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//go:build linux
// +build linux
package sysinfo
import (
"unsafe"
"golang.org/x/sys/unix"
)
// NUMANodeCount queries the system for the count of Memory Nodes available
// for use to this process.
func NUMANodeCount() int {
// this is the correct flag name (not defined in the unix package)
//nolint:revive
MPOL_F_MEMS_ALLOWED := (1 << 2)
var mask [1024 / 64]uintptr
_, _, err := unix.RawSyscall6(unix.SYS_GET_MEMPOLICY, 0, uintptr(unsafe.Pointer(&mask[0])), uintptr(len(mask)*8), 0, uintptr(MPOL_F_MEMS_ALLOWED), 0)
if err != 0 {
return 0
}
// For every available thread a bit is set in the mask.
nmem := 0
for _, e := range mask {
if e == 0 {
continue
}
nmem += int(popcnt(uint64(e)))
}
return nmem
}
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