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Re: [Qemu-block] [Qemu-devel] [PATCH for-2.3 v2] raw-posix: Deprecate ai
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-block] [Qemu-devel] [PATCH for-2.3 v2] raw-posix: Deprecate aio=threads fallback without O_DIRECT |
Date: |
Thu, 19 Mar 2015 12:14:25 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) |
Kevin Wolf <address@hidden> writes:
> Currently, if the user requests aio=native, but forgets to choose a
> cache mode that sets O_DIRECT, that request is silently ignored and raw
> falls back to aio=threads.
>
> Deprecate that behaviour so we can make it an error in future qemu
> versions.
>
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
> v2:
> - Use error_printf() instead of fprintf(stderr, ...) so that the warning will
> appear on the HMP monitor instead of stderr for drive_add.
>
> Markus suggested error_report(), which would have the advantage of
> displaying
> the option string and position in the config file. However, the result was a
> line that was so full that it wasn't very prominent as a warning any more.
> Making the warning very visible was the reason for using fprintf in v1.
>
> After thinking more about it, I came to the conclusion that for a
> deprecation
> warning like this, being visible is more important than finding the bad
> option quickly. The hope is anyway that nobody runs a setup like this, and
> even then the warning will last only for one release before we'll get a real
> error.
Judgement call, obviously yours to make.
Reviewed-by: Markus Armbruster <address@hidden>