Re: vioif vs if_vio

2016-09-24 Thread Paul Goyette 

On Sat, 24 Sep 2016, Thor Lancelot Simon wrote:


On Sat, Sep 24, 2016 at 02:02:16PM +0800, Paul Goyette wrote:

Shouldn't the vioif(4) device be more properly named if_vio(4), to be
consistent with other network interfaces?


I think the code was imported with the same filenames as its original
source, to ease merging of updates.


With its current name, it could never successfully exist as an auto-loaded
kernel module, since the auto-load code assumes the if_ prefix!


Sounds like a bug in the auto-load code.


More like a design feature!  Referencing the "tun" in ifconfig will 
auto-load the if_tun module, for example.


In any case, it appears that while the autoconfig name for the virtual 
I/O device's network interface is vioif, the actual interface name is 
if_vio which means it will "just work" when it gets modularized.  This 
is consistent after all, and to assert otherwise was an error on my 
part.



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Re: Plan: journalling fixes for WAPBL

2016-09-24 Thread Warner Losh 
On Sat, Sep 24, 2016 at 2:01 AM, David Holland  wrote:
> On Fri, Sep 23, 2016 at 07:51:32PM +0200, Manuel Bouyer wrote:
>  > > > *if you have the write cache disabled*
>  > >
>  > > *Running with the write cache enabled is a bad idea*
>  >
>  > On ATA devices, you can't permanently disable the write cache. You have
>  > to do it on every power cycles.
>
> There are also drives that ignore attempts to turn off write caching.

These drives lie to the host and say that caching is off, when it
really is still on, right?

Warner

Re: vioif vs if_vio

2016-09-24 Thread Thor Lancelot Simon 
On Sat, Sep 24, 2016 at 02:02:16PM +0800, Paul Goyette wrote:
> Shouldn't the vioif(4) device be more properly named if_vio(4), to be
> consistent with other network interfaces?

I think the code was imported with the same filenames as its original
source, to ease merging of updates.

> With its current name, it could never successfully exist as an auto-loaded
> kernel module, since the auto-load code assumes the if_ prefix!

Sounds like a bug in the auto-load code.

Thor

Re: FUA and TCQ (was: Plan: journalling fixes for WAPBL)

2016-09-24 Thread Thor Lancelot Simon 
On Fri, Sep 23, 2016 at 01:02:26PM +, paul.kon...@dell.com wrote:
> 
> > On Sep 23, 2016, at 5:49 AM, Edgar Fu??  wrote:
> > 
> >> The whole point of tagged queueing is to let you *not* set [the write 
> >> cache] bit in the mode pages and still get good performance.
> > I don't get that. My understanding was that TCQ allowed the drive to 
> > re-order 
> > commands within the bounds described by the tags. With the write cache 
> > disabled, all write commands must hit stable storage before being reported 
> > completed. So what's the point of tagging with cacheing disabled?
> 
> I'm not sure.  But I have the impression that in the real world tagging is 
> rarely, if ever, used.

I'm not sure what you mean.  Do you mean that tagging is rarely, if ever,
used _to establish write barriers_, or do you mean that tagging is rarely,
if ever used, period?

If the latter, you're way, way wrong.

Thor

Re: Plan: journalling fixes for WAPBL

2016-09-24 Thread David Holland 
On Fri, Sep 23, 2016 at 07:51:32PM +0200, Manuel Bouyer wrote:
 > > > *if you have the write cache disabled*
 > > 
 > > *Running with the write cache enabled is a bad idea*
 > 
 > On ATA devices, you can't permanently disable the write cache. You have
 > to do it on every power cycles.

There are also drives that ignore attempts to turn off write caching.

-- 
David A. Holland
dholl...@netbsd.org

vioif vs if_vio

2016-09-24 Thread Paul Goyette 
Shouldn't the vioif(4) device be more properly named if_vio(4), to be 
consistent with other network interfaces?


With its current name, it could never successfully exist as an 
auto-loaded kernel module, since the auto-load code assumes the if_ 
prefix!



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| Paul Goyette | PGP Key fingerprint: | E-mail addresses:  |
| (Retired)| FA29 0E3B 35AF E8AE 6651 | paul at whooppee.com   |
| Kernel Developer | 0786 F758 55DE 53BA 7731 | pgoyette at netbsd.org |
+--+--++