1 // Copyright 2012 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 // Lock-free stack. 6 // The following code runs only on g0 stack. 7 8 package runtime 9 10 import "unsafe" 11 12 func lfstackpush(head *uint64, node *lfnode) { 13 node.pushcnt++ 14 new := lfstackPack(node, node.pushcnt) 15 if node1, _ := lfstackUnpack(new); node1 != node { 16 println("runtime: lfstackpush invalid packing: node=", node, " cnt=", hex(node.pushcnt), " packed=", hex(new), " -> node=", node1, "\n") 17 throw("lfstackpush") 18 } 19 for { 20 old := atomicload64(head) 21 node.next = old 22 if cas64(head, old, new) { 23 break 24 } 25 } 26 } 27 28 func lfstackpop(head *uint64) unsafe.Pointer { 29 for { 30 old := atomicload64(head) 31 if old == 0 { 32 return nil 33 } 34 node, _ := lfstackUnpack(old) 35 next := atomicload64(&node.next) 36 if cas64(head, old, next) { 37 return unsafe.Pointer(node) 38 } 39 } 40 } 41
