banan-os/kernel/include/kernel/Lock/Mutex.h

132 lines
2.6 KiB
C++

#pragma once
#include <BAN/Atomic.h>
#include <BAN/NoCopyMove.h>
#include <kernel/Scheduler.h>
#include <sys/types.h>
namespace Kernel
{
class Mutex
{
BAN_NON_COPYABLE(Mutex);
BAN_NON_MOVABLE(Mutex);
public:
Mutex() = default;
void lock()
{
auto tid = Scheduler::current_tid();
if (tid == m_locker)
ASSERT(m_lock_depth > 0);
else
{
while (!m_locker.compare_exchange(-1, tid))
Scheduler::get().yield();
ASSERT(m_lock_depth == 0);
}
m_lock_depth++;
}
bool try_lock()
{
auto tid = Scheduler::current_tid();
if (tid == m_locker)
ASSERT(m_lock_depth > 0);
else
{
if (!m_locker.compare_exchange(-1, tid))
return false;
ASSERT(m_lock_depth == 0);
}
m_lock_depth++;
}
void unlock()
{
ASSERT(m_locker == Scheduler::current_tid());
ASSERT(m_lock_depth > 0);
if (--m_lock_depth == 0)
m_locker = -1;
}
pid_t locker() const { return m_locker; }
bool is_locked() const { return m_locker != -1; }
uint32_t lock_depth() const { return m_lock_depth; }
private:
BAN::Atomic<pid_t> m_locker { -1 };
uint32_t m_lock_depth { 0 };
};
class PriorityMutex
{
BAN_NON_COPYABLE(PriorityMutex);
BAN_NON_MOVABLE(PriorityMutex);
public:
PriorityMutex() = default;
void lock()
{
auto tid = Scheduler::current_tid();
if (tid == m_locker)
ASSERT(m_lock_depth > 0);
else
{
bool has_priority = tid ? !Thread::current().is_userspace() : true;
if (has_priority)
m_queue_length++;
while (!(has_priority || m_queue_length == 0) || !m_locker.compare_exchange(-1, tid))
Scheduler::get().yield();
ASSERT(m_lock_depth == 0);
}
m_lock_depth++;
}
bool try_lock()
{
auto tid = Scheduler::current_tid();
if (tid == m_locker)
ASSERT(m_lock_depth > 0);
else
{
bool has_priority = tid ? !Thread::current().is_userspace() : true;
if (!(has_priority || m_queue_length == 0) || !m_locker.compare_exchange(-1, tid))
return false;
if (has_priority)
m_queue_length++;
ASSERT(m_lock_depth == 0);
}
m_lock_depth++;
}
void unlock()
{
auto tid = Scheduler::current_tid();
ASSERT(m_locker == tid);
ASSERT(m_lock_depth > 0);
if (--m_lock_depth == 0)
{
bool has_priority = tid ? !Thread::current().is_userspace() : true;
if (has_priority)
m_queue_length--;
m_locker = -1;
}
}
pid_t locker() const { return m_locker; }
bool is_locked() const { return m_locker != -1; }
uint32_t lock_depth() const { return m_lock_depth; }
private:
BAN::Atomic<pid_t> m_locker { -1 };
uint32_t m_lock_depth { 0 };
BAN::Atomic<uint32_t> m_queue_length { 0 };
};
}