On 9.11.18 г. 12:43 ч., fdmanana@xxxxxxxxxx wrote:
> From: Filipe Manana <fdmanana@xxxxxxxx>
>
> We currently are in a loop finding each range (corresponding to a btree
> node/leaf) in a log root's extent io tree and then clean it up. This is a
> waste of time since we are traversing the extent io tree's rb_tree more
> times then needed (one for a range lookup and another for cleaning it up)
> without any good reason.
>
> We free the log trees when we are in the critical section of a transaction
> commit (the transaction state is set to TRANS_STATE_COMMIT_DOING), so it's
> of great convenience to do everything as fast as possible in order to
> reduce the time we block other tasks from starting a new transaction.
>
> So fix this by traversing the extent io tree once and cleaning up all its
> records in one go while traversing it.
>
> Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
Reviewed-by: Nikolay Borisov <nborisov@xxxxxxxx>
> ---
> fs/btrfs/tree-log.c | 16 ++--------------
> 1 file changed, 2 insertions(+), 14 deletions(-)
>
> diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
> index d49edd25f2e5..aac3749f697f 100644
> --- a/fs/btrfs/tree-log.c
> +++ b/fs/btrfs/tree-log.c
> @@ -3204,8 +3204,6 @@ static void free_log_tree(struct btrfs_trans_handle *trans,
> struct btrfs_root *log)
> {
> int ret;
> - u64 start;
> - u64 end;
> struct walk_control wc = {
> .free = 1,
> .process_func = process_one_buffer
> @@ -3216,18 +3214,8 @@ static void free_log_tree(struct btrfs_trans_handle *trans,
> if (ret)
> btrfs_abort_transaction(trans, ret);
>
> - while (1) {
> - ret = find_first_extent_bit(&log->dirty_log_pages,
> - 0, &start, &end,
> - EXTENT_DIRTY | EXTENT_NEW | EXTENT_NEED_WAIT,
> - NULL);
> - if (ret)
> - break;
> -
> - clear_extent_bits(&log->dirty_log_pages, start, end,
> - EXTENT_DIRTY | EXTENT_NEW | EXTENT_NEED_WAIT);
> - }
> -
> + clear_extent_bits(&log->dirty_log_pages, 0, (u64)-1,
> + EXTENT_DIRTY | EXTENT_NEW | EXTENT_NEED_WAIT);
> free_extent_buffer(log->node);
> kfree(log);
> }
>
