RE: per device queues for cciss 2.6.0

From: Miller, Mike (OS Dev)
Date: Wed Mar 10 2004 - 08:32:16 EST

Yes, the controller has a single command buffer. It can hold 1024 outstanding commands.


-----Original Message-----
From: Jeff Garzik [mailto:jgarzik@xxxxxxxxx]
Sent: Tuesday, March 09, 2004 5:39 PM
To: Miller, Mike (OS Dev)
Cc: axboe@xxxxxxx; akpm@xxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
Subject: Re: per device queues for cciss 2.6.0

Miller, Mike (OS Dev) wrote:
> The command buffer as it is now is per hba. We realize that there may be issues with volumes being starved out but the change was done to make the current driver work with multiple logical volumes. When we move to per logical volume locking scheme we can also implement a per logical volume command structure.

The starvation problem is pretty easy to solve... see attached.

I was mainly asking about the hardware itself... does the _hardware_
have a single command buffer, or a per-device command buffer?


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