GoのSync.mutexを内部実装から理解したい（awoke編）

    for {
        // Don't spin in starvation mode, ownership is handed off to waiters
        // so we won't be able to acquire the mutex anyway.
        if old&(mutexLocked|mutexStarving) == mutexLocked && runtime_canSpin(iter) {
            // Active spinning makes sense.
            // Try to set mutexWoken flag to inform Unlock
            // to not wake other blocked goroutines.
            if !awoke && old&mutexWoken == 0 && old>>mutexWaiterShift != 0 &&
                atomic.CompareAndSwapInt32(&m.state, old, old|mutexWoken) {
                awoke = true
            }
            runtime_doSpin()
            iter++
            old = m.state
            continue
        }
        new := old

        省略....
        if awoke {
            // The goroutine has been woken from sleep,
            // so we need to reset the flag in either case.
            if new&mutexWoken == 0 {
                throw("sync: inconsistent mutex state")
            }
            new &^= mutexWoken
        }

func (m *Mutex) unlockSlow(new int32) {

    if new&mutexStarving == 0 {
        old := new
        for {

            if old>>mutexWaiterShift == 0 || old&(mutexLocked|mutexWoken|mutexStarving) != 0 { <----ここ
                return
            }
            // Grab the right to wake someone.
            new = (old - 1<<mutexWaiterShift) | mutexWoken    <----ここ
            if atomic.CompareAndSwapInt32(&m.state, old, new) {
                runtime_Semrelease(&m.sema, false, 1)
                return
            }
            old = m.state
        }
    } else {
        runtime_Semrelease(&m.sema, true, 1)
    }

            runtime_SemacquireMutex(&m.sema, queueLifo, 1)
            starving = starving || runtime_nanotime()-waitStartTime > starvationThresholdNs
            old = m.state
            if old&mutexStarving != 0 {
                省略...
                break
            }
            awoke = true
            iter = 0

spin中awoke=trueとなるGが生まれて、stateにmutexWokenフラグが立つ
↓
Unlock側で old&(mutexLocked|mutexWoken|mutexStarving) != 0 の条件がtrueになりreturnするので、sema.goで目覚めさせる動きをしない
↓
awoke=trueとなったＧがLockSlow()でCASを取得するまではmutexWokenは解除されないので、unLockではsema.go経由での目覚ましはなし

unlockでmutexWokenを付け、そのままsema.goで目覚めさせる流れに
↓
mutex.goにいるGがspin中に入っても、old&mutexWoken == 0に引っかかるのでどのGもawoke=falseのままで、
new &^= mutexWokenでmutexWokenがはがれない
↓
unlockから起こされたGが、awoke=trueとなり、そこからは１と一緒