Re: [PATCH v6 13/14] arm64, acpi, numa: NUMA support based on SRAT and SLIT

From: David Daney
Date: Thu May 12 2016 - 11:27:25 EST


On 05/12/2016 02:49 AM, Catalin Marinas wrote:
On Wed, May 11, 2016 at 05:06:13PM -0700, David Daney wrote:
On 05/11/2016 03:39 AM, Catalin Marinas wrote:
[...]

I wonder whether you could replace the get_mpidr_in_madt() function with
something like acpi_get_phys_id(). It looks like get_mpidr_in_madt()
duplicates functionality already available elsewhere.

I just tried that, and it doesn't work.

The problem is that this code is being run very early in the boot, and
kmalloc cannot be used. acpi_get_phys_id() and its ilk can only be used
once we have working kmalloc. We need to extract the NUMA information early
like this precisely because it is needed to initializing the slab system

Notice that we are using early_acpi_os_unmap_memory() et al. in
get_mpidr_in_madt() explicitly for this reason.

In summary: I don't think we need another revision of this patch, it is like
this for a good reason.

Slightly confusing, in another reply you said you are going to address
my comment. So, is it doable?

I don't think so.

My previous reply, to the thread in 0/14, was prematurely made with the incorrect assumption that it was a simple change. Now, after really digging in to the code, and attempting to do as you suggested, I have changed my mind.

As I indicated above, there are no remaining suggestions or requests for changes to this patch set pending action. Unless people find additional problems, I think it is ready for merging.

I know that Will and Rafael were discussing the proper timing for merging this in the other thread, so I leave it in their hands at this point.

Thanks,
David Daney