Re: [PATCH] block: fix -EAGAIN IOPOLL task/vm accounting

[Jens Axboe <axboe@kernel.dk>]

On 8/31/20 11:42 PM, Christoph Hellwig wrote:
> On Mon, Aug 31, 2020 at 08:18:48AM -0600, Jens Axboe wrote:
>>> We'll still need a flag with the above to skip the submit_bio_noacct
>>> bios.  But I think it is the right way to go.  Eventually we'll also
>>> need to push the accounting down into the individual bio based drivers.
>>
>> For the iocb propagation, we'd really need the caller to mark the iocb
>> as IOCB_ACCOUNTED (or whatever) if BIO_ACCOUNTED is set, since we can't
>> do that further down the stack as we really don't know if we hit -EAGAIN
>> before or after the bio was accounted... Which kind of sucks, as it'll
>> be hard to contain in a generic fashion.
> 
> Well, that's why I think the only proper fix is to only account a bio
> when we know the driver is actually going to submit it.

Yeah I agree, it's a lot less code too. Which is basically back to my
original RFC, I'll see if I can clean it up a bit.

-- 
Jens Axboe