Re: [LSF/MM/BPF TOPIC] Improving Zoned Storage Support

[Bart Van Assche <bvanassche@acm.org>]

On 1/16/24 15:34, Damien Le Moal wrote:
> FYI, I am about to post 20-something patches that completely remove zone write
> locking and replace it with "zone write plugging". That is done above the IO
> scheduler and also provides zone append emulation for drives that ask for it.
> 
> With this change:
>   - Zone append emulation is moved to the block layer, as a generic
> implementation. sd and dm zone append emulation code is removed.
>   - Any scheduler can be used, including "none". mq-deadline zone block device
> special support is removed.
>   - Overall, a lot less code (the series removes more code than it adds).
>   - Reordering problems such as due to IO priority is resolved as well.
> 
> This will need a lot of testing, which we are working on. But your help with
> testing on UFS devices will be appreciated as well.

When posting this patch series, please include performance results
(IOPS) for a zoned null_blk device instance. mq-deadline doesn't support
more than 200 K IOPS, which is less than what UFS devices support. I
hope that this performance bottleneck will be solved with the new
approach.

Thank you,

Bart.