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/*
* Copyright (c) 2020, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/Debug.h>
#include <Kernel/Thread.h>
#include <Kernel/WaitQueue.h>
namespace Kernel {
bool WaitQueue::should_add_blocker(Thread::Blocker& b, void* data)
{
VERIFY(data != nullptr); // Thread that is requesting to be blocked
VERIFY(m_lock.is_locked());
VERIFY(b.blocker_type() == Thread::Blocker::Type::Queue);
if (m_wake_requested || !m_should_block) {
m_wake_requested = false;
dbgln_if(WAITQUEUE_DEBUG, "WaitQueue @ {}: do not block thread {}, {}", this, data, m_should_block ? "wake was pending" : "not blocking");
return false;
}
dbgln_if(WAITQUEUE_DEBUG, "WaitQueue @ {}: should block thread {}", this, data);
return true;
}
u32 WaitQueue::wake_one()
{
u32 did_wake = 0;
ScopedSpinLock lock(m_lock);
dbgln_if(WAITQUEUE_DEBUG, "WaitQueue @ {}: wake_one", this);
bool did_unblock_one = do_unblock([&](Thread::Blocker& b, void* data, bool& stop_iterating) {
VERIFY(data);
VERIFY(b.blocker_type() == Thread::Blocker::Type::Queue);
auto& blocker = static_cast<Thread::QueueBlocker&>(b);
dbgln_if(WAITQUEUE_DEBUG, "WaitQueue @ {}: wake_one unblocking {}", this, data);
if (blocker.unblock()) {
stop_iterating = true;
did_wake = 1;
return true;
}
return false;
});
m_wake_requested = !did_unblock_one;
dbgln_if(WAITQUEUE_DEBUG, "WaitQueue @ {}: wake_one woke {} threads", this, did_wake);
return did_wake;
}
u32 WaitQueue::wake_n(u32 wake_count)
{
if (wake_count == 0)
return 0; // should we assert instead?
ScopedSpinLock lock(m_lock);
dbgln_if(WAITQUEUE_DEBUG, "WaitQueue @ {}: wake_n({})", this, wake_count);
u32 did_wake = 0;
bool did_unblock_some = do_unblock([&](Thread::Blocker& b, void* data, bool& stop_iterating) {
VERIFY(data);
VERIFY(b.blocker_type() == Thread::Blocker::Type::Queue);
auto& blocker = static_cast<Thread::QueueBlocker&>(b);
dbgln_if(WAITQUEUE_DEBUG, "WaitQueue @ {}: wake_n unblocking {}", this, data);
VERIFY(did_wake < wake_count);
if (blocker.unblock()) {
if (++did_wake >= wake_count)
stop_iterating = true;
return true;
}
return false;
});
m_wake_requested = !did_unblock_some;
dbgln_if(WAITQUEUE_DEBUG, "WaitQueue @ {}: wake_n({}) woke {} threads", this, wake_count, did_wake);
return did_wake;
}
u32 WaitQueue::wake_all()
{
ScopedSpinLock lock(m_lock);
dbgln_if(WAITQUEUE_DEBUG, "WaitQueue @ {}: wake_all", this);
u32 did_wake = 0;
bool did_unblock_any = do_unblock([&](Thread::Blocker& b, void* data, bool&) {
VERIFY(data);
VERIFY(b.blocker_type() == Thread::Blocker::Type::Queue);
auto& blocker = static_cast<Thread::QueueBlocker&>(b);
dbgln_if(WAITQUEUE_DEBUG, "WaitQueue @ {}: wake_all unblocking {}", this, data);
if (blocker.unblock()) {
did_wake++;
return true;
}
return false;
});
m_wake_requested = !did_unblock_any;
dbgln_if(WAITQUEUE_DEBUG, "WaitQueue @ {}: wake_all woke {} threads", this, did_wake);
return did_wake;
}
}
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