// Dequeue an M.
			mp = muintptr(v &^ locked).ptr()
			if atomic.Casuintptr(&l.key, v, uintptr(mp.nextwaitm)) {
				// Dequeued an M.  Wake it.
				semawakeup(mp)
				break
			}
		}
	}
	gp.m.mLockProfile.recordUnlock(l)
	gp.m.locks--
	if gp.m.locks < 0 {
		throw("runtime·unlock: lock count")
	}
	if gp.m.locks == 0 && gp.preempt { // restore the preemption request in case we've cleared it in newstack

	lockedExt     uint32      // tracking for external LockOSThread
	lockedInt     uint32      // tracking for internal lockOSThread
	nextwaitm     muintptr    // next m waiting for lock

	mLockProfile mLockProfile // fields relating to runtime.lock contention
	profStack    []uintptr    // used for memory/block/mutex stack traces

	// wait* are used to carry arguments from gopark into park_m, because

		{"(*Pinner).Pin", Method, 21},
		{"(*Pinner).Unpin", Method, 21},
		{"(*StackRecord).Stack", Method, 0},
		{"(*TypeAssertionError).Error", Method, 0},
		{"(*TypeAssertionError).RuntimeError", Method, 0},
		{"BlockProfile", Func, 1},
		{"BlockProfileRecord", Type, 1},
		{"BlockProfileRecord.Count", Field, 1},
		{"BlockProfileRecord.Cycles", Field, 1},
		{"BlockProfileRecord.StackRecord", Field, 1},
		{"Breakpoint", Func, 0},

// malloc and runtime locks for mLockProfile.
// TODO(mknyszek): Implement lazy allocation if this becomes a problem.
func mProfStackInit(mp *m) {
	if debug.profstackdepth == 0 {
		// debug.profstack is set to 0 by the user, or we're being called from
		// schedinit before parsedebugvars.
		return
	}
	mp.profStack = makeProfStackFP()
	mp.mLockProfile.stack = makeProfStackFP()
}

pkg runtime (windows-386), const GOOS = "windows"
pkg runtime (windows-amd64), const GOARCH = "amd64"
pkg runtime (windows-amd64), const GOOS = "windows"
pkg runtime, const Compiler = "gc"
pkg runtime, func BlockProfile([]BlockProfileRecord) (int, bool)
pkg runtime, func SetBlockProfileRate(int)
pkg runtime, method (*BlockProfileRecord) Stack() []uintptr
pkg runtime, type BlockProfileRecord struct