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SubjectRe: [PATCH 4/4] x86/CPU/AMD: Calculate LLC ID from number of sharing threads
On Mon, Mar 26, 2018 at 01:35:16AM -0500, Suravee Suthikulpanit wrote:
> diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c
> index 54d04d5..67f4790 100644
> --- a/arch/x86/kernel/cpu/cacheinfo.c
> +++ b/arch/x86/kernel/cpu/cacheinfo.c
> @@ -637,6 +637,43 @@ static int find_num_cache_leaves(struct cpuinfo_x86 *c)
> return i;
> }
>
> +void cacheinfo_amd_init_llc_id(struct cpuinfo_x86 *c, int cpu, u8 node_id)
> +{
> + /*
> + * We may have multiple LLCs if L3 caches exist, so check if we
> + * have an L3 cache by looking at the L3 cache CPUID leaf.
> + */
> + if (!cpuid_edx(0x80000006))
> + return;
> +
> + if (c->x86 < 0x17) {
> + /* LLC is at the node level. */
> + per_cpu(cpu_llc_id, cpu) = node_id;
> + } else if (c->x86 == 0x17 &&
> + c->x86_model >= 0 && c->x86_model <= 0x1F) {
> + /*
> + * LLC is at the core complex level.
> + * Core complex id is ApicId[3] for these processors.
> + */
> + per_cpu(cpu_llc_id, cpu) = c->apicid >> 3;
> + } else {
> + /* LLC ID is calculated from the number of thread sharing. */
> + u32 eax, ebx, ecx, edx, num_sharing_cache = 0;
> + u32 llc_index = find_num_cache_leaves(c) - 1;
> +
> + cpuid_count(0x8000001d, llc_index, &eax, &ebx, &ecx, &edx);
> + if (eax)
> + num_sharing_cache = ((eax >> 14) & 0xfff) + 1;
> +
> + if (num_sharing_cache) {
> + int bits = get_count_order(num_sharing_cache) - 1;
> +
> + per_cpu(cpu_llc_id, cpu) = c->apicid >> bits;
> + }
> + }
> +}
> +EXPORT_SYMBOL_GPL(cacheinfo_amd_init_llc_id);

That function needs to be exported to modules because...?

--
Regards/Gruss,
Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--

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