diff options
| author | Zhang Yi <yi.zhang@huawei.com> | 2024-05-20 21:18:31 +0800 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2024-07-05 12:45:36 -0400 |
| commit | 7c73ddb7589fb8ddb1136b6306dfb72089c81511 (patch) | |
| tree | a04eb046d6c0c9c5015e2d7fc73ffa00156914cb | |
| parent | 8262fe9a902c8a7b68c8521ebe18360a9145bada (diff) | |
jbd2: speed up jbd2_transaction_committed()
jbd2_transaction_committed() is used to check whether a transaction with
the given tid has already committed, it holds j_state_lock in read mode
and check the tid of current running transaction and committing
transaction, but holding the j_state_lock is expensive.
We have already stored the sequence number of the most recently
committed transaction in journal t->j_commit_sequence, we could do this
check by comparing it with the given tid instead. If the given tid isn't
smaller than j_commit_sequence, we can ensure that the given transaction
has been committed. That way we could drop the expensive lock and
achieve about 10% ~ 20% performance gains in concurrent DIOs on may
virtual machine with 100G ramdisk.
fio -filename=/mnt/foo -direct=1 -iodepth=10 -rw=$rw -ioengine=libaio \
-bs=4k -size=10G -numjobs=10 -runtime=60 -overwrite=1 -name=test \
-group_reporting
Before:
overwrite IOPS=88.2k, BW=344MiB/s
read IOPS=95.7k, BW=374MiB/s
rand overwrite IOPS=98.7k, BW=386MiB/s
randread IOPS=102k, BW=397MiB/s
After:
overwrite IOPS=105k, BW=410MiB/s
read IOPS=112k, BW=436MiB/s
rand overwrite IOPS=104k, BW=404MiB/s
randread IOPS=111k, BW=432MiB/s
CC: Dave Chinner <david@fromorbit.com>
Suggested-by: Dave Chinner <david@fromorbit.com>
Link: https://lore.kernel.org/linux-ext4/ZjILCPNZRHeazSqV@dread.disaster.area/
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://patch.msgid.link/20240520131831.2910790-1-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| -rw-r--r-- | fs/jbd2/commit.c | 2 | ||||
| -rw-r--r-- | fs/jbd2/journal.c | 12 |
2 files changed, 2 insertions, 12 deletions
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index 6d3fc992287d..ec5ed7eb1938 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -1107,7 +1107,7 @@ restart_loop: commit_transaction->t_state = T_COMMIT_CALLBACK; J_ASSERT(commit_transaction == journal->j_committing_transaction); - journal->j_commit_sequence = commit_transaction->t_tid; + WRITE_ONCE(journal->j_commit_sequence, commit_transaction->t_tid); journal->j_committing_transaction = NULL; commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time)); diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index 8d782a88aee1..25ef4fc80667 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -775,17 +775,7 @@ EXPORT_SYMBOL(jbd2_fc_end_commit_fallback); /* Return 1 when transaction with given tid has already committed. */ int jbd2_transaction_committed(journal_t *journal, tid_t tid) { - int ret = 1; - - read_lock(&journal->j_state_lock); - if (journal->j_running_transaction && - journal->j_running_transaction->t_tid == tid) - ret = 0; - if (journal->j_committing_transaction && - journal->j_committing_transaction->t_tid == tid) - ret = 0; - read_unlock(&journal->j_state_lock); - return ret; + return tid_geq(READ_ONCE(journal->j_commit_sequence), tid); } EXPORT_SYMBOL(jbd2_transaction_committed); |