mirror of
https://github.com/RGBCube/serenity
synced 2025-07-25 15:17:36 +00:00
Kernel: Move all tasks-related code to the Tasks subdirectory
This commit is contained in:
parent
788022d5d1
commit
1b04726c85
184 changed files with 245 additions and 243 deletions
87
Kernel/Tasks/AtomicEdgeAction.h
Normal file
87
Kernel/Tasks/AtomicEdgeAction.h
Normal file
|
@ -0,0 +1,87 @@
|
|||
/*
|
||||
* Copyright (c) 2021, the SerenityOS developers.
|
||||
*
|
||||
* SPDX-License-Identifier: BSD-2-Clause
|
||||
*/
|
||||
|
||||
#pragma once
|
||||
|
||||
#include <AK/Atomic.h>
|
||||
#include <Kernel/Arch/Processor.h>
|
||||
|
||||
namespace Kernel {
|
||||
|
||||
template<typename AtomicRefCountType>
|
||||
class AtomicEdgeAction {
|
||||
public:
|
||||
template<typename FirstRefAction>
|
||||
bool ref(FirstRefAction first_ref_action)
|
||||
{
|
||||
AtomicRefCountType expected = 0;
|
||||
AtomicRefCountType desired = (1 << 1) | 1;
|
||||
// Least significant bit indicates we're busy protecting/unprotecting
|
||||
for (;;) {
|
||||
if (m_atomic_ref_count.compare_exchange_strong(expected, desired, AK::memory_order_relaxed))
|
||||
break;
|
||||
|
||||
Processor::wait_check();
|
||||
|
||||
expected &= ~1;
|
||||
desired = expected + (1 << 1);
|
||||
VERIFY(desired > expected);
|
||||
if (expected == 0)
|
||||
desired |= 1;
|
||||
}
|
||||
|
||||
atomic_thread_fence(AK::memory_order_acquire);
|
||||
|
||||
if (expected == 0) {
|
||||
first_ref_action();
|
||||
|
||||
// drop the busy flag
|
||||
m_atomic_ref_count.store(desired & ~1, AK::memory_order_release);
|
||||
return true;
|
||||
}
|
||||
return false;
|
||||
}
|
||||
|
||||
template<typename LastRefAction>
|
||||
bool unref(LastRefAction last_ref_action)
|
||||
{
|
||||
AtomicRefCountType expected = 1 << 1;
|
||||
AtomicRefCountType desired = (1 << 1) | 1;
|
||||
// Least significant bit indicates we're busy protecting/unprotecting
|
||||
for (;;) {
|
||||
if (m_atomic_ref_count.compare_exchange_strong(expected, desired, AK::memory_order_relaxed))
|
||||
break;
|
||||
|
||||
Processor::wait_check();
|
||||
|
||||
expected &= ~1;
|
||||
VERIFY(expected != 0); // Someone should always have at least one reference
|
||||
|
||||
if (expected == 1 << 1) {
|
||||
desired = (1 << 1) | 1;
|
||||
} else {
|
||||
desired = expected - (1 << 1);
|
||||
VERIFY(desired < expected);
|
||||
}
|
||||
}
|
||||
|
||||
AK::atomic_thread_fence(AK::memory_order_release);
|
||||
|
||||
if (expected == 1 << 1) {
|
||||
last_ref_action();
|
||||
|
||||
// drop the busy flag and release reference
|
||||
m_atomic_ref_count.store(0, AK::memory_order_release);
|
||||
return true;
|
||||
}
|
||||
return false;
|
||||
}
|
||||
|
||||
private:
|
||||
Atomic<AtomicRefCountType> m_atomic_ref_count { 0 };
|
||||
};
|
||||
|
||||
}
|
Loading…
Add table
Add a link
Reference in a new issue