[dev.power64] code review 160200044: build: merge default into dev.power64

src/pkg/runtime/netpoll_epoll.go

+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build linux
+
+package runtime
+
+import "unsafe"
+
+func epollcreate(size int32) int32
+func epollcreate1(flags int32) int32
+
+//go:noescape
+func epollctl(epfd, op, fd int32, ev *epollevent) int32
+
+//go:noescape
+func epollwait(epfd int32, ev *epollevent, nev, timeout int32) int32
+func closeonexec(fd int32)
+
+var (
+        epfd           int32 = -1 // epoll descriptor
+        netpolllasterr int32
+)
+
+func netpollinit() {
+        epfd = epollcreate1(_EPOLL_CLOEXEC)
+        if epfd >= 0 {
+                return
+        }
+        epfd = epollcreate(1024)
+        if epfd >= 0 {
+                closeonexec(epfd)
+                return
+        }
+        println("netpollinit: failed to create epoll descriptor", -epfd)
+        gothrow("netpollinit: failed to create descriptor")
+}
+
+func netpollopen(fd uintptr, pd *pollDesc) int32 {
+        var ev epollevent
+        ev.events = _EPOLLIN | _EPOLLOUT | _EPOLLRDHUP | _EPOLLET
+        *(**pollDesc)(unsafe.Pointer(&ev.data)) = pd
+        return -epollctl(epfd, _EPOLL_CTL_ADD, int32(fd), &ev)
+}
+
+func netpollclose(fd uintptr) int32 {
+        var ev epollevent
+        return -epollctl(epfd, _EPOLL_CTL_DEL, int32(fd), &ev)
+}
+
+func netpollarm(pd *pollDesc, mode int) {
+        gothrow("unused")
+}
+
+// polls for ready network connections
+// returns list of goroutines that become runnable
+func netpoll(block bool) (gp *g) {
+        if epfd == -1 {
+                return
+        }
+        waitms := int32(-1)
+        if !block {
+                waitms = 0
+        }
+        var events [128]epollevent
+retry:
+        n := epollwait(epfd, &events[0], int32(len(events)), waitms)
+        if n < 0 {
+                if n != -_EINTR && n != netpolllasterr {
+                        netpolllasterr = n
+                        println("runtime: epollwait on fd", epfd, "failed with", -n)
+                }
+                goto retry
+        }
+        for i := int32(0); i < n; i++ {
+                ev := &events[i]
+                if ev.events == 0 {
+                        continue
+                }
+                var mode int32
+                if ev.events&(_EPOLLIN|_EPOLLRDHUP|_EPOLLHUP|_EPOLLERR) != 0 {
+                        mode += 'r'
+                }
+                if ev.events&(_EPOLLOUT|_EPOLLHUP|_EPOLLERR) != 0 {
+                        mode += 'w'
+                }
+                if mode != 0 {
+                        pd := *(**pollDesc)(unsafe.Pointer(&ev.data))
+                        netpollready((**g)(noescape(unsafe.Pointer(&gp))), pd, mode)
+                }
+        }
+        if block && gp == nil {
+                goto retry
+        }
+        return gp
+}