From: Andi Kleen <redacted>
Date: Thu, 28 Aug 2008 00:57:25 +0200

David Miller [off-list ref] writes:

quoted

From: Andi Kleen <redacted>
Date: Thu, 28 Aug 2008 00:34:10 +0200

quoted

It fixes an old performance problem at least. I'm not aware 
of any new ones in this area because the code in this 
function hasn't changed since I last looked.

That's exactly what this thread is about, things got slower for
some reason even though nothing specifically changed in this area.

I reread the original bug and it says nothing about a regression
(unless I'm blind). I think the reporter just ran into the slowness that
was pretty much always there[1] (and which my patch improves)

It's a regression compared to older kernels.  It got slower by a
factor of 5 or something like that.