From 1d18b5cabc89f9c0ea0a3a1d738d5a02d478117f Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Sun, 14 Jul 2024 16:32:11 -0400 Subject: bcachefs: __bch2_read(): call trans_begin() on every loop iter perusal of /sys/kernel/debug/bcachefs/*/btree_transaction_stats shows that the read path has been acculumalating unneeded paths on the reflink btree, which we don't want. The solution is to call bch2_trans_begin(), which drops paths not used on previous loop iteration. bch2_readahead: Max mem used: 0 Transaction duration: count: 194235 since mount recent duration of events min: 150 ns max: 9 ms total: 838 ms mean: 4 us 6 us stddev: 34 us 7 us time between events min: 10 ns max: 15 h mean: 2 s 12 s stddev: 2 s 3 ms Maximum allocated btree paths (193): path: idx 2 ref 0:0 P btree=extents l=0 pos 270943112:392:U32_MAX locks 0 path: idx 3 ref 1:0 S btree=extents l=0 pos 270943112:24578:U32_MAX locks 1 path: idx 4 ref 0:0 P btree=reflink l=0 pos 0:24773509:0 locks 0 path: idx 5 ref 0:0 P S btree=reflink l=0 pos 0:24773631:0 locks 1 path: idx 6 ref 0:0 P S btree=reflink l=0 pos 0:24773759:0 locks 1 path: idx 7 ref 0:0 P S btree=reflink l=0 pos 0:24773887:0 locks 1 path: idx 8 ref 0:0 P S btree=reflink l=0 pos 0:24774015:0 locks 1 path: idx 9 ref 0:0 P S btree=reflink l=0 pos 0:24774143:0 locks 1 path: idx 10 ref 0:0 P S btree=reflink l=0 pos 0:24774271:0 locks 1 Signed-off-by: Kent Overstreet --- fs/bcachefs/io_read.c | 45 +++++++++++++++++++-------------------------- 1 file changed, 19 insertions(+), 26 deletions(-) (limited to 'fs') diff --git a/fs/bcachefs/io_read.c b/fs/bcachefs/io_read.c index 8b484c75757c..4531c9ab3e12 100644 --- a/fs/bcachefs/io_read.c +++ b/fs/bcachefs/io_read.c @@ -1147,34 +1147,27 @@ void __bch2_read(struct bch_fs *c, struct bch_read_bio *rbio, struct btree_iter iter; struct bkey_buf sk; struct bkey_s_c k; - u32 snapshot; int ret; BUG_ON(flags & BCH_READ_NODECODE); bch2_bkey_buf_init(&sk); -retry: - bch2_trans_begin(trans); - iter = (struct btree_iter) { NULL }; - - ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot); - if (ret) - goto err; - bch2_trans_iter_init(trans, &iter, BTREE_ID_extents, - SPOS(inum.inum, bvec_iter.bi_sector, snapshot), + POS(inum.inum, bvec_iter.bi_sector), BTREE_ITER_slots); + while (1) { unsigned bytes, sectors, offset_into_extent; enum btree_id data_btree = BTREE_ID_extents; - /* - * read_extent -> io_time_reset may cause a transaction restart - * without returning an error, we need to check for that here: - */ - ret = bch2_trans_relock(trans); + bch2_trans_begin(trans); + + u32 snapshot; + ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot); if (ret) - break; + goto err; + + bch2_btree_iter_set_snapshot(&iter, snapshot); bch2_btree_iter_set_pos(&iter, POS(inum.inum, bvec_iter.bi_sector)); @@ -1182,7 +1175,7 @@ retry: k = bch2_btree_iter_peek_slot(&iter); ret = bkey_err(k); if (ret) - break; + goto err; offset_into_extent = iter.pos.offset - bkey_start_offset(k.k); @@ -1193,7 +1186,7 @@ retry: ret = bch2_read_indirect_extent(trans, &data_btree, &offset_into_extent, &sk); if (ret) - break; + goto err; k = bkey_i_to_s_c(sk.k); @@ -1213,7 +1206,7 @@ retry: data_btree, k, offset_into_extent, failed, flags); if (ret) - break; + goto err; if (flags & BCH_READ_LAST_FRAGMENT) break; @@ -1223,16 +1216,16 @@ retry: ret = btree_trans_too_many_iters(trans); if (ret) + goto err; +err: + if (ret && + !bch2_err_matches(ret, BCH_ERR_transaction_restart) && + ret != READ_RETRY && + ret != READ_RETRY_AVOID) break; } -err: - bch2_trans_iter_exit(trans, &iter); - - if (bch2_err_matches(ret, BCH_ERR_transaction_restart) || - ret == READ_RETRY || - ret == READ_RETRY_AVOID) - goto retry; + bch2_trans_iter_exit(trans, &iter); bch2_trans_put(trans); bch2_bkey_buf_exit(&sk, c); -- cgit v1.2.3