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authorTheodore Ts'o <tytso@mit.edu>2010-05-16 05:00:00 -0400
committerTheodore Ts'o <tytso@mit.edu>2010-05-16 05:00:00 -0400
commitc35a56a090eacefca07afeb994029b57d8dd8025 (patch)
tree2a42c07c270b07725d9798bc89bc9aa0aaf2c184
parentc445e3e0a5c2804524dec6e55f66d63f6bc5bc3e (diff)
downloadop-kernel-dev-c35a56a090eacefca07afeb994029b57d8dd8025.zip
op-kernel-dev-c35a56a090eacefca07afeb994029b57d8dd8025.tar.gz
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" <tytso@mit.edu>
-rw-r--r--fs/jbd2/transaction.c5
1 files changed, 1 insertions, 4 deletions
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index bfc70f5..e214d68 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);
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