Re: [PATCH 18/23] btrfs: drop the commit_cycles stuff for data reservations

[Nikolay Borisov <nborisov@suse.com>]

On 1.02.20 г. 0:36 ч., Josef Bacik wrote:
> This was an old wart left over from how we previously did data
> reservations.  Before we could have people race in and take a
> reservation while we were flushing space, so we needed to make sure we
> looped a few times before giving up.  Now that we're using the ticketing
> infrastructure we don't have to worry about this and can drop the logic
> altogether.
> 
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>

Reviewed-by: Nikolay Borisov <nborisov@suse.com>

> ---
>  fs/btrfs/space-info.c | 22 ++--------------------
>  1 file changed, 2 insertions(+), 20 deletions(-)
> 
> diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
> index 13a3692a0122..3060754a3341 100644
> --- a/fs/btrfs/space-info.c
> +++ b/fs/btrfs/space-info.c
> @@ -858,7 +858,6 @@ static void priority_reclaim_data_space(struct btrfs_fs_info *fs_info,
>  					int states_nr)
>  {
>  	int flush_state = 0;
> -	int commit_cycles = 2;
>  
>  	while (!space_info->full) {
>  		flush_space(fs_info, space_info, U64_MAX, ALLOC_CHUNK_FORCE);
> @@ -869,21 +868,9 @@ static void priority_reclaim_data_space(struct btrfs_fs_info *fs_info,
>  		}
>  		spin_unlock(&space_info->lock);
>  	}
> -again:
> -	while (flush_state < states_nr) {
> -		u64 flush_bytes = U64_MAX;
> -
> -		if (!commit_cycles) {
> -			if (states[flush_state] == FLUSH_DELALLOC_WAIT) {
> -				flush_state++;
> -				continue;
> -			}
> -			if (states[flush_state] == COMMIT_TRANS)
> -				flush_bytes = ticket->bytes;
> -		}
>  
> -		flush_space(fs_info, space_info, flush_bytes,
> -			    states[flush_state]);
> +	while (flush_state < states_nr) {
> +		flush_space(fs_info, space_info, U64_MAX, states[flush_state]);

nit: Wouldn't make much of a difference but I wonder if the semantic
here is closer to a for loop rather than a while.

>  		spin_lock(&space_info->lock);
>  		if (ticket->bytes == 0) {
>  			spin_unlock(&space_info->lock);
> @@ -892,11 +879,6 @@ static void priority_reclaim_data_space(struct btrfs_fs_info *fs_info,
>  		spin_unlock(&space_info->lock);
>  		flush_state++;
>  	}
> -	if (commit_cycles) {
> -		commit_cycles--;
> -		flush_state = 0;
> -		goto again;
> -	}
>  }
>  
>  static void wait_reserve_ticket(struct btrfs_fs_info *fs_info,
>