diff options
| author | Austin Clements <austin@google.com> | 2016-02-15 17:37:04 -0500 |
|---|---|---|
| committer | Austin Clements <austin@google.com> | 2016-03-16 20:13:02 +0000 |
| commit | e4a95b63433cc95c81782713b917b2941e48cb39 (patch) | |
| tree | c75e4309ada98df7b4a5bd9e2d177983cc417c1f /src/runtime | |
| parent | d7cedc4b74f902a3a1b429fb27f85380f6955a6f (diff) | |
| download | go-e4a95b63433cc95c81782713b917b2941e48cb39.tar.xz | |
runtime: record channel in sudog
Given a G, there's currently no way to find the channel it's blocking
on. We'll need this information to fix a (probably theoretical) bug in
select and to implement concurrent stack shrinking, so record the
channel in the sudog.
For #12967.
Change-Id: If8fb63a140f1d07175818824d08c0ebeec2bdf66
Reviewed-on: https://go-review.googlesource.com/20035
Reviewed-by: Rick Hudson <rlh@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Diffstat (limited to 'src/runtime')
| -rw-r--r-- | src/runtime/chan.go | 4 | ||||
| -rw-r--r-- | src/runtime/proc.go | 3 | ||||
| -rw-r--r-- | src/runtime/runtime2.go | 5 | ||||
| -rw-r--r-- | src/runtime/select.go | 2 |
4 files changed, 12 insertions, 2 deletions
diff --git a/src/runtime/chan.go b/src/runtime/chan.go index 85cbe5a5a7..cc64d30a68 100644 --- a/src/runtime/chan.go +++ b/src/runtime/chan.go @@ -209,6 +209,7 @@ func chansend(t *chantype, c *hchan, ep unsafe.Pointer, block bool, callerpc uin mysg.waitlink = nil mysg.g = gp mysg.selectdone = nil + mysg.c = c gp.waiting = mysg gp.param = nil c.sendq.enqueue(mysg) @@ -229,6 +230,7 @@ func chansend(t *chantype, c *hchan, ep unsafe.Pointer, block bool, callerpc uin if mysg.releasetime > 0 { blockevent(mysg.releasetime-t0, 2) } + mysg.c = nil releaseSudog(mysg) return true } @@ -469,6 +471,7 @@ func chanrecv(t *chantype, c *hchan, ep unsafe.Pointer, block bool) (selected, r gp.waiting = mysg mysg.g = gp mysg.selectdone = nil + mysg.c = c gp.param = nil c.recvq.enqueue(mysg) goparkunlock(&c.lock, "chan receive", traceEvGoBlockRecv, 3) @@ -483,6 +486,7 @@ func chanrecv(t *chantype, c *hchan, ep unsafe.Pointer, block bool) (selected, r } closed := gp.param == nil gp.param = nil + mysg.c = nil releaseSudog(mysg) return true, !closed } diff --git a/src/runtime/proc.go b/src/runtime/proc.go index 758a0a898c..aea1f0d18c 100644 --- a/src/runtime/proc.go +++ b/src/runtime/proc.go @@ -329,6 +329,9 @@ func releaseSudog(s *sudog) { if s.waitlink != nil { throw("runtime: sudog with non-nil waitlink") } + if s.c != nil { + throw("runtime: sudog with non-nil c") + } gp := getg() if gp.param != nil { throw("runtime: releaseSudog with non-nil gp.param") diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go index 3ac8f196c5..ac437def26 100644 --- a/src/runtime/runtime2.go +++ b/src/runtime/runtime2.go @@ -215,13 +215,14 @@ type gobuf struct { // selecttype. type sudog struct { g *g - selectdone *uint32 + selectdone *uint32 // CAS to 1 to win select race (may point to stack) next *sudog prev *sudog - elem unsafe.Pointer // data element + elem unsafe.Pointer // data element (may point to stack) releasetime int64 ticket uint32 waitlink *sudog // g.waiting list + c *hchan // channel } type gcstats struct { diff --git a/src/runtime/select.go b/src/runtime/select.go index ddc3d81638..fff8afa9ff 100644 --- a/src/runtime/select.go +++ b/src/runtime/select.go @@ -385,6 +385,7 @@ loop: sg.releasetime = -1 } sg.waitlink = gp.waiting + sg.c = c gp.waiting = sg switch cas.kind { @@ -416,6 +417,7 @@ loop: for sg1 := gp.waiting; sg1 != nil; sg1 = sg1.waitlink { sg1.selectdone = nil sg1.elem = nil + sg1.c = nil } gp.waiting = nil for i := int(sel.ncase) - 1; i >= 0; i-- { |