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 */)

// 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
		}

		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.
//

	// Clear the scavenged bits when we alloc the range.
	m.pallocBits.allocRange(i, n)
	m.scavenged.clearRange(i, n)
}

// allocAll sets every bit in the bitmap to 1 and updates
// the scavenged bits appropriately.
func (m *pallocData) allocAll() {
	// Clear the scavenged bits when we alloc the range.
	m.pallocBits.allocAll()
	m.scavenged.clearAll()

	s.scavenger.wake()
}

// Stop cleans up the scavenger's resources. The scavenger
// must be parked for this to work.
func (s *Scavenger) Stop() {
	lock(&s.scavenger.lock)
	parked := s.scavenger.parked
	unlock(&s.scavenger.lock)
	if !parked {
		panic("tried to clean up scavenger that is not parked")
	}
	close(s.stop)
	s.Wake()
	<-s.done
}

type ScavengeIndex struct {

	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

			t.Errorf("chunk %d nilness mismatch", i)
		}
		if !checkPallocBits(t, gb.PallocBits(), wb.PallocBits()) {
			t.Logf("in chunk %d (mallocBits)", i)
		}
		if !checkPallocBits(t, gb.Scavenged(), wb.Scavenged()) {
			t.Logf("in chunk %d (scavenged)", i)
		}
	}
	// TODO(mknyszek): Verify summaries too?
}

func TestPageAllocGrow(t *testing.T) {
	if GOOS == "openbsd" && testing.Short() {

		allocTotal = 32 << 20

		// The page cache could hide 64 8-KiB pages from the scavenger today.
		maxPageCache = (8 << 10) * 64
	)

	// How big the allocations are needs to depend on the page size.
	// If the page size is too big and the allocations are too small,
	// they might not be aligned to the physical page size, so the scavenger
	// will gloss over them.
	pageSize := os.Getpagesize()
	var allocChunk int

		}
		scavenge.assistTime.Add(now - start)
	}

	// Initialize the span.
	h.initSpan(s, typ, spanclass, base, npages)

	// Commit and account for any scavenged memory that the span now owns.
	nbytes := npages * pageSize
	if scav != 0 {
		// sysUsed all the pages that are actually available
		// in the span since some of them might be scavenged.

	}
}

func TestScavengedBitsCleared(t *testing.T) {
	var mismatches [128]BitsMismatch
	if n, ok := CheckScavengedBitsCleared(mismatches[:]); !ok {
		t.Errorf("uncleared scavenged bits")
		for _, m := range mismatches[:n] {
			t.Logf("\t@ address 0x%x", m.Base)
			t.Logf("\t|  got: %064b", m.Got)
			t.Logf("\t| want: %064b", m.Want)
		}
		t.FailNow()
	}
}