Hello,
Sorry for my long silence, getting all situated took longer than I expected. I
just wrote something very quickly to try and make btrfs sleep longer if there
were writers while we were sleeping during an fsync. Running the fs_mark test,
btrfs by itself gets walloped by ext3, so I'm ignoring that for now. With
btrfs+my patch we seem to get about the same performance, except in the -S2 and
-S5 cases, which are
Sync method: SYSTEM SYNC/SINGLE FSYNC: Issue sync() after main write loop and 1
file fsync() per subdirectory
Sync method: POST: Reopen and fsync() each file in order after main write loop
Now I don't think thats good enough so this is going to require more work, but
I'm also kind of new to journalling stuff so I wanted to run this by people to
see if I'm going in the right direction. Might as well get put on the right
track before I go hacking around at things. Thank you,
Josef
diff -r 1765acb6d268 transaction.c
--- a/transaction.c Tue Aug 07 16:35:25 2007 -0400
+++ b/transaction.c Tue Aug 07 17:29:12 2007 -0400
@@ -56,6 +56,7 @@ static int join_transaction(struct btrfs
root->fs_info->generation++;
root->fs_info->running_transaction = cur_trans;
cur_trans->num_writers = 0;
+ cur_trans->writers_while_asleep = 0;
cur_trans->transid = root->fs_info->generation;
init_waitqueue_head(&cur_trans->writer_wait);
init_waitqueue_head(&cur_trans->commit_wait);
@@ -67,6 +68,7 @@ static int join_transaction(struct btrfs
init_bit_radix(&cur_trans->dirty_pages);
}
cur_trans->num_writers++;
+ cur_trans->writers_while_asleep++;
return 0;
}
@@ -454,12 +456,16 @@ int btrfs_commit_transaction(struct btrf
mutex_lock(&root->fs_info->trans_mutex);
}
}
- while (trans->transaction->num_writers > 1) {
+ while (trans->transaction->num_writers > 1 ||
+ trans->transaction->writers_while_asleep > 0) {
+
WARN_ON(cur_trans != trans->transaction);
+
prepare_to_wait(&trans->transaction->writer_wait, &wait,
TASK_UNINTERRUPTIBLE);
if (trans->transaction->num_writers <= 1)
break;
+ trans->transaction->writers_while_asleep = 0;
mutex_unlock(&root->fs_info->fs_mutex);
mutex_unlock(&root->fs_info->trans_mutex);
schedule();
diff -r 1765acb6d268 transaction.h
--- a/transaction.h Tue Aug 07 16:35:25 2007 -0400
+++ b/transaction.h Tue Aug 07 17:23:30 2007 -0400
@@ -26,6 +26,7 @@ struct btrfs_transaction {
int in_commit;
int use_count;
int commit_done;
+ unsigned long writers_while_asleep;
struct list_head list;
struct radix_tree_root dirty_pages;
unsigned long start_time;
_______________________________________________
Btrfs-devel mailing list
[email protected]
http://oss.oracle.com/mailman/listinfo/btrfs-devel
