ctxt->stats->sectors_moved);
int ret = 0;
ret = bch2_copygc_get_buckets(ctxt, buckets_in_flight, &buckets);
if (ret)
goto err;
darray_for_each(buckets, i) {
if (kthread_should_stop() || freezing(current))
break;
f = move_bucket_in_flight_add(buckets_in_flight, *i);
ret = PTR_ERR_OR_ZERO(f);
if (ret == -EEXIST) { /* rare race: copygc_get_buckets returned same bucket more than once */
ret = 0;
continue;
}
if (ret == -ENOMEM) { /* flush IO, continue later */
ret = 0;
break;
}
ret = bch2_evacuate_bucket(ctxt, f, f->bucket.k.bucket,
f->bucket.k.gen, data_opts);
if (ret)
goto err;
*did_work = true;
}
err:
darray_exit(&buckets);
/* no entries in LRU btree found, or got to end: */
if (bch2_err_matches(ret, ENOENT))
ret = 0;
if (ret < 0 && !bch2_err_matches(ret, EROFS))
bch_err_msg(c, ret, "from bch2_move_data()");
moved = atomic64_read(&ctxt->stats->sectors_moved) - moved;
trace_and_count(c, copygc, c, moved, 0, 0, 0);
return ret;
}
/*
* 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)
{
s64 wait = S64_MAX, fragmented_allowed, fragmented;
for_each_rw_member(c, ca) {
struct bch_dev_usage usage = bch2_dev_usage_read(ca);
fragmented_allowed = ((__dev_buckets_available(ca, usage, BCH_WATERMARK_stripe) *
ca->mi.bucket_size) >> 1);
fragmented = 0;
for (unsigned i = 0; i < BCH_DATA_NR; i++)
if (data_type_movable(i))
fragmented += usage.d[i].fragmented;
wait = min(wait, max(0LL, fragmented_allowed - fragmented));
}
return wait;
}
void bch2_copygc_wait_to_text(struct printbuf *out, struct bch_fs *c)
{
printbuf_tabstop_push(out, 32);
prt_printf(out, "running:\t%u\n", c->copygc_running);
prt_printf(out, "copygc_wait:\t%llu\n", c->copygc_wait);
prt_printf(out, "copygc_wait_at:\t%llu\n", c->copygc_wait_at);
prt_printf(out, "Currently waiting for:\t");
prt_human_readable_u64(out, max(0LL, c->copygc_wait -
atomic64_read(&c->io_clock[WRITE].now)) << 9);
prt_newline(out);
prt_printf(out, "Currently waiting since:\t");
prt_human_readable_u64(out, max(0LL,
atomic64_read(&c->io_clock[WRITE].now) -
c->copygc_wait_at) << 9);
prt_newline(out);
prt_printf(out, "Currently calculated wait:\t");
prt_human_readable_u64(out, bch2_copygc_wait_amount(c));
prt_newline(out);
}
static int bch2_copygc_thread(void *arg)
{
struct bch_fs *c = arg;
struct moving_context ctxt;
struct bch_move_stats move_stats;
struct io_clock *clock = &c->io_clock[WRITE];
struct buckets_in_flight *buckets;
u64 last, wait;
int ret = 0;
buckets = kzalloc(sizeof(struct buckets_in_flight), GFP_KERNEL);
if (!buckets)
return -ENOMEM;
ret = rhashtable_init(&buckets->table, &bch_move_bucket_params);
bch_err_msg(c, ret, "allocating copygc buckets in flight");
if (ret) {
kfree(buckets);
return ret;
}
set_freezable();
bch2_move_stats_init(&move_stats, "copygc");
bch2_moving_ctxt_init(&ctxt, c, NULL, &move_stats,
writepoint_ptr(&c->copygc_write_point),
false);
while (!ret && !kthread_should_stop()) {
bool did_work = false;
bch2_trans_unlock_long(ctxt.trans);
cond_resched();
if (!c->copy_gc_enabled) {
move_buckets_wait(&ctxt, buckets, true);
kthread_wait_freezable(c->copy_gc_enabled ||
kthread_should_stop());
}
if (unlikely(freezing(current))) {
move_buckets_wait(&ctxt, buckets, true);
__refrigerator(false);
continue;
}
last = atomic64_read(&clock->now);
wait = bch2_copygc_wait_amount(c);
if (wait > clock->max_slop) {
c->copygc_wait_at = last;
c->copygc_wait = last + wait;
move_buckets_wait(&ctxt, buckets, true);
trace_and_count(c, copygc_wait, c, wait, last + wait);
bch2_kthread_io_clock_wait(clock, last + wait,
MAX_SCHEDULE_TIMEOUT);
continue;
}
c->copygc_wait = 0;
c->copygc_running = true;
ret = bch2_copygc(&ctxt, buckets, &did_work);
c->copygc_running = false;
wake_up(&c->copygc_running_wq);
if (!wait && !did_work) {
u64 min_member_capacity = bch2_min_rw_member_capacity(c);
if (min_member_capacity == U64_MAX)
min_member_capacity = 128 * 2048;
move_buckets_wait(&ctxt, buckets, true);
bch2_kthread_io_clock_wait(clock, last + (min_member_capacity >> 6),
MAX_SCHEDULE_TIMEOUT);
}
}
move_buckets_wait(&ctxt, buckets, true);
rhashtable_destroy(&buckets->table);
kfree(buckets);
bch2_moving_ctxt_exit(&ctxt);
bch2_move_stats_exit(&move_stats, c);
return 0;
}
void bch2_copygc_stop(struct bch_fs *c)
{
if (c->copygc_thread) {
kthread_stop(c->copygc_thread);
put_task_struct(c->copygc_thread);
}
c->copygc_thread = NULL;
}
int bch2_copygc_start(struct bch_fs *c)
{
struct task_struct *t;
int ret;
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, c, "bch-copygc/%s", c->name);
ret = PTR_ERR_OR_ZERO(t);
bch_err_msg(c, ret, "creating copygc thread");
if (ret)
return ret;
get_task_struct(t);
c->copygc_thread = t;
wake_up_process(c->copygc_thread);
return 0;
}
void bch2_fs_copygc_init(struct bch_fs *c)
{
init_waitqueue_head(&c->copygc_running_wq);
c->copygc_running = false;
}
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