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jbd2: Use atomic variables to avoid taking t_handle_lock in jbd2_journal_stop

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By using an atomic_t for t_updates and t_outstanding credits, this
should allow us to not need to take transaction t_handle_lock in
jbd2_journal_stop().

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o
2010-08-02 08:43:25 -04:00
parent 8b67f04ab9
commit a51dca9cd3
4 changed files with 51 additions and 41 deletions
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13
fs/jbd2/commit.c
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@@ -417,12 +417,12 @@ void jbd2_journal_commit_transaction(journal_t *journal)
stats.run.rs_locked);
spin_lock(&commit_transaction->t_handle_lock);
while (commit_transaction->t_updates) {
while (atomic_read(&commit_transaction->t_updates)) {
DEFINE_WAIT(wait);
prepare_to_wait(&journal->j_wait_updates, &wait,
TASK_UNINTERRUPTIBLE);
if (commit_transaction->t_updates) {
if (atomic_read(&commit_transaction->t_updates)) {
spin_unlock(&commit_transaction->t_handle_lock);
spin_unlock(&journal->j_state_lock);
schedule();
@@ -433,7 +433,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
}
spin_unlock(&commit_transaction->t_handle_lock);
J_ASSERT (commit_transaction->t_outstanding_credits <=
J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
journal->j_max_transaction_buffers);
/*
@@ -527,11 +527,12 @@ void jbd2_journal_commit_transaction(journal_t *journal)
stats.run.rs_logging = jiffies;
stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
stats.run.rs_logging);
stats.run.rs_blocks = commit_transaction->t_outstanding_credits;
stats.run.rs_blocks =
atomic_read(&commit_transaction->t_outstanding_credits);
stats.run.rs_blocks_logged = 0;
J_ASSERT(commit_transaction->t_nr_buffers <=
commit_transaction->t_outstanding_credits);
atomic_read(&commit_transaction->t_outstanding_credits));
err = 0;
descriptor = NULL;
@@ -616,7 +617,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
* the free space in the log, but this counter is changed
* by jbd2_journal_next_log_block() also.
*/
commit_transaction->t_outstanding_credits--;
atomic_dec(&commit_transaction->t_outstanding_credits);
/* Bump b_count to prevent truncate from stumbling over
the shadowed buffer! @@@ This can go if we ever get