inUse addrRanges

	// scav stores the scavenger state.
	scav struct {
		// index is an efficient index of chunks that have pages available to
		// scavenge.
		index scavengeIndex

		// releasedBg is the amount of memory released in the background this
		// scavenge cycle.
		releasedBg atomic.Uintptr

		// releasedEager is the amount of memory released eagerly this scavenge
		// cycle.
		releasedEager atomic.Uintptr

const lockRankLeafRank lockRank = 1000

// lockNames gives the names associated with each of the above ranks.
var lockNames = []string{
	lockRankSysmon:          "sysmon",
	lockRankScavenge:        "scavenge",
	lockRankForcegc:         "forcegc",
	lockRankDefer:           "defer",
	lockRankSweepWaiters:    "sweepWaiters",
	lockRankAssistQueue:     "assistQueue",
	lockRankSweep:           "sweep",

			},
		},
		"/cpu/classes/scavenge/assist:cpu-seconds": {
			deps: makeStatDepSet(cpuStatsDep),
			compute: func(in *statAggregate, out *metricValue) {
				out.kind = metricKindFloat64
				out.scalar = float64bits(nsToSec(in.cpuStats.ScavengeAssistTime))
			},
		},
		"/cpu/classes/scavenge/background:cpu-seconds": {
			deps: makeStatDepSet(cpuStatsDep),

	scavAssistCpu := scavenge.assistTime.Load()
	scavBgCpu := scavenge.backgroundTime.Load()

	// Update cumulative GC CPU stats.
	s.GCAssistTime += markAssistCpu
	s.GCDedicatedTime += markDedicatedCpu + markFractionalCpu
	s.GCIdleTime += markIdleCpu
	s.GCTotalTime += markAssistCpu + markDedicatedCpu + markFractionalCpu + markIdleCpu

	// Update cumulative scavenge CPU stats.

		sysMap(unsafe.Pointer(need.base.addr()), need.size(), p.sysStat)
		sysUsed(unsafe.Pointer(need.base.addr()), need.size(), need.size())
		p.summaryMappedReady += need.size()
	}

	// Update the scavenge index.
	p.summaryMappedReady += p.scav.index.sysGrow(base, limit, p.sysStat)
}

// sysGrow increases the index's backing store in response to a heap growth.
//
// Returns the amount of memory added to sysStat.

		// close to done sweeping.

		// Move the scavenge gen forward (signaling
		// that there's new work to do) and wake the scavenger.
		//
		// The scavenger is signaled by the last sweeper because once
		// sweeping is done, we will definitely have useful work for
		// the scavenger to do, since the scavenger only runs over the
		// heap once per GC cycle. This update is not done during sweep

	limiterEventMarkAssist                             // Refers to mark assist (see gcAssistAlloc).
	limiterEventScavengeAssist                         // Refers to a scavenge assist (see allocSpan).
	limiterEventIdle                                   // Refers to time a P spent on the idle list.

	limiterEventBits = 3
)

	// Reset assist time and background time stats.
	//
	// Do this now, instead of at the start of the next GC cycle, because
	// these two may keep accumulating even if the GC is not active.
	scavenge.assistTime.Store(0)
	scavenge.backgroundTime.Store(0)

	// Reset idle time stat.
	sched.idleTime.Store(0)

	if work.userForced {
		memstats.numforcedgc++
	}

	waitReasonGCAssistWait                            // "GC assist wait"
	waitReasonGCSweepWait                             // "GC sweep wait"
	waitReasonGCScavengeWait                          // "GC scavenge wait"
	waitReasonChanReceive                             // "chan receive"
	waitReasonChanSend                                // "chan send"
	waitReasonFinalizerWait                           // "finalizer wait"

			cache: ^chunk.pages64(chunkPageIndex(addr)),
			scav:  chunk.scavenged.block64(chunkPageIndex(addr)),
		}
	}

	// Set the page bits as allocated and clear the scavenged bits, but
	// be careful to only set and clear the relevant bits.
	cpi := chunkPageIndex(c.base)
	chunk.allocPages64(cpi, c.cache)
	chunk.scavenged.clearBlock64(cpi, c.cache&c.scav /* free and scavenged */)