Re: [PATCH] serialize bus scanning

[Christoph Hellwig <hch@lst.de>]

On Thu, Aug 28, 2003 at 06:29:08AM +1000, Anton Blanchard wrote:
> 
> Hi,
> 
> > Synchronize all scanning activity, this fixes long-standing races
> > vs /proc/scsi/scsi and sysfs addition and deletion of devices.
> > 
> > Note that this does not serialize removing, the lists will get
> > their own locking soon.
> 
> Ive started playing with parallel probe in the lab (on some large ppc64
> boxes). I know we have a lot of work to do before this will all work,
> but would it be possible to make this semaphore per host?

you can just add a per-host mutex and lock it in the same places as
indicated by the comment in the patch.  

> Even with a per host semaphore, it annoys me how long it takes to spin
> up 7 disks especially if a few of them are dead. Longer term are we
> planning to overlap spinup of disks on the same host?

I have no plans to do that but if someone comes up with a proper
patch that would be nice.