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Fix page sizes #1184

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merged 7 commits into from
Mar 9, 2025
Merged

Fix page sizes #1184

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259f6b4
update VirtualList to new page size API
archbirdplus Feb 28, 2025
0680a7f
Resolve TODO
archbirdplus Mar 9, 2025
4d6de49
replace pageSize() with page_size_max in comptime
archbirdplus Mar 9, 2025
a8df301
determine maxSizeBytes at runtime
archbirdplus Mar 9, 2025
94f8182
remove assertion
archbirdplus Mar 9, 2025
a78cce4
add aarch64 linux to CI
archbirdplus Mar 9, 2025
a44876a
revert CI
archbirdplus Mar 9, 2025
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28 changes: 16 additions & 12 deletions src/utils/list.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -433,9 +433,11 @@ pub fn ListUnmanaged(comptime T: type) type {
};
}

const pageSize = 4096;
const page_size_min = std.heap.page_size_min;
const page_size_max = std.heap.page_size_max;
const pageSize = std.heap.pageSize;

fn reserveMemory(len: usize) [*]align(pageSize) u8 {
fn reserveMemory(len: usize) [*]align(page_size_min) u8 {
if(builtin.os.tag == .windows) {
return @ptrCast(@alignCast(std.os.windows.VirtualAlloc(null, len, std.os.windows.MEM_RESERVE, std.os.windows.PAGE_READWRITE) catch |err| {
std.log.err("Got error while reserving virtual memory of size {}: {s}", .{len, @errorName(err)});
Expand All @@ -449,7 +451,7 @@ fn reserveMemory(len: usize) [*]align(pageSize) u8 {
}
}

fn commitMemory(start: [*]align(pageSize) u8, len: usize) void {
fn commitMemory(start: [*]align(page_size_min) u8, len: usize) void {
if(builtin.os.tag == .windows) {
_ = std.os.windows.VirtualAlloc(start, len, std.os.windows.MEM_COMMIT, std.os.windows.PAGE_READWRITE) catch |err| {
std.log.err("Got error while committing virtual memory of size {}: {s}.", .{len, @errorName(err)});
Expand All @@ -463,7 +465,7 @@ fn commitMemory(start: [*]align(pageSize) u8, len: usize) void {
}
}

fn releaseMemory(start: [*]align(pageSize) u8, len: usize) void {
fn releaseMemory(start: [*]align(page_size_min) u8, len: usize) void {
if(builtin.os.tag == .windows) {
std.os.windows.VirtualFree(start, 0, std.os.windows.MEM_RELEASE);
} else {
Expand All @@ -474,23 +476,25 @@ fn releaseMemory(start: [*]align(pageSize) u8, len: usize) void {
/// A list that reserves a continuous region of virtual memory without actually committing its pages.
/// This allows it to grow without ever invalidating pointers.
pub fn VirtualList(T: type, maxSize: u32) type {
const maxSizeBytes = std.mem.alignForward(usize, @as(usize, maxSize)*@sizeOf(T), pageSize);
std.debug.assert(@sizeOf(T) <= pageSize);
return struct {
mem: [*]align(pageSize) T,
mem: [*]align(page_size_min) T,
len: u32,
committedCapacity: u32,

fn maxSizeBytes() usize {
return std.mem.alignForward(usize, @as(usize, maxSize)*@sizeOf(T), pageSize());
}

pub fn init() @This() {
return .{
.mem = @ptrCast(reserveMemory(maxSizeBytes)),
.mem = @ptrCast(reserveMemory(maxSizeBytes())),
.len = 0,
.committedCapacity = 0,
};
}

pub fn deinit(self: @This()) void {
releaseMemory(@ptrCast(self.mem), maxSizeBytes);
releaseMemory(@ptrCast(self.mem), maxSizeBytes());
}

pub fn items(self: *@This()) []T {
Expand All @@ -503,10 +507,10 @@ pub fn VirtualList(T: type, maxSize: u32) type {

pub fn ensureCapacity(self: *@This(), newCapacity: usize) void {
if(newCapacity > self.committedCapacity) {
const alignedCapacity = std.mem.alignForward(usize, self.committedCapacity*@sizeOf(T), pageSize);
const newAlignedCapacity = std.mem.alignForward(usize, newCapacity*@sizeOf(T), pageSize);
const alignedCapacity = std.mem.alignForward(usize, self.committedCapacity*@sizeOf(T), pageSize());
const newAlignedCapacity = std.mem.alignForward(usize, newCapacity*@sizeOf(T), pageSize());

commitMemory(@alignCast(@as([*]align(pageSize) u8, @ptrCast(self.mem))[alignedCapacity..]), newAlignedCapacity - alignedCapacity);
commitMemory(@alignCast(@as([*]align(page_size_min) u8, @ptrCast(self.mem))[alignedCapacity..]), newAlignedCapacity - alignedCapacity);
self.committedCapacity = @intCast(newAlignedCapacity/@sizeOf(T));
}
}
Expand Down