Re: [PATCHSET v2 0/2] io_uring: handle short reads internally

Stefan Metzmacher
2020-08-17T09:26:22Z

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Hi Jens,

> Since we've had a few cases of applications not dealing with this
> appopriately, I believe the safest course of action is to ensure that
> we don't return short reads when we really don't have to.
>
> The first patch is just a prep patch that retains iov_iter state over
> retries, while the second one actually enables just doing retries if
> we get a short read back.
>
> This passes all my testing, both liburing regression tests but also
> tests that explicitly trigger internal short reads and hence retry
> based on current state. No short reads are passed back to the
> application.

Thanks! I was going to ask about exactly that :-)

It wasn't clear why returning short reads were justified by resulting
in better performance... As it means the application needs to do
a lot more work and syscalls.

Will this be backported?

metze

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