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Message-ID: <3DBD5FDE.6070604@colorfullife.com>
Date: Mon, 28 Oct 2002 17:03:42 +0100
From: Manfred Spraul <manfred@colorfullife.com>
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To: Nikita Danilov <Nikita@Namesys.COM>
CC: Marcus Alanen <marcus@infa.abo.fi>, Alan Cox <alan@lxorguk.ukuu.org.uk>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH,RFC] faster kmalloc lookup
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Nikita Danilov wrote:

>Marcus Alanen writes:
> > >Most kmalloc calls get constant size argument (usually
> > >sizeof(something)). So, if switch() is used in stead of loop (and
> > >kmalloc made inline), compiler would be able to optimize away
> > >cache_sizes[] selection completely. Attached (ugly) patch does this.
> > 
> > Perhaps a compile-time test to check if the argument is
> > a constant, and only in that case call your new kmalloc, otherwise
> > a non-inline kmalloc call? With your current patch, a non-constant
> > size argument to kmalloc means that the function is inlined anyway,
> > leading to unnecessary bloat in the resulting image.
>
>Yes, exactly.
>  
>
I agree, I have an old patch that does that.

http://www.colorfullife.com/~manfred/slab/patch-km_div

Please ignore the part about fixed point division, it's not needed - the 
'div' instructions is now outside of the hot path.

The problem is that the -mm tree contains around 10 slab patches, I want 
to see them in Linus' tree before I add further patches.

--
    Manfred

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