linux/fs/bcachefs/rebalance.c
Kent Overstreet fa8e94faee bcachefs: Heap allocate printbufs
This patch changes printbufs dynamically allocate and reallocate a
buffer as needed. Stack usage has become a bit of a problem, and a major
cause of that has been static size string buffers on the stack.

The most involved part of this refactoring is that printbufs must now be
exited with printbuf_exit().

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:25 -04:00

350 lines
8.1 KiB
C

// 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>
/*
* Check if an extent should be moved:
* returns -1 if it should not be moved, or
* device of pointer that should be moved, if known, or INT_MAX if unknown
*/
static int __bch2_rebalance_pred(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_compression &&
!bch2_bkey_is_incompressible(k))
bkey_for_each_ptr_decode(k.k, ptrs, p, entry)
if (!p.ptr.cached &&
p.crc.compression_type !=
bch2_compression_opt_to_type[io_opts->background_compression])
return p.ptr.dev;
if (io_opts->background_target)
bkey_for_each_ptr_decode(k.k, ptrs, p, entry)
if (!p.ptr.cached &&
!bch2_dev_in_target(c, p.ptr.dev, io_opts->background_target))
return p.ptr.dev;
return -1;
}
void bch2_rebalance_add_key(struct bch_fs *c,
struct bkey_s_c k,
struct bch_io_opts *io_opts)
{
atomic64_t *counter;
int dev;
dev = __bch2_rebalance_pred(c, k, io_opts);
if (dev < 0)
return;
counter = dev < INT_MAX
? &bch_dev_bkey_exists(c, dev)->rebalance_work
: &c->rebalance.work_unknown_dev;
if (atomic64_add_return(k.k->size, counter) == k.k->size)
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)
{
if (__bch2_rebalance_pred(c, k, io_opts) >= 0) {
data_opts->target = io_opts->background_target;
data_opts->nr_replicas = 1;
data_opts->btree_insert_flags = 0;
return DATA_ADD_REPLICAS;
} else {
return DATA_SKIP;
}
}
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);
}
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;
struct bch_move_stats move_stats;
unsigned long start, prev_start;
unsigned long prev_run_time, prev_run_cputime;
unsigned long cputime, prev_cputime;
u64 io_start;
long throttle;
set_freezable();
io_start = atomic64_read(&clock->now);
p = rebalance_work(c);
prev_start = jiffies;
prev_cputime = curr_cputime();
bch_move_stats_init(&move_stats, "rebalance");
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->throttled_until_iotime = io_start +
div_u64(w.dev_most_full_capacity *
(20 - w.dev_most_full_percent),
50);
if (atomic64_read(&clock->now) + clock->max_slop <
r->throttled_until_iotime) {
r->throttled_until_cputime = start + throttle;
r->state = REBALANCE_THROTTLED;
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 = atomic64_read(&clock->now);
p = w;
prev_start = start;
prev_cputime = cputime;
r->state = REBALANCE_RUNNING;
memset(&move_stats, 0, sizeof(move_stats));
rebalance_work_reset(c);
bch2_move_data(c,
0, POS_MIN,
BTREE_ID_NR, POS_MAX,
/* ratelimiting disabled for now */
NULL, /* &r->pd.rate, */
writepoint_ptr(&c->rebalance_write_point),
rebalance_pred, NULL,
&move_stats);
}
return 0;
}
void bch2_rebalance_work_to_text(struct printbuf *out, struct bch_fs *c)
{
struct bch_fs_rebalance *r = &c->rebalance;
struct rebalance_work w = rebalance_work(c);
out->tabstops[0] = 20;
pr_buf(out, "fullest_dev (%i):", w.dev_most_full_idx);
pr_tab(out);
bch2_hprint(out, w.dev_most_full_work << 9);
pr_buf(out, "/");
bch2_hprint(out, w.dev_most_full_capacity << 9);
pr_newline(out);
pr_buf(out, "total work:");
pr_tab(out);
bch2_hprint(out, w.total_work << 9);
pr_buf(out, "/");
bch2_hprint(out, c->capacity << 9);
pr_newline(out);
pr_buf(out, "rate:");
pr_tab(out);
pr_buf(out, "%u", r->pd.rate.rate);
pr_newline(out);
switch (r->state) {
case REBALANCE_WAITING:
pr_buf(out, "waiting");
break;
case REBALANCE_THROTTLED:
pr_buf(out, "throttled for %lu sec or ",
(r->throttled_until_cputime - jiffies) / HZ);
bch2_hprint(out,
(r->throttled_until_iotime -
atomic64_read(&c->io_clock[WRITE].now)) << 9);
pr_buf(out, " io");
break;
case REBALANCE_RUNNING:
pr_buf(out, "running");
break;
}
pr_newline(out);
}
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->rebalance.thread)
return 0;
if (c->opts.nochanges)
return 0;
p = kthread_create(bch2_rebalance_thread, c, "bch-rebalance/%s", c->name);
if (IS_ERR(p)) {
bch_err(c, "error creating rebalance thread: %li", PTR_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);
}