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bcachefs: Coalesce accounting keys before journal replay

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This fixes a performance regression in journal replay; without
colaescing accounting keys we have multiple keys at the same position,
which means journal_keys_peek_upto() has to skip past many overwritten
keys - turning journal replay into an O(n^2) algorithm.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2024-06-04 18:31:13 -04:00
parent 1d16c605cc
commit 2e8d686a4a
2 changed files with 20 additions and 0 deletions
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2
fs/bcachefs/btree_journal_iter.h
View File

@ -2,6 +2,8 @@
#ifndef _BCACHEFS_BTREE_JOURNAL_ITER_H
#define _BCACHEFS_BTREE_JOURNAL_ITER_H
#include "bkey.h"
struct journal_iter {
struct list_head list;
enum btree_id btree_id;

18
fs/bcachefs/disk_accounting.c
View File

@ -2,6 +2,7 @@
#include "bcachefs.h"
#include "bcachefs_ioctl.h"
#include "btree_journal_iter.h"
#include "btree_update.h"
#include "btree_write_buffer.h"
#include "buckets.h"
@ -344,7 +345,9 @@ int bch2_accounting_read(struct bch_fs *c)
goto err;
struct journal_keys *keys = &c->journal_keys;
struct journal_key *dst = keys->data;
move_gap(keys, keys->nr);
darray_for_each(*keys, i) {
if (i->k->k.type == KEY_TYPE_accounting) {
struct bkey_s_c k = bkey_i_to_s_c(i->k);
@ -358,11 +361,26 @@ int bch2_accounting_read(struct bch_fs *c)
if (applied)
continue;
if (i + 1 < &darray_top(*keys) &&
i[1].k->k.type == KEY_TYPE_accounting &&
!journal_key_cmp(i, i + 1)) {
BUG_ON(bversion_cmp(i[0].k->k.version, i[1].k->k.version) >= 0);
i[1].journal_seq = i[0].journal_seq;
bch2_accounting_accumulate(bkey_i_to_accounting(i[1].k),
bkey_s_c_to_accounting(k));
continue;
}
ret = accounting_read_key(c, k);
if (ret)
goto err;
}
*dst++ = *i;
}
keys->gap = keys->nr = dst - keys->data;
percpu_down_read(&c->mark_lock);
preempt_disable();