scavenger.sleep(workTime)
	}
}

// scavenge scavenges nbytes worth of free pages, starting with the
// highest address first. Successive calls continue from where it left
// off until the heap is exhausted. force makes all memory available to
// scavenge, ignoring huge page heuristics.
//
// Returns the amount of memory scavenged in bytes.
//

// the ranges of described in alloc and scavenge.
func makePallocData(alloc, scavenged []BitRange) *PallocData {
	b := new(PallocData)
	for _, v := range alloc {
		if v.N == 0 {
			// Skip N==0. It's harmless and allocRange doesn't
			// handle this case.
			continue
		}
		b.AllocRange(v.I, v.N)
	}
	for _, v := range scavenged {
		if v.N == 0 {
			// See the previous loop.
			continue
		}

const ranks = `
# Sysmon
NONE
< sysmon
< scavenge, forcegc;

# Defer
NONE < defer;

# GC
NONE <
  sweepWaiters,
  assistQueue,
  sweep;

# Test only
NONE < testR, testW;

NONE < timerSend;

# Scheduler, timers, netpoll
NONE < allocmW, execW, cpuprof, pollCache, pollDesc, wakeableSleep;
scavenge, sweep, testR, wakeableSleep, timerSend < hchan;
assistQueue,
  cpuprof,

	if test {
		// Set up the scavenge index via sysAlloc so the test can free it later.
		scavIndexSize := uintptr(len(scavengeIndexArray)) * unsafe.Sizeof(atomicScavChunkData{})
		s.chunks = ((*[(1 << heapAddrBits) / pallocChunkBytes]atomicScavChunkData)(sysAlloc(scavIndexSize, sysStat)))[:]
		mappedReady = scavIndexSize
	} else {
		// Set up the scavenge index.
		s.chunks = scavengeIndexArray[:]
	}

		panic("must populate all stubs")
	}

	// Install hooks.
	s.scavenger.sleepStub = s.Sleep
	s.scavenger.scavenge = s.Scavenge
	s.scavenger.shouldStop = s.ShouldStop
	s.scavenger.gomaxprocs = s.GoMaxProcs

	// Start up scavenger goroutine, and wait for it to be ready.
	stop := make(chan struct{})
	s.stop = stop
	done := make(chan struct{})
	s.done = done
	go func() {

	},
	{
		Name: "/cpu/classes/scavenge/total:cpu-seconds",
		Description: "Estimated total CPU time spent performing tasks that return " +
			"unused memory to the underlying platform. " +
			"This metric is an overestimate, and not directly comparable to " +
			"system CPU time measurements. Compare only with other /cpu/classes " +
			"metrics. Sum of all metrics in /cpu/classes/scavenge.",
		Kind:       KindFloat64,

	condemned = nil

	// Clear the condemned memory.
	runtime.GC()

	// At this point, the background scavenger is likely running
	// and could pick up the work, so the next line of code doesn't
	// end up doing anything. That's fine. What's important is that
	// this test fails somewhat regularly if the runtime doesn't
	// scavenge on heap growth, and doesn't fail at all otherwise.

	/cpu/classes/scavenge/assist:cpu-seconds
		Estimated total CPU time spent returning unused memory to the
		underlying platform in response eagerly in response to memory
		pressure. This metric is an overestimate, and not directly
		comparable to system CPU time measurements. Compare only with
		other /cpu/classes metrics.

	/cpu/classes/scavenge/background:cpu-seconds

		case "/cpu/classes/idle:cpu-seconds":
			cpu.idle = samples[i].Value.Float64()
		case "/cpu/classes/scavenge/assist:cpu-seconds":
			cpu.scavengeAssist = samples[i].Value.Float64()
		case "/cpu/classes/scavenge/background:cpu-seconds":
			cpu.scavengeBg = samples[i].Value.Float64()
		case "/cpu/classes/scavenge/total:cpu-seconds":
			cpu.scavengeTotal = samples[i].Value.Float64()
		case "/cpu/classes/total:cpu-seconds":

		s = h.allocMSpanLocked()
	}
	unlock(&h.lock)

HaveSpan:
	// Decide if we need to scavenge in response to what we just allocated.
	// Specifically, we track the maximum amount of memory to scavenge of all
	// the alternatives below, assuming that the maximum satisfies *all*
	// conditions we check (e.g. if we need to scavenge X to satisfy the
	// memory limit and Y to satisfy heap-growth scavenging, and Y > X, then