// sweeping, so we can read h.sweepArenas, and so
	// traceGCSweepStart/Done pair on the P.
	mp := acquirem()

	trace := traceAcquire()
	if trace.ok() {
		trace.GCSweepStart()
		traceRelease(trace)
	}

	arenas := h.sweepArenas
	locked := false
	for npage > 0 {
		// Pull from accumulated credit first.
		if credit := h.reclaimCredit.Load(); credit > 0 {
			take := credit

				// acquire/release because this is part of the
				// goroutine's trace state, and it must be atomic
				// with respect to the tracer.
				gp.inMarkAssist = false
				traceRelease(trace)
			} else {
				// This state is tracked even if tracing isn't enabled.
				// It's only used by the new tracer.
				// See the comment on enteredMarkAssistForTracing.
				gp.inMarkAssist = false
			}

	}

	// Run the background mark worker.
	gp := node.gp.ptr()
	trace := traceAcquire()
	casgstatus(gp, _Gwaiting, _Grunnable)
	if trace.ok() {
		trace.GoUnpark(gp, 0)
		traceRelease(trace)
	}
	return gp, now
}

// resetLive sets up the controller state for the next mark phase after the end
// of the previous one. Must be called after endCycle and before commit, before

	// Update it under gcsema to avoid gctrace getting wrong values.
	work.userForced = trigger.kind == gcTriggerCycle

	trace := traceAcquire()
	if trace.ok() {
		trace.GCStart()
		traceRelease(trace)
	}

	// Check that all Ps have finished deferred mcache flushes.
	for _, p := range allp {
		if fg := p.mcache.flushGen.Load(); fg != mheap_.sweepgen {

			inittrace.bytes += uint64(fullSize)
		}

		if traceAllocFreeEnabled() {
			trace := traceAcquire()
			if trace.ok() {
				trace.HeapObjectAlloc(uintptr(x), typ)
				traceRelease(trace)
			}
		}
	}

	if assistG != nil {
		// Account for internal fragmentation in the assist
		// debt now that we know it.
		//
		// N.B. Use the full size because that's how the rest