Re: [PATCH 2/5] btrfs: allow block group background reclaim for !zoned fs'es

[Johannes Thumshirn <Johannes.Thumshirn@wdc.com>]

On 22/03/2022 18:38, Josef Bacik wrote:
>> +static inline bool should_reclaim_block_group(struct btrfs_block_group *block_group,
>> +					      u64 bytes_freed)
>> +{
>> +	const struct btrfs_space_info *space_info = block_group->space_info;
>> +	const int reclaim_thresh = READ_ONCE(space_info->bg_reclaim_threshold);
>> +	const u64 new_val = block_group->used;
>> +	const u64 old_val = new_val + bytes_freed;
>> +	u64 thresh;
>> +
> 
> Actually do we want to do a
> 
> if (btrfs_zoned())
> 	return false;
> 
> here and leave the auto reclaim zoned behavior the way it is?  Or do you want to
> delete your stuff and rely on this as the way that we setup zoned block groups
> for relocation?  If we use this then you could make the
> fs_info->bg_reclaim_threshold also apply here.  Thanks,
> 
>

I actually like the per-space info knob for the individual block groups and then
the global one to kick in reclaim.