Re: [PATCH RT 00/02] SLOB optimizations

[Steven Rostedt <rostedt@goodmis.org>]

On Wed, 21 Dec 2005, Ingo Molnar wrote:

>
> * Steven Rostedt <rostedt@goodmis.org> wrote:
>
> > > > http://marc.theaimsgroup.com/?l=linux-kernel&m=113510997009883&w=2
> > >
> > > Quite a long list of unsupported features. These academic papers
> > > usually only focus on one thing. The SLAB allocator has to work
> > > for a variety of situations though.
> > >
> > > It would help to explain what ultimately will be better in the new slab
> > > allocator. The complexity could be taken care of by reorganizing the code.
> >
> > Honestly, what I would like is a simpler solution, whether we go with
> > a new approach or reorganize the current slab.  I need to get -rt
> > working, and the code in slab is pulling my resources more than they
> > can extend. I'm capable to convert slab today as it is for RT but it
> > will probably take longer than I can afford.
>
> please, lets let the -rt tree out of the equation. The SLAB code is fine
> on upstream, and it was a pure practical maintainance decision to go for
> SLOB in the -rt tree. Yes, the SLAB code is complex, but i could hardly
> list any complexity in it tht isnt justified with a performance
> argument. _Maybe_ the SLAB code could be further cleaned up, maybe it
> could even be replaced, but we'd have to see the patches first. In any
> case, the -rt tree is not an argument that matters.

You're right about the -rt tree not being an argument for upstream.  I
used it as an example of the complexities.  This is not limited to -rt,
but for any other changes as well.  Years ago I tried changing the slab to
run on a small embedded device with very little memory, and I was pretty
much overwhelmed.

Now I see that people are converting it for NUMA. I give them a lot of
credit, since they must be smarter than I ;)

-- Steve

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