Re: [PATCH 06/26] block: Introduce zone write plugging

Damien Le Moal
2024-02-05T23:48:20Z

On 2/6/24 02:48, Bart Van Assche wrote:
> On 2/1/24 23:30, Damien Le Moal wrote:
>> The next plugged BIO is unplugged and issued once the write request completes.
>
> So this patch series is orthogonal to my patch series that implements zoned
> write pipelining?

I don't know.

>> simultaneously without lock contention.
>
> This is not correct. Device usage is not maximized since zone write bios
> are serialized. Pipelining zoned writes results in higher device
> utilization.

I meant to say that the locking scheme does not get in the way of maximizing
device utilization/parallelism. If you are only writing to a single zone, then
sure, it does not matter since the drive will be used at qd=1 for that case.

>> +#define blk_zone_wplug_lock(zwplug, flags) \
>> + spin_lock_irqsave(&zwplug->lock, flags)
>> +
>> +#define blk_zone_wplug_unlock(zwplug, flags) \
>> + spin_unlock_irqrestore(&zwplug->lock, flags)
>
> Hmm ... these macros may make code harder to read rather than improve
> readability of the code.

I do not see how they make the code less readable. The macro names are not clear
enough ?

--
Damien Le Moal
Western Digital Research