linux-kernel - Re: slab: setup allocators earlier in the boot sequence

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Message-Id: <1244796837.7172.95.camel@pasglop>
Date:	Fri, 12 Jun 2009 18:53:57 +1000
From:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:	Pekka Enberg <penberg@...helsinki.fi>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Linux Kernel list <linux-kernel@...r.kernel.org>,
	linux-mm <linux-mm@...ck.org>, mingo@...e.hu,
	cl@...ux-foundation.org, akpm@...ux-foundation.org, npiggin@...e.de
Subject: Re: slab: setup allocators earlier in the boot sequence

> Yes, you're obviously right. I overlooked the fact that arch code have
> their own special slab_is_available() heuristics (yikes!).
> 
> But are you happy with the two patches I posted so I can push them to
> Linus?

I won't be able to test them until tomorrow. However, I think the first
one becomes unnecessary with the second one applied (provided you didn't
miss a case), no ?

I still prefer my approach of having a more fine grained control of what
bits to remove. First because applying a mask is less expensive than a
conditional branch (I used a negative mask because it would be too easy
to miss bits otherwise) and second, because it allows for masking of
other bits easily, for example, __GFP_IO for the suspend path etc...

Now, if you find it a bit too ugly, feel free to rename smellybits to
something else and create an accessor function for setting what bits are
masked out, but I still believe that the basic idea behind my patch is
saner than yours :-)

Cheers,
Ben.

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