diff --git a/vendor/golang.org/x/sys/unix/affinity_linux.go b/vendor/golang.org/x/sys/unix/affinity_linux.go
index 72afe33..6e5c81a 100644
--- a/vendor/golang.org/x/sys/unix/affinity_linux.go
+++ b/vendor/golang.org/x/sys/unix/affinity_linux.go
@@ -7,6 +7,7 @@
 package unix
 
 import (
+	"math/bits"
 	"unsafe"
 )
 
@@ -79,46 +80,7 @@
 func (s *CPUSet) Count() int {
 	c := 0
 	for _, b := range s {
-		c += onesCount64(uint64(b))
+		c += bits.OnesCount64(uint64(b))
 	}
 	return c
 }
-
-// onesCount64 is a copy of Go 1.9's math/bits.OnesCount64.
-// Once this package can require Go 1.9, we can delete this
-// and update the caller to use bits.OnesCount64.
-func onesCount64(x uint64) int {
-	const m0 = 0x5555555555555555 // 01010101 ...
-	const m1 = 0x3333333333333333 // 00110011 ...
-	const m2 = 0x0f0f0f0f0f0f0f0f // 00001111 ...
-	const m3 = 0x00ff00ff00ff00ff // etc.
-	const m4 = 0x0000ffff0000ffff
-
-	// Implementation: Parallel summing of adjacent bits.
-	// See "Hacker's Delight", Chap. 5: Counting Bits.
-	// The following pattern shows the general approach:
-	//
-	//   x = x>>1&(m0&m) + x&(m0&m)
-	//   x = x>>2&(m1&m) + x&(m1&m)
-	//   x = x>>4&(m2&m) + x&(m2&m)
-	//   x = x>>8&(m3&m) + x&(m3&m)
-	//   x = x>>16&(m4&m) + x&(m4&m)
-	//   x = x>>32&(m5&m) + x&(m5&m)
-	//   return int(x)
-	//
-	// Masking (& operations) can be left away when there's no
-	// danger that a field's sum will carry over into the next
-	// field: Since the result cannot be > 64, 8 bits is enough
-	// and we can ignore the masks for the shifts by 8 and up.
-	// Per "Hacker's Delight", the first line can be simplified
-	// more, but it saves at best one instruction, so we leave
-	// it alone for clarity.
-	const m = 1<<64 - 1
-	x = x>>1&(m0&m) + x&(m0&m)
-	x = x>>2&(m1&m) + x&(m1&m)
-	x = (x>>4 + x) & (m2 & m)
-	x += x >> 8
-	x += x >> 16
-	x += x >> 32
-	return int(x) & (1<<7 - 1)
-}