Adding upstream version 1.16.10.upstream/1.16.10upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 460 insertions, 0 deletions

diff --git a/src/runtime/mgcscavenge_test.go b/src/runtime/mgcscavenge_test.go
new file mode 100644
index 0000000..2503430
--- /dev/null
+++ b/src/runtime/mgcscavenge_test.go
@@ -0,0 +1,460 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package runtime_test
+
+import (
+	"fmt"
+	"math/rand"
+	. "runtime"
+	"testing"
+)
+
+// makePallocData produces an initialized PallocData by setting
+// 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
+		}
+		b.ScavengedSetRange(v.I, v.N)
+	}
+	return b
+}
+
+func TestFillAligned(t *testing.T) {
+	fillAlignedSlow := func(x uint64, m uint) uint64 {
+		if m == 1 {
+			return x
+		}
+		out := uint64(0)
+		for i := uint(0); i < 64; i += m {
+			for j := uint(0); j < m; j++ {
+				if x&(uint64(1)<<(i+j)) != 0 {
+					out |= ((uint64(1) << m) - 1) << i
+					break
+				}
+			}
+		}
+		return out
+	}
+	check := func(x uint64, m uint) {
+		want := fillAlignedSlow(x, m)
+		if got := FillAligned(x, m); got != want {
+			t.Logf("got:  %064b", got)
+			t.Logf("want: %064b", want)
+			t.Errorf("bad fillAligned(%016x, %d)", x, m)
+		}
+	}
+	for m := uint(1); m <= 64; m *= 2 {
+		tests := []uint64{
+			0x0000000000000000,
+			0x00000000ffffffff,
+			0xffffffff00000000,
+			0x8000000000000001,
+			0xf00000000000000f,
+			0xf00000010050000f,
+			0xffffffffffffffff,
+			0x0000000000000001,
+			0x0000000000000002,
+			0x0000000000000008,
+			uint64(1) << (m - 1),
+			uint64(1) << m,
+			// Try a few fixed arbitrary examples.
+			0xb02b9effcf137016,
+			0x3975a076a9fbff18,
+			0x0f8c88ec3b81506e,
+			0x60f14d80ef2fa0e6,
+		}
+		for _, test := range tests {
+			check(test, m)
+		}
+		for i := 0; i < 1000; i++ {
+			// Try a pseudo-random numbers.
+			check(rand.Uint64(), m)
+
+			if m > 1 {
+				// For m != 1, let's construct a slightly more interesting
+				// random test. Generate a bitmap which is either 0 or
+				// randomly set bits for each m-aligned group of m bits.
+				val := uint64(0)
+				for n := uint(0); n < 64; n += m {
+					// For each group of m bits, flip a coin:
+					// * Leave them as zero.
+					// * Set them randomly.
+					if rand.Uint64()%2 == 0 {
+						val |= (rand.Uint64() & ((1 << m) - 1)) << n
+					}
+				}
+				check(val, m)
+			}
+		}
+	}
+}
+
+func TestPallocDataFindScavengeCandidate(t *testing.T) {
+	type test struct {
+		alloc, scavenged []BitRange
+		min, max         uintptr
+		want             BitRange
+	}
+	tests := map[string]test{
+		"MixedMin1": {
+			alloc:     []BitRange{{0, 40}, {42, PallocChunkPages - 42}},
+			scavenged: []BitRange{{0, 41}, {42, PallocChunkPages - 42}},
+			min:       1,
+			max:       PallocChunkPages,
+			want:      BitRange{41, 1},
+		},
+		"MultiMin1": {
+			alloc:     []BitRange{{0, 63}, {65, 20}, {87, PallocChunkPages - 87}},
+			scavenged: []BitRange{{86, 1}},
+			min:       1,
+			max:       PallocChunkPages,
+			want:      BitRange{85, 1},
+		},
+	}
+	// Try out different page minimums.
+	for m := uintptr(1); m <= 64; m *= 2 {
+		suffix := fmt.Sprintf("Min%d", m)
+		tests["AllFree"+suffix] = test{
+			min:  m,
+			max:  PallocChunkPages,
+			want: BitRange{0, PallocChunkPages},
+		}
+		tests["AllScavenged"+suffix] = test{
+			scavenged: []BitRange{{0, PallocChunkPages}},
+			min:       m,
+			max:       PallocChunkPages,
+			want:      BitRange{0, 0},
+		}
+		tests["NoneFree"+suffix] = test{
+			alloc:     []BitRange{{0, PallocChunkPages}},
+			scavenged: []BitRange{{PallocChunkPages / 2, PallocChunkPages / 2}},
+			min:       m,
+			max:       PallocChunkPages,
+			want:      BitRange{0, 0},
+		}
+		tests["StartFree"+suffix] = test{
+			alloc: []BitRange{{uint(m), PallocChunkPages - uint(m)}},
+			min:   m,
+			max:   PallocChunkPages,
+			want:  BitRange{0, uint(m)},
+		}
+		tests["StartFree"+suffix] = test{
+			alloc: []BitRange{{uint(m), PallocChunkPages - uint(m)}},
+			min:   m,
+			max:   PallocChunkPages,
+			want:  BitRange{0, uint(m)},
+		}
+		tests["EndFree"+suffix] = test{
+			alloc: []BitRange{{0, PallocChunkPages - uint(m)}},
+			min:   m,
+			max:   PallocChunkPages,
+			want:  BitRange{PallocChunkPages - uint(m), uint(m)},
+		}
+		tests["Straddle64"+suffix] = test{
+			alloc: []BitRange{{0, 64 - uint(m)}, {64 + uint(m), PallocChunkPages - (64 + uint(m))}},
+			min:   m,
+			max:   2 * m,
+			want:  BitRange{64 - uint(m), 2 * uint(m)},
+		}
+		tests["BottomEdge64WithFull"+suffix] = test{
+			alloc:     []BitRange{{64, 64}, {128 + 3*uint(m), PallocChunkPages - (128 + 3*uint(m))}},
+			scavenged: []BitRange{{1, 10}},
+			min:       m,
+			max:       3 * m,
+			want:      BitRange{128, 3 * uint(m)},
+		}
+		tests["BottomEdge64WithPocket"+suffix] = test{
+			alloc:     []BitRange{{64, 62}, {127, 1}, {128 + 3*uint(m), PallocChunkPages - (128 + 3*uint(m))}},
+			scavenged: []BitRange{{1, 10}},
+			min:       m,
+			max:       3 * m,
+			want:      BitRange{128, 3 * uint(m)},
+		}
+		tests["Max0"+suffix] = test{
+			scavenged: []BitRange{{0, PallocChunkPages - uint(m)}},
+			min:       m,
+			max:       0,
+			want:      BitRange{PallocChunkPages - uint(m), uint(m)},
+		}
+		if m <= 8 {
+			tests["OneFree"] = test{
+				alloc: []BitRange{{0, 40}, {40 + uint(m), PallocChunkPages - (40 + uint(m))}},
+				min:   m,
+				max:   PallocChunkPages,
+				want:  BitRange{40, uint(m)},
+			}
+			tests["OneScavenged"] = test{
+				alloc:     []BitRange{{0, 40}, {40 + uint(m), PallocChunkPages - (40 + uint(m))}},
+				scavenged: []BitRange{{40, 1}},
+				min:       m,
+				max:       PallocChunkPages,
+				want:      BitRange{0, 0},
+			}
+		}
+		if m > 1 {
+			tests["MaxUnaligned"+suffix] = test{
+				scavenged: []BitRange{{0, PallocChunkPages - uint(m*2-1)}},
+				min:       m,
+				max:       m - 2,
+				want:      BitRange{PallocChunkPages - uint(m), uint(m)},
+			}
+			tests["SkipSmall"+suffix] = test{
+				alloc: []BitRange{{0, 64 - uint(m)}, {64, 5}, {70, 11}, {82, PallocChunkPages - 82}},
+				min:   m,
+				max:   m,
+				want:  BitRange{64 - uint(m), uint(m)},
+			}
+			tests["SkipMisaligned"+suffix] = test{
+				alloc: []BitRange{{0, 64 - uint(m)}, {64, 63}, {127 + uint(m), PallocChunkPages - (127 + uint(m))}},
+				min:   m,
+				max:   m,
+				want:  BitRange{64 - uint(m), uint(m)},
+			}
+			tests["MaxLessThan"+suffix] = test{
+				scavenged: []BitRange{{0, PallocChunkPages - uint(m)}},
+				min:       m,
+				max:       1,
+				want:      BitRange{PallocChunkPages - uint(m), uint(m)},
+			}
+		}
+	}
+	if PhysHugePageSize > uintptr(PageSize) {
+		// Check hugepage preserving behavior.
+		bits := uint(PhysHugePageSize / uintptr(PageSize))
+		if bits < PallocChunkPages {
+			tests["PreserveHugePageBottom"] = test{
+				alloc: []BitRange{{bits + 2, PallocChunkPages - (bits + 2)}},
+				min:   1,
+				max:   3, // Make it so that max would have us try to break the huge page.
+				want:  BitRange{0, bits + 2},
+			}
+			if 3*bits < PallocChunkPages {
+				// We need at least 3 huge pages in a chunk for this test to make sense.
+				tests["PreserveHugePageMiddle"] = test{
+					alloc: []BitRange{{0, bits - 10}, {2*bits + 10, PallocChunkPages - (2*bits + 10)}},
+					min:   1,
+					max:   12, // Make it so that max would have us try to break the huge page.
+					want:  BitRange{bits, bits + 10},
+				}
+			}
+			tests["PreserveHugePageTop"] = test{
+				alloc: []BitRange{{0, PallocChunkPages - bits}},
+				min:   1,
+				max:   1, // Even one page would break a huge page in this case.
+				want:  BitRange{PallocChunkPages - bits, bits},
+			}
+		} else if bits == PallocChunkPages {
+			tests["PreserveHugePageAll"] = test{
+				min:  1,
+				max:  1, // Even one page would break a huge page in this case.
+				want: BitRange{0, PallocChunkPages},
+			}
+		} else {
+			// The huge page size is greater than pallocChunkPages, so it should
+			// be effectively disabled. There's no way we can possible scavenge
+			// a huge page out of this bitmap chunk.
+			tests["PreserveHugePageNone"] = test{
+				min:  1,
+				max:  1,
+				want: BitRange{PallocChunkPages - 1, 1},
+			}
+		}
+	}
+	for name, v := range tests {
+		v := v
+		t.Run(name, func(t *testing.T) {
+			b := makePallocData(v.alloc, v.scavenged)
+			start, size := b.FindScavengeCandidate(PallocChunkPages-1, v.min, v.max)
+			got := BitRange{start, size}
+			if !(got.N == 0 && v.want.N == 0) && got != v.want {
+				t.Fatalf("candidate mismatch: got %v, want %v", got, v.want)
+			}
+		})
+	}
+}
+
+// Tests end-to-end scavenging on a pageAlloc.
+func TestPageAllocScavenge(t *testing.T) {
+	if GOOS == "openbsd" && testing.Short() {
+		t.Skip("skipping because virtual memory is limited; see #36210")
+	}
+	type test struct {
+		request, expect uintptr
+	}
+	minPages := PhysPageSize / PageSize
+	if minPages < 1 {
+		minPages = 1
+	}
+	type setup struct {
+		beforeAlloc map[ChunkIdx][]BitRange
+		beforeScav  map[ChunkIdx][]BitRange
+		expect      []test
+		afterScav   map[ChunkIdx][]BitRange
+	}
+	tests := map[string]setup{
+		"AllFreeUnscavExhaust": {
+			beforeAlloc: map[ChunkIdx][]BitRange{
+				BaseChunkIdx:     {},
+				BaseChunkIdx + 1: {},
+				BaseChunkIdx + 2: {},
+			},
+			beforeScav: map[ChunkIdx][]BitRange{
+				BaseChunkIdx:     {},
+				BaseChunkIdx + 1: {},
+				BaseChunkIdx + 2: {},
+			},
+			expect: []test{
+				{^uintptr(0), 3 * PallocChunkPages * PageSize},
+			},
+			afterScav: map[ChunkIdx][]BitRange{
+				BaseChunkIdx:     {{0, PallocChunkPages}},
+				BaseChunkIdx + 1: {{0, PallocChunkPages}},
+				BaseChunkIdx + 2: {{0, PallocChunkPages}},
+			},
+		},
+		"NoneFreeUnscavExhaust": {
+			beforeAlloc: map[ChunkIdx][]BitRange{
+				BaseChunkIdx:     {{0, PallocChunkPages}},
+				BaseChunkIdx + 1: {},
+				BaseChunkIdx + 2: {{0, PallocChunkPages}},
+			},
+			beforeScav: map[ChunkIdx][]BitRange{
+				BaseChunkIdx:     {},
+				BaseChunkIdx + 1: {{0, PallocChunkPages}},
+				BaseChunkIdx + 2: {},
+			},
+			expect: []test{
+				{^uintptr(0), 0},
+			},
+			afterScav: map[ChunkIdx][]BitRange{
+				BaseChunkIdx:     {},
+				BaseChunkIdx + 1: {{0, PallocChunkPages}},
+				BaseChunkIdx + 2: {},
+			},
+		},
+		"ScavHighestPageFirst": {
+			beforeAlloc: map[ChunkIdx][]BitRange{
+				BaseChunkIdx: {},
+			},
+			beforeScav: map[ChunkIdx][]BitRange{
+				BaseChunkIdx: {{uint(minPages), PallocChunkPages - uint(2*minPages)}},
+			},
+			expect: []test{
+				{1, minPages * PageSize},
+			},
+			afterScav: map[ChunkIdx][]BitRange{
+				BaseChunkIdx: {{uint(minPages), PallocChunkPages - uint(minPages)}},
+			},
+		},
+		"ScavMultiple": {
+			beforeAlloc: map[ChunkIdx][]BitRange{
+				BaseChunkIdx: {},
+			},
+			beforeScav: map[ChunkIdx][]BitRange{
+				BaseChunkIdx: {{uint(minPages), PallocChunkPages - uint(2*minPages)}},
+			},
+			expect: []test{
+				{minPages * PageSize, minPages * PageSize},
+				{minPages * PageSize, minPages * PageSize},
+			},
+			afterScav: map[ChunkIdx][]BitRange{
+				BaseChunkIdx: {{0, PallocChunkPages}},
+			},
+		},
+		"ScavMultiple2": {
+			beforeAlloc: map[ChunkIdx][]BitRange{
+				BaseChunkIdx:     {},
+				BaseChunkIdx + 1: {},
+			},
+			beforeScav: map[ChunkIdx][]BitRange{
+				BaseChunkIdx:     {{uint(minPages), PallocChunkPages - uint(2*minPages)}},
+				BaseChunkIdx + 1: {{0, PallocChunkPages - uint(2*minPages)}},
+			},
+			expect: []test{
+				{2 * minPages * PageSize, 2 * minPages * PageSize},
+				{minPages * PageSize, minPages * PageSize},
+				{minPages * PageSize, minPages * PageSize},
+			},
+			afterScav: map[ChunkIdx][]BitRange{
+				BaseChunkIdx:     {{0, PallocChunkPages}},
+				BaseChunkIdx + 1: {{0, PallocChunkPages}},
+			},
+		},
+		"ScavDiscontiguous": {
+			beforeAlloc: map[ChunkIdx][]BitRange{
+				BaseChunkIdx:       {},
+				BaseChunkIdx + 0xe: {},
+			},
+			beforeScav: map[ChunkIdx][]BitRange{
+				BaseChunkIdx:       {{uint(minPages), PallocChunkPages - uint(2*minPages)}},
+				BaseChunkIdx + 0xe: {{uint(2 * minPages), PallocChunkPages - uint(2*minPages)}},
+			},
+			expect: []test{
+				{2 * minPages * PageSize, 2 * minPages * PageSize},
+				{^uintptr(0), 2 * minPages * PageSize},
+				{^uintptr(0), 0},
+			},
+			afterScav: map[ChunkIdx][]BitRange{
+				BaseChunkIdx:       {{0, PallocChunkPages}},
+				BaseChunkIdx + 0xe: {{0, PallocChunkPages}},
+			},
+		},
+	}
+	if PageAlloc64Bit != 0 {
+		tests["ScavAllVeryDiscontiguous"] = setup{
+			beforeAlloc: map[ChunkIdx][]BitRange{
+				BaseChunkIdx:          {},
+				BaseChunkIdx + 0x1000: {},
+			},
+			beforeScav: map[ChunkIdx][]BitRange{
+				BaseChunkIdx:          {},
+				BaseChunkIdx + 0x1000: {},
+			},
+			expect: []test{
+				{^uintptr(0), 2 * PallocChunkPages * PageSize},
+				{^uintptr(0), 0},
+			},
+			afterScav: map[ChunkIdx][]BitRange{
+				BaseChunkIdx:          {{0, PallocChunkPages}},
+				BaseChunkIdx + 0x1000: {{0, PallocChunkPages}},
+			},
+		}
+	}
+	for name, v := range tests {
+		v := v
+		runTest := func(t *testing.T, mayUnlock bool) {
+			b := NewPageAlloc(v.beforeAlloc, v.beforeScav)
+			defer FreePageAlloc(b)
+
+			for iter, h := range v.expect {
+				if got := b.Scavenge(h.request, mayUnlock); got != h.expect {
+					t.Fatalf("bad scavenge #%d: want %d, got %d", iter+1, h.expect, got)
+				}
+			}
+			want := NewPageAlloc(v.beforeAlloc, v.afterScav)
+			defer FreePageAlloc(want)
+
+			checkPageAlloc(t, want, b)
+		}
+		t.Run(name, func(t *testing.T) {
+			runTest(t, false)
+		})
+		t.Run(name+"MayUnlock", func(t *testing.T) {
+			runTest(t, true)
+		})
+	}
+}