linux-ext4 - Re: [PATCH 14/22] jbd2: Drop pointless wakeup from jbd2_journal

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Message-ID: <20191021173403.GG27850@mit.edu>
Date:   Mon, 21 Oct 2019 13:34:03 -0400
From:   "Theodore Y. Ts'o" <tytso@....edu>
To:     Jan Kara <jack@...e.cz>
Cc:     linux-ext4@...r.kernel.org
Subject: Re: [PATCH 14/22] jbd2: Drop pointless wakeup from
 jbd2_journal_stop()

On Fri, Oct 04, 2019 at 12:06:00AM +0200, Jan Kara wrote:
> When we drop last handle from a transaction and journal->j_barrier_count
> > 0, jbd2_journal_stop() wakes up journal->j_wait_transaction_locked
> wait queue. This looks pointless - wait for outstanding handles always
> happens on journal->j_wait_updates waitqueue.
> journal->j_wait_transaction_locked is used to wait for transaction state
> changes and by start_this_handle() for waiting until
> journal->j_barrier_count drops to 0. The first case is clearly
> irrelevant here since only jbd2 thread changes transaction state. The
> second case looks related but jbd2_journal_unlock_updates() is
> responsible for the wakeup in this case. So just drop the wakeup.
> 
> Signed-off-by: Jan Kara <jack@...e.cz>

Looks good; feel free to add:

Reviewed-by: Theodore Ts'o <tytso@....edu>