Re: [PATCH v2 1/2] kmem_cache: include allocators code directly intoslab_common

From: Glauber Costa
Date: Wed Oct 24 2012 - 10:35:03 EST


On 10/24/2012 06:29 PM, Christoph Lameter wrote:
> On Wed, 24 Oct 2012, Glauber Costa wrote:
>
>> Because of that, we either have to move all the entry points to the
>> mm/slab.h and rely heavily on the pre-processor, or include all .c files
>> in here.
>
> Hmm... That is a bit of a radical solution. The global optimizations now
> possible with the new gcc compiler include the ability to fold functions
> across different linkable objects. Andi, is that usable for kernel builds?
>

In general, it takes quite a lot of time to take all those optimizations
for granted. We still live a lot of time with multiple compiler versions
building distros, etc, for quite some time.

I would expect the end result for anyone not using such a compiler to be
a sudden performance drop when using a new kernel. Not really pleasant.

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