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SubjectRe: [PATCH 10/26] x86-64, NUMA: Move apicid to numa mapping initialization from amd_scan_nodes() to amd_numa_init()
On 02/12/2011 08:10 PM, Tejun Heo wrote:
> This brings amd initialization behavior closer to that of acpi.
>
> Signed-off-by: Tejun Heo<tj@kernel.org>
> Cc: Yinghai Lu<yinghai@kernel.org>
> Cc: Brian Gerst<brgerst@gmail.com>
> Cc: Cyrill Gorcunov<gorcunov@gmail.com>
> Cc: Shaohui Zheng<shaohui.zheng@intel.com>
> Cc: David Rientjes<rientjes@google.com>
> Cc: Ingo Molnar<mingo@elte.hu>
> Cc: H. Peter Anvin<hpa@linux.intel.com>
> ---
> arch/x86/mm/amdtopology_64.c | 40 ++++++++++++++++++++++------------------
> 1 files changed, 22 insertions(+), 18 deletions(-)
>
> diff --git a/arch/x86/mm/amdtopology_64.c b/arch/x86/mm/amdtopology_64.c
> index c5eddfa..4056333 100644
> --- a/arch/x86/mm/amdtopology_64.c
> +++ b/arch/x86/mm/amdtopology_64.c
> @@ -74,8 +74,9 @@ int __init amd_numa_init(void)
> unsigned long end = PFN_PHYS(max_pfn);
> unsigned numnodes;
> unsigned long prevbase;
> - int i, nb;
> + int i, j, nb;
> u32 nodeid, reg;
> + unsigned int bits, cores, apicid_base;
>
> if (!early_pci_allowed())
> return -EINVAL;
> @@ -176,6 +177,26 @@ int __init amd_numa_init(void)
>
> if (!nodes_weight(mem_nodes_parsed))
> return -ENOENT;
> +
> + /*
> + * We seem to have valid NUMA configuration. Map apicids to nodes
> + * using the coreid bits from early_identify_cpu.
> + */
> + bits = boot_cpu_data.x86_coreid_bits;
> + cores = 1<< bits;
> + apicid_base = 0;
> +
> + /* get the APIC ID of the BSP early for systems with apicid lifting */
> + early_get_boot_cpu_id();
> + if (boot_cpu_physical_apicid> 0) {
> + pr_info("BSP APIC ID: %02x\n", boot_cpu_physical_apicid);
> + apicid_base = boot_cpu_physical_apicid;
^^^
> + }
> +
> + for_each_node_mask(i, cpu_nodes_parsed)
> + for (j = apicid_base; j< cores + apicid_base; j++)
> + set_apicid_to_node((i<< bits) + j, i);
> +
> return 0;
> }
>

Hi Tejun, while you at it, it seems apicid_base conditional assignment is
redundant here (boot_cpu_physical_apicid is unsigned int) so we might have
something like

apicid_start = boot_cpu_physical_apicid;
apicid_end = apicid_start + cores;

for_each_node_mask(i, cpu_nodes_parsed) {
for (j = apicid_start; j < apicid_end; j++)
set_apicid_to_node((i << bits) + j, i);
}

But of course it should be considered as followup update just to not
mess the things. (probably need to check if we ever may reach this point
with boot_cpu_physical_apicid = -1U). Just a thought.
--
Cyrill


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