26#include <seastar/core/thread_impl.hh>
27#include <seastar/core/future.hh>
28#include <seastar/core/do_with.hh>
33#include <seastar/util/assert.hh>
34#include <seastar/util/std-compat.hh>
35#include <seastar/util/modules.hh>
37#include <boost/intrusive/list.hpp>
75SEASTAR_MODULE_EXPORT_BEGIN
77class thread_attributes;
82 std::optional<seastar::scheduling_group> sched_group;
84 size_t stack_size = 0;
86SEASTAR_MODULE_EXPORT_END
89extern thread_local jmp_buf_link g_unthreaded_context;
94class thread_context final :
private task {
95 struct stack_deleter {
96 void operator()(
char *ptr)
const noexcept;
98 stack_deleter(
int valgrind_id);
100 using stack_holder = std::unique_ptr<char[], stack_deleter>;
103 noncopyable_function<void ()> _func;
104 jmp_buf_link _context;
106 bool _joined =
false;
108 boost::intrusive::list_member_hook<> _all_link;
109 using all_thread_list = boost::intrusive::list<thread_context,
110 boost::intrusive::member_hook<thread_context, boost::intrusive::list_member_hook<>,
111 &thread_context::_all_link>,
112 boost::intrusive::constant_time_size<false>>;
114 static thread_local all_thread_list _all_threads;
116 static void s_main(
int lo,
int hi);
117 void setup(
size_t stack_size);
119 stack_holder make_stack(
size_t stack_size);
120 virtual void run_and_dispose() noexcept override;
122 thread_context(thread_attributes attr, noncopyable_function<
void ()> func);
126 bool should_yield() const;
129 task* waiting_task() noexcept
override {
return _done.waiting_task(); }
131 friend void thread_impl::switch_in(thread_context*);
132 friend void thread_impl::switch_out(thread_context*);
133 friend scheduling_group thread_impl::sched_group(
const thread_context*);
146 std::unique_ptr<thread_context> _context;
147 static thread_local thread* _current;
156 template <
typename Func>
163 template <
typename Func>
172 ~thread() { SEASTAR_ASSERT(!_context || _context->_joined); }
188 return need_preempt();
201 static bool running_in_thread() {
202 return thread_impl::get() !=
nullptr;
206template <
typename Func>
209 : _context(
std::make_unique<thread_context>(
std::move(attr),
std::move(func))) {
212template <
typename Func>
221 _context->_joined =
true;
222 return _context->_done.get_future();
225SEASTAR_MODULE_EXPORT_BEGIN
249template <
typename Func,
typename... Args>
251futurize_t<std::invoke_result_t<Func, Args...>>
253 using return_type = std::invoke_result_t<Func, Args...>;
257 std::tuple<Args...> args;
263 auto wp = std::make_unique<work>(work{std::move(attr), std::forward<Func>(func), std::forward_as_tuple(std::forward<Args>(args)...)});
265 auto ret = w.pr.get_future();
266 w.th =
thread(std::move(w.attr), [&w] {
267 futurize<return_type>::apply(std::move(w.func), std::move(w.args)).forward_to(std::move(w.pr));
269 return w.th.join().then([ret = std::move(ret)] ()
mutable {
270 return std::move(ret);
271 }).
finally([wp = std::move(wp)] {});
286template <
typename Func,
typename... Args>
288futurize_t<std::invoke_result_t<Func, Args...>>
289async(Func&& func, Args&&... args)
noexcept {
294SEASTAR_MODULE_EXPORT_END
A representation of a possibly not-yet-computed value.
Definition: future.hh:1197
thread - stateful thread of execution
Definition: thread.hh:145
~thread()
Destroys a thread object.
Definition: thread.hh:172
thread(thread &&x) noexcept=default
Moves a thread object.
static void maybe_yield()
Yield if this thread ought to call yield() now.
Definition: thread.hh:195
static void yield()
Voluntarily defer execution of current thread.
thread()=default
Constructs a thread object that does not represent a thread of execution.
static bool should_yield()
Checks whether this thread ought to call yield() now.
Definition: thread.hh:187
thread & operator=(thread &&x) noexcept=default
Move-assigns a thread object.
future yield() noexcept
Returns a future which is not ready but is scheduled to resolve soon.
Class that holds attributes controling the behavior of a thread.
Definition: thread.hh:80
futurize_t< std::invoke_result_t< Func, Args... > > async(thread_attributes attr, Func &&func, Args &&... args) noexcept
Definition: thread.hh:252
future join()
Waits for thread execution to terminate.
Definition: thread.hh:220
Seastar API namespace.
Definition: abort_on_ebadf.hh:26
Converts a type to a future type, if it isn't already.
Definition: future.hh:1786