Re: [RFC] ext4: Don't send extra barrier during fsync if there are no dirty pages.

[Jeff Moyer]

"Ted Ts'o" <tytso@xxxxxxx> writes:

> On Thu, Aug 05, 2010 at 05:20:12AM +0300, Avi Kivity wrote:
>> 
>> Why not?  To be clear, I'm talking about an io_submit() with
>> multiple IO_CMD_FSYNC requests, with a kernel implementation that is
>> able to batch these requests.
>
> IO_CMD_FSYNC doesn't exist right now, but sure, it means we don't have

Well, there's IOCB_CMD_FSYNC.  But still, this isn't the same thing as
what's requested.  If I understand correctly, what is requested is a
mechanism to flush out all data for multiple file descriptors and follow
that with a single barrier/flush (and yes, Ted did give a summary of the
commands that would be required to accomplish that).

There still remains the question of why this should be tied to the AIO
submission interface.


Cheers,
Jeff
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