Re: [PATCH] SLUB: revert direct page allocator pass through

["Zhang, Yanmin" <yanmin_zhang@linux.intel.com>]

On Sat, 2009-01-24 at 02:37 +1100, Nick Piggin wrote:
> On Saturday 24 January 2009 02:27:29 Christoph Lameter wrote:
> > On Sat, 24 Jan 2009, Nick Piggin wrote:
> > > > I thought higher order allocations were not supposed to be used in
> > > > performance critical paths?
> > >
> > > ? You use them all the time in SLUB alone.
> >
> > But SLUB compensates for the slow higher order allocs by using them as
> > buffers for smaller objects.. The higher order allocs are in the slow
> > paths.
> 
> I don't quite know what you're asking of me. If you see higher order
> allocations in performance critical code, then you answer your own
> question?
> 
> However, I don't know if netperf udp 4K over loopback is totally
> realistic. Maybe real network drivers have different allocation patterns.
Client/server model and distributed systems are popular. To be flexible,
these applications mostly can be configured in one machine, or in a group of
machines. If in one machine, they are used to communicate with network loopback.
I once touched a big distributed telecom application which use UDP to communicate
between front-end and back-end. If they merge front-end and back-end to one machine
based on some customers' requirements to reduce cost, that will be an example.

> If I were you I wouldn't be too hasty to make big changes based on that
> alone, if it could introduce regression in somewhere more important.