On Thu, Nov 27, 2008 at 10:39:31AM +0100, Peter Zijlstra wrote:

With it being called from writeback that might not be true for all
workloads. One thing you can do about it is use the regular per-cpu
counter stuff, which allows you to do an approximation of the global
number (it also does all the hotplug stuff for you already).

The way it's used in writeback is utterly stupid and should be fixed :)

But otherwise agreed.