diff options
| author | Josef Bacik <josef@redhat.com> | 2009-10-08 23:30:04 +0400 |
|---|---|---|
| committer | Chris Mason <chris.mason@oracle.com> | 2009-10-08 23:30:04 +0400 |
| commit | ff782e0a131c7f669445c07fe5c7ba91e043b7ed (patch) | |
| tree | ff7773e6ce60bf977ed29897c13605f257647684 | |
| parent | e3ccfa989752c083ceb23c823a84f7ce3a081e61 (diff) | |
| download | linux-ff782e0a131c7f669445c07fe5c7ba91e043b7ed.tar.xz | |
Btrfs: optimize fsync for the single writer case
This patch optimizes the tree logging stuff so it doesn't always wait 1 jiffie
for new people to join the logging transaction if there is only ever 1 writer.
This helps a little bit with latency where we have something like RPM where it
will fdatasync every file it writes, and so waiting the 1 jiffie for every
fdatasync really starts to add up.
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
| -rw-r--r-- | fs/btrfs/ctree.h | 2 | ||||
| -rw-r--r-- | fs/btrfs/tree-log.c | 12 |
2 files changed, 13 insertions, 1 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index a362dd617e97..16ddb19dda86 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1010,6 +1010,8 @@ struct btrfs_root { atomic_t log_commit[2]; unsigned long log_transid; unsigned long log_batch; + pid_t log_start_pid; + bool log_multiple_pids; u64 objectid; u64 last_trans; diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index 4d7d9abef42f..78f6254ac2d9 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -137,11 +137,20 @@ static int start_log_trans(struct btrfs_trans_handle *trans, mutex_lock(&root->log_mutex); if (root->log_root) { + if (!root->log_start_pid) { + root->log_start_pid = current->pid; + root->log_multiple_pids = false; + } else if (root->log_start_pid != current->pid) { + root->log_multiple_pids = true; + } + root->log_batch++; atomic_inc(&root->log_writers); mutex_unlock(&root->log_mutex); return 0; } + root->log_multiple_pids = false; + root->log_start_pid = current->pid; mutex_lock(&root->fs_info->tree_log_mutex); if (!root->fs_info->log_root_tree) { ret = btrfs_init_log_root_tree(trans, root->fs_info); @@ -1985,7 +1994,7 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, if (atomic_read(&root->log_commit[(index1 + 1) % 2])) wait_log_commit(trans, root, root->log_transid - 1); - while (1) { + while (root->log_multiple_pids) { unsigned long batch = root->log_batch; mutex_unlock(&root->log_mutex); schedule_timeout_uninterruptible(1); @@ -2011,6 +2020,7 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, root->log_batch = 0; root->log_transid++; log->log_transid = root->log_transid; + root->log_start_pid = 0; smp_mb(); /* * log tree has been flushed to disk, new modifications of |