mpagecache_test.go

Documentation: runtime

     1  // Copyright 2019 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package runtime_test
     6  
     7  import (
     8  	"internal/goos"
     9  	"math/rand"
    10  	. "runtime"
    11  	"testing"
    12  )
    13  
    14  func checkPageCache(t *testing.T, got, want PageCache) {
    15  	if got.Base() != want.Base() {
    16  		t.Errorf("bad pageCache base: got 0x%x, want 0x%x", got.Base(), want.Base())
    17  	}
    18  	if got.Cache() != want.Cache() {
    19  		t.Errorf("bad pageCache bits: got %016x, want %016x", got.Base(), want.Base())
    20  	}
    21  	if got.Scav() != want.Scav() {
    22  		t.Errorf("bad pageCache scav: got %016x, want %016x", got.Scav(), want.Scav())
    23  	}
    24  }
    25  
    26  func TestPageCacheAlloc(t *testing.T) {
    27  	base := PageBase(BaseChunkIdx, 0)
    28  	type hit struct {
    29  		npages uintptr
    30  		base   uintptr
    31  		scav   uintptr
    32  	}
    33  	tests := map[string]struct {
    34  		cache PageCache
    35  		hits  []hit
    36  	}{
    37  		"Empty": {
    38  			cache: NewPageCache(base, 0, 0),
    39  			hits: []hit{
    40  				{1, 0, 0},
    41  				{2, 0, 0},
    42  				{3, 0, 0},
    43  				{4, 0, 0},
    44  				{5, 0, 0},
    45  				{11, 0, 0},
    46  				{12, 0, 0},
    47  				{16, 0, 0},
    48  				{27, 0, 0},
    49  				{32, 0, 0},
    50  				{43, 0, 0},
    51  				{57, 0, 0},
    52  				{64, 0, 0},
    53  				{121, 0, 0},
    54  			},
    55  		},
    56  		"Lo1": {
    57  			cache: NewPageCache(base, 0x1, 0x1),
    58  			hits: []hit{
    59  				{1, base, PageSize},
    60  				{1, 0, 0},
    61  				{10, 0, 0},
    62  			},
    63  		},
    64  		"Hi1": {
    65  			cache: NewPageCache(base, 0x1<<63, 0x1),
    66  			hits: []hit{
    67  				{1, base + 63*PageSize, 0},
    68  				{1, 0, 0},
    69  				{10, 0, 0},
    70  			},
    71  		},
    72  		"Swiss1": {
    73  			cache: NewPageCache(base, 0x20005555, 0x5505),
    74  			hits: []hit{
    75  				{2, 0, 0},
    76  				{1, base, PageSize},
    77  				{1, base + 2*PageSize, PageSize},
    78  				{1, base + 4*PageSize, 0},
    79  				{1, base + 6*PageSize, 0},
    80  				{1, base + 8*PageSize, PageSize},
    81  				{1, base + 10*PageSize, PageSize},
    82  				{1, base + 12*PageSize, PageSize},
    83  				{1, base + 14*PageSize, PageSize},
    84  				{1, base + 29*PageSize, 0},
    85  				{1, 0, 0},
    86  				{10, 0, 0},
    87  			},
    88  		},
    89  		"Lo2": {
    90  			cache: NewPageCache(base, 0x3, 0x2<<62),
    91  			hits: []hit{
    92  				{2, base, 0},
    93  				{2, 0, 0},
    94  				{1, 0, 0},
    95  			},
    96  		},
    97  		"Hi2": {
    98  			cache: NewPageCache(base, 0x3<<62, 0x3<<62),
    99  			hits: []hit{
   100  				{2, base + 62*PageSize, 2 * PageSize},
   101  				{2, 0, 0},
   102  				{1, 0, 0},
   103  			},
   104  		},
   105  		"Swiss2": {
   106  			cache: NewPageCache(base, 0x3333<<31, 0x3030<<31),
   107  			hits: []hit{
   108  				{2, base + 31*PageSize, 0},
   109  				{2, base + 35*PageSize, 2 * PageSize},
   110  				{2, base + 39*PageSize, 0},
   111  				{2, base + 43*PageSize, 2 * PageSize},
   112  				{2, 0, 0},
   113  			},
   114  		},
   115  		"Hi53": {
   116  			cache: NewPageCache(base, ((uint64(1)<<53)-1)<<10, ((uint64(1)<<16)-1)<<10),
   117  			hits: []hit{
   118  				{53, base + 10*PageSize, 16 * PageSize},
   119  				{53, 0, 0},
   120  				{1, 0, 0},
   121  			},
   122  		},
   123  		"Full53": {
   124  			cache: NewPageCache(base, ^uint64(0), ((uint64(1)<<16)-1)<<10),
   125  			hits: []hit{
   126  				{53, base, 16 * PageSize},
   127  				{53, 0, 0},
   128  				{1, base + 53*PageSize, 0},
   129  			},
   130  		},
   131  		"Full64": {
   132  			cache: NewPageCache(base, ^uint64(0), ^uint64(0)),
   133  			hits: []hit{
   134  				{64, base, 64 * PageSize},
   135  				{64, 0, 0},
   136  				{1, 0, 0},
   137  			},
   138  		},
   139  		"FullMixed": {
   140  			cache: NewPageCache(base, ^uint64(0), ^uint64(0)),
   141  			hits: []hit{
   142  				{5, base, 5 * PageSize},
   143  				{7, base + 5*PageSize, 7 * PageSize},
   144  				{1, base + 12*PageSize, 1 * PageSize},
   145  				{23, base + 13*PageSize, 23 * PageSize},
   146  				{63, 0, 0},
   147  				{3, base + 36*PageSize, 3 * PageSize},
   148  				{3, base + 39*PageSize, 3 * PageSize},
   149  				{3, base + 42*PageSize, 3 * PageSize},
   150  				{12, base + 45*PageSize, 12 * PageSize},
   151  				{11, 0, 0},
   152  				{4, base + 57*PageSize, 4 * PageSize},
   153  				{4, 0, 0},
   154  				{6, 0, 0},
   155  				{36, 0, 0},
   156  				{2, base + 61*PageSize, 2 * PageSize},
   157  				{3, 0, 0},
   158  				{1, base + 63*PageSize, 1 * PageSize},
   159  				{4, 0, 0},
   160  				{2, 0, 0},
   161  				{62, 0, 0},
   162  				{1, 0, 0},
   163  			},
   164  		},
   165  	}
   166  	for name, test := range tests {
   167  		test := test
   168  		t.Run(name, func(t *testing.T) {
   169  			c := test.cache
   170  			for i, h := range test.hits {
   171  				b, s := c.Alloc(h.npages)
   172  				if b != h.base {
   173  					t.Fatalf("bad alloc base #%d: got 0x%x, want 0x%x", i, b, h.base)
   174  				}
   175  				if s != h.scav {
   176  					t.Fatalf("bad alloc scav #%d: got %d, want %d", i, s, h.scav)
   177  				}
   178  			}
   179  		})
   180  	}
   181  }
   182  
   183  func TestPageCacheFlush(t *testing.T) {
   184  	if GOOS == "openbsd" && testing.Short() {
   185  		t.Skip("skipping because virtual memory is limited; see #36210")
   186  	}
   187  	bits64ToBitRanges := func(bits uint64, base uint) []BitRange {
   188  		var ranges []BitRange
   189  		start, size := uint(0), uint(0)
   190  		for i := 0; i < 64; i++ {
   191  			if bits&(1<<i) != 0 {
   192  				if size == 0 {
   193  					start = uint(i) + base
   194  				}
   195  				size++
   196  			} else {
   197  				if size != 0 {
   198  					ranges = append(ranges, BitRange{start, size})
   199  					size = 0
   200  				}
   201  			}
   202  		}
   203  		if size != 0 {
   204  			ranges = append(ranges, BitRange{start, size})
   205  		}
   206  		return ranges
   207  	}
   208  	runTest := func(t *testing.T, base uint, cache, scav uint64) {
   209  		// Set up the before state.
   210  		beforeAlloc := map[ChunkIdx][]BitRange{
   211  			BaseChunkIdx: {{base, 64}},
   212  		}
   213  		beforeScav := map[ChunkIdx][]BitRange{
   214  			BaseChunkIdx: {},
   215  		}
   216  		b := NewPageAlloc(beforeAlloc, beforeScav)
   217  		defer FreePageAlloc(b)
   218  
   219  		// Create and flush the cache.
   220  		c := NewPageCache(PageBase(BaseChunkIdx, base), cache, scav)
   221  		c.Flush(b)
   222  		if !c.Empty() {
   223  			t.Errorf("pageCache flush did not clear cache")
   224  		}
   225  
   226  		// Set up the expected after state.
   227  		afterAlloc := map[ChunkIdx][]BitRange{
   228  			BaseChunkIdx: bits64ToBitRanges(^cache, base),
   229  		}
   230  		afterScav := map[ChunkIdx][]BitRange{
   231  			BaseChunkIdx: bits64ToBitRanges(scav, base),
   232  		}
   233  		want := NewPageAlloc(afterAlloc, afterScav)
   234  		defer FreePageAlloc(want)
   235  
   236  		// Check to see if it worked.
   237  		checkPageAlloc(t, want, b)
   238  	}
   239  
   240  	// Empty.
   241  	runTest(t, 0, 0, 0)
   242  
   243  	// Full.
   244  	runTest(t, 0, ^uint64(0), ^uint64(0))
   245  
   246  	// Random.
   247  	for i := 0; i < 100; i++ {
   248  		// Generate random valid base within a chunk.
   249  		base := uint(rand.Intn(PallocChunkPages/64)) * 64
   250  
   251  		// Generate random cache.
   252  		cache := rand.Uint64()
   253  		scav := rand.Uint64() & cache
   254  
   255  		// Run the test.
   256  		runTest(t, base, cache, scav)
   257  	}
   258  }
   259  
   260  func TestPageAllocAllocToCache(t *testing.T) {
   261  	if GOOS == "openbsd" && testing.Short() {
   262  		t.Skip("skipping because virtual memory is limited; see #36210")
   263  	}
   264  	type test struct {
   265  		beforeAlloc map[ChunkIdx][]BitRange
   266  		beforeScav  map[ChunkIdx][]BitRange
   267  		hits        []PageCache // expected base addresses and patterns
   268  		afterAlloc  map[ChunkIdx][]BitRange
   269  		afterScav   map[ChunkIdx][]BitRange
   270  	}
   271  	tests := map[string]test{
   272  		"AllFree": {
   273  			beforeAlloc: map[ChunkIdx][]BitRange{
   274  				BaseChunkIdx: {},
   275  			},
   276  			beforeScav: map[ChunkIdx][]BitRange{
   277  				BaseChunkIdx: {{1, 1}, {64, 64}},
   278  			},
   279  			hits: []PageCache{
   280  				NewPageCache(PageBase(BaseChunkIdx, 0), ^uint64(0), 0x2),
   281  				NewPageCache(PageBase(BaseChunkIdx, 64), ^uint64(0), ^uint64(0)),
   282  				NewPageCache(PageBase(BaseChunkIdx, 128), ^uint64(0), 0),
   283  				NewPageCache(PageBase(BaseChunkIdx, 192), ^uint64(0), 0),
   284  			},
   285  			afterAlloc: map[ChunkIdx][]BitRange{
   286  				BaseChunkIdx: {{0, 256}},
   287  			},
   288  		},
   289  		"ManyArena": {
   290  			beforeAlloc: map[ChunkIdx][]BitRange{
   291  				BaseChunkIdx:     {{0, PallocChunkPages}},
   292  				BaseChunkIdx + 1: {{0, PallocChunkPages}},
   293  				BaseChunkIdx + 2: {{0, PallocChunkPages - 64}},
   294  			},
   295  			beforeScav: map[ChunkIdx][]BitRange{
   296  				BaseChunkIdx:     {{0, PallocChunkPages}},
   297  				BaseChunkIdx + 1: {{0, PallocChunkPages}},
   298  				BaseChunkIdx + 2: {},
   299  			},
   300  			hits: []PageCache{
   301  				NewPageCache(PageBase(BaseChunkIdx+2, PallocChunkPages-64), ^uint64(0), 0),
   302  			},
   303  			afterAlloc: map[ChunkIdx][]BitRange{
   304  				BaseChunkIdx:     {{0, PallocChunkPages}},
   305  				BaseChunkIdx + 1: {{0, PallocChunkPages}},
   306  				BaseChunkIdx + 2: {{0, PallocChunkPages}},
   307  			},
   308  		},
   309  		"NotContiguous": {
   310  			beforeAlloc: map[ChunkIdx][]BitRange{
   311  				BaseChunkIdx:        {{0, PallocChunkPages}},
   312  				BaseChunkIdx + 0xff: {{0, 0}},
   313  			},
   314  			beforeScav: map[ChunkIdx][]BitRange{
   315  				BaseChunkIdx:        {{0, PallocChunkPages}},
   316  				BaseChunkIdx + 0xff: {{31, 67}},
   317  			},
   318  			hits: []PageCache{
   319  				NewPageCache(PageBase(BaseChunkIdx+0xff, 0), ^uint64(0), ((uint64(1)<<33)-1)<<31),
   320  			},
   321  			afterAlloc: map[ChunkIdx][]BitRange{
   322  				BaseChunkIdx:        {{0, PallocChunkPages}},
   323  				BaseChunkIdx + 0xff: {{0, 64}},
   324  			},
   325  			afterScav: map[ChunkIdx][]BitRange{
   326  				BaseChunkIdx:        {{0, PallocChunkPages}},
   327  				BaseChunkIdx + 0xff: {{64, 34}},
   328  			},
   329  		},
   330  		"First": {
   331  			beforeAlloc: map[ChunkIdx][]BitRange{
   332  				BaseChunkIdx: {{0, 32}, {33, 31}, {96, 32}},
   333  			},
   334  			beforeScav: map[ChunkIdx][]BitRange{
   335  				BaseChunkIdx: {{1, 4}, {31, 5}, {66, 2}},
   336  			},
   337  			hits: []PageCache{
   338  				NewPageCache(PageBase(BaseChunkIdx, 0), 1<<32, 1<<32),
   339  				NewPageCache(PageBase(BaseChunkIdx, 64), (uint64(1)<<32)-1, 0x3<<2),
   340  			},
   341  			afterAlloc: map[ChunkIdx][]BitRange{
   342  				BaseChunkIdx: {{0, 128}},
   343  			},
   344  		},
   345  		"Fail": {
   346  			beforeAlloc: map[ChunkIdx][]BitRange{
   347  				BaseChunkIdx: {{0, PallocChunkPages}},
   348  			},
   349  			hits: []PageCache{
   350  				NewPageCache(0, 0, 0),
   351  				NewPageCache(0, 0, 0),
   352  				NewPageCache(0, 0, 0),
   353  			},
   354  			afterAlloc: map[ChunkIdx][]BitRange{
   355  				BaseChunkIdx: {{0, PallocChunkPages}},
   356  			},
   357  		},
   358  		"RetainScavBits": {
   359  			beforeAlloc: map[ChunkIdx][]BitRange{
   360  				BaseChunkIdx: {{0, 1}, {10, 2}},
   361  			},
   362  			beforeScav: map[ChunkIdx][]BitRange{
   363  				BaseChunkIdx: {{0, 4}, {11, 1}},
   364  			},
   365  			hits: []PageCache{
   366  				NewPageCache(PageBase(BaseChunkIdx, 0), ^uint64(0x1|(0x3<<10)), 0x7<<1),
   367  			},
   368  			afterAlloc: map[ChunkIdx][]BitRange{
   369  				BaseChunkIdx: {{0, 64}},
   370  			},
   371  			afterScav: map[ChunkIdx][]BitRange{
   372  				BaseChunkIdx: {{0, 1}, {11, 1}},
   373  			},
   374  		},
   375  	}
   376  	// Disable these tests on iOS since we have a small address space.
   377  	// See #46860.
   378  	if PageAlloc64Bit != 0 && goos.IsIos == 0 {
   379  		const chunkIdxBigJump = 0x100000 // chunk index offset which translates to O(TiB)
   380  
   381  		// This test is similar to the one with the same name for
   382  		// pageAlloc.alloc and serves the same purpose.
   383  		// See mpagealloc_test.go for details.
   384  		sumsPerPhysPage := ChunkIdx(PhysPageSize / PallocSumBytes)
   385  		baseChunkIdx := BaseChunkIdx &^ (sumsPerPhysPage - 1)
   386  		tests["DiscontiguousMappedSumBoundary"] = test{
   387  			beforeAlloc: map[ChunkIdx][]BitRange{
   388  				baseChunkIdx + sumsPerPhysPage - 1: {{0, PallocChunkPages - 1}},
   389  				baseChunkIdx + chunkIdxBigJump:     {{1, PallocChunkPages - 1}},
   390  			},
   391  			beforeScav: map[ChunkIdx][]BitRange{
   392  				baseChunkIdx + sumsPerPhysPage - 1: {},
   393  				baseChunkIdx + chunkIdxBigJump:     {},
   394  			},
   395  			hits: []PageCache{
   396  				NewPageCache(PageBase(baseChunkIdx+sumsPerPhysPage-1, PallocChunkPages-64), 1<<63, 0),
   397  				NewPageCache(PageBase(baseChunkIdx+chunkIdxBigJump, 0), 1, 0),
   398  				NewPageCache(0, 0, 0),
   399  			},
   400  			afterAlloc: map[ChunkIdx][]BitRange{
   401  				baseChunkIdx + sumsPerPhysPage - 1: {{0, PallocChunkPages}},
   402  				baseChunkIdx + chunkIdxBigJump:     {{0, PallocChunkPages}},
   403  			},
   404  		}
   405  	}
   406  	for name, v := range tests {
   407  		v := v
   408  		t.Run(name, func(t *testing.T) {
   409  			b := NewPageAlloc(v.beforeAlloc, v.beforeScav)
   410  			defer FreePageAlloc(b)
   411  
   412  			for _, expect := range v.hits {
   413  				checkPageCache(t, b.AllocToCache(), expect)
   414  				if t.Failed() {
   415  					return
   416  				}
   417  			}
   418  			want := NewPageAlloc(v.afterAlloc, v.afterScav)
   419  			defer FreePageAlloc(want)
   420  
   421  			checkPageAlloc(t, want, b)
   422  		})
   423  	}
   424  }
   425
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