Commit e16d3d162a
Changed files (1)
lib
std
lib/std/Thread.zig
@@ -8,7 +8,10 @@
//! primitives that operate on kernel threads. For concurrency primitives that support
//! both evented I/O and async I/O, see the respective names in the top level std namespace.
-data: Data,
+const std = @import("std.zig");
+const os = std.os;
+const target = std.Target.current;
+const Atomic = std.atomic.Atomic;
pub const AutoResetEvent = @import("Thread/AutoResetEvent.zig");
pub const Futex = @import("Thread/Futex.zig");
@@ -18,118 +21,59 @@ pub const Mutex = @import("Thread/Mutex.zig");
pub const Semaphore = @import("Thread/Semaphore.zig");
pub const Condition = @import("Thread/Condition.zig");
-pub const use_pthreads = std.Target.current.os.tag != .windows and builtin.link_libc;
+pub const spinLoopHint = @compileError("deprecated: use std.atomic.spinLoopHint");
-const Thread = @This();
-const std = @import("std.zig");
-const builtin = std.builtin;
-const os = std.os;
-const mem = std.mem;
-const windows = std.os.windows;
-const c = std.c;
-const assert = std.debug.assert;
+pub const use_pthreads = target.os.tag != .windows and std.builtin.link_libc;
+
+const Impl = if (target.os.tag == .windows)
+ WindowsThreadImpl
+else if (use_pthreads)
+ PosixThreadImpl
+else if (target.os.tag == .linux)
+ LinuxThreadImpl
+else
+ @compileLog("Unsupported operating system", target.os.tag);
+
+impl: Impl,
-const bad_startfn_ret = "expected return type of startFn to be 'u8', 'noreturn', 'void', or '!void'";
/// Represents a kernel thread handle.
/// May be an integer or a pointer depending on the platform.
/// On Linux and POSIX, this is the same as Id.
-pub const Handle = if (use_pthreads)
- c.pthread_t
-else switch (std.Target.current.os.tag) {
- .linux => i32,
- .windows => windows.HANDLE,
- else => void,
-};
+pub const Handle = Impl.ThreadHandle;
/// Represents a unique ID per thread.
/// May be an integer or pointer depending on the platform.
/// On Linux and POSIX, this is the same as Handle.
-pub const Id = switch (std.Target.current.os.tag) {
- .windows => windows.DWORD,
- else => Handle,
-};
-
-pub const Data = if (use_pthreads)
- struct {
- handle: Thread.Handle,
- memory: []u8,
- }
-else switch (std.Target.current.os.tag) {
- .linux => struct {
- handle: Thread.Handle,
- memory: []align(mem.page_size) u8,
- },
- .windows => struct {
- handle: Thread.Handle,
- alloc_start: *c_void,
- heap_handle: windows.HANDLE,
- },
- else => struct {},
-};
+pub const Id = Impl.ThreadId;
-pub const spinLoopHint = @compileError("deprecated: use std.atomic.spinLoopHint");
-
-/// Returns the ID of the calling thread.
-/// Makes a syscall every time the function is called.
-/// On Linux and POSIX, this Id is the same as a Handle.
+/// Returns the platform ID of the callers thread.
+/// Attempts to use thread locals and avoid syscalls when possible.
pub fn getCurrentId() Id {
- if (use_pthreads) {
- return c.pthread_self();
- } else return switch (std.Target.current.os.tag) {
- .linux => os.linux.gettid(),
- .windows => windows.kernel32.GetCurrentThreadId(),
- else => @compileError("Unsupported OS"),
- };
+ return Impl.getCurrentId();
}
-/// Returns the handle of this thread.
-/// On Linux and POSIX, this is the same as Id.
-/// On Linux, it is possible that the thread spawned with `spawn`
-/// finishes executing entirely before the clone syscall completes. In this
-/// case, this function will return 0 rather than the no-longer-existing thread's
-/// pid.
-pub fn handle(self: Thread) Handle {
- return self.data.handle;
-}
+pub const CpuCountError = error{
+ PermissionDenied,
+ SystemResources,
+ Unexpected,
+};
-pub fn wait(self: *Thread) void {
- if (use_pthreads) {
- const err = c.pthread_join(self.data.handle, null);
- switch (err) {
- 0 => {},
- os.EINVAL => unreachable,
- os.ESRCH => unreachable,
- os.EDEADLK => unreachable,
- else => unreachable,
- }
- std.heap.c_allocator.free(self.data.memory);
- std.heap.c_allocator.destroy(self);
- } else switch (std.Target.current.os.tag) {
- .linux => {
- while (true) {
- const pid_value = @atomicLoad(i32, &self.data.handle, .SeqCst);
- if (pid_value == 0) break;
- const rc = os.linux.futex_wait(&self.data.handle, os.linux.FUTEX_WAIT, pid_value, null);
- switch (os.linux.getErrno(rc)) {
- 0 => continue,
- os.EINTR => continue,
- os.EAGAIN => continue,
- else => unreachable,
- }
- }
- os.munmap(self.data.memory);
- },
- .windows => {
- windows.WaitForSingleObjectEx(self.data.handle, windows.INFINITE, false) catch unreachable;
- windows.CloseHandle(self.data.handle);
- windows.HeapFree(self.data.heap_handle, 0, self.data.alloc_start);
- },
- else => @compileError("Unsupported OS"),
- }
+/// Returns the platforms view on the number of logical CPU cores available.
+pub fn getCpuCount() CpuCountError!usize {
+ return Impl.getCpuCount();
}
-pub const SpawnError = error{
+/// Configuration options for hints on how to spawn threads.
+pub const SpawnConfig = struct {
+ // TODO compile-time call graph analysis to determine stack upper bound
+ // https://github.com/ziglang/zig/issues/157
+
+ /// Size in bytes of the Thread's stack
+ stack_size: usize = 16 * 1024 * 1024,
+};
+
+pub const SpawnError = error {
/// A system-imposed limit on the number of threads was encountered.
/// There are a number of limits that may trigger this error:
/// * the RLIMIT_NPROC soft resource limit (set via setrlimit(2)),
@@ -159,248 +103,376 @@ pub const SpawnError = error{
Unexpected,
};
-// Given `T`, the type of the thread startFn, extract the expected type for the
-// context parameter.
-fn SpawnContextType(comptime T: type) type {
- const TI = @typeInfo(T);
- if (TI != .Fn)
- @compileError("expected function type, found " ++ @typeName(T));
-
- if (TI.Fn.args.len != 1)
- @compileError("expected function with single argument, found " ++ @typeName(T));
+/// Spawns a new thread which executes `function` using `args` and returns a handle the spawned thread.
+/// `config` can be used as hints to the platform for now to spawn and execute the `function`.
+/// The caller must eventually either call `join()` to wait for the thread to finish and free its resources
+/// or call `detach()` to excuse the caller from calling `join()` and have the thread clean up its resources on completion`.
+pub fn spawn(
+ config: SpawnConfig,
+ comptime function: anytype,
+ args: std.meta.ArgsTuple(function),
+) SpawnError!Thread {
+ if (std.builtin.single_threaded) {
+ @compileError("cannot spawn thread when building in single-threaded mode");
+ }
- return TI.Fn.args[0].arg_type orelse
- @compileError("cannot use a generic function as thread startFn");
+ const impl = try Thread.spawn(config, function, args);
+ return .{ .impl = impl };
}
-/// Spawns a new thread executing startFn, returning an handle for it.
-/// Caller must call wait on the returned thread.
-/// The `startFn` function must take a single argument of type T and return a
-/// value of type u8, noreturn, void or !void.
-/// The `context` parameter is of type T and is passed to the spawned thread.
-pub fn spawn(comptime startFn: anytype, context: SpawnContextType(@TypeOf(startFn))) SpawnError!*Thread {
- if (builtin.single_threaded) @compileError("cannot spawn thread when building in single-threaded mode");
- // TODO compile-time call graph analysis to determine stack upper bound
- // https://github.com/ziglang/zig/issues/157
- const default_stack_size = 16 * 1024 * 1024;
+/// Used by the Thread implementations to call the spawned function with the arguments.
+fn callFn(comptime f: anytype, args: anytype) switch (Impl) {
+ WindowsThreadImpl => windows.DWORD,
+ LinuxThreadImpl => u8,
+ PosixThreadImpl => ?*c_void,
+ else => unreachable,
+} {
+ const default_value = if (Impl == PosixThreadImpl) null else 0;
+ const bad_fn_ret = "expected return type of startFn to be 'u8', 'noreturn', 'void', or '!void'";
+
+ switch (@typeInfo(@typeInfo(@TypeOf(f)).Fn.return_type.?)) {
+ .NoReturn => {
+ @call(.{}, f, args);
+ },
+ .Void => {
+ @call(.{}, f, args);
+ return default_value;
+ },
+ .Int => |info| {
+ if (info.bits != 8) {
+ @compileError(bad_fn_ret);
+ }
- const Context = @TypeOf(context);
+ const status = @call(.{}, f, args);
+ if (Impl != PosixThreadImpl) {
+ return status;
+ }
- if (std.Target.current.os.tag == .windows) {
- const WinThread = struct {
- const OuterContext = struct {
- thread: Thread,
- inner: Context,
- };
- fn threadMain(raw_arg: windows.LPVOID) callconv(.C) windows.DWORD {
- const arg = if (@sizeOf(Context) == 0) undefined //
- else @ptrCast(*Context, @alignCast(@alignOf(Context), raw_arg)).*;
+ // pthreads don't support exit status, ignore value
+ _ = status;
+ return default_value;
+ },
+ .ErrorUnion => |info| {
+ if (info.payload != void) {
+ @compileError(bad_fn_ret);
+ }
- switch (@typeInfo(@typeInfo(@TypeOf(startFn)).Fn.return_type.?)) {
- .NoReturn => {
- startFn(arg);
- },
- .Void => {
- startFn(arg);
- return 0;
- },
- .Int => |info| {
- if (info.bits != 8) {
- @compileError(bad_startfn_ret);
- }
- return startFn(arg);
- },
- .ErrorUnion => |info| {
- if (info.payload != void) {
- @compileError(bad_startfn_ret);
- }
- startFn(arg) catch |err| {
- std.debug.warn("error: {s}\n", .{@errorName(err)});
- if (@errorReturnTrace()) |trace| {
- std.debug.dumpStackTrace(trace.*);
- }
- };
- return 0;
- },
- else => @compileError(bad_startfn_ret),
+ @call(.{}, f, args) catch |err| {
+ std.debug.warn("error: {s}\n", .{@errorName(err)});
+ if (@errorReturnTrace()) |trace| {
+ std.debug.dumpStackTrace(trace.*);
}
+ };
+
+ return default_value;
+ },
+ else => {
+ @compileError(bad_fn_ret);
+ },
+ }
+}
+
+/// Retrns the handle of this thread
+/// On Linux and POSIX, this is the same as Id.
+pub fn getHandle(self: Thread) Handle {
+ return self.impl.getHandle();
+}
+
+/// Release the obligation of the caller to call `join()` and have the thread clean up its own resources on completion.
+pub fn detach(self: Thread) void {
+ return self.impl.detach();
+}
+
+/// Waits for the thread to complete, then deallocates any resources created on `spawn()`.
+pub fn join(self: Thread) void {
+ return self.impl.join();
+}
+
+/// State to synchronize detachment of spawner thread to spawned thread
+const Completion = Atomic(enum {
+ running,
+ detached,
+ completed,
+});
+
+const WindowsThreadImpl = struct {
+ const windows = os.windows;
+
+ pub const ThreadHandle = windows.HANDLE;
+ pub const ThreadId = windows.DWORD;
+
+ fn getCurrentId() ThreadId {
+ return windows.kernel.GetCurrentThreadId();
+ }
+
+ fn getCpuCount() !usize {
+ return windows.peb().NumberOfProcessors;
+ }
+
+ thread: *ThreadCompletion,
+
+ const ThreadCompletion = struct {
+ completion: Completion,
+ heap_ptr: windows.PVOID,
+ heap_handle: windows.HANDLE,
+ thread_handle: windows.HANDLE = undefined,
+
+ fn free(self: ThreadCompletion) void {
+ const status = windows.kernel32.HeapFree(self.heap_handle, 0, self.heap_ptr);
+ assert(status == 0);
+ }
+ };
+
+ fn spawn(config: SpawnConfig, comptime f: anytype, args: anytype) !Impl {
+ const Args = @TypeOf(args);
+ const Instance = struct {
+ fn_args: Args,
+ thread: ThreadCompletion,
+
+ fn entryFn(raw_ptr: *windows.PVOID) callconv(.C) windows.DWORD {
+ const self = @ptrCast(*@This(), @alignCast(@alignOf(@This()), raw_ptr));
+ defer switch (self.thread.completion.swap(.completed, .Acquire)) {
+ .running => {},
+ .completed => unreachable,
+ .detached => self.thread.free(),
+ };
+ return callFn(f, self.fn_args);
}
};
const heap_handle = windows.kernel32.GetProcessHeap() orelse return error.OutOfMemory;
- const byte_count = @alignOf(WinThread.OuterContext) + @sizeOf(WinThread.OuterContext);
- const bytes_ptr = windows.kernel32.HeapAlloc(heap_handle, 0, byte_count) orelse return error.OutOfMemory;
- errdefer assert(windows.kernel32.HeapFree(heap_handle, 0, bytes_ptr) != 0);
- const bytes = @ptrCast([*]u8, bytes_ptr)[0..byte_count];
- const outer_context = std.heap.FixedBufferAllocator.init(bytes).allocator.create(WinThread.OuterContext) catch unreachable;
- outer_context.* = WinThread.OuterContext{
- .thread = Thread{
- .data = Thread.Data{
- .heap_handle = heap_handle,
- .alloc_start = bytes_ptr,
- .handle = undefined,
- },
+ const alloc_bytes = @alignOf(Instance) + @sizeOf(Instance);
+ const alloc_ptr = windows.kernel32.HeapAlloc(heap_handle, 0, alloc_bytes) orelse return error.OutOfMemory;
+ errdefer assert(windows.kernel32.HeapFree(heap_handle, 0, alloc_ptr) != 0);
+
+ const instance_bytes = @ptrCast([*]u8, alloc_ptr)[0..alloc_bytes];
+ const instance = std.heap.FixedBufferAllocator.init(instance_bytes).allocator.create(Instance) catch unreachable;
+ instance.* = .{
+ .fn_args = args,
+ .thread = .{
+ .completion = Completion.init(.running),
+ .heap_ptr = alloc_ptr,
+ .heap_handle = heap_handle,
},
- .inner = context,
};
- const parameter = if (@sizeOf(Context) == 0) null else @ptrCast(*c_void, &outer_context.inner);
- outer_context.thread.data.handle = windows.kernel32.CreateThread(null, default_stack_size, WinThread.threadMain, parameter, 0, null) orelse {
- switch (windows.kernel32.GetLastError()) {
- else => |err| return windows.unexpectedError(err),
- }
+ const stack_size = std.math.min(64 * 1024, std.math.cast(u32, config.stack_size) catch std.math.maxInt(u32));
+
+ const parameter = @ptrCast(*c_void, impl);
+
+ instance.thread.thread_handle = windows.CreateThread(null, stack_size, Impl.entry, parameter, 0, null) orelse {
+ return windows.unexpectedError(windows.kernel32.GetLastError());
};
- return &outer_context.thread;
+
+ return .{ .thread = &instance.thread };
}
- const MainFuncs = struct {
- fn linuxThreadMain(ctx_addr: usize) callconv(.C) u8 {
- const arg = if (@sizeOf(Context) == 0) undefined //
- else @intToPtr(*Context, ctx_addr).*;
-
- switch (@typeInfo(@typeInfo(@TypeOf(startFn)).Fn.return_type.?)) {
- .NoReturn => {
- startFn(arg);
- },
- .Void => {
- startFn(arg);
- return 0;
- },
- .Int => |info| {
- if (info.bits != 8) {
- @compileError(bad_startfn_ret);
- }
- return startFn(arg);
- },
- .ErrorUnion => |info| {
- if (info.payload != void) {
- @compileError(bad_startfn_ret);
- }
- startFn(arg) catch |err| {
- std.debug.warn("error: {s}\n", .{@errorName(err)});
- if (@errorReturnTrace()) |trace| {
- std.debug.dumpStackTrace(trace.*);
- }
- };
- return 0;
- },
- else => @compileError(bad_startfn_ret),
- }
+ fn getHandle(self: Impl) ThreadHandle {
+ return self.thread.thread_handle;
+ }
+
+ fn detach(self: Impl) void {
+ windows.CloseHandle(self.thread.thread_handle);
+ switch (self.thread.completion.swap(.detached, .AcqRel)) {
+ .running => {},
+ .completed => self.thread.free(),
+ .detached => unreachable,
}
- fn posixThreadMain(ctx: ?*c_void) callconv(.C) ?*c_void {
- const arg = if (@sizeOf(Context) == 0) undefined //
- else @ptrCast(*Context, @alignCast(@alignOf(Context), ctx)).*;
-
- switch (@typeInfo(@typeInfo(@TypeOf(startFn)).Fn.return_type.?)) {
- .NoReturn => {
- startFn(arg);
- },
- .Void => {
- startFn(arg);
- return null;
- },
- .Int => |info| {
- if (info.bits != 8) {
- @compileError(bad_startfn_ret);
- }
- // pthreads don't support exit status, ignore value
- _ = startFn(arg);
- return null;
- },
- .ErrorUnion => |info| {
- if (info.payload != void) {
- @compileError(bad_startfn_ret);
- }
- startFn(arg) catch |err| {
- std.debug.warn("error: {s}\n", .{@errorName(err)});
- if (@errorReturnTrace()) |trace| {
- std.debug.dumpStackTrace(trace.*);
- }
- };
- return null;
- },
- else => @compileError(bad_startfn_ret),
- }
+ }
+
+ fn join(self: Impl) void {
+ windows.WaitForSingleObjectEx(self.thread.thread_handle, windows.INFINITE, false) catch unreachable;
+ windows.CloseHandle(self.thread.thread_handle);
+ self.thread.free();
+ }
+};
+
+const PosixThreadImpl = struct {
+ const c = std.c;
+
+ pub const ThreadHandle = c.pthread_t;
+ pub const ThreadId = ThreadHandle;
+
+ fn getCurrentId() ThreadId {
+ return c.pthread_self();
+ }
+
+ fn getCpuCount() !usize {
+ switch (target.os.tag) {
+ .linux => return LinuxThreadImpl.getCpuCount(),
+ .openbsd => {
+ var count: c_int = undefined;
+ var count_size: usize = @sizeOf(c_int);
+ const mib = [_]c_int{ os.CTL_HW, os.HW_NCPUONLINE };
+ os.sysctl(&mib, &count, &count_size, null, 0) catch |err| switch (err) {
+ error.NameTooLong, error.UnknownName => unreachable,
+ else => |e| return e,
+ };
+ return @intCast(usize, count);
+ },
+ .haiku => {
+ var count: u32 = undefined;
+ var system_info: os.system_info = undefined;
+ _ = os.system.get_system_info(&system_info); // always returns B_OK
+ count = system_info.cpu_count;
+ return @intCast(usize, count);
+ },
+ else => {
+ var count: c_int = undefined;
+ var count_len: usize = @sizeOf(c_int);
+ const name = if (comptime target.isDarwin()) "hw.logicalcpu" else "hw.ncpu";
+ os.sysctlbynameZ(name, &count, &count_len, null, 0) catch |err| switch (err) {
+ error.NameTooLong, error.UnknownName => unreachable,
+ else => |e| return e,
+ };
+ return @intCast(usize, count);
+ },
}
- };
+ }
+
+ handle: ThreadHandle,
+
+ fn spawn(config: SpawnConfig, comptime f: anytype, args: anytype) !Impl {
+ const Args = @TypeOf(args);
+ const allocator = std.heap.c_allocator;
+ const Instance = struct {
+ fn entryFn(raw_arg: ?*c_void) callconv(.C) ?*c_void {
+ const args_ptr = @ptrCast(*Args, @alignCast(@alignOf(Args), raw_arg orelse unreachable));
+ defer allocator.destroy(args_ptr);
+ return callFn(f, args_ptr.*);
+ }
+ };
+
+ const args_ptr = try allocator.create(Args);
+ errdefer allocator.destroy(args_ptr);
- if (Thread.use_pthreads) {
var attr: c.pthread_attr_t = undefined;
if (c.pthread_attr_init(&attr) != 0) return error.SystemResources;
defer assert(c.pthread_attr_destroy(&attr) == 0);
- const thread_obj = try std.heap.c_allocator.create(Thread);
- errdefer std.heap.c_allocator.destroy(thread_obj);
- if (@sizeOf(Context) > 0) {
- thread_obj.data.memory = try std.heap.c_allocator.allocAdvanced(
- u8,
- @alignOf(Context),
- @sizeOf(Context),
- .at_least,
- );
- errdefer std.heap.c_allocator.free(thread_obj.data.memory);
- mem.copy(u8, thread_obj.data.memory, mem.asBytes(&context));
- } else {
- thread_obj.data.memory = @as([*]u8, undefined)[0..0];
- }
-
// Use the same set of parameters used by the libc-less impl.
- assert(c.pthread_attr_setstacksize(&attr, default_stack_size) == 0);
- assert(c.pthread_attr_setguardsize(&attr, mem.page_size) == 0);
+ const stack_size = std.math.max(config.stack_size, 16 * 1024);
+ assert(c.pthread_attr_setstacksize(&attr, stack_size) == 0);
+ assert(c.pthread_attr_setguardsize(&attr, std.mem.page_size) == 0);
- const err = c.pthread_create(
- &thread_obj.data.handle,
+ var handle: c.pthread_t = undefined;
+ return switch (c.pthread_create(
+ &handle,
&attr,
- MainFuncs.posixThreadMain,
- thread_obj.data.memory.ptr,
- );
- switch (err) {
- 0 => return thread_obj,
- os.EAGAIN => return error.SystemResources,
+ Instance.entryFn,
+ @ptrCast(*c_void, args_ptr),
+ )) {
+ 0 => .{ .handle = handle },
+ os.EAGAIN => error.SystemResources,
os.EPERM => unreachable,
os.EINVAL => unreachable,
- else => return os.unexpectedErrno(err),
- }
+ else => os.unexpectedErrno(err),
+ };
+ }
+
+ fn getHandle(self: Impl) ThreadHandle {
+ return self.handle;
+ }
- return thread_obj;
+ fn detach(self: Impl) void {
+ switch (c.pthread_detach(self.handle)) {
+ os.EINVAL => unreachable,
+ os.ESRCH => unreachable,
+ else => unreachable,
+ }
}
- var guard_end_offset: usize = undefined;
- var stack_end_offset: usize = undefined;
- var thread_start_offset: usize = undefined;
- var context_start_offset: usize = undefined;
- var tls_start_offset: usize = undefined;
- const mmap_len = blk: {
- var l: usize = mem.page_size;
- // Allocate a guard page right after the end of the stack region
- guard_end_offset = l;
- // The stack itself, which grows downwards.
- l = mem.alignForward(l + default_stack_size, mem.page_size);
- stack_end_offset = l;
- // Above the stack, so that it can be in the same mmap call, put the Thread object.
- l = mem.alignForward(l, @alignOf(Thread));
- thread_start_offset = l;
- l += @sizeOf(Thread);
- // Next, the Context object.
- if (@sizeOf(Context) != 0) {
- l = mem.alignForward(l, @alignOf(Context));
- context_start_offset = l;
- l += @sizeOf(Context);
+ fn join(self: Impl) void {
+ switch (c.pthread_join(self.handle, null)) {
+ 0 => {},
+ os.EINVAL => unreachable,
+ os.ESRCH => unreachable,
+ os.EDEADLK => unreachable,
+ else => unreachable,
}
- // Finally, the Thread Local Storage, if any.
- l = mem.alignForward(l, os.linux.tls.tls_image.alloc_align);
- tls_start_offset = l;
- l += os.linux.tls.tls_image.alloc_size;
- // Round the size to the page size.
- break :blk mem.alignForward(l, mem.page_size);
+ }
+};
+
+const LinuxThreadImpl = struct {
+ const linux = os.linux;
+
+ pub const ThreadHandle = i32;
+ pub const ThreadId = ThreadHandle;
+
+ threadlocal var tls_thread_id: ?ThreadId = null;
+
+ fn getCurrentId() ThreadId {
+ return tls_thread_id orelse {
+ const tid = linux.gettid();
+ tls_thread_id = tid;
+ return tid;
+ };
+ }
+
+ fn getCpuCount() !usize {
+ const cpu_set = try os.sched_getaffinity(0);
+ return @as(usize, os.CPU_COUNT(cpu_set)); // TODO should not need this usize cast
+ }
+
+ thread: *ThreadCompletion,
+
+ const ThreadCompletion = struct {
+ completion: Completion = Completion.init(.running),
+ child_tid: Atomic(i32) = Atomic(i32).init(0),
+ parent_tid: i32 = undefined,
+ mapped: []align(std.mem.page_size) u8,
};
- const mmap_slice = mem: {
- // Map the whole stack with no rw permissions to avoid
- // committing the whole region right away
- const mmap_slice = os.mmap(
+ fn spawn(config: SpawnConfig, comptime f: anytype, args: anytype) !Impl {
+ const Args = @TypeOf(args);
+ const Instance = struct {
+ fn_args: Args,
+ thread: ThreadCompletion,
+
+ fn entryFn(raw_arg: usize) callconv(.C) u8 {
+ const self = @intToPtr(*@This(), raw_arg);
+ defer switch (self.thread.completion.swap(.completed, .Acquire)) {
+ .running => {},
+ .completed => unreachable,
+ .detached => {
+ const memory = self.thread.mapped;
+ __unmap_and_exit(@ptrToInt(memory.ptr), memory.len);
+ },
+ };
+ return callFn(f, self.fn_args);
+ }
+ };
+
+ var guard_offset: usize = undefined;
+ var stack_offset: usize = undefined;
+ var tls_offset: usize = undefined;
+ var instance_offset: usize = undefined;
+
+ const map_bytes = blk: {
+ var bytes: usize = std.mem.page_size;
+ guard_offset = bytes;
+
+ bytes += std.math.max(std.mem.page_size, config.stack_size);
+ bytes = std.mem.alignForward(bytes, std.mem.page_size);
+ stack_offset = bytes;
+
+ bytes = std.mem.alignForward(bytes, linux.tls.tls_image.alloc_align);
+ tls_offset = bytes;
+ bytes += linux.tls.tls_image.alloc_size;
+
+ bytes = std.mem.alignForward(bytes, @alignOf(Instance));
+ instance_offset = bytes;
+ bytes += @sizeOf(Instance);
+
+ bytes = std.mem.alignForward(bytes, std.mem.page_size);
+ break :blk bytes;
+ };
+
+ // map all memory needed without read/write permissions
+ // to avoid committing the whole region right away
+ const mapped = os.mmap(
null,
- mmap_len,
+ map_bytes,
os.PROT_NONE,
os.MAP_PRIVATE | os.MAP_ANONYMOUS,
-1,
@@ -411,175 +483,170 @@ pub fn spawn(comptime startFn: anytype, context: SpawnContextType(@TypeOf(startF
error.PermissionDenied => unreachable,
else => |e| return e,
};
- errdefer os.munmap(mmap_slice);
+ errdefer os.munmap(mapped);
- // Map everything but the guard page as rw
+ // map everything but the guard page as read/write
os.mprotect(
- mmap_slice[guard_end_offset..],
+ mapped[guard_offset..],
os.PROT_READ | os.PROT_WRITE,
) catch |err| switch (err) {
error.AccessDenied => unreachable,
else => |e| return e,
};
- break :mem mmap_slice;
- };
-
- const mmap_addr = @ptrToInt(mmap_slice.ptr);
-
- const thread_ptr = @alignCast(@alignOf(Thread), @intToPtr(*Thread, mmap_addr + thread_start_offset));
- thread_ptr.data.memory = mmap_slice;
+ // Prepare the TLS segment and prepare a user_desc struct when needed on i386
+ var tls_ptr = os.linux.tls.prepareTLS(mapped[tls_offset..]);
+ var user_desc: if (target.cpu.arch == .i386) os.linux.user_desc else void = undefined;
+ if (target.cpu.arch == .i386) {
+ defer tls_ptr = @ptrToInt(&user_desc);
+ user_desc = .{
+ .entry_number = os.linux.tls.tls_image.gdt_entry_number,
+ .base_addr = tks_ptr,
+ .limit = 0xfffff,
+ .seg_32bit = 1,
+ .contents = 0, // Data
+ .read_exec_only = 0,
+ .limit_in_pages = 1,
+ .seg_not_present = 0,
+ .useable = 1,
+ };
+ }
- var arg: usize = undefined;
- if (@sizeOf(Context) != 0) {
- arg = mmap_addr + context_start_offset;
- const context_ptr = @alignCast(@alignOf(Context), @intToPtr(*Context, arg));
- context_ptr.* = context;
- }
+ const instance = @ptrCast(*Instance, @alignCast(@alignOf(Instance), &mapped[instance_offset]));
+ instance.* = .{
+ .fn_args = args,
+ .thread = .{ .mapped = .mapped },
+ };
- if (std.Target.current.os.tag == .linux) {
const flags: u32 = os.CLONE_VM | os.CLONE_FS | os.CLONE_FILES |
os.CLONE_SIGHAND | os.CLONE_THREAD | os.CLONE_SYSVSEM |
os.CLONE_PARENT_SETTID | os.CLONE_CHILD_CLEARTID |
os.CLONE_DETACHED | os.CLONE_SETTLS;
- // This structure is only needed when targeting i386
- var user_desc: if (std.Target.current.cpu.arch == .i386) os.linux.user_desc else void = undefined;
-
- const tls_area = mmap_slice[tls_start_offset..];
- const tp_value = os.linux.tls.prepareTLS(tls_area);
-
- const newtls = blk: {
- if (std.Target.current.cpu.arch == .i386) {
- user_desc = os.linux.user_desc{
- .entry_number = os.linux.tls.tls_image.gdt_entry_number,
- .base_addr = tp_value,
- .limit = 0xfffff,
- .seg_32bit = 1,
- .contents = 0, // Data
- .read_exec_only = 0,
- .limit_in_pages = 1,
- .seg_not_present = 0,
- .useable = 1,
- };
- break :blk @ptrToInt(&user_desc);
- } else {
- break :blk tp_value;
- }
- };
- const rc = os.linux.clone(
- MainFuncs.linuxThreadMain,
- mmap_addr + stack_end_offset,
+ return switch (linux.getErrno(linux.clone(
+ Instance.entryFn,
+ @ptrToInt(&mapped[stack_offset]),
flags,
- arg,
- &thread_ptr.data.handle,
- newtls,
- &thread_ptr.data.handle,
- );
- switch (os.errno(rc)) {
- 0 => return thread_ptr,
- os.EAGAIN => return error.ThreadQuotaExceeded,
+ @ptrToInt(instance),
+ &instance.thread.parent_tid,
+ tls_ptr,
+ &instance.thread.child_tid.value,
+ ))) {
+ 0 => .{ .thread = &instance.thread },
+ os.EAGAIN => error.ThreadQuotaExceeded,
os.EINVAL => unreachable,
- os.ENOMEM => return error.SystemResources,
+ os.ENOMEM => error.SystemResources,
os.ENOSPC => unreachable,
os.EPERM => unreachable,
os.EUSERS => unreachable,
- else => |err| return os.unexpectedErrno(err),
- }
- } else {
- @compileError("Unsupported OS");
+ else => |err| os.unexpectedErrno(err),
+ };
}
-}
-pub const CpuCountError = error{
- PermissionDenied,
- SystemResources,
- Unexpected,
-};
+ fn getHandle(self: Impl) ThreadHandle {
+ return self.thread.parent_tid;
+ }
-pub fn cpuCount() CpuCountError!usize {
- switch (std.Target.current.os.tag) {
- .linux => {
- const cpu_set = try os.sched_getaffinity(0);
- return @as(usize, os.CPU_COUNT(cpu_set)); // TODO should not need this usize cast
- },
- .windows => {
- return os.windows.peb().NumberOfProcessors;
- },
- .openbsd => {
- var count: c_int = undefined;
- var count_size: usize = @sizeOf(c_int);
- const mib = [_]c_int{ os.CTL_HW, os.HW_NCPUONLINE };
- os.sysctl(&mib, &count, &count_size, null, 0) catch |err| switch (err) {
- error.NameTooLong, error.UnknownName => unreachable,
- else => |e| return e,
- };
- return @intCast(usize, count);
- },
- .haiku => {
- var count: u32 = undefined;
- // var system_info: os.system_info = undefined;
- // const rc = os.system.get_system_info(&system_info);
- count = system_info.cpu_count;
- return @intCast(usize, count);
- },
- else => {
- var count: c_int = undefined;
- var count_len: usize = @sizeOf(c_int);
- const name = if (comptime std.Target.current.isDarwin()) "hw.logicalcpu" else "hw.ncpu";
- os.sysctlbynameZ(name, &count, &count_len, null, 0) catch |err| switch (err) {
- error.NameTooLong, error.UnknownName => unreachable,
- else => |e| return e,
- };
- return @intCast(usize, count);
- },
+ fn detach(self: Impl) void {
+ switch (self.thread.completion.swap(.detached, .AcqRel)) {
+ .running => {},
+ .completed => self.join(),
+ .detached => unreachable,
+ }
}
-}
-pub fn getCurrentThreadId() u64 {
- switch (std.Target.current.os.tag) {
- .linux => {
- // Use the syscall directly as musl doesn't provide a wrapper.
- return @bitCast(u32, os.linux.gettid());
- },
- .windows => {
- return os.windows.kernel32.GetCurrentThreadId();
- },
- .macos, .ios, .watchos, .tvos => {
- var thread_id: u64 = undefined;
- // Pass thread=null to get the current thread ID.
- assert(c.pthread_threadid_np(null, &thread_id) == 0);
- return thread_id;
- },
- .dragonfly => {
- return @bitCast(u32, c.lwp_gettid());
- },
- .netbsd => {
- return @bitCast(u32, c._lwp_self());
- },
- .freebsd => {
- return @bitCast(u32, c.pthread_getthreadid_np());
- },
- .openbsd => {
- return @bitCast(u32, c.getthrid());
- },
- .haiku => {
- return @bitCast(u32, c.find_thread(null));
- },
- else => {
- @compileError("getCurrentThreadId not implemented for this platform");
- },
+ fn join(self: Impl) void {
+ defer self.thread.free();
+
+ var spin: u8 = 10;
+ while (true) {
+ const tid = self.thread.child_tid.load(.Acquire);
+ if (tid == 0) {
+ break;
+ }
+
+ if (spin > 0) {
+ spin -= 1;
+ std.atomic.spinLoopHint();
+ continue;
+ }
+
+ switch (linux.getErrno(linux.futex_wait(
+ &self.thread.child_tid.value,
+ linux.FUTEX_WAIT,
+ tid,
+ null,
+ ))) {
+ 0 => continue,
+ os.EINTR => continue,
+ os.EAGAIN => continue,
+ else => unreachable,
+ }
+ }
}
-}
-test "std.Thread" {
- if (!builtin.single_threaded) {
- _ = AutoResetEvent;
- _ = Futex;
- _ = ResetEvent;
- _ = StaticResetEvent;
- _ = Mutex;
- _ = Semaphore;
- _ = Condition;
+ // Calls `munmap(ptr, len)` then `exit(1)` without touching the stack (which lives in `ptr`).
+ // Ported over from musl libc's pthread detached implementation.
+ extern fn __unmap_and_exit(ptr: usize, len: usize) callconv(.C) noreturn;
+ comptime {
+ asm(switch (target.cpu.arch) {
+ .i386 => (
+ \\.text
+ \\.global __unmap_and_exit
+ \\.type __unmap_and_exit, @function
+ \\__unmap_and_exit:
+ \\ movl $91, %eax
+ \\ movl 4(%esp), %ebx
+ \\ movl 8(%esp), %ecx
+ \\ int $128
+ \\ xorl %ebx, %ebx
+ \\ movl $1, %eax
+ \\ int $128
+ ),
+ .x86_64 => (
+ \\.text
+ \\.global __unmap_and_exit
+ \\.type __unmap_and_exit, @function
+ \\__unmap_and_exit:
+ \\ movl $11, %eax
+ \\ syscall
+ \\ xor %rdi, %rdi
+ \\ movl $60, %eax
+ \\ syscall
+ ),
+ .arm, .armeb, .aarch64, .aarch64_be, .aarch64_32 => (
+ \\.text
+ \\.global __unmap_and_exit
+ \\.type __unmap_and_exit, @function
+ \\__unmap_and_exit:
+ \\ mov r7, #91
+ \\ svc 0
+ \\ mov r7, #1
+ \\ svc 0
+ ),
+ .mips, .mipsel, .mips64, .mips64el => (
+ \\.set noreorder
+ \\.global __unmap_and_exit
+ \\.type __unmap_and_exit, @function
+ \\__unmap_and_exit:
+ \\ li $2, 4091
+ \\ syscall
+ \\ li $4, 0
+ \\ li $2, 4001
+ \\ syscall
+ ),
+ .powerpc, .powerpc64, .powerpc64le => (
+ \\.text
+ \\.global __unmap_and_exit
+ \\.type __unmap_and_exit, @function
+ \\__unmap_and_exit:
+ \\ li 0, 91
+ \\ sc
+ \\ li 0, 1
+ \\ sc
+ \\ blr
+ ),
+ else => @compileError("Platform not supported"),
+ });
}
-}
+};
\ No newline at end of file