Re: how can I cleanly exclude memory from the kernel memory allocator?

[Larry Bassel <lbassel@codeaurora.org>]

On 24 Mar 11 19:27, Nicolas Pitre wrote:
> On Thu, 24 Mar 2011, Larry Bassel wrote:
> 
> > I want to (early in system initialization) exclude some
> > contiguous physical memory from one or more memory banks
> > so that it won't be mapped in the normal kernel 1-to-1 mapping
> > (so that it can be mapped uncached, strongly ordered, etc.
> > as needed -- I know that it is forbidden to have a cached
> > and an uncached mapping to the same memory) and so that it
> > won't be freed into the kernel memory allocator (so that
> > it won't fragment and can be allocated using genalloc).
> > 
> > I have tried to find a clean way to do this, but none of
> > the approaches I've considered seem very good:
> > 
> > 1. Add a hook to the memory tag parsing routine to (possibly)
> > change each tag before arm_add_memory() is called,
> > or alter arm_add_memory() itself.
> 
> There is already a hook for that.  In your machine descriptor you can 
> add a .fixup method to do just that.  See tag_fixup_mem32() in 
> arch/arm/mach-orion5x/common.c for a usage example.

OK, please ignore my previous mail, I see that .fixup can be
used to adjust tags. It appears to me, however, that using a
.reserve function calling memblock_reserve will be an
easier way of doing what I need.

Thanks.

> 
> 
> Nicolas

Larry
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