Re: [PATCH v2] fs: Add aio iopriority support for block_dev

[Jens Axboe]

On 5/3/18 2:15 PM, Adam Manzanares wrote:
> 
> 
> On 5/3/18 11:33 AM, Matthew Wilcox wrote:
>> On Thu, May 03, 2018 at 11:21:14AM -0700, adam.manzanares@xxxxxxx wrote:
>>> If we want to avoid bloating struct kiocb, I suggest we turn the private field
>>> into a union of the private and ki_ioprio field. It seems like the users of
>>> the private field all use it at a point where we can yank the priority from
>>> the kiocb before the private field is used. Comments and suggestions welcome.
>>
>> Or we could just make ki_hint a u8 or u16 ... seems unlikely we'll need
>> 32 bits of ki_hint.  (currently defined values are 1-5)
> 
> I like the approach of using a u16 for the ki_hint. I'll update and 
> resubmit.

It's intended to be a mask. If you do shrink it for now, then we need some
guard code to ensure it can always carry what it needs to.

-- 
Jens Axboe