Re: [bg-linux] [PATCH 5/7] [RFC] force 32-byte aligned kmallocs

From: Kazutomo Yoshii
Date: Thu May 19 2011 - 23:21:35 EST

On 05/19/2011 09:13 PM, Benjamin Herrenschmidt wrote:
On Fri, 2011-05-20 at 12:08 +1000, Benjamin Herrenschmidt wrote:
On Thu, 2011-05-19 at 20:32 -0500, Kazutomo Yoshii wrote:
Actually DMA sends invalidate requests to the snoop unit(L2 level).
BGP SoC is a bit different from other 4xx base.
Well, some other 44x also have a snooping L2 (more or less), but L1 is
usually the problem.
Hrm... looking at the doco you pointed me to, it looks like the L1 -is-
coherent, it gets snoop kills from the L2.
Right, L1D is coherent if write throug is set.
L1I(virtually tagged) is not coherent, btw.

Ok so we do need to make this non-coherent cache stuff a runtime option
(well, we need that for 440+476 too anyways so may as well do it now).
What sort of runtime option do you mean?

- kaz
As for the alignment of kmalloc, it looks like a hack that should be
done in the torus code itself.


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