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

Nikolay Borisov
2020-02-03T16:02:59Z

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,
>