Re: [PATCH 0/2] x86: Speed up ioremap operations

[Andrew Morton]

On Wed, 27 Aug 2014 17:59:27 -0500 Mike Travis <travis@xxxxxxx> wrote:

> 
> We have a large university system in the UK that is experiencing
> very long delays modprobing the driver for a specific I/O device.
> The delay is from 8-10 minutes per device and there are 31 devices
> in the system.  This 4 to 5 hour delay in starting up those I/O
> devices is very much a burden on the customer.

That's nuts.

> There are two causes for requiring a restart/reload of the drivers.
> First is periodic preventive maintenance (PM) and the second is if
> any of the devices experience a fatal error.  Both of these trigger
> this excessively long delay in bringing the system back up to full
> capability.
> 
> The problem was tracked down to a very slow IOREMAP operation and
> the excessively long ioresource lookup to insure that the user is
> not attempting to ioremap RAM.  These patches provide a speed up
> to that function.

With what result?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/