From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:48842 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726636AbeJPRc2 (ORCPT ); Tue, 16 Oct 2018 13:32:28 -0400 From: Jan Kara To: Ted Tso Cc: , Adrian Hunter , Jan Kara Subject: [PATCH] jbd2: Avoid long hold times of j_state_lock while committing a transaction Date: Tue, 16 Oct 2018 11:42:48 +0200 Message-Id: <20181016094248.21359-1-jack@suse.cz> Sender: linux-ext4-owner@vger.kernel.org List-ID: We can hold j_state_lock for writing at the beginning of jbd2_journal_commit_transaction() for a rather long time (reportedly for 30 ms) due cleaning revoke bits of all revoked buffers under it. The handling of revoke tables as well as cleaning of t_reserved_list, and checkpoint lists does not need j_state_lock for anything. Furthermore the transaction is in T_LOCKED state and we waited for all outstanding handles so nobody is going to be adding anything to the transaction. Just drop the lock for unnecessary operations. Reported-and-tested-by: Adrian Hunter Suggested-by: "Theodore Y. Ts'o" Signed-off-by: Jan Kara --- fs/jbd2/commit.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index 150cc030b4d7..356b75fa3101 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -422,6 +422,7 @@ void jbd2_journal_commit_transaction(journal_t *journal) stats.run.rs_locked); stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start, stats.run.rs_locked); + write_unlock(&journal->j_state_lock); spin_lock(&commit_transaction->t_handle_lock); while (atomic_read(&commit_transaction->t_updates)) { @@ -431,9 +432,7 @@ void jbd2_journal_commit_transaction(journal_t *journal) TASK_UNINTERRUPTIBLE); if (atomic_read(&commit_transaction->t_updates)) { spin_unlock(&commit_transaction->t_handle_lock); - write_unlock(&journal->j_state_lock); schedule(); - write_lock(&journal->j_state_lock); spin_lock(&commit_transaction->t_handle_lock); } finish_wait(&journal->j_wait_updates, &wait); @@ -505,6 +504,7 @@ void jbd2_journal_commit_transaction(journal_t *journal) atomic_sub(atomic_read(&journal->j_reserved_credits), &commit_transaction->t_outstanding_credits); + write_lock(&journal->j_state_lock); trace_jbd2_commit_flushing(journal, commit_transaction); stats.run.rs_flushing = jiffies; stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked, -- 2.16.4