[dm-devel] [PATCH] dm-mpath: requeue I/O during pg_init

Hannes Reinecke hare at suse.de
Tue Nov 5 13:45:34 UTC 2013


On 11/05/2013 02:31 PM, Alasdair G Kergon wrote:
> On Tue, Nov 05, 2013 at 02:10:55PM +0100, Hannes Reinecke wrote:
>> If this is just a left-over from the original port to request-based
>> (for bio-based we _have_ to queue internally as there's no request
>> queue to be had), fine, we should be removing it.
> 
> I think that is the case.
> 
>> But there _might_ be some corner cases which require us to do internal
>> queueing.
>  
> We *only* add I/O to the internal queue in map_io() - which can always
> be replaced with REQUEUE,  As long as we still 'wake up' the queue
> immediately when we are ready to receive the I/O, I can't think of any
> other reason.  And it would let us remove quite a bit of tricky code!
> 
Precisely what I was thinking.

I'll be cobbling together a patch.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare at suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
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