Re: [PATCH RFC 1/2] fs/iomap/direct-io: pass NOWAIT to bio flags

[Konstantin Khlebnikov]

On 04/05/2020 19.00, Christoph Hellwig wrote:
> On Mon, May 04, 2020 at 06:54:53PM +0300, Konstantin Khlebnikov wrote:
> > This is required to avoid waiting in lower layers.
> >
> > Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
>
> This looks sensible.  Did you run this through xfstests?

Nope. It seems xfstests has one trivial test for NOWAIT - generic/471
It tests only write with/without extent, nothing about contention.

I've added nowait into fio and played with it a little.
https://github.com/axboe/fio/pull/972

With these patches I see EAGAINs when queue is flooded.