From c35a56a090eacefca07afeb994029b57d8dd8025 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sun, 16 May 2010 05:00:00 -0400 Subject: [PATCH] jbd2: Improve scalability by not taking j_state_lock in jbd2_journal_stop() One of the most contended locks in the jbd2 layer is j_state_lock when running dbench. This is especially true if using the real-time kernel with its "sleeping spinlocks" patch that replaces spinlocks with priority inheriting mutexes --- but it also shows up on large SMP benchmarks. Thanks to John Stultz for pointing this out. Reviewed by Mingming Cao and Jan Kara. Signed-off-by: "Theodore Ts'o" --- fs/jbd2/transaction.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index bfc70f57900f..e214d68620ac 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -1311,7 +1311,6 @@ int jbd2_journal_stop(handle_t *handle) if (handle->h_sync) transaction->t_synchronous_commit = 1; current->journal_info = NULL; - spin_lock(&journal->j_state_lock); spin_lock(&transaction->t_handle_lock); transaction->t_outstanding_credits -= handle->h_buffer_credits; transaction->t_updates--; @@ -1340,8 +1339,7 @@ int jbd2_journal_stop(handle_t *handle) jbd_debug(2, "transaction too old, requesting commit for " "handle %p\n", handle); /* This is non-blocking */ - __jbd2_log_start_commit(journal, transaction->t_tid); - spin_unlock(&journal->j_state_lock); + jbd2_log_start_commit(journal, transaction->t_tid); /* * Special case: JBD2_SYNC synchronous updates require us @@ -1351,7 +1349,6 @@ int jbd2_journal_stop(handle_t *handle) err = jbd2_log_wait_commit(journal, tid); } else { spin_unlock(&transaction->t_handle_lock); - spin_unlock(&journal->j_state_lock); } lock_map_release(&handle->h_lockdep_map);