svn commit: r326731 - head/sys/ufs/ffs

[Poul-Henning Kamp]

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In message <CANCZdfrQPSey1h+X_09GNJaeZqsZh6FmDXe6avO66qKEfAL=Pg at mail.gmail.com>, Warner Losh writes:

>That would be strange given that BIO_ORDERED is @gibbs baby ?
>
>Nah... I wrote the iosched code... and I find the concept somewhat flawed
>since it is at the disk level, not the partition level, so it winds up
>interfering with mixed traffic. And it really only makes sense for writes,
>but it affects reads. And it is a poor fit to Ata semantics, and not a lot
>better for scsi. And for nvme it creates a bottleneck in hardware carefully
>designed to be free of bottlenecks...

Don't take my comment as an endorsement of BIO_ORDERED...

I think ordering is strictly a consumer responsibility for exactly
(and then some) of the reasons you mention.

"End to end principle in systems design" and all that...

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.