Commit 5f43b013 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcachefs: btree node prefetching in check_topology 



btree_and_journal_iter is old code that we want to get rid of, but we're
not ready to yet.

lack of btree node prefetching is, it turns out, a real performance
issue for fsck on spinning rust, so - add it.

Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent fc634d8e

fs/bcachefs/btree_cache.c

+7 −3
Original line number Diff line number Diff line
@@ -711,6 +711,9 @@ static noinline struct btree *bch2_btree_node_fill(struct btree_trans *trans, 
	b = bch2_btree_node_mem_alloc(trans, level != 0);



	if (bch2_err_matches(PTR_ERR_OR_ZERO(b), ENOMEM)) {

		if (!path)

			return b;



		trans->memory_allocation_failure = true;

		trace_and_count(c, trans_restart_memory_allocation_failure, trans, _THIS_IP_, path);

		return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_fill_mem_alloc_fail));
@@ -760,7 +763,8 @@ static noinline struct btree *bch2_btree_node_fill(struct btree_trans *trans, 
	}



	if (!six_relock_type(&b->c.lock, lock_type, seq)) {

		if (path)

		BUG_ON(!path);



		trace_and_count(c, trans_restart_relock_after_fill, trans, _THIS_IP_, path);

		return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_relock_after_fill));

	}
@@ -1096,7 +1100,7 @@ int bch2_btree_node_prefetch(struct btree_trans *trans, 
	struct btree_cache *bc = &c->btree_cache;

	struct btree *b;



	BUG_ON(trans && !btree_node_locked(path, level + 1));

	BUG_ON(path && !btree_node_locked(path, level + 1));

	BUG_ON(level >= BTREE_MAX_DEPTH);



	b = btree_cache_find(bc, k);

fs/bcachefs/btree_gc.c

+3 −0
Original line number Diff line number Diff line
@@ -390,6 +390,7 @@ static int bch2_btree_repair_topology_recurse(struct btree_trans *trans, struct 
	bch2_bkey_buf_init(&prev_k);

	bch2_bkey_buf_init(&cur_k);

	bch2_btree_and_journal_iter_init_node_iter(trans, &iter, b);

	iter.prefetch = true;



	while ((k = bch2_btree_and_journal_iter_peek(&iter)).k) {

		BUG_ON(bpos_lt(k.k->p, b->data->min_key));
@@ -479,6 +480,7 @@ static int bch2_btree_repair_topology_recurse(struct btree_trans *trans, struct 


	bch2_btree_and_journal_iter_exit(&iter);

	bch2_btree_and_journal_iter_init_node_iter(trans, &iter, b);

	iter.prefetch = true;



	while ((k = bch2_btree_and_journal_iter_peek(&iter)).k) {

		bch2_bkey_buf_reassemble(&cur_k, c, k);
@@ -964,6 +966,7 @@ static int bch2_gc_btree_init_recurse(struct btree_trans *trans, struct btree *b 
	if (b->c.level > target_depth) {

		bch2_btree_and_journal_iter_exit(&iter);

		bch2_btree_and_journal_iter_init_node_iter(trans, &iter, b);

		iter.prefetch = true;



		while ((k = bch2_btree_and_journal_iter_peek(&iter)).k) {

			struct btree *child;

fs/bcachefs/btree_journal_iter.c

+31 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



#include "bcachefs.h"

#include "bkey_buf.h"

#include "bset.h"

#include "btree_cache.h"

#include "btree_journal_iter.h"

#include "journal_io.h"
@@ -334,9 +336,38 @@ void bch2_btree_and_journal_iter_advance(struct btree_and_journal_iter *iter) 
		iter->pos = bpos_successor(iter->pos);

}



static void btree_and_journal_iter_prefetch(struct btree_and_journal_iter *_iter)

{

	struct btree_and_journal_iter iter = *_iter;

	struct bch_fs *c = iter.trans->c;

	unsigned level = iter.journal.level;

	struct bkey_buf tmp;

	unsigned nr = test_bit(BCH_FS_started, &c->flags)

		? (level > 1 ? 0 :  2)

		: (level > 1 ? 1 : 16);



	iter.prefetch = false;

	bch2_bkey_buf_init(&tmp);



	while (nr--) {

		bch2_btree_and_journal_iter_advance(&iter);

		struct bkey_s_c k = bch2_btree_and_journal_iter_peek(&iter);

		if (!k.k)

			break;



		bch2_bkey_buf_reassemble(&tmp, c, k);

		bch2_btree_node_prefetch(iter.trans, NULL, tmp.k, iter.journal.btree_id, level - 1);

	}



	bch2_bkey_buf_exit(&tmp, c);

}



struct bkey_s_c bch2_btree_and_journal_iter_peek(struct btree_and_journal_iter *iter)

{

	struct bkey_s_c btree_k, journal_k, ret;



	if (iter->prefetch && iter->journal.level)

		btree_and_journal_iter_prefetch(iter);

again:

	if (iter->at_end)

		return bkey_s_c_null;

fs/bcachefs/btree_journal_iter.h

+1 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ struct btree_and_journal_iter { 
	struct journal_iter	journal;

	struct bpos		pos;

	bool			at_end;

	bool			prefetch;

};



struct bkey_i *bch2_journal_keys_peek_upto(struct bch_fs *, enum btree_id,