nbytes := npages * pageSize
	if scav != 0 {
		// sysUsed all the pages that are actually available
		// in the span since some of them might be scavenged.
		sysUsed(unsafe.Pointer(base), nbytes, scav)
		gcController.heapReleased.add(-int64(scav))
	}
	// Update stats.
	gcController.heapFree.add(-int64(nbytes - scav))
	if typ == spanAllocHeap {
		gcController.heapInUse.add(int64(nbytes))

		// response, broke down. This may be transient, so temporarily switch to
		// sleeping a fixed, conservative amount.
		s.sleepRatio = startingScavSleepRatio
		s.controllerCooldown = 5e9 // 5 seconds.

		// Signal the scav trace printer to output this.
		s.controllerFailed()
	}
}

// controllerFailed indicates that the scavenger's scheduling
// controller failed.
func (s *scavengerState) controllerFailed() {
	lock(&s.lock)

// improve parallelism, the garbage collector breaks up scan jobs for
// objects larger than maxObletBytes into "oblets" of at most
// maxObletBytes. When scanning encounters the beginning of a large
// object, it scans only the first oblet and enqueues the remaining
// oblets as new scan jobs.

package runtime

import (
	"internal/cpu"
	"internal/runtime/atomic"
	"unsafe"

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	fixedRootFreeGStacks
	fixedRootCount

	// rootBlockBytes is the number of bytes to scan per data or
	// BSS root.
	rootBlockBytes = 256 << 10

	// maxObletBytes is the maximum bytes of an object to scan at
	// once. Larger objects will be split up into "oblets" of at
	// most this size. Since we can scan 1–2 MB/ms, 128 KB bounds
	// scan preemption at ~100 µs.
	//
	// This must be > _MaxSmallSize so that the object base is the

	// seven lines a few times in this source file. The copies below
	// refer back to the pattern established by this original as the
	// "LMS-substring iterator".
	//
	// In every scan through the text, c0, c1 are successive characters of text.
	// In this backward scan, c0 == text[i] and c1 == text[i+1].
	// By scanning backward, we can keep track of whether the current
	// position is type-S or type-L according to the usual definition:
	//