Re: [PATCH -next RFC 2/6] block: refactor to split bio thoroughly

[Jens Axboe]

On 3/29/22 8:40 AM, Christoph Hellwig wrote:
> On Tue, Mar 29, 2022 at 08:35:29AM -0600, Jens Axboe wrote:
>>> But more importantly why does your use case even have splits that get
>>> submitted together?  Is this a case of Linus' stupidly low default
>>> max_sectors when the hardware supports more, or is the hardware limited
>>> to a low number of sectors per request?  Or do we hit another reason
>>> for the split?
>>
>> See the posted use case, it's running 512kb ios on a 128kb device.
> 
> That is an awfully low limit these days.  I'm really not sure we should
> optimize the block layer for that.

That's exactly what my replies have been saying. I don't think this is
a relevant thing to optimize for.

Fixing fairness for wakeups seems useful, however.

-- 
Jens Axboe