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Add WasmPageAllocator tests

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This commit is contained in:
Benjamin Feng 2019-12-05 21:54:57 -06:00
parent f2b0dbea74
commit eb495d934b
1 changed files with 43 additions and 5 deletions
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48
lib/std/heap.zig
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@ -256,7 +256,7 @@ const WasmPageAllocator = struct {
used = 0,
free = 1,
pub const all_used: u8 = 0;
pub const none_free: u8 = 0;
};
const FreeBlock = struct {
@ -265,7 +265,11 @@ const WasmPageAllocator = struct {
const Io = std.packed_int_array.PackedIntIo(u1, .Little);
fn totalPages(self: FreeBlock) usize {
return self.data.len * 8;
return self.data.len * 128;
}
fn isInitialized(self: FreeBlock) bool {
return self.data.len > 0;
}
fn getBit(self: FreeBlock, idx: usize) PageStatus {
@ -319,7 +323,9 @@ const WasmPageAllocator = struct {
}
};
const conventional = FreeBlock{ .data = &[_]u128{ 0, 0 } };
var _conventional_data = [_]u128{0} ** 16;
// Marking `conventional` as const saves ~40 bytes
var conventional = FreeBlock{ .data = &_conventional_data };
var extended = FreeBlock{ .data = &[_]u128{} };
fn extendedOffset() usize {
@ -379,14 +385,14 @@ const WasmPageAllocator = struct {
}
if (free_end > extendedOffset()) {
if (extended.totalPages() == 0) {
if (!extended.isInitialized()) {
// Steal the last page from the memory currently being recycled
// TODO: would it be better if we use the first page instead?
free_end -= 1;
extended.data = @intToPtr([*]u128, free_end * std.mem.page_size)[0 .. std.mem.page_size / @sizeOf(u128)];
// Since this is the first page being freed and we consume it, assume *nothing* is free.
std.mem.set(u128, extended.data, PageStatus.all_used);
std.mem.set(u128, extended.data, PageStatus.none_free);
}
const clamped_start = std.math.max(extendedOffset(), free_start);
extended.recycle(clamped_start - extendedOffset(), free_end - clamped_start);
@ -790,6 +796,38 @@ test "c_allocator" {
}
}
test "WasmPageAllocator internals" {
if (std.Target.current.isWasm()) {
const none_free = WasmPageAllocator.PageStatus.none_free;
std.debug.assert(none_free == WasmPageAllocator.conventional.data[0]); // Passes if this test runs first
std.debug.assert(!WasmPageAllocator.extended.isInitialized()); // Passes if this test runs first
const tmp = try page_allocator.alloc(u8, 1);
testing.expect(none_free == WasmPageAllocator.conventional.data[0]);
page_allocator.free(tmp);
testing.expect(none_free < WasmPageAllocator.conventional.data[0]);
const a_little_free = WasmPageAllocator.conventional.data[0];
const tmp_large = try page_allocator.alloc(u8, std.mem.page_size + 1);
testing.expect(a_little_free == WasmPageAllocator.conventional.data[0]);
const tmp_small = try page_allocator.alloc(u8, 1);
testing.expect(none_free == WasmPageAllocator.conventional.data[0]);
page_allocator.free(tmp_small);
testing.expect(a_little_free == WasmPageAllocator.conventional.data[0]);
page_allocator.free(tmp_large);
testing.expect(a_little_free < WasmPageAllocator.conventional.data[0]);
const more_free = WasmPageAllocator.conventional.data[0];
const supersize = try page_allocator.alloc(u8, std.mem.page_size * (WasmPageAllocator.conventional.totalPages() + 1));
testing.expect(more_free == WasmPageAllocator.conventional.data[0]);
testing.expect(!WasmPageAllocator.extended.isInitialized());
page_allocator.free(supersize);
testing.expect(WasmPageAllocator.extended.isInitialized());
testing.expect(more_free < WasmPageAllocator.conventional.data[0]);
}
}
test "PageAllocator" {
const allocator = page_allocator;
try testAllocator(allocator);