From 43de721a33b214b253c07672c4c6ba7548f2d3e7 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Wed, 13 Jul 2022 06:03:21 -0400 Subject: bcachefs: Unlock in bch2_trans_begin() if we've held locks more than 10us We try to ensure we never hold btree locks for too long - bcachefs tries to be soft realtime. This adds a check when restarting a transaction, where a transaction restart is cheap - if we've been holding locks for too long, drop and retake them. Signed-off-by: Kent Overstreet --- fs/bcachefs/btree_iter.c | 10 +++++++++- fs/bcachefs/btree_types.h | 3 +++ 2 files changed, 12 insertions(+), 1 deletion(-) (limited to 'fs/bcachefs') diff --git a/fs/bcachefs/btree_iter.c b/fs/bcachefs/btree_iter.c index b90aff2ad775..68d9d8ee6f97 100644 --- a/fs/bcachefs/btree_iter.c +++ b/fs/bcachefs/btree_iter.c @@ -3224,12 +3224,19 @@ void bch2_trans_begin(struct btree_trans *trans) path->preserve = false; } - bch2_trans_cond_resched(trans); + if (!trans->restarted && + (need_resched() || + ktime_get_ns() - trans->last_begin_time > BTREE_TRANS_MAX_LOCK_HOLD_TIME_NS)) { + bch2_trans_unlock(trans); + cond_resched(); + bch2_trans_relock(trans); + } if (trans->restarted) bch2_btree_path_traverse_all(trans); trans->restarted = false; + trans->last_begin_time = ktime_get_ns(); } static void bch2_trans_alloc_paths(struct btree_trans *trans, struct bch_fs *c) @@ -3259,6 +3266,7 @@ void __bch2_trans_init(struct btree_trans *trans, struct bch_fs *c, memset(trans, 0, sizeof(*trans)); trans->c = c; trans->fn = fn; + trans->last_begin_time = ktime_get_ns(); trans->task = current; trans->journal_replay_not_finished = !test_bit(JOURNAL_REPLAY_DONE, &c->journal.flags); diff --git a/fs/bcachefs/btree_types.h b/fs/bcachefs/btree_types.h index 2eb8cc11aec4..b184ec512499 100644 --- a/fs/bcachefs/btree_types.h +++ b/fs/bcachefs/btree_types.h @@ -382,10 +382,13 @@ struct btree_trans_commit_hook { #define BTREE_TRANS_MEM_MAX (1U << 16) +#define BTREE_TRANS_MAX_LOCK_HOLD_TIME_NS 10000 + struct btree_trans { struct bch_fs *c; const char *fn; struct list_head list; + u64 last_begin_time; struct btree *locking; unsigned locking_path_idx; struct bpos locking_pos; -- cgit v1.2.3