scx_utils: addressing #1282 concerns

on 32 bits packing the value by high and low bits with an always even
sized Vec.

rust/scx_utils/src/gpu.rs

@@ -1,7 +1,7 @@
 #![cfg(feature = "gpu-topology")]
 
 use crate::misc::read_file_usize;
-use crate::{Cpumask, NR_CPUS_POSSIBLE};
+use crate::{Cpumask, NR_CPU_IDS};
 use nvml_wrapper::bitmasks::InitFlags;
 use nvml_wrapper::enum_wrappers::device::Clock;
 use nvml_wrapper::Nvml;
@@ -50,10 +50,13 @@ pub fn create_gpus() -> BTreeMap<usize, Vec<Gpu>> {
                 continue;
             };
 
-            let cpu_mask = if let Ok(cpu_affinity) = nvidia_gpu.cpu_affinity(*NR_CPUS_POSSIBLE) {
+            let cpu_mask = if let Ok(cpu_affinity) = nvidia_gpu.cpu_affinity(*NR_CPU_IDS) {
                 // Note: nvml returns it as an arch dependent array of integrals
                 #[cfg(target_pointer_width = "32")]
-                let cpu_affinity = cpu_affinity.into_iter().map(|aff| aff as u64).collect();
+                let cpu_affinity: Vec<u64> = cpu_affinity
+                    .chunks_exact(2)
+                    .map(|pair| (pair[1] as u64) << 32 | pair[0] as u64)
+                    .collect();
                 Cpumask::from_vec(cpu_affinity)
             } else {
                 Cpumask::new()