orbis-kernel: Add SharedAtomic utility

Initial shared atomic implementation for Darwin
This commit is contained in:
DH 2024-10-31 22:54:16 +03:00
parent d83a0723a7
commit 7d0f277ad5
10 changed files with 578 additions and 97 deletions

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@ -3,6 +3,7 @@ set(CMAKE_POSITION_INDEPENDENT_CODE on)
add_library(obj.orbis-utils-ipc OBJECT
src/utils/SharedMutex.cpp
src/utils/SharedCV.cpp
src/utils/SharedAtomic.cpp
)
add_library(obj.orbis-kernel OBJECT
src/module.cpp
@ -89,6 +90,12 @@ target_include_directories(obj.orbis-utils-ipc
${CMAKE_CURRENT_SOURCE_DIR}/include/orbis
)
if(${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
target_compile_definitions(obj.orbis-utils-ipc PUBLIC ORBIS_HAS_FUTEX)
elseif(${CMAKE_SYSTEM_NAME} STREQUAL "Darwin")
target_compile_definitions(obj.orbis-utils-ipc PUBLIC ORBIS_HAS_ULOCK)
endif()
add_library(orbis-utils-ipc STATIC)
add_library(orbis-kernel STATIC)
add_library(orbis-kernel-shared SHARED)

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@ -2,3 +2,165 @@
#include "error/ErrorCode.hpp" // IWYU pragma: export
#include "error/SysResult.hpp" // IWYU pragma: export
#include <system_error>
namespace orbis {
static orbis::ErrorCode toErrorCode(std::errc errc) {
if (errc == std::errc{}) {
return {};
}
switch (errc) {
case std::errc::address_family_not_supported:
return orbis::ErrorCode::AFNOSUPPORT;
case std::errc::address_in_use:
return orbis::ErrorCode::ADDRINUSE;
case std::errc::address_not_available:
return orbis::ErrorCode::ADDRNOTAVAIL;
case std::errc::already_connected:
return orbis::ErrorCode::ISCONN;
case std::errc::argument_out_of_domain:
return orbis::ErrorCode::DOM;
case std::errc::bad_address:
return orbis::ErrorCode::FAULT;
case std::errc::bad_file_descriptor:
return orbis::ErrorCode::BADF;
case std::errc::bad_message:
return orbis::ErrorCode::BADMSG;
case std::errc::broken_pipe:
return orbis::ErrorCode::PIPE;
case std::errc::connection_aborted:
return orbis::ErrorCode::CONNABORTED;
case std::errc::connection_already_in_progress:
return orbis::ErrorCode::ALREADY;
case std::errc::connection_refused:
return orbis::ErrorCode::CONNREFUSED;
case std::errc::connection_reset:
return orbis::ErrorCode::CONNRESET;
case std::errc::cross_device_link:
return orbis::ErrorCode::XDEV;
case std::errc::destination_address_required:
return orbis::ErrorCode::DESTADDRREQ;
case std::errc::device_or_resource_busy:
return orbis::ErrorCode::BUSY;
case std::errc::directory_not_empty:
return orbis::ErrorCode::NOTEMPTY;
case std::errc::executable_format_error:
return orbis::ErrorCode::NOEXEC;
case std::errc::file_exists:
return orbis::ErrorCode::EXIST;
case std::errc::file_too_large:
return orbis::ErrorCode::FBIG;
case std::errc::filename_too_long:
return orbis::ErrorCode::NAMETOOLONG;
case std::errc::function_not_supported:
return orbis::ErrorCode::NOSYS;
case std::errc::host_unreachable:
return orbis::ErrorCode::HOSTUNREACH;
case std::errc::identifier_removed:
return orbis::ErrorCode::IDRM;
case std::errc::illegal_byte_sequence:
return orbis::ErrorCode::ILSEQ;
case std::errc::inappropriate_io_control_operation:
return orbis::ErrorCode::NOTTY;
case std::errc::interrupted:
return orbis::ErrorCode::INTR;
case std::errc::invalid_argument:
return orbis::ErrorCode::INVAL;
case std::errc::invalid_seek:
return orbis::ErrorCode::SPIPE;
case std::errc::io_error:
return orbis::ErrorCode::IO;
case std::errc::is_a_directory:
return orbis::ErrorCode::ISDIR;
case std::errc::message_size:
return orbis::ErrorCode::MSGSIZE;
case std::errc::network_down:
return orbis::ErrorCode::NETDOWN;
case std::errc::network_reset:
return orbis::ErrorCode::NETRESET;
case std::errc::network_unreachable:
return orbis::ErrorCode::NETUNREACH;
case std::errc::no_buffer_space:
return orbis::ErrorCode::NOBUFS;
case std::errc::no_child_process:
return orbis::ErrorCode::CHILD;
case std::errc::no_link:
return orbis::ErrorCode::NOLINK;
case std::errc::no_lock_available:
return orbis::ErrorCode::NOLCK;
case std::errc::no_message:
return orbis::ErrorCode::NOMSG;
case std::errc::no_protocol_option:
return orbis::ErrorCode::NOPROTOOPT;
case std::errc::no_space_on_device:
return orbis::ErrorCode::NOSPC;
case std::errc::no_such_device_or_address:
return orbis::ErrorCode::NXIO;
case std::errc::no_such_device:
return orbis::ErrorCode::NODEV;
case std::errc::no_such_file_or_directory:
return orbis::ErrorCode::NOENT;
case std::errc::no_such_process:
return orbis::ErrorCode::SRCH;
case std::errc::not_a_directory:
return orbis::ErrorCode::NOTDIR;
case std::errc::not_a_socket:
return orbis::ErrorCode::NOTSOCK;
case std::errc::not_connected:
return orbis::ErrorCode::NOTCONN;
case std::errc::not_enough_memory:
return orbis::ErrorCode::NOMEM;
case std::errc::not_supported:
return orbis::ErrorCode::NOTSUP;
case std::errc::operation_canceled:
return orbis::ErrorCode::CANCELED;
case std::errc::operation_in_progress:
return orbis::ErrorCode::INPROGRESS;
case std::errc::operation_not_permitted:
return orbis::ErrorCode::PERM;
case std::errc::operation_would_block:
return orbis::ErrorCode::WOULDBLOCK;
case std::errc::permission_denied:
return orbis::ErrorCode::ACCES;
case std::errc::protocol_error:
return orbis::ErrorCode::PROTO;
case std::errc::protocol_not_supported:
return orbis::ErrorCode::PROTONOSUPPORT;
case std::errc::read_only_file_system:
return orbis::ErrorCode::ROFS;
case std::errc::resource_deadlock_would_occur:
return orbis::ErrorCode::DEADLK;
case std::errc::result_out_of_range:
return orbis::ErrorCode::RANGE;
case std::errc::text_file_busy:
return orbis::ErrorCode::TXTBSY;
case std::errc::timed_out:
return orbis::ErrorCode::TIMEDOUT;
case std::errc::too_many_files_open_in_system:
return orbis::ErrorCode::NFILE;
case std::errc::too_many_files_open:
return orbis::ErrorCode::MFILE;
case std::errc::too_many_links:
return orbis::ErrorCode::MLINK;
case std::errc::too_many_symbolic_link_levels:
return orbis::ErrorCode::LOOP;
case std::errc::value_too_large:
return orbis::ErrorCode::OVERFLOW;
case std::errc::wrong_protocol_type:
return orbis::ErrorCode::PROTOTYPE;
default:
return orbis::ErrorCode::FAULT;
}
}
inline constexpr orbis::ErrorCode toErrorCode(const std::error_code &code) {
if (!code) {
return {};
}
if (code.category() != std::generic_category()) {
return orbis::ErrorCode::DOOFUS;
}
return toErrorCode(static_cast<std::errc>(code.value()));
}
} // namespace orbis

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@ -0,0 +1,165 @@
#pragma once
#include <atomic>
#include <chrono>
#include <cstdint>
#include <functional>
#include <limits>
#include <system_error>
#include <thread>
#include <type_traits>
namespace orbis {
inline void yield() { std::this_thread::yield(); }
inline void relax() {
#if defined(__GNUC__) && (defined __i386__ || defined __x86_64__)
__builtin_ia32_pause();
#else
yield();
#endif
}
static constexpr auto kRelaxSpinCount = 12;
static constexpr auto kSpinCount = 16;
inline namespace utils {
bool try_spin_wait(auto &&pred) {
for (std::size_t i = 0; i < kSpinCount; ++i) {
if (pred()) {
return true;
}
if (i < kRelaxSpinCount) {
relax();
} else {
yield();
}
}
return false;
}
bool spin_wait(auto &&pred, auto &&spinCond) {
if (try_spin_wait(pred)) {
return true;
}
while (spinCond()) {
if (pred()) {
return true;
}
}
return false;
}
struct shared_atomic32 : std::atomic<std::uint32_t> {
using atomic::atomic;
using atomic::operator=;
template <typename Clock, typename Dur>
[[nodiscard]] std::errc wait(std::uint32_t oldValue,
std::chrono::time_point<Clock, Dur> timeout) {
if (try_spin_wait(
[&] { return load(std::memory_order::acquire) != oldValue; })) {
return {};
}
auto now = Clock::now();
if (timeout < now) {
return std::errc::timed_out;
}
return wait_impl(
oldValue,
std::chrono::duration_cast<std::chrono::microseconds>(timeout - now));
}
[[nodiscard]] std::errc wait(std::uint32_t oldValue,
std::chrono::microseconds usec_timeout) {
return wait_impl(oldValue, usec_timeout);
}
[[nodiscard]] std::errc wait(std::uint32_t oldValue) {
if (try_spin_wait(
[&] { return load(std::memory_order::acquire) != oldValue; })) {
return {};
}
return wait_impl(oldValue);
}
auto wait(auto &fn) -> decltype(fn(std::declval<std::uint32_t &>())) {
while (true) {
std::uint32_t lastValue;
if (try_spin_wait([&] {
lastValue = load(std::memory_order::acquire);
return fn(lastValue);
})) {
return;
}
while (wait_impl(lastValue) != std::errc{}) {
}
}
}
int notify_one() const { return notify_n(1); }
int notify_all() const { return notify_n(std::numeric_limits<int>::max()); }
int notify_n(int count) const;
// Atomic operation; returns old value, or pair of old value and return value
// (cancel op if evaluates to false)
template <typename F, typename RT = std::invoke_result_t<F, std::uint32_t &>>
std::conditional_t<std::is_void_v<RT>, std::uint32_t,
std::pair<std::uint32_t, RT>>
fetch_op(F &&func) {
std::uint32_t _new;
std::uint32_t old = load(std::memory_order::relaxed);
while (true) {
_new = old;
if constexpr (std::is_void_v<RT>) {
std::invoke(std::forward<F>(func), _new);
if (compare_exchange_strong(old, _new)) [[likely]] {
return old;
}
} else {
RT ret = std::invoke(std::forward<F>(func), _new);
if (!ret || compare_exchange_strong(old, _new)) [[likely]] {
return {old, std::move(ret)};
}
}
}
}
// Atomic operation; returns function result value
template <typename F, typename RT = std::invoke_result_t<F, std::uint32_t &>>
RT op(F &&func) {
std::uint32_t _new;
std::uint32_t old = load(std::memory_order::relaxed);
while (true) {
_new = old;
if constexpr (std::is_void_v<RT>) {
std::invoke(std::forward<F>(func), _new);
if (compare_exchange_strong(old, _new)) [[likely]] {
return;
}
} else {
RT result = std::invoke(std::forward<F>(func), _new);
if (compare_exchange_strong(old, _new)) [[likely]] {
return result;
}
}
}
}
private:
[[nodiscard]] std::errc wait_impl(std::uint32_t oldValue,
std::chrono::microseconds usec_timeout =
std::chrono::microseconds::max());
};
} // namespace utils
} // namespace orbis

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@ -1,8 +1,12 @@
#pragma once
#include "orbis/utils/SharedAtomic.hpp"
#include <chrono>
#include <cstdint>
#include <mutex>
#include <orbis/utils/AtomicOp.hpp>
#include <orbis/utils/SharedMutex.hpp>
#include <system_error>
namespace orbis {
inline namespace utils {
@ -11,16 +15,18 @@ class shared_cv final {
enum : unsigned {
c_waiter_mask = 0xffff,
c_signal_mask = 0x7fff0000,
#ifdef ORBIS_HAS_FUTEX
c_locked_mask = 0x80000000,
#endif
c_signal_one = c_waiter_mask + 1,
};
std::atomic<unsigned> m_value{0};
shared_atomic32 m_value{0};
protected:
// Increment waiter count
unsigned add_waiter() noexcept {
return atomic_op(m_value, [](unsigned &value) -> unsigned {
return m_value.op([](unsigned &value) -> unsigned {
if ((value & c_signal_mask) == c_signal_mask ||
(value & c_waiter_mask) == c_waiter_mask) {
// Signal or waiter overflow, return immediately
@ -34,8 +40,8 @@ protected:
}
// Internal waiting function
int impl_wait(shared_mutex &mutex, unsigned _val,
std::uint64_t usec_timeout) noexcept;
std::errc impl_wait(shared_mutex &mutex, unsigned _val,
std::uint64_t usec_timeout) noexcept;
// Try to notify up to _count threads
void impl_wake(shared_mutex &mutex, int _count) noexcept;
@ -43,10 +49,25 @@ protected:
public:
constexpr shared_cv() = default;
int wait(shared_mutex &mutex, std::uint64_t usec_timeout = -1) noexcept {
std::errc
wait(std::unique_lock<shared_mutex> &lock,
std::chrono::microseconds timeout = std::chrono::microseconds::max()) {
return wait(*lock.mutex(), timeout.count());
}
template <typename Rep, typename Period>
std::errc wait(std::unique_lock<shared_mutex> &lock,
std::chrono::duration<Rep, Period> timeout) {
return wait(
lock,
std::chrono::duration_cast<std::chrono::microseconds>(timeout).count());
}
std::errc wait(shared_mutex &mutex,
std::uint64_t usec_timeout = -1) noexcept {
const unsigned _val = add_waiter();
if (!_val) {
return 0;
return {};
}
mutex.unlock();

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@ -1,8 +1,9 @@
#pragma once
#include <atomic>
#include <mutex>
#include <orbis/utils/AtomicOp.hpp>
#include <orbis/utils/SharedAtomic.hpp>
#include <system_error>
namespace orbis {
inline namespace utils {
@ -16,11 +17,11 @@ class shared_mutex final {
c_err = 1u << 31,
};
std::atomic<unsigned> m_value{};
shared_atomic32 m_value{};
void impl_lock_shared(unsigned val);
void impl_unlock_shared(unsigned old);
int impl_wait();
std::errc impl_wait();
void impl_signal();
void impl_lock(unsigned val);
void impl_unlock(unsigned old);
@ -99,10 +100,10 @@ public:
}
// Check whether can immediately obtain an exclusive (writer) lock
bool is_free() const { return m_value.load() == 0; }
[[nodiscard]] bool is_free() const { return m_value.load() == 0; }
// Check whether can immediately obtain a shared (reader) lock
bool is_lockable() const { return m_value.load() < c_one - 1; }
[[nodiscard]] bool is_lockable() const { return m_value.load() < c_one - 1; }
private:
// For CV

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@ -33,7 +33,7 @@ orbis::ErrorCode orbis::EventFlag::wait(Thread *thread, std::uint8_t waitMode,
thread->evfIsCancelled = -1;
std::unique_lock lock(queueMtx);
int result = 0;
orbis::ErrorCode result = {};
while (true) {
if (isDeleted) {
if (thread->evfIsCancelled == UINT64_MAX)
@ -78,10 +78,10 @@ orbis::ErrorCode orbis::EventFlag::wait(Thread *thread, std::uint8_t waitMode,
waitingThreads.emplace_back(waitingThread);
if (timeout) {
result = thread->sync_cv.wait(queueMtx, *timeout);
result = toErrorCode(thread->sync_cv.wait(queueMtx, *timeout));
update_timeout();
} else {
result = thread->sync_cv.wait(queueMtx);
result = toErrorCode(thread->sync_cv.wait(queueMtx));
}
if (thread->evfIsCancelled == UINT64_MAX) {

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@ -1,9 +1,8 @@
#include "umtx.hpp"
#include "error.hpp"
#include "orbis/KernelContext.hpp"
#include "orbis/thread.hpp"
#include "orbis/utils/AtomicOp.hpp"
#include "orbis/utils/Logs.hpp"
#include "time.hpp"
#include <limits>
namespace orbis {
@ -41,7 +40,7 @@ uint UmtxChain::notify_n(const UmtxKey &key, sint count) {
return 0;
uint n = 0;
while (count > 0) {
while (count > 0) {
it->second.thr = nullptr;
it->second.cv.notify_all(mtx);
it = erase(it);
@ -57,9 +56,7 @@ uint UmtxChain::notify_n(const UmtxKey &key, sint count) {
return n;
}
uint UmtxChain::notify_one(const UmtxKey &key) {
return notify_n(key, 1);
}
uint UmtxChain::notify_one(const UmtxKey &key) { return notify_n(key, 1); }
uint UmtxChain::notify_all(const UmtxKey &key) {
return notify_n(key, std::numeric_limits<sint>::max());
@ -94,7 +91,7 @@ orbis::ErrorCode orbis::umtx_wait(Thread *thread, ptr<void> addr, ulong id,
if (val == id) {
if (ut + 1 == 0) {
while (true) {
result = ErrorCode{node->second.cv.wait(chain.mtx)};
result = orbis::toErrorCode(node->second.cv.wait(chain.mtx));
if (result != ErrorCode{} || node->second.thr != thread)
break;
}
@ -102,7 +99,8 @@ orbis::ErrorCode orbis::umtx_wait(Thread *thread, ptr<void> addr, ulong id,
auto start = std::chrono::steady_clock::now();
std::uint64_t udiff = 0;
while (true) {
result = ErrorCode{node->second.cv.wait(chain.mtx, ut - udiff)};
result =
orbis::toErrorCode(node->second.cv.wait(chain.mtx, ut - udiff));
if (node->second.thr != thread)
break;
udiff = std::chrono::duration_cast<std::chrono::microseconds>(
@ -193,7 +191,7 @@ static ErrorCode do_lock_normal(Thread *thread, ptr<umutex> m, uint flags,
auto [chain, key, lock] = g_context.getUmtxChain1(thread, flags, m);
auto node = chain.enqueue(key, thread);
if (m->owner.compare_exchange_strong(owner, owner | kUmutexContested)) {
error = ErrorCode{node->second.cv.wait(chain.mtx, ut)};
error = orbis::toErrorCode(node->second.cv.wait(chain.mtx, ut));
if (error == ErrorCode{} && node->second.thr == thread) {
error = ErrorCode::TIMEDOUT;
}
@ -323,7 +321,6 @@ orbis::ErrorCode orbis::umtx_cv_wait(Thread *thread, ptr<ucond> cv,
ORBIS_LOG_WARNING("umtx_cv_wait: CLOCK_ID", wflags, cv->clockid);
// std::abort();
return ErrorCode::NOSYS;
}
if ((wflags & kCvWaitAbsTime) != 0 && ut + 1) {
ORBIS_LOG_WARNING("umtx_cv_wait: ABSTIME unimplemented", wflags);
@ -353,7 +350,7 @@ orbis::ErrorCode orbis::umtx_cv_wait(Thread *thread, ptr<ucond> cv,
if (result == ErrorCode{}) {
if (ut + 1 == 0) {
while (true) {
result = ErrorCode{node->second.cv.wait(chain.mtx, ut)};
result = orbis::toErrorCode(node->second.cv.wait(chain.mtx, ut));
if (result != ErrorCode{} || node->second.thr != thread) {
break;
}
@ -362,7 +359,8 @@ orbis::ErrorCode orbis::umtx_cv_wait(Thread *thread, ptr<ucond> cv,
auto start = std::chrono::steady_clock::now();
std::uint64_t udiff = 0;
while (true) {
result = ErrorCode{node->second.cv.wait(chain.mtx, ut - udiff)};
result =
orbis::toErrorCode(node->second.cv.wait(chain.mtx, ut - udiff));
if (node->second.thr != thread) {
break;
}
@ -457,7 +455,7 @@ orbis::ErrorCode orbis::umtx_rw_rdlock(Thread *thread, ptr<urwlock> rwlock,
if (ut + 1 == 0) {
while (true) {
result = ErrorCode{node->second.cv.wait(chain.mtx, ut)};
result = orbis::toErrorCode(node->second.cv.wait(chain.mtx, ut));
if (result != ErrorCode{} || node->second.thr != thread) {
break;
}
@ -466,7 +464,8 @@ orbis::ErrorCode orbis::umtx_rw_rdlock(Thread *thread, ptr<urwlock> rwlock,
auto start = std::chrono::steady_clock::now();
std::uint64_t udiff = 0;
while (true) {
result = ErrorCode{node->second.cv.wait(chain.mtx, ut - udiff)};
result =
orbis::toErrorCode(node->second.cv.wait(chain.mtx, ut - udiff));
if (node->second.thr != thread)
break;
udiff = std::chrono::duration_cast<std::chrono::microseconds>(
@ -557,7 +556,7 @@ orbis::ErrorCode orbis::umtx_rw_wrlock(Thread *thread, ptr<urwlock> rwlock,
if (ut + 1 == 0) {
while (true) {
error = ErrorCode{node->second.cv.wait(chain.mtx, ut)};
error = orbis::toErrorCode(node->second.cv.wait(chain.mtx, ut));
if (error != ErrorCode{} || node->second.thr != thread) {
break;
}
@ -566,7 +565,8 @@ orbis::ErrorCode orbis::umtx_rw_wrlock(Thread *thread, ptr<urwlock> rwlock,
auto start = std::chrono::steady_clock::now();
std::uint64_t udiff = 0;
while (true) {
error = ErrorCode{node->second.cv.wait(chain.mtx, ut - udiff)};
error =
orbis::toErrorCode(node->second.cv.wait(chain.mtx, ut - udiff));
if (node->second.thr != thread)
break;
udiff = std::chrono::duration_cast<std::chrono::microseconds>(
@ -729,7 +729,7 @@ orbis::ErrorCode orbis::umtx_sem_wait(Thread *thread, ptr<usem> sem,
if (!sem->count) {
if (ut + 1 == 0) {
while (true) {
result = ErrorCode{node->second.cv.wait(chain.mtx, ut)};
result = orbis::toErrorCode(node->second.cv.wait(chain.mtx, ut));
if (result != ErrorCode{} || node->second.thr != thread)
break;
}
@ -737,7 +737,8 @@ orbis::ErrorCode orbis::umtx_sem_wait(Thread *thread, ptr<usem> sem,
auto start = std::chrono::steady_clock::now();
std::uint64_t udiff = 0;
while (true) {
result = ErrorCode{node->second.cv.wait(chain.mtx, ut - udiff)};
result =
orbis::toErrorCode(node->second.cv.wait(chain.mtx, ut - udiff));
if (node->second.thr != thread)
break;
udiff = std::chrono::duration_cast<std::chrono::microseconds>(

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@ -0,0 +1,95 @@
#include "utils/SharedAtomic.hpp"
using namespace orbis;
#ifdef ORBIS_HAS_FUTEX
#include <linux/futex.h>
std::errc shared_atomic32::wait_impl(std::uint32_t oldValue,
std::chrono::microseconds usec_timeout) {
auto usec_timeout_count = usec_timeout.count();
struct timespec timeout{};
timeout.tv_nsec = (usec_timeout_count % 1000'000) * 1000;
timeout.tv_sec = (usec_timeout_count / 1000'000);
int result = syscall(
SYS_futex, this, FUTEX_WAIT, oldValue,
usec_timeout != std::chrono::microseconds::max() ? &timeout : nullptr, 0,
0);
if (result < 0) {
return static_cast<std::errc>(errno);
}
return {};
}
int shared_atomic32::notify_n(int count) const {
return syscall(SYS_futex, this, FUTEX_WAKE, count);
}
#elif defined(ORBIS_HAS_ULOCK)
#include <limits>
#define UL_COMPARE_AND_WAIT 1
#define UL_UNFAIR_LOCK 2
#define UL_COMPARE_AND_WAIT_SHARED 3
#define UL_UNFAIR_LOCK64_SHARED 4
#define UL_COMPARE_AND_WAIT64 5
#define UL_COMPARE_AND_WAIT64_SHARED 6
#define ULF_WAKE_ALL 0x00000100
#define ULF_WAKE_THREAD 0x00000200
#define ULF_WAKE_ALLOW_NON_OWNER 0x00000400
#define ULF_WAIT_WORKQ_DATA_CONTENTION 0x00010000
#define ULF_WAIT_CANCEL_POINT 0x00020000
#define ULF_WAIT_ADAPTIVE_SPIN 0x00040000
#define ULF_NO_ERRNO 0x01000000
#define UL_OPCODE_MASK 0x000000FF
#define UL_FLAGS_MASK 0xFFFFFF00
#define ULF_GENERIC_MASK 0xFFFF0000
extern int __ulock_wait(uint32_t operation, void *addr, uint64_t value,
uint32_t timeout);
extern int __ulock_wake(uint32_t operation, void *addr, uint64_t wake_value);
std::errc shared_atomic32::wait_impl(std::uint32_t oldValue,
std::chrono::microseconds usec_timeout) {
int result = __ulock_wait(UL_COMPARE_AND_WAIT_SHARED, (void *)this, oldValue,
usec_timeout.count());
if (result < 0) {
return static_cast<std::errc>(errno);
}
return {};
}
int shared_atomic32::notify_n(int count) const {
int result = 0;
uint32_t operation = UL_COMPARE_AND_WAIT_SHARED | ULF_NO_ERRNO;
if (count == 1) {
result = __ulock_wake(operation, (void *)this, 0);
} else if (count == std::numeric_limits<int>::max()) {
result = __ulock_wake(ULF_WAKE_ALL | operation, (void *)this, 0);
} else {
for (int i = 0; i < count; ++i) {
auto ret = __ulock_wake(operation, (void *)this, 0);
if (ret != 0) {
if (result == 0) {
result = ret;
}
break;
}
result++;
}
}
return result;
}
#else
#error Unimplemented atomic for this platform
#endif

View File

@ -1,35 +1,30 @@
#include "orbis/utils/SharedCV.hpp"
#include "orbis/utils/Logs.hpp"
#include <chrono>
#ifdef ORBIS_HAS_FUTEX
#include <linux/futex.h>
#include <syscall.h>
#include <unistd.h>
#endif
namespace orbis::utils {
int shared_cv::impl_wait(shared_mutex &mutex, unsigned _val,
std::uint64_t usec_timeout) noexcept {
std::errc shared_cv::impl_wait(shared_mutex &mutex, unsigned _val,
std::uint64_t usec_timeout) noexcept {
// Not supposed to fail
if (!_val) {
std::abort();
}
// Wait with timeout
struct timespec timeout {};
timeout.tv_nsec = (usec_timeout % 1000'000) * 1000;
timeout.tv_sec = (usec_timeout / 1000'000);
int result = 0;
std::errc result = {};
while (true) {
result = syscall(SYS_futex, &m_value, FUTEX_WAIT, _val,
usec_timeout + 1 ? &timeout : nullptr, 0, 0);
if (result < 0) {
result = errno;
}
result = m_value.wait(_val, std::chrono::microseconds(usec_timeout));
// Cleanup
const auto old = atomic_fetch_op(m_value, [&](unsigned &value) {
const auto old = m_value.fetch_op([&](unsigned &value) {
// Remove waiter if no signals
if (!(value & ~c_waiter_mask) && result != EAGAIN) {
if (!(value & ~c_waiter_mask) &&
result != std::errc::resource_unavailable_try_again) {
value -= 1;
}
@ -38,23 +33,32 @@ int shared_cv::impl_wait(shared_mutex &mutex, unsigned _val,
value -= c_signal_one;
}
#ifdef ORBIS_HAS_FUTEX
if (value & c_locked_mask) {
value -= c_locked_mask;
}
#endif
});
#ifdef ORBIS_HAS_FUTEX
// Lock is already acquired
if (old & c_locked_mask) {
return 0;
return {};
}
// Wait directly (waiter has been added)
if (old & c_signal_mask) {
return mutex.impl_wait();
}
#else
if (old & c_signal_mask) {
result = {};
break;
}
#endif
// Possibly spurious wakeup
if (result != EAGAIN) {
if (result != std::errc::resource_unavailable_try_again) {
break;
}
@ -66,27 +70,69 @@ int shared_cv::impl_wait(shared_mutex &mutex, unsigned _val,
}
void shared_cv::impl_wake(shared_mutex &mutex, int _count) noexcept {
unsigned _old = m_value.load();
const bool is_one = _count == 1;
#ifdef ORBIS_HAS_FUTEX
while (true) {
unsigned _old = m_value.load();
const bool is_one = _count == 1;
// Enqueue _count waiters
// Enqueue _count waiters
_count = std::min<int>(_count, _old & c_waiter_mask);
if (_count <= 0)
return;
// Try to lock the mutex
const bool locked = mutex.lock_forced(_count);
const int max_sig = m_value.op([&](unsigned &value) {
// Verify the number of waiters
int max_sig = std::min<int>(_count, value & c_waiter_mask);
// Add lock signal (mutex was immediately locked)
if (locked && max_sig)
value |= c_locked_mask;
else if (locked)
std::abort();
// Add normal signals
value += c_signal_one * max_sig;
// Remove waiters
value -= max_sig;
_old = value;
return max_sig;
});
if (max_sig < _count) {
// Fixup mutex
mutex.lock_forced(max_sig - _count);
_count = max_sig;
}
if (_count) {
// Wake up one thread + requeue remaining waiters
unsigned awake_count = locked ? 1 : 0;
if (auto r = syscall(SYS_futex, &m_value, FUTEX_REQUEUE, awake_count,
_count - awake_count, &mutex, 0);
r < _count) {
// Keep awaking waiters
_count = is_one ? 1 : INT_MAX;
continue;
}
}
break;
}
#else
unsigned _old = m_value.load();
_count = std::min<int>(_count, _old & c_waiter_mask);
if (_count <= 0)
return;
// Try to lock the mutex
const bool locked = mutex.lock_forced(_count);
mutex.lock_forced(1);
const int max_sig = atomic_op(m_value, [&](unsigned &value) {
// Verify the number of waiters
const int wakeupWaiters = m_value.op([&](unsigned &value) {
int max_sig = std::min<int>(_count, value & c_waiter_mask);
// Add lock signal (mutex was immediately locked)
if (locked && max_sig)
value |= c_locked_mask;
else if (locked)
std::abort();
// Add normal signals
value += c_signal_one * max_sig;
@ -96,21 +142,11 @@ void shared_cv::impl_wake(shared_mutex &mutex, int _count) noexcept {
return max_sig;
});
if (max_sig < _count) {
// Fixup mutex
mutex.lock_forced(max_sig - _count);
_count = max_sig;
if (wakeupWaiters > 0) {
m_value.notify_n(wakeupWaiters);
}
if (_count) {
// Wake up one thread + requeue remaining waiters
unsigned awake_count = locked ? 1 : 0;
if (auto r = syscall(SYS_futex, &m_value, FUTEX_REQUEUE, awake_count,
_count - awake_count, &mutex, 0);
r < _count) {
// Keep awaking waiters
return impl_wake(mutex, is_one ? 1 : INT_MAX);
}
}
mutex.unlock();
#endif
}
} // namespace orbis::utils

View File

@ -1,6 +1,5 @@
#include "utils/SharedMutex.hpp"
#include "utils/Logs.hpp"
#include <linux/futex.h>
#include <syscall.h>
#include <unistd.h>
#include <xmmintrin.h>
@ -48,7 +47,7 @@ void shared_mutex::impl_lock_shared(unsigned val) {
if ((old % c_sig) + c_one >= c_sig)
std::abort(); // "shared_mutex overflow"
while (impl_wait() != 0) {}
while (impl_wait() != std::errc{}) {}
lock_downgrade();
}
void shared_mutex::impl_unlock_shared(unsigned old) {
@ -60,9 +59,9 @@ void shared_mutex::impl_unlock_shared(unsigned old) {
impl_signal();
}
}
int shared_mutex::impl_wait() {
std::errc shared_mutex::impl_wait() {
while (true) {
const auto [old, ok] = atomic_fetch_op(m_value, [](unsigned &value) {
const auto [old, ok] = m_value.fetch_op([](unsigned &value) {
if (value >= c_sig) {
value -= c_sig;
return true;
@ -75,19 +74,17 @@ int shared_mutex::impl_wait() {
break;
}
int result = syscall(SYS_futex, &m_value, FUTEX_WAIT, old, 0, 0, 0);
if (result < 0) {
result = errno;
}
if (result == EINTR) {
return EINTR;
auto result = m_value.wait(old);
if (result == std::errc::interrupted) {
return result;
}
}
return{};
}
void shared_mutex::impl_signal() {
m_value += c_sig;
syscall(SYS_futex, &m_value, FUTEX_WAKE, 1, 0, 0, 0);
m_value.notify_one();
}
void shared_mutex::impl_lock(unsigned val) {
if (val >= c_err)
@ -123,7 +120,7 @@ void shared_mutex::impl_lock(unsigned val) {
if ((old % c_sig) + c_one >= c_sig)
std::abort(); // "shared_mutex overflow"
while (impl_wait() != 0) {}
while (impl_wait() != std::errc{}) {}
}
void shared_mutex::impl_unlock(unsigned old) {
if (old - c_one >= c_err)
@ -155,27 +152,23 @@ void shared_mutex::impl_lock_upgrade() {
return;
}
while (impl_wait() != 0) {}
while (impl_wait() != std::errc{}) {}
}
bool shared_mutex::lock_forced(int count) {
if (count == 0)
return false;
if (count > 0) {
// Lock
return atomic_op(m_value, [&](unsigned &v) {
return m_value.op([&](std::uint32_t &v) {
if (v & c_sig) {
v -= c_sig;
v += c_one * count;
return true;
}
if (v == 0) {
v += c_one * count;
return true;
}
bool firstLock = v == 0;
v += c_one * count;
return false;
return firstLock;
});
}