From df3c1e9a05ff25aca9f54a6c08b77003e2e32bf1 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sat, 8 Mar 2014 18:13:52 -0500 Subject: jbd2: don't unplug after writing revoke records During commit process, keep the block device plugged after we are done writing the revoke records, until we are finished writing the rest of the commit records in the journal. This will allow most of the journal blocks to be written in a single I/O operation, instead of separating the the revoke blocks from the rest of the journal blocks. Signed-off-by: "Theodore Ts'o" --- fs/jbd2/commit.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'fs/jbd2/commit.c') diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index cf2fc059406..765b31da402 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -555,7 +555,6 @@ void jbd2_journal_commit_transaction(journal_t *journal) blk_start_plug(&plug); jbd2_journal_write_revoke_records(journal, commit_transaction, &log_bufs, WRITE_SYNC); - blk_finish_plug(&plug); jbd_debug(3, "JBD2: commit phase 2b\n"); @@ -582,7 +581,6 @@ void jbd2_journal_commit_transaction(journal_t *journal) err = 0; bufs = 0; descriptor = NULL; - blk_start_plug(&plug); while (commit_transaction->t_buffers) { /* Find the next buffer to be journaled... */ -- cgit v1.2.3-70-g09d2 From 42cf3452d5f5b0817d27c93e4e7d7eab6e89077d Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sat, 8 Mar 2014 19:51:16 -0500 Subject: jbd2: calculate statistics without holding j_state_lock and j_list_lock The two hottest locks, and thus the biggest scalability bottlenecks, in the jbd2 layer, are the j_list_lock and j_state_lock. This has inspired some people to do some truly unnatural things[1]. [1] https://www.usenix.org/system/files/conference/fast14/fast14-paper_kang.pdf We don't need to be holding both j_state_lock and j_list_lock while calculating the journal statistics, so move those calculations to the very end of jbd2_journal_commit_transaction. Signed-off-by: "Theodore Ts'o" --- fs/jbd2/commit.c | 36 ++++++++++++++++++------------------ 1 file changed, 18 insertions(+), 18 deletions(-) (limited to 'fs/jbd2/commit.c') diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index 765b31da402..af36252b5b2 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -1083,24 +1083,7 @@ restart_loop: atomic_read(&commit_transaction->t_handle_count); trace_jbd2_run_stats(journal->j_fs_dev->bd_dev, commit_transaction->t_tid, &stats.run); - - /* - * Calculate overall stats - */ - spin_lock(&journal->j_history_lock); - journal->j_stats.ts_tid++; - if (commit_transaction->t_requested) - journal->j_stats.ts_requested++; - journal->j_stats.run.rs_wait += stats.run.rs_wait; - journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay; - journal->j_stats.run.rs_running += stats.run.rs_running; - journal->j_stats.run.rs_locked += stats.run.rs_locked; - journal->j_stats.run.rs_flushing += stats.run.rs_flushing; - journal->j_stats.run.rs_logging += stats.run.rs_logging; - journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count; - journal->j_stats.run.rs_blocks += stats.run.rs_blocks; - journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged; - spin_unlock(&journal->j_history_lock); + stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0; commit_transaction->t_state = T_COMMIT_CALLBACK; J_ASSERT(commit_transaction == journal->j_committing_transaction); @@ -1157,4 +1140,21 @@ restart_loop: spin_unlock(&journal->j_list_lock); write_unlock(&journal->j_state_lock); wake_up(&journal->j_wait_done_commit); + + /* + * Calculate overall stats + */ + spin_lock(&journal->j_history_lock); + journal->j_stats.ts_tid++; + journal->j_stats.ts_requested += stats.ts_requested; + journal->j_stats.run.rs_wait += stats.run.rs_wait; + journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay; + journal->j_stats.run.rs_running += stats.run.rs_running; + journal->j_stats.run.rs_locked += stats.run.rs_locked; + journal->j_stats.run.rs_flushing += stats.run.rs_flushing; + journal->j_stats.run.rs_logging += stats.run.rs_logging; + journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count; + journal->j_stats.run.rs_blocks += stats.run.rs_blocks; + journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged; + spin_unlock(&journal->j_history_lock); } -- cgit v1.2.3-70-g09d2 From d4e839d4a9dc31d0c229e616146b01e1ace56604 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sat, 8 Mar 2014 22:34:10 -0500 Subject: jbd2: add transaction to checkpoint list earlier We don't otherwise need j_list_lock during the rest of commit phase #7, so add the transaction to the checkpoint list at the very end of commit phase #6. This allows us to drop j_list_lock earlier, which is a good thing since it is a super hot lock. Signed-off-by: "Theodore Ts'o" --- fs/jbd2/commit.c | 39 ++++++++++++++++++++------------------- 1 file changed, 20 insertions(+), 19 deletions(-) (limited to 'fs/jbd2/commit.c') diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index af36252b5b2..5f26139a165 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -1065,6 +1065,25 @@ restart_loop: goto restart_loop; } + /* Add the transaction to the checkpoint list + * __journal_remove_checkpoint() can not destroy transaction + * under us because it is not marked as T_FINISHED yet */ + if (journal->j_checkpoint_transactions == NULL) { + journal->j_checkpoint_transactions = commit_transaction; + commit_transaction->t_cpnext = commit_transaction; + commit_transaction->t_cpprev = commit_transaction; + } else { + commit_transaction->t_cpnext = + journal->j_checkpoint_transactions; + commit_transaction->t_cpprev = + commit_transaction->t_cpnext->t_cpprev; + commit_transaction->t_cpnext->t_cpprev = + commit_transaction; + commit_transaction->t_cpprev->t_cpnext = + commit_transaction; + } + spin_unlock(&journal->j_list_lock); + /* Done with this transaction! */ jbd_debug(3, "JBD2: commit phase 7\n"); @@ -1103,24 +1122,6 @@ restart_loop: write_unlock(&journal->j_state_lock); - if (journal->j_checkpoint_transactions == NULL) { - journal->j_checkpoint_transactions = commit_transaction; - commit_transaction->t_cpnext = commit_transaction; - commit_transaction->t_cpprev = commit_transaction; - } else { - commit_transaction->t_cpnext = - journal->j_checkpoint_transactions; - commit_transaction->t_cpprev = - commit_transaction->t_cpnext->t_cpprev; - commit_transaction->t_cpnext->t_cpprev = - commit_transaction; - commit_transaction->t_cpprev->t_cpnext = - commit_transaction; - } - spin_unlock(&journal->j_list_lock); - /* Drop all spin_locks because commit_callback may be block. - * __journal_remove_checkpoint() can not destroy transaction - * under us because it is not marked as T_FINISHED yet */ if (journal->j_commit_callback) journal->j_commit_callback(journal, commit_transaction); @@ -1131,7 +1132,7 @@ restart_loop: write_lock(&journal->j_state_lock); spin_lock(&journal->j_list_lock); commit_transaction->t_state = T_FINISHED; - /* Recheck checkpoint lists after j_list_lock was dropped */ + /* Check if the transaction can be dropped now that we are finished */ if (commit_transaction->t_checkpoint_list == NULL && commit_transaction->t_checkpoint_io_list == NULL) { __jbd2_journal_drop_transaction(journal, commit_transaction); -- cgit v1.2.3-70-g09d2