Re: [RFC][PATCH] Check write to slab memory which freed already using mudflap

[Nick Piggin <npiggin@suse.de>]

On Fri, Jul 10, 2009 at 02:04:53AM -0700, David Rientjes wrote:
> On Fri, 10 Jul 2009, Ingo Molnar wrote:
> 
> > > SLAB is (slowly) going away so you might want to port this to SLUB 
> > > as well so we can merge both.
> > 
> > and SLQB which will replace both? :-/
> > 
> 
> I'm not sure what the status of slqb is, although I would have expected it 
> to have been pushed for inclusion in 2.6.31 as a slab allocator 
> alternative.  Nick, any forecast for inclusion?

Just had a hiccup with testing in the last cycle, so we decided
not to merge it this time. I hope next window.


> SLUB has a pretty noticeable performance degradation on benchmarks such as 
> netperf TCP_RR with high numbers of threads (see my post about it: 
> http://marc.info/?l=linux-kernel&m=123839191416472).  CONFIG_SLAB is the 
> optimal configuration for workloads that share similiar slab thrashing 
> patterns (which my patchset dealt with in an indirect way and yet still 
> didn't match slab's performance).  I haven't yet seen data that suggests 
> anything other than CONFIG_SLAB has parity with such a benchmark.

I did do various netperf runs, but I can't remember whether I tried
to reproduce your test case with SLQB.  I'll try ;)

I don't think there are any known performance regressions for SLQB
versus others, but OTOH I don't think it has been widely performance
tested (I don't think many people performance test -next).