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bcachefs: Improve journal free space calculations

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Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2020-11-14 12:29:21 -05:00 committed by Kent Overstreet
parent ebb84d0941
commit b6df4325cd
4 changed files with 109 additions and 78 deletions
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25
fs/bcachefs/journal.c
View File

@ -1147,7 +1147,7 @@ void bch2_journal_debug_to_text(struct printbuf *out, struct journal *j)
}
pr_buf(out,
"current entry:\tidx %u refcount %u\n",
"current entry:\t\tidx %u refcount %u\n",
s.idx, journal_state_count(s, s.idx));
i = s.idx;
@ -1164,6 +1164,20 @@ void bch2_journal_debug_to_text(struct printbuf *out, struct journal *j)
test_bit(JOURNAL_NEED_WRITE, &j->flags),
test_bit(JOURNAL_REPLAY_DONE, &j->flags));
pr_buf(out, "space:\n");
pr_buf(out, "\tdiscarded\t%u:%u\n",
j->space[journal_space_discarded].next_entry,
j->space[journal_space_discarded].total);
pr_buf(out, "\tclean ondisk\t%u:%u\n",
j->space[journal_space_clean_ondisk].next_entry,
j->space[journal_space_clean_ondisk].total);
pr_buf(out, "\tclean\t\t%u:%u\n",
j->space[journal_space_clean].next_entry,
j->space[journal_space_clean].total);
pr_buf(out, "\ttotal\t\t%u:%u\n",
j->space[journal_space_total].next_entry,
j->space[journal_space_total].total);
for_each_member_device_rcu(ca, c, i,
&c->rw_devs[BCH_DATA_journal]) {
struct journal_device *ja = &ca->journal;
@ -1174,12 +1188,13 @@ void bch2_journal_debug_to_text(struct printbuf *out, struct journal *j)
pr_buf(out,
"dev %u:\n"
"\tnr\t\t%u\n"
"\tbucket size\t%u\n"
"\tavailable\t%u:%u\n"
"\tdiscard_idx\t\t%u\n"
"\tdirty_idx_ondisk\t%u (seq %llu)\n"
"\tdirty_idx\t\t%u (seq %llu)\n"
"\tdiscard_idx\t%u\n"
"\tdirty_ondisk\t%u (seq %llu)\n"
"\tdirty_idx\t%u (seq %llu)\n"
"\tcur_idx\t\t%u (seq %llu)\n",
i, ja->nr,
i, ja->nr, ca->mi.bucket_size,
bch2_journal_dev_buckets_available(j, ja, journal_space_discarded),
ja->sectors_free,
ja->discard_idx,

138
fs/bcachefs/journal_reclaim.c
View File

@ -71,84 +71,94 @@ static inline unsigned get_unwritten_sectors(struct journal *j, unsigned *idx)
return sectors;
}
static struct journal_space {
unsigned next_entry;
unsigned remaining;
} __journal_space_available(struct journal *j, unsigned nr_devs_want,
static struct journal_space
journal_dev_space_available(struct journal *j, struct bch_dev *ca,
enum journal_space_from from)
{
struct journal_device *ja = &ca->journal;
unsigned sectors, buckets, unwritten, idx = j->reservations.unwritten_idx;
if (from == journal_space_total)
return (struct journal_space) {
.next_entry = ca->mi.bucket_size,
.total = ca->mi.bucket_size * ja->nr,
};
buckets = bch2_journal_dev_buckets_available(j, ja, from);
sectors = ja->sectors_free;
/*
* We that we don't allocate the space for a journal entry
* until we write it out - thus, account for it here:
*/
while ((unwritten = get_unwritten_sectors(j, &idx))) {
if (unwritten >= sectors) {
if (!buckets) {
sectors = 0;
break;
}
buckets--;
sectors = ca->mi.bucket_size;
}
sectors -= unwritten;
}
if (sectors < ca->mi.bucket_size && buckets) {
buckets--;
sectors = ca->mi.bucket_size;
}
return (struct journal_space) {
.next_entry = sectors,
.total = sectors + buckets * ca->mi.bucket_size,
};
}
static struct journal_space __journal_space_available(struct journal *j, unsigned nr_devs_want,
enum journal_space_from from)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
struct bch_dev *ca;
unsigned sectors_next_entry = UINT_MAX;
unsigned sectors_total = UINT_MAX;
unsigned i, nr_devs = 0;
unsigned unwritten_sectors;
unsigned i, pos, nr_devs = 0;
struct journal_space space, dev_space[BCH_SB_MEMBERS_MAX];
BUG_ON(nr_devs_want > ARRAY_SIZE(dev_space));
rcu_read_lock();
for_each_member_device_rcu(ca, c, i,
&c->rw_devs[BCH_DATA_journal]) {
struct journal_device *ja = &ca->journal;
unsigned buckets_this_device, sectors_this_device;
unsigned idx = j->reservations.unwritten_idx;
if (!ja->nr)
if (!ca->journal.nr)
continue;
buckets_this_device = bch2_journal_dev_buckets_available(j, ja, from);
sectors_this_device = ja->sectors_free;
/*
* We that we don't allocate the space for a journal entry
* until we write it out - thus, account for it here:
*/
while ((unwritten_sectors = get_unwritten_sectors(j, &idx))) {
if (unwritten_sectors >= sectors_this_device) {
if (!buckets_this_device) {
sectors_this_device = 0;
break;
}
buckets_this_device--;
sectors_this_device = ca->mi.bucket_size;
}
sectors_this_device -= unwritten_sectors;
}
if (sectors_this_device < ca->mi.bucket_size &&
buckets_this_device) {
buckets_this_device--;
sectors_this_device = ca->mi.bucket_size;
}
if (!sectors_this_device)
space = journal_dev_space_available(j, ca, from);
if (!space.next_entry)
continue;
sectors_next_entry = min(sectors_next_entry,
sectors_this_device);
for (pos = 0; pos < nr_devs; pos++)
if (space.total > dev_space[pos].total)
break;
sectors_total = min(sectors_total,
buckets_this_device * ca->mi.bucket_size +
sectors_this_device);
nr_devs++;
array_insert_item(dev_space, nr_devs, pos, space);
}
rcu_read_unlock();
if (nr_devs < nr_devs_want)
return (struct journal_space) { 0, 0 };
return (struct journal_space) {
.next_entry = sectors_next_entry,
.remaining = max_t(int, 0, sectors_total - sectors_next_entry),
};
/*
* We sorted largest to smallest, and we want the smallest out of the
* @nr_devs_want largest devices:
*/
return dev_space[nr_devs_want - 1];
}
void bch2_journal_space_available(struct journal *j)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
struct bch_dev *ca;
struct journal_space discarded, clean_ondisk, clean;
unsigned clean;
unsigned overhead, u64s_remaining = 0;
unsigned max_entry_size = min(j->buf[0].buf_size >> 9,
j->buf[1].buf_size >> 9);
@ -189,27 +199,25 @@ void bch2_journal_space_available(struct journal *j)
goto out;
}
if (!fifo_free(&j->pin)) {
ret = cur_entry_journal_pin_full;
goto out;
}
nr_devs_want = min_t(unsigned, nr_online, c->opts.metadata_replicas);
discarded = __journal_space_available(j, nr_devs_want, journal_space_discarded);
clean_ondisk = __journal_space_available(j, nr_devs_want, journal_space_clean_ondisk);
clean = __journal_space_available(j, nr_devs_want, journal_space_clean);
for (i = 0; i < journal_space_nr; i++)
j->space[i] = __journal_space_available(j, nr_devs_want, i);
if (!discarded.next_entry)
clean = j->space[journal_space_clean].total;
if (!j->space[journal_space_discarded].next_entry)
ret = cur_entry_journal_full;
else if (!fifo_free(&j->pin))
ret = cur_entry_journal_pin_full;
overhead = DIV_ROUND_UP(clean.remaining, max_entry_size) *
overhead = DIV_ROUND_UP(clean, max_entry_size) *
journal_entry_overhead(j);
u64s_remaining = clean.remaining << 6;
u64s_remaining = clean << 6;
u64s_remaining = max_t(int, 0, u64s_remaining - overhead);
u64s_remaining /= 4;
out:
j->cur_entry_sectors = !ret ? discarded.next_entry : 0;
j->cur_entry_sectors = !ret ? j->space[journal_space_discarded].next_entry : 0;
j->cur_entry_error = ret;
journal_set_remaining(j, u64s_remaining);
journal_check_may_get_unreserved(j);

6
fs/bcachefs/journal_reclaim.h
View File

@ -4,12 +4,6 @@
#define JOURNAL_PIN (32 * 1024)
enum journal_space_from {
journal_space_discarded,
journal_space_clean_ondisk,
journal_space_clean,
};
static inline void journal_reclaim_kick(struct journal *j)
{
struct task_struct *p = READ_ONCE(j->reclaim_thread);

18
fs/bcachefs/journal_types.h
View File

@ -9,8 +9,6 @@
#include "super_types.h"
#include "fifo.h"
struct journal_res;
#define JOURNAL_BUF_BITS 2
#define JOURNAL_BUF_NR (1U << JOURNAL_BUF_BITS)
#define JOURNAL_BUF_MASK (JOURNAL_BUF_NR - 1)
@ -122,6 +120,20 @@ union journal_preres_state {
#define JOURNAL_ENTRY_CLOSED_VAL (JOURNAL_ENTRY_OFFSET_MAX - 1)
#define JOURNAL_ENTRY_ERROR_VAL (JOURNAL_ENTRY_OFFSET_MAX)
struct journal_space {
/* Units of 512 bytes sectors: */
unsigned next_entry; /* How big the next journal entry can be */
unsigned total;
};
enum journal_space_from {
journal_space_discarded,
journal_space_clean_ondisk,
journal_space_clean,
journal_space_total,
journal_space_nr,
};
/*
* JOURNAL_NEED_WRITE - current (pending) journal entry should be written ASAP,
* either because something's waiting on the write to complete or because it's
@ -216,6 +228,8 @@ struct journal {
struct journal_entry_pin_list *data;
} pin;
struct journal_space space[journal_space_nr];
u64 replay_journal_seq;
u64 replay_journal_seq_end;