Rename cond_x16 to shared_cond

Extend capacity from 16 to 32.
Remove redundant m_total counter.

Utilities/cond.cpp

@@ -196,46 +196,51 @@ void unique_cond::imp_notify() noexcept
 	balanced_awaken(m_value, 1);
 }
 
-bool cond_x16::imp_wait(u32 slot, u64 _timeout) noexcept
+bool shared_cond::imp_wait(u32 slot, u64 _timeout) noexcept
 {
-	const u32 wait_bit = c_wait << slot;
-	const u32 lock_bit = c_lock << slot;
+	if (slot >= 32)
+	{
+		// Invalid argument, assume notified
+		return true;
+	}
+
+	const u64 wait_bit = c_wait << slot;
+	const u64 lock_bit = c_lock << slot;
 
 	// Change state from c_lock to c_wait
-	const u32 old_ = m_cvx16.fetch_op([=](u32& cvx16)
+	const u64 old_ = m_cvx32.fetch_op([=](u64& cvx32)
 	{
-		if (cvx16 & wait_bit)
+		if (cvx32 & wait_bit)
 		{
-			// c_sig -> c_lock
-			cvx16 &= ~wait_bit;
+			// c_lock -> c_wait
+			cvx32 &= ~(lock_bit & ~wait_bit);
 		}
 		else
 		{
-			cvx16 |= wait_bit;
-			cvx16 &= ~lock_bit;
+			// c_sig -> c_lock
+			cvx32 |= lock_bit;
 		}
 	});
 
-	if (old_ & wait_bit)
+	if ((old_ & wait_bit) == 0)
 	{
 		// Already signaled, return without waiting
 		return true;
 	}
 
-	return balanced_wait_until(m_cvx16, _timeout, [&](u32& cvx16, auto... ret) -> int
+	return balanced_wait_until(m_cvx32, _timeout, [&](u64& cvx32, auto... ret) -> int
 	{
-		if (cvx16 & lock_bit)
+		if ((cvx32 & wait_bit) == 0)
 		{
 			// c_sig -> c_lock
-			cvx16 &= ~wait_bit;
+			cvx32 |= lock_bit;
 			return +1;
 		}
 
 		if constexpr (sizeof...(ret))
 		{
 			// Retire
-			cvx16 |= lock_bit;
-			cvx16 &= ~wait_bit;
+			cvx32 |= lock_bit;
 			return -1;
 		}
 
@@ -243,16 +248,14 @@ bool cond_x16::imp_wait(u32 slot, u64 _timeout) noexcept
 	});
 }
 
-void cond_x16::imp_notify() noexcept
+void shared_cond::imp_notify() noexcept
 {
-	auto [old, ok] = m_cvx16.fetch_op([](u32& v)
+	auto [old, ok] = m_cvx32.fetch_op([](u64& cvx32)
 	{
-		const u32 lock_mask = v >> 16;
-		const u32 wait_mask = v & 0xffff;
-
-		if (const u32 sig_mask = lock_mask ^ wait_mask)
+		if (const u64 sig_mask = cvx32 & 0xffffffff)
 		{
-			v |= sig_mask | sig_mask << 16;
+			cvx32 &= 0xffffffffull << 32;
+			cvx32 |= sig_mask << 32;
 			return true;
 		}
 
@@ -260,14 +263,14 @@ void cond_x16::imp_notify() noexcept
 	});
 
 	// Determine if some waiters need a syscall notification
-	const u32 wait_mask = old & (~old >> 16);
+	const u64 wait_mask = old & (~old >> 32);
 
 	if (UNLIKELY(!ok || !wait_mask))
 	{
 		return;
 	}
 
-	balanced_awaken<true>(m_cvx16, utils::popcnt32(wait_mask));
+	balanced_awaken<true>(m_cvx32, utils::popcnt32(wait_mask));
 }
 
 bool lf_queue_base::wait(u64 _timeout)

Utilities/cond.h

@@ -176,61 +176,60 @@ public:
 	}
 };
 
-// Packed version of cond_one, supports up to 16 readers.
-class cond_x16
+// Condition variable fused with a pseudo-mutex supporting only reader locks (up to 32 readers).
+class shared_cond
 {
 	// For information, shouldn't modify
-	enum : u32
+	enum : u64
 	{
+		// Wait bit is aligned for compatibility with 32-bit futex.
 		c_wait = 1,
-		c_lock = 1 << 16,
-		c_sig  = 1 << 16 | 1,
+		c_sig  = 1ull << 32,
+		c_lock = 1ull << 32 | 1,
 	};
 
-	// Split in 16-bit parts for convenient bit combining
-	atomic_t<u32> m_cvx16{0};
+	// Split in 32-bit parts for convenient bit combining
+	atomic_t<u64> m_cvx32{0};
 
-	// Effectively unused, only counts readers
-	atomic_t<u32> m_total{0};
-
-	class lock_x16
+	class shared_lock
 	{
-		cond_x16* m_this;
+		shared_cond* m_this;
 		u32 m_slot;
 
-		friend class cond_x16;
+		friend class shared_cond;
 
 	public:
-		lock_x16(cond_x16* _this) noexcept
+		shared_lock(shared_cond* _this) noexcept
 			: m_this(_this)
 		{
-			// Spin if the number of readers exceeds 16
-			while (UNLIKELY(m_this->m_total++ >= 16))
-				m_this->m_total--;
-
 			// Lock and remember obtained slot index
-			m_slot = m_this->m_cvx16.atomic_op([](u32& cvx16)
+			m_slot = m_this->m_cvx32.atomic_op([](u64& cvx32)
 			{
 				// Combine used bits and invert to find least significant bit unused
-				const u32 slot = utils::cnttz32(~((cvx16 & 0xffff) | (cvx16 >> 16)), true);
+				const u32 slot = utils::cnttz32(~((cvx32 & 0xffffffff) | (cvx32 >> 32)), true);
 
-				// Set lock bit
-				cvx16 |= c_lock << slot;
-
-				AUDIT(slot < 16);
+				// Set lock bits (does nothing if all slots are used)
+				const u64 bit = (1ull << slot) & 0xffffffff;
+				cvx32 |= bit | (bit << 32);
 				return slot;
 			});
 		}
 
-		lock_x16(const lock_x16&) = delete;
+		shared_lock(const shared_lock&) = delete;
 
-		lock_x16& operator=(const lock_x16&) = delete;
+		shared_lock& operator=(const shared_lock&) = delete;
 
-		~lock_x16()
+		~shared_lock()
 		{
-			// Clear the slot
-			m_this->m_cvx16 &= ~((c_wait | c_lock) << m_slot);
-			m_this->m_total -= 1;
+			// Clear the slot (does nothing if all slots are used)
+			const u64 bit = (1ull << m_slot) & 0xffffffff;
+			m_this->m_cvx32 &= ~(bit | (bit << 32));
+		}
+
+		explicit operator bool() const noexcept
+		{
+			// Check success
+			return m_slot < 32;
 		}
 
 		bool wait(u64 usec_timeout = -1) const noexcept
@@ -243,14 +242,20 @@ class cond_x16
 	void imp_notify() noexcept;
 
 public:
-	constexpr cond_x16() = default;
+	constexpr shared_cond() = default;
 
-	lock_x16 lock_one() noexcept
+	shared_lock try_shared_lock() noexcept
 	{
-		return lock_x16(this);
+		return shared_lock(this);
 	}
 
-	bool wait(lock_x16 const& lock, u64 usec_timeout = -1) noexcept
+	u32 count() const noexcept
+	{
+		const u64 cvx32 = m_cvx32;
+		return utils::popcnt32(cvx32 | (cvx32 >> 32));
+	}
+
+	bool wait(shared_lock const& lock, u64 usec_timeout = -1) noexcept
 	{
 		AUDIT(lock.m_this == this);
 		return imp_wait(lock.m_slot, usec_timeout);
@@ -258,7 +263,7 @@ public:
 
 	void notify_all() noexcept
 	{
-		if (LIKELY(!m_cvx16))
+		if (LIKELY(!m_cvx32))
 			return;
 
 		imp_notify();

Utilities/sync.h

@@ -233,9 +233,16 @@ bool balanced_wait_until(atomic_t<T>& var, u64 usec_timeout, Pred&& pred)
 	timeout.tv_sec  = usec_timeout / 1000000;
 	timeout.tv_nsec = (usec_timeout % 1000000) * 1000;
 
+	char* ptr = reinterpret_cast<char*>(&var);
+
+	if constexpr (sizeof(T) == 8)
+	{
+		ptr += 4 * IS_BE_MACHINE;
+	}
+
 	while (!test_pred(value))
 	{
-		if (futex(&var, FUTEX_WAIT_PRIVATE, static_cast<u32>(value), is_inf ? nullptr : &timeout) == 0)
+		if (futex(ptr, FUTEX_WAIT_PRIVATE, static_cast<u32>(value), is_inf ? nullptr : &timeout) == 0)
 		{
 			if (!test_pred(value, nullptr))
 			{
@@ -284,9 +291,16 @@ void balanced_awaken(atomic_t<T>& var, u32 weight)
 		NtReleaseKeyedEvent(nullptr, &var, false, nullptr);
 	}
 #else
+	char* ptr = reinterpret_cast<char*>(&var);
+
+	if constexpr (sizeof(T) == 8)
+	{
+		ptr += 4 * IS_BE_MACHINE;
+	}
+
 	if (All || weight)
 	{
-		futex(&var, FUTEX_WAKE_PRIVATE, All ? INT_MAX : std::min<u32>(INT_MAX, weight));
+		futex(ptr, FUTEX_WAKE_PRIVATE, All ? INT_MAX : std::min<u32>(INT_MAX, weight));
 	}
 
 	return;

rpcs3/Emu/Cell/SPUThread.cpp

@@ -2401,7 +2401,12 @@ s64 spu_thread::get_ch_value(u32 ch)
 				fmt::throw_exception("Not supported: event mask 0x%x" HERE, mask1);
 			}
 
-			const auto pseudo_lock = vm::reservation_notifier(raddr, 128).lock_one();
+			const auto pseudo_lock = vm::reservation_notifier(raddr, 128).try_shared_lock();
+
+			if (!pseudo_lock)
+			{
+				fmt::throw_exception("Unexpected: reservation notifier lock failed");
+			}
 
 			while (res = get_events(), !res)
 			{

rpcs3/Emu/Memory/vm.h

@@ -7,7 +7,7 @@
 
 class shared_mutex;
 class cpu_thread;
-class cond_x16;
+class shared_cond;
 
 namespace vm
 {
@@ -102,9 +102,9 @@ namespace vm
 	}
 
 	// Get reservation sync variable
-	inline cond_x16& reservation_notifier(u32 addr, u32 size)
+	inline shared_cond& reservation_notifier(u32 addr, u32 size)
 	{
-		return *reinterpret_cast<cond_x16*>(g_reservations2 + addr / 128 * 8);
+		return *reinterpret_cast<shared_cond*>(g_reservations2 + addr / 128 * 8);
 	}
 
 	void reservation_lock_internal(atomic_t<u64>&);