[release-branch.go1.8] net/http: update bundled http2 for gracefulShutdownCh lock...

This updates the bundled x/net/http2 repo to git rev 186fd3fc (from
the net repo's release-branch.go1.8) for:

    [release-branch.go1.8] http2: fix lock contention slowdown due to gracefulShutdownCh
    https://golang.org/cl/43459

Fixes #20302

Change-Id: Ia01a44c6749292de9c16ca330bdebe1e52458b18
Reviewed-on: https://go-review.googlesource.com/43996
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Chris Broadfoot <cbro@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/net/http/h2_bundle.go b/src/net/http/h2_bundle.go
index 4536b2ff5deb1ae8a7d464107a8dac66b7da9da3..e473bb2a135d72045f9b0dab2e69384171da5e83 100644 (file)
--- a/src/net/http/h2_bundle.go
+++ b/src/net/http/h2_bundle.go
@@ -1,4 +1,4 @@
-// Code generated by golang.org/x/tools/cmd/bundle.
+// Code generated by golang.org/x/tools/cmd/bundle. DO NOT EDIT.
 //go:generate bundle -o h2_bundle.go -prefix http2 -underscore golang.org/x/net/http2
 
 // Package http2 implements the HTTP/2 protocol.
@@ -3536,9 +3536,13 @@ func (sc *http2serverConn) serve() {
                sc.idleTimerCh = sc.idleTimer.C
        }
 
-       var gracefulShutdownCh <-chan struct{}
+       var gracefulShutdownCh chan struct{}
        if sc.hs != nil {
-               gracefulShutdownCh = http2h1ServerShutdownChan(sc.hs)
+               ch := http2h1ServerShutdownChan(sc.hs)
+               if ch != nil {
+                       gracefulShutdownCh = make(chan struct{})
+                       go sc.awaitGracefulShutdown(ch, gracefulShutdownCh)
+               }
        }
 
        go sc.readFrames()
@@ -3587,6 +3591,14 @@ func (sc *http2serverConn) serve() {
        }
 }
 
+func (sc *http2serverConn) awaitGracefulShutdown(sharedCh <-chan struct{}, privateCh chan struct{}) {
+       select {
+       case <-sc.doneServing:
+       case <-sharedCh:
+               close(privateCh)
+       }
+}
+
 // readPreface reads the ClientPreface greeting from the peer
 // or returns an error on timeout or an invalid greeting.
 func (sc *http2serverConn) readPreface() error {
@@ -6003,7 +6015,6 @@ func http2commaSeparatedTrailers(req *Request) (string, error) {
        }
        if len(keys) > 0 {
                sort.Strings(keys)
-
                return strings.Join(keys, ","), nil
        }
        return "", nil