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Subject: Re: slab: setup allocators earlier in the boot sequence
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Nick Piggin <npiggin@suse.de>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>,
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> > Sure, I think we can do what you want with the patch below.
> 
> I don't really like adding branches to slab allocator like this.
> init code all needs to know what services are available, and
> this includes the scheduler if it wants to do anything sleeping
> (including sleeping slab allocations).
> 
> Core mm code is the last place to put in workarounds for broken
> callers...

Right, and that's also a reason why I decided for having that
"smellybits" approach since applying a mask is going to be a lot less
cycle consuming than a conditional branch (especially on small embedded
CPUs, the conditional branch on modern stuff should be be reasonably
harmless).

Nick, have you seen my patch ? What do you think ?

Cheers,
Ben.