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// SPDX-License-Identifier: GPL-2.0
#include "bcachefs.h"
#include "alloc_foreground.h"
#include "btree_iter.h"
#include "buckets.h"
#include "clock.h"
#include "disk_groups.h"
#include "extents.h"
#include "io.h"
#include "move.h"
#include "rebalance.h"
#include "super-io.h"
#include "trace.h"
#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/sched/cputime.h>
static inline bool rebalance_ptr_pred(struct bch_fs *c,
struct extent_ptr_decoded p,
struct bch_io_opts *io_opts)
{
if (io_opts->background_target &&
!bch2_dev_in_target(c, p.ptr.dev, io_opts->background_target) &&
!p.ptr.cached)
return true;
if (io_opts->background_compression &&
p.crc.compression_type !=
bch2_compression_opt_to_type[io_opts->background_compression])
return true;
return false;
}
void bch2_rebalance_add_key(struct bch_fs *c,
struct bkey_s_c k,
struct bch_io_opts *io_opts)
{
struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
const union bch_extent_entry *entry;
struct extent_ptr_decoded p;
if (!io_opts->background_target &&
!io_opts->background_compression)
return;
bkey_for_each_ptr_decode(k.k, ptrs, p, entry)
if (rebalance_ptr_pred(c, p, io_opts)) {
struct bch_dev *ca = bch_dev_bkey_exists(c, p.ptr.dev);
if (atomic64_add_return(p.crc.compressed_size,
&ca->rebalance_work) ==
p.crc.compressed_size)
rebalance_wakeup(c);
}
}
void bch2_rebalance_add_work(struct bch_fs *c, u64 sectors)
{
if (atomic64_add_return(sectors, &c->rebalance.work_unknown_dev) ==
sectors)
rebalance_wakeup(c);
}
static enum data_cmd rebalance_pred(struct bch_fs *c, void *arg,
struct bkey_s_c k,
struct bch_io_opts *io_opts,
struct data_opts *data_opts)
{
struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
const union bch_extent_entry *entry;
struct extent_ptr_decoded p;
unsigned nr_replicas = 0;
bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
nr_replicas += !p.ptr.cached;
if (rebalance_ptr_pred(c, p, io_opts))
goto found;
}
if (nr_replicas < io_opts->data_replicas)
goto found;
return DATA_SKIP;
found:
data_opts->target = io_opts->background_target;
data_opts->btree_insert_flags = 0;
return DATA_ADD_REPLICAS;
}
struct rebalance_work {
int dev_most_full_idx;
unsigned dev_most_full_percent;
u64 dev_most_full_work;
u64 dev_most_full_capacity;
u64 total_work;
};
static void rebalance_work_accumulate(struct rebalance_work *w,
u64 dev_work, u64 unknown_dev, u64 capacity, int idx)
{
unsigned percent_full;
u64 work = dev_work + unknown_dev;
if (work < dev_work || work < unknown_dev)
work = U64_MAX;
work = min(work, capacity);
percent_full = div64_u64(work * 100, capacity);
if (percent_full >= w->dev_most_full_percent) {
w->dev_most_full_idx = idx;
w->dev_most_full_percent = percent_full;
w->dev_most_full_work = work;
w->dev_most_full_capacity = capacity;
}
if (w->total_work + dev_work >= w->total_work &&
w->total_work + dev_work >= dev_work)
w->total_work += dev_work;
}
static struct rebalance_work rebalance_work(struct bch_fs *c)
{
struct bch_dev *ca;
struct rebalance_work ret = { .dev_most_full_idx = -1 };
u64 unknown_dev = atomic64_read(&c->rebalance.work_unknown_dev);
unsigned i;
for_each_online_member(ca, c, i)
rebalance_work_accumulate(&ret,
atomic64_read(&ca->rebalance_work),
unknown_dev,
bucket_to_sector(ca, ca->mi.nbuckets -
ca->mi.first_bucket),
i);
rebalance_work_accumulate(&ret,
unknown_dev, 0, c->capacity, -1);
return ret;
}
static void rebalance_work_reset(struct bch_fs *c)
{
struct bch_dev *ca;
unsigned i;
for_each_online_member(ca, c, i)
atomic64_set(&ca->rebalance_work, 0);
atomic64_set(&c->rebalance.work_unknown_dev, 0);
}
static unsigned long curr_cputime(void)
{
u64 utime, stime;
task_cputime_adjusted(current, &utime, &stime);
return nsecs_to_jiffies(utime + stime);
}
static int bch2_rebalance_thread(void *arg)
{
struct bch_fs *c = arg;
struct bch_fs_rebalance *r = &c->rebalance;
struct io_clock *clock = &c->io_clock[WRITE];
struct rebalance_work w, p;
unsigned long start, prev_start;
unsigned long prev_run_time, prev_run_cputime;
unsigned long cputime, prev_cputime;
unsigned long io_start;
long throttle;
set_freezable();
io_start = atomic_long_read(&clock->now);
p = rebalance_work(c);
prev_start = jiffies;
prev_cputime = curr_cputime();
while (!kthread_wait_freezable(r->enabled)) {
cond_resched();
start = jiffies;
cputime = curr_cputime();
prev_run_time = start - prev_start;
prev_run_cputime = cputime - prev_cputime;
w = rebalance_work(c);
BUG_ON(!w.dev_most_full_capacity);
if (!w.total_work) {
r->state = REBALANCE_WAITING;
kthread_wait_freezable(rebalance_work(c).total_work);
continue;
}
/*
* If there isn't much work to do, throttle cpu usage:
*/
throttle = prev_run_cputime * 100 /
max(1U, w.dev_most_full_percent) -
prev_run_time;
if (w.dev_most_full_percent < 20 && throttle > 0) {
r->state = REBALANCE_THROTTLED;
r->throttled_until_iotime = io_start +
div_u64(w.dev_most_full_capacity *
(20 - w.dev_most_full_percent),
50);
r->throttled_until_cputime = start + throttle;
bch2_kthread_io_clock_wait(clock,
r->throttled_until_iotime,
throttle);
continue;
}
/* minimum 1 mb/sec: */
r->pd.rate.rate =
max_t(u64, 1 << 11,
r->pd.rate.rate *
max(p.dev_most_full_percent, 1U) /
max(w.dev_most_full_percent, 1U));
io_start = atomic_long_read(&clock->now);
p = w;
prev_start = start;
prev_cputime = cputime;
r->state = REBALANCE_RUNNING;
memset(&r->move_stats, 0, sizeof(r->move_stats));
rebalance_work_reset(c);
bch2_move_data(c,
/* ratelimiting disabled for now */
NULL, /* &r->pd.rate, */
writepoint_ptr(&c->rebalance_write_point),
POS_MIN, POS_MAX,
rebalance_pred, NULL,
&r->move_stats);
}
return 0;
}
ssize_t bch2_rebalance_work_show(struct bch_fs *c, char *buf)
{
struct printbuf out = _PBUF(buf, PAGE_SIZE);
struct bch_fs_rebalance *r = &c->rebalance;
struct rebalance_work w = rebalance_work(c);
char h1[21], h2[21];
bch2_hprint(&PBUF(h1), w.dev_most_full_work << 9);
bch2_hprint(&PBUF(h2), w.dev_most_full_capacity << 9);
pr_buf(&out, "fullest_dev (%i):\t%s/%s\n",
w.dev_most_full_idx, h1, h2);
bch2_hprint(&PBUF(h1), w.total_work << 9);
bch2_hprint(&PBUF(h2), c->capacity << 9);
pr_buf(&out, "total work:\t\t%s/%s\n", h1, h2);
pr_buf(&out, "rate:\t\t\t%u\n", r->pd.rate.rate);
switch (r->state) {
case REBALANCE_WAITING:
pr_buf(&out, "waiting\n");
break;
case REBALANCE_THROTTLED:
bch2_hprint(&PBUF(h1),
(r->throttled_until_iotime -
atomic_long_read(&c->io_clock[WRITE].now)) << 9);
pr_buf(&out, "throttled for %lu sec or %s io\n",
(r->throttled_until_cputime - jiffies) / HZ,
h1);
break;
case REBALANCE_RUNNING:
pr_buf(&out, "running\n");
pr_buf(&out, "pos %llu:%llu\n",
r->move_stats.pos.inode,
r->move_stats.pos.offset);
break;
}
return out.pos - buf;
}
void bch2_rebalance_stop(struct bch_fs *c)
{
struct task_struct *p;
c->rebalance.pd.rate.rate = UINT_MAX;
bch2_ratelimit_reset(&c->rebalance.pd.rate);
p = rcu_dereference_protected(c->rebalance.thread, 1);
c->rebalance.thread = NULL;
if (p) {
/* for sychronizing with rebalance_wakeup() */
synchronize_rcu();
kthread_stop(p);
put_task_struct(p);
}
}
int bch2_rebalance_start(struct bch_fs *c)
{
struct task_struct *p;
if (c->opts.nochanges)
return 0;
p = kthread_create(bch2_rebalance_thread, c, "bch_rebalance");
if (IS_ERR(p))
return PTR_ERR(p);
get_task_struct(p);
rcu_assign_pointer(c->rebalance.thread, p);
wake_up_process(p);
return 0;
}
void bch2_fs_rebalance_init(struct bch_fs *c)
{
bch2_pd_controller_init(&c->rebalance.pd);
atomic64_set(&c->rebalance.work_unknown_dev, S64_MAX);
}
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