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runtime: count scavenged bits for new allocation for new page allocator

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This change makes it so that the new page allocator returns the number
of pages that are scavenged in a new allocation so that mheap can update
memstats appropriately.

The accounting could be embedded into pageAlloc, but that would make
the new allocator more difficult to test.

Updates #35112.

Change-Id: I0f94f563d7af2458e6d534f589d2e7dd6af26d12
Reviewed-on: https://go-review.googlesource.com/c/go/+/195698
Reviewed-by: Austin Clements <austin@google.com>
This commit is contained in:
Michael Anthony Knyszek 2019-09-10 18:53:51 +00:00 • committed by Michael Knyszek
parent 73317080e1
commit e1ddf0507c
5 changed files with 281 additions and 76 deletions
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92
src/runtime/mpallocbits_test.go
View file

@ -113,6 +113,98 @@ func checkPallocSum(t *testing.T, got, want PallocSum) {
}
}
func TestMallocBitsPopcntRange(t *testing.T) {
type test struct {
i, n uint // bit range to popcnt over.
want uint // expected popcnt result on that range.
}
tests := map[string]struct {
init []BitRange // bit ranges to set to 1 in the bitmap.
tests []test // a set of popcnt tests to run over the bitmap.
}{
"None": {
tests: []test{
{0, 1, 0},
{5, 3, 0},
{2, 11, 0},
{PallocChunkPages/4 + 1, PallocChunkPages / 2, 0},
{0, PallocChunkPages, 0},
},
},
"All": {
init: []BitRange{{0, PallocChunkPages}},
tests: []test{
{0, 1, 1},
{5, 3, 3},
{2, 11, 11},
{PallocChunkPages/4 + 1, PallocChunkPages / 2, PallocChunkPages / 2},
{0, PallocChunkPages, PallocChunkPages},
},
},
"Half": {
init: []BitRange{{PallocChunkPages / 2, PallocChunkPages / 2}},
tests: []test{
{0, 1, 0},
{5, 3, 0},
{2, 11, 0},
{PallocChunkPages/2 - 1, 1, 0},
{PallocChunkPages / 2, 1, 1},
{PallocChunkPages/2 + 10, 1, 1},
{PallocChunkPages/2 - 1, 2, 1},
{PallocChunkPages / 4, PallocChunkPages / 4, 0},
{PallocChunkPages / 4, PallocChunkPages/4 + 1, 1},
{PallocChunkPages/4 + 1, PallocChunkPages / 2, PallocChunkPages/4 + 1},
{0, PallocChunkPages, PallocChunkPages / 2},
},
},
"OddBound": {
init: []BitRange{{0, 111}},
tests: []test{
{0, 1, 1},
{5, 3, 3},
{2, 11, 11},
{110, 2, 1},
{99, 50, 12},
{110, 1, 1},
{111, 1, 0},
{99, 1, 1},
{120, 1, 0},
{PallocChunkPages / 2, PallocChunkPages / 2, 0},
{0, PallocChunkPages, 111},
},
},
"Scattered": {
init: []BitRange{
{1, 3}, {5, 1}, {7, 1}, {10, 2}, {13, 1}, {15, 4},
{21, 1}, {23, 1}, {26, 2}, {30, 5}, {36, 2}, {40, 3},
{44, 6}, {51, 1}, {53, 2}, {58, 3}, {63, 1}, {67, 2},
{71, 10}, {84, 1}, {89, 7}, {99, 2}, {103, 1}, {107, 2},
{111, 1}, {113, 1}, {115, 1}, {118, 1}, {120, 2}, {125, 5},
},
tests: []test{
{0, 11, 6},
{0, 64, 39},
{13, 64, 40},
{64, 64, 34},
{0, 128, 73},
{1, 128, 74},
{0, PallocChunkPages, 75},
},
},
}
for name, v := range tests {
v := v
t.Run(name, func(t *testing.T) {
b := makePallocBits(v.init)
for _, h := range v.tests {
if got := b.PopcntRange(h.i, h.n); got != h.want {
t.Errorf("bad popcnt (i=%d, n=%d): got %d, want %d", h.i, h.n, got, h.want)
}
}
})
}
}
// Ensures computing bit summaries works as expected by generating random
// bitmaps and checking against a reference implementation.
func TestPallocBitsSummarizeRandom(t *testing.T) {