Thanks, Ted, for your feedback! I'll submit a modified version. - Alex
On 07.04.19 18:52, Theodore Ts'o wrote: > On Mon, Mar 18, 2019 at 07:42:37PM +0100, Alexander Lochmann wrote: >> /*t >> - * Where in the log does this transaction's commit start? [no locking] >> + * Where in the log does this transaction's commit start? >> + * [journal_t.j_state_lock] >> */ >> unsigned long t_log_start; > > Well, technically, that's not quite right. It's only assigned in one > location, and we hold j_state_lock, yes. But that's because we need > to access journal->j_head. At the point where we set t_log_start, the > transaction has already been locked down (transaction->t_state > > T_LOCKED). > > Similarly, we happen to be holding j_state where it is currently being > accessed, but it's not because we needed the lock in order to access > t_log_start safely. > >> /* >> - * When transaction started >> + * When transaction started [journal_t.j_state_lock] >> */ >> unsigned long t_start; > > And again, not really. The primary place where t_start is set is when > the transaction is firstt created, before it's visible anywhere else. > after that, it is used exclusively by the commit thread, and so no > locking is necessary. It's true that in the places where it is used, > j_state_lock happens to be taken, but it's strictly not necessary. > >> >> /* >> - * When commit was requested >> + * When commit was requested [journal_t.j_state_lock] >> */ >> unsigned long t_requested; > > Yes, that appears to be correct. > >> >> /* >> - * Checkpointing stats [j_checkpoint_sem] >> + * Checkpointing stats [journal_t.j_list_lock] >> */ >> struct transaction_chp_stats_s t_chp_stats; >> > > This appears to be correct. > > - Ted > -- Technische Universität Dortmund Alexander Lochmann PGP key: 0xBC3EF6FD Otto-Hahn-Str. 16 phone: +49.231.7556141 D-44227 Dortmund fax: +49.231.7556116 http://ess.cs.tu-dortmund.de/Staff/al
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