// now must be the timestamp from the end of the STW pause.
func (l *gcCPULimiterState) finishGCTransition(now int64) {
	if !l.transitioning {
		throw("finishGCTransition called without starting one?")
	}
	// Count the full nprocs set of CPU time because the world is stopped
	// between startGCTransition and finishGCTransition. Even though the GC
	// isn't running on all CPUs, it is preventing user code from doing so,

		if l.NeedUpdate(advance(0)) {
			t.Fatal("need update even though just updated")
		}

		// Test transitioning the bucket to enable the GC.

		l.StartGCTransition(true, advance(109*time.Millisecond))
		l.FinishGCTransition(advance(2*time.Millisecond + 1*time.Microsecond))

		if expect := uint64((2*time.Millisecond + 1*time.Microsecond) * procs); l.Fill() != expect {
			t.Fatalf("expected fill of %d, got %d cpu-ns", expect, l.Fill())
		}

}

func (l *GCCPULimiter) StartGCTransition(enableGC bool, now int64) {
	l.limiter.startGCTransition(enableGC, now)
}

func (l *GCCPULimiter) FinishGCTransition(now int64) {
	l.limiter.finishGCTransition(now)
}

func (l *GCCPULimiter) Update(now int64) {
	l.limiter.update(now)
}

func (l *GCCPULimiter) AddAssistTime(t int64) {
	l.limiter.addAssistTime(t)
}

	// Concurrent mark.
	systemstack(func() {
		now = startTheWorldWithSema(0, stw)
		work.pauseNS += now - stw.startedStopping
		work.tMark = now

		// Release the CPU limiter.
		gcCPULimiter.finishGCTransition(now)
	})

	// Release the world sema before Gosched() in STW mode
	// because we will need to reacquire it later but before
	// this goroutine becomes runnable again, and we could
	// self-deadlock otherwise.