btrfs: process ticket outside global reserve critical section

In steal_from_global_rsv() there's no need to process the ticket inside
the critical section of the global reserve. Move the ticket processing to
happen after the critical section. This helps reduce contention on the
global reserve's spinlock.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index 62e1ba7..957477e 100644 (file)
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -1062,13 +1062,14 @@ static bool steal_from_global_rsv(struct btrfs_space_info *space_info,
                return false;
        }
        global_rsv->reserved -= ticket->bytes;
+       if (global_rsv->reserved < global_rsv->size)
+               global_rsv->full = false;
+       spin_unlock(&global_rsv->lock);
+
        remove_ticket(space_info, ticket);
        ticket->bytes = 0;
        wake_up(&ticket->wait);
        space_info->tickets_id++;
-       if (global_rsv->reserved < global_rsv->size)
-               global_rsv->full = false;
-       spin_unlock(&global_rsv->lock);
 
        return true;
 }