Re: [PATCH -v10 0/4] Lock-less list

[Peter Zijlstra <peterz@infradead.org>]

On Wed, 2011-01-19 at 16:52 -0800, Andrew Morton wrote:
> On Thu, 20 Jan 2011 08:45:58 +0800
> Huang Ying <ying.huang@intel.com> wrote:
> 
> > On Thu, 2011-01-20 at 05:55 +0800, Andrew Morton wrote:
> > > I'm trying to remember why we're talking about this.
> > > 
> > > You had an ACPI-based "hardware error reporting" thing.  And that
> > > required an nmi-context memory allocator.  And that required a
> > > "lockless" list implementation.
> > > 
> > > Yes?
> > 
> > Yes.  But the "lockless" list implementation is general, it can be used
> > by other part of kernel too,  such as irq_work and xlist in
> > net/rds/xlist.h in the patchset.
> 
> Well.  Lots of things are general but that doesn't mean we toss them
> into the kernel when we already have plenty of infrastructure to handle
> that sort of thing.
> 
> otoh, hoisting xlist.h out of net/rds and making it generally available
> is a good thing.
> 
> otooh, net/rds/ probably didn't need xlist at all and could have used
> existing general code.
> 
> So...  I'd say that unless and until the NMI-context allocator is
> merged, the case for merging the lockless list code is a bit marginal? 
> Or have you identified other code sites which could use llist and which
> would gain some benefit from migrating?

In fact, I have a patch ready and waiting to revert the whole irq_work
stuff, that too seems to be a superfluous generalization.