Re: [PATCH V2 1/1] pmem: set QUEUE_FLAG_NOWAIT

[Chaitanya Kulkarni <chaitanyak@nvidia.com>]

On 8/2/23 08:27, Jeff Moyer wrote:
> Christoph Hellwig <hch@lst.de> writes:
>
>> Given that pmem simply loops over an arbitrarily large bio I think
>> we also need a threshold for which to allow nowait I/O.  While it
>> won't block for giant I/Os, doing all of them in the submitter
>> context isn't exactly the idea behind the nowait I/O.
>>
>> I'm not really sure what a good theshold would be, though.
> There's no mention of the latency of the submission side in the
> documentation for RWF_NOWAIT.  The man page says "Do not wait for data
> which is not immediately available."  Data in pmem *is* immediately
> available.  If we wanted to enforce a latency threshold for submission,
> it would have to be configurable and, ideally, a part of the API.  I
> don't think it's something we should even try to guarantee, though,
> unless application writers are asking for it.

I need to see the usecase from application writter who cannot come
with a solution so kernel have to provide this interface, I'll be happy
to do that ..

> So, I think with the change to return -EAGAIN for writes to poisoned
> memory, this patch is probably ok.

I believe you mean the same one I've  provided earlier incremental ..

> Chaitanya, could you send a v2?

sure ...

-ck