@@ -2,7 +2,6 @@ package sysinfo // import "github.com/docker/docker/pkg/sysinfo"

 import (

 	"runtime"

-	"unsafe"

 	"golang.org/x/sys/unix"

 )

@@ -14,23 +13,15 @@ import (

 // Returns 0 on errors. Use |runtime.NumCPU| in that case.

 func numCPU() int {

 	// Gets the affinity mask for a process: The very one invoking this function.

-	pid, _, _ := unix.RawSyscall(unix.SYS_GETPID, 0, 0, 0)

+	pid := unix.Getpid()

-	var mask [1024 / 64]uintptr

-	_, _, err := unix.RawSyscall(unix.SYS_SCHED_GETAFFINITY, pid, uintptr(len(mask)*8), uintptr(unsafe.Pointer(&mask[0])))

-	if err != 0 {

+	var mask unix.CPUSet

+	err := unix.SchedGetaffinity(pid, &mask)

+	if err != nil {

 		return 0

 	}

-	// For every available thread a bit is set in the mask.

-	ncpu := 0

-	for _, e := range mask {

-		if e == 0 {

-			continue

-		}

-		ncpu += int(popcnt(uint64(e)))

-	}

-	return ncpu

+	return mask.Count()

 }

 // NumCPU returns the number of CPUs which are currently online

@@ -13,6 +13,16 @@ var (

 	getProcessAffinityMask = kernel32.NewProc("GetProcessAffinityMask")

 )

+// Returns bit count of 1, used by NumCPU

+func popcnt(x uint64) (n byte) {

+	x -= (x >> 1) & 0x5555555555555555

+	x = (x>>2)&0x3333333333333333 + x&0x3333333333333333

+	x += x >> 4

+	x &= 0x0f0f0f0f0f0f0f0f

+	x *= 0x0101010101010101

+	return byte(x >> 56)

+}

+

 func numCPU() int {

 	// Gets the affinity mask for a process

 	var mask, sysmask uintptr

@@ -146,13 +146,3 @@ func isCpusetListAvailable(provided, available string) (bool, error) {

 	}

 	return true, nil

 }

-

-// Returns bit count of 1, used by NumCPU

-func popcnt(x uint64) (n byte) {

-	x -= (x >> 1) & 0x5555555555555555

-	x = (x>>2)&0x3333333333333333 + x&0x3333333333333333

-	x += x >> 4

-	x &= 0x0f0f0f0f0f0f0f0f

-	x *= 0x0101010101010101

-	return byte(x >> 56)

-}