Re: [PATCH] patch-slab-split-03-tail

[Manfred Spraul <manfred@colorfullife.com>]

Randy.Dunlap wrote:
> 
> Did you look at http://www.usenix.org/events/usenix01/bonwick.html
> for it?
> 
Thanks for the link - that describes the newer, per-cpu extensions to 
slab. Quite similar to the Linux implementation.

The text also contains a link to the original paper:

http://www.usenix.org/publications/library/proceedings/bos94/bonwick.html

Bonwick used one partially sorted list [as linux in 2.2, and 2.4.<10], 
instead of seperate lists - move tail was not an option.

The new paper contains one interesting comment:
<<<<<<<
An object cache's CPU layer contains per-CPU state that must be 
protected either by per-CPU locking or by disabling interrupts. We 
selected per-CPU locking for several reasons:
[...]
  x    Performance. On most modern processors, grabbing an uncontended 
lock is cheaper than modifying the processor interrupt level.
<<<<<<<<

Which cpus have slow local_irq_disable() implementations? At least for 
my Duron, this doesn't seem to be the case [~ 4 cpu cycles for cli]


--
	Manfred