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[kernel] Simplify event and wait_queue

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Previously event tried to read its value in event::wake_observer, which
required jumping through some hoops in how wait_queue was designed, so
that a value wouldn't be wasted if the wait_queue was empty. Now, read
the event value in event::wait after returning from the thread::block
call instead, which simplifies the whole process and lets us simplify
the wait_queue API as well.
This commit is contained in:
Justin C. Miller
2023-02-19 14:34:03 -08:00
parent 94b2a79f79
commit 274891854f
3 changed files with 15 additions and 45 deletions
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15
src/kernel/objects/event.cpp
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@@ -28,22 +28,15 @@ event::wait()
// Wait for event::signal() to wake us with a value
thread &current = thread::current();
m_queue.add_thread(&current);
return current.block();
current.block();
return read();
}
void
event::wake_observer()
{
util::scoped_lock lock {m_queue.get_lock()};
thread *t = m_queue.get_next_unlocked();
if (!t) return;
uint64_t value = read();
if (value) {
m_queue.pop_next_unlocked();
lock.release();
t->wake(value);
}
thread *t = m_queue.pop_next();
if (t) t->wake();
}
} // namespace obj