On Tue, Nov 29, 2011 at 10:02 AM, Pekka Enberg <penberg@xxxxxxxxxx> wrote:
>
> The most important ones are from Christoph Lameter and Eric Dumazet that fix
> stability issues on non-x86 architectures.
>
> Christoph Lameter (1):
> slub: use irqsafe_cpu_cmpxchg for put_cpu_partial
Quite frankly, I think "this_cpu_cmpxchg()" is pure crap, and this fix
was wrong, wrong, WRONG.
Dammit, the emulation is just bad.
The *only* architecture that implements "this_cpu_cmpxchg()" specially
seems to be x86.
So every other architecture uses the emulated one, AND THE EMULATED
ONE DOES NOT MATCH THE X86 SEMANTICS!
Sorry for shouting, but that's just *incredibly* stupid.
What's extra stupid is that s390 actually separately implements the
irq-safe version, and does it with code that seems to be generic, and
actually uses "cmpxchg()" like the regular "this_cpu_cmpxchg()" name
implies!
In other words, I would suggest that:
- we get rid of that totally crazy idiotic "irqsafe" crap. The normal
one should be irq-safe. It's named "cmpxchg", for chrissake!
- we make the non-arch-specific "this_cpu_cmpxchg()" use the correct
s390 routines instead of the pure and utter *shit* it uses now.
Yes, I'm upset. This "random percpu crap for SLUB" has been going on
too f*cking long, and it has been *continually* plagued by just pure
sh*t like this.
Seriously. Stop taking patches from Christoph in this area until they
have been vetted for sanity and completeness. This kind of ugly "let's
mis-name our functions in really subtle ways so that they work on x86
but nowhere else" needs to stop.
I pulled this crap because clearly it fixes a bug, but just stop it.
Show some TASTE!
Linus
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