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c/multi: Fix condition var waiting for wait thread.

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Spurious wakeups happen, have to actually have a condition
to check in a loop with the cond var wait.
This commit is contained in:
Ryan Pavlik 2022-05-20 14:09:37 -05:00
parent d523001b6e
commit fd3a0a1435
2 changed files with 14 additions and 3 deletions
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10
src/xrt/compositor/multi/comp_multi_compositor.c
View file

@ -226,6 +226,7 @@ run_func(void *ptr)
while (os_thread_helper_is_running_locked(&mc->wait_thread.oth)) {
if (mc->wait_thread.xcsem == NULL && mc->wait_thread.xcf == NULL) {
//! @todo what condition should we spin on here to handle spurious wakeups?
os_thread_helper_wait_locked(&mc->wait_thread.oth);
// Fall through here on stopping to clean up and outstanding waits.
}
@ -274,6 +275,8 @@ run_func(void *ptr)
mc->wait_thread.waiting = false;
if (mc->wait_thread.blocked) {
// Release one thread
mc->wait_thread.blocked = false;
os_thread_helper_signal_locked(&mc->wait_thread.oth);
}
}
@ -289,9 +292,12 @@ wait_for_wait_thread_locked(struct multi_compositor *mc)
// Should we wait for the last frame.
if (mc->wait_thread.waiting) {
COMP_TRACE_IDENT(blocked);
// OK, wait until the wait thread releases us by setting blocked to false
mc->wait_thread.blocked = true;
os_thread_helper_wait_locked(&mc->wait_thread.oth);
mc->wait_thread.blocked = false;
while (mc->wait_thread.blocked) {
os_thread_helper_wait_locked(&mc->wait_thread.oth);
}
}
}

7
src/xrt/compositor/multi/comp_multi_private.h
View file

@ -146,7 +146,12 @@ struct multi_compositor
//! Is the thread waiting, if so the client should block.
bool waiting;
//! Is the client thread blocked, if so it should be woken up.
/*!
* Is the client thread blocked?
*
* Set to true by the client thread,
* cleared by the wait thread to release the client thread.
*/
bool blocked;
} wait_thread;