Queue upcall locking (was: [dm-devel] [RFC][PATCH] fix dm_any_congested() to properly sync up with suspend code path)

[Mikulas Patocka]

On Mon, 10 Nov 2008, Peter Zijlstra wrote:

> > If you have a physical disk that has many LVM volumes on it, you end up in 
> > a situation when disk congestion state change is reported to all the 
> > volumes. So it will create O(n) problem at the other side.
> 
> *sigh* I can almost understand why people want to use lvm to combine
> multiple disks, but why make the partition thing even worse...

To protect the services from each other --- so that mail storm won't blow 
user's directories, users blowing their space can't corrupt the system 
updates, logs are kept safely even if other partition overflows etc.

I just know some admins who prefer to have separate filesystems instead of 
quotas for this purpose.

Mikulas