[dm-devel] [PATCH 1/3] Send KOBJ_ADD event after dm resume ioctl.

[David Zeuthen]

On Fri, Mar 19, 2010 at 11:55 AM, Mike Snitzer <snitzer at redhat.com> wrote:

> Thing is, this isn't scalable at all.  Having all these arbitrary rules
> issuing IOs to devices that aren't usable is a complete waste of time.
> On enterprise systems that have 100s (*shudder* 1000s) of LUNs, this
> udev rules' freedom to access such unusable devices is really working
> against us (if the goal is to activate devices as quickly and reliably
> as possible).
>

Please, Mike, whether to probe devices or not is a separate discussion
and it's not really helpful to reiterate that discussion.

(Please do see various mailing lists archives for that particular
discussion;
FWIW, you will notice that what udev is doing is actually desirable. If you
examine the kernel sources, you will find that the kernel itself submits
IO to the block devices - partition table probing for starters. If you
search
harder you will find *raw numbers* (instead of speculation like "100s
(*shudder* 1000s)" showing what udev is doing is not a problem...)

    David
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