throw("newosproc")
	}
}

// Version of newosproc that doesn't require a valid G.
//
//go:nosplit
func newosproc0(stacksize uintptr, fn unsafe.Pointer) {
	stack := sysAlloc(stacksize, &memstats.stacks_sys)
	if stack == nil {
		writeErrStr(failallocatestack)
		exit(1)
	}
	// This code "knows" it's being called once from the library

		t.FailNow()
	}
}

type acLink struct {
	x [1 << 20]byte
}

var arenaCollisionSink []*acLink

func TestArenaCollision(t *testing.T) {
	testenv.MustHaveExec(t)

	// Test that mheap.sysAlloc handles collisions with other
	// memory mappings.
	if os.Getenv("TEST_ARENA_COLLISION") != "1" {
		cmd := testenv.CleanCmdEnv(exec.Command(os.Args[0], "-test.run=^TestArenaCollision$", "-test.v"))

		n := 64 * 1024 / goarch.PtrSize
		if n < cap(h.allspans)*3/2 {
			n = cap(h.allspans) * 3 / 2
		}
		var new []*mspan
		sp := (*slice)(unsafe.Pointer(&new))
		sp.array = sysAlloc(uintptr(n)*goarch.PtrSize, &memstats.other_sys)
		if sp.array == nil {
			throw("runtime: cannot allocate memory")
		}
		sp.len = len(h.allspans)
		sp.cap = n
		if len(h.allspans) > 0 {

	nptr := size / goarch.PtrSize
	if uintptr(len(tmpbuf)) < nptr/8+1 {
		if tmpbuf != nil {
			sysFree(unsafe.Pointer(&tmpbuf[0]), uintptr(len(tmpbuf)), &memstats.other_sys)
		}
		n := nptr/8 + 1
		p := sysAlloc(n, &memstats.other_sys)
		if p == nil {
			throw("heapdump: out of memory")
		}
		tmpbuf = (*[1 << 30]byte)(p)[:n]
	}
	// Convert heap bitmap to pointer bitmap.
	clear(tmpbuf[:nptr/8+1])
	s := spanOf(p)

	}
	return
}
func osinit_hack_trampoline()

// mmap is used to do low-level memory allocation via mmap. Don't allow stack
// splits, since this function (used by sysAlloc) is called in a lot of low-level
// parts of the runtime and callers often assume it won't acquire any locks.
//
//go:nosplit

		}
		throw("newosproc")
	}
}

// Version of newosproc that doesn't require a valid G.
//
//go:nosplit
func newosproc0(stacksize uintptr, fn unsafe.Pointer) {
	stack := sysAlloc(stacksize, &memstats.stacks_sys)
	if stack == nil {
		writeErrStr(failallocatestack)
		exit(1)
	}
	ret := clone(cloneFlags, unsafe.Pointer(uintptr(stack)+stacksize), nil, nil, fn)
	if ret < 0 {

					assertInEpsilon(t, "GC utilization", c[n-1].gcUtilization, c[n-2].gcUtilization, 0.005)
				}
			},
		},
		{
			// This tests the GC pacer's response to a small change in allocation rate.
			name:          "StepAlloc",
			gcPercent:     100,
			memoryLimit:   math.MaxInt64,
			globalsBytes:  32 << 10,
			nCores:        8,
			allocRate:     constant(33.0).sum(ramp(66.0, 1).delay(50)),
			scanRate:      constant(1024.0),

	for c := chunkIndex(base); c < chunkIndex(limit); c++ {
		if p.chunks[c.l1()] == nil {
			// Create the necessary l2 entry.
			const l2Size = unsafe.Sizeof(*p.chunks[0])
			r := sysAlloc(l2Size, p.sysStat)
			if r == nil {
				throw("pageAlloc: out of memory")
			}
			if !p.test {
				// Make the chunk mapping eligible or ineligible
				// for huge pages, depending on what our current

			}
		}

		// If a value is live at the end of the block and
		// isn't in a register, generate a use for the spill location.
		// We need to remember this information so that
		// the liveness analysis in stackalloc is correct.
		for _, e := range s.live[b.ID] {
			vi := &s.values[e.ID]
			if vi.regs != 0 {
				// in a register, we'll use that source for the merge.
				continue
			}
			if vi.rematerializeable {

	testSysStat.add(-int64(p.summaryMappedReady))

	// Free the mapped space for chunks.
	for i := range p.chunks {
		if x := p.chunks[i]; x != nil {
			p.chunks[i] = nil
			// This memory comes from sysAlloc and will always be page-aligned.
			sysFree(unsafe.Pointer(x), unsafe.Sizeof(*p.chunks[0]), testSysStat)
		}
	}
}

// BaseChunkIdx is a convenient chunkIdx value which works on both