On Mon, 2023-04-03 at 13:32 +0300, Kalle Valo wrote:
>
> I would expect that there's polling if you are waiting something from
> hardware, or maybe when implementing a spin lock, but not when waiting
> for another kernel thread. This just doesn't feel right but I don't have
> time to propose a good alternative either, sorry.
>
I have found a solution that uses an owner variable with a spin lock
to determine which side to free completion object. Simply show two use
cases below:
Use case 1: (normal case; free completion object by work 1)
work 1 work 2
wait
(spin_lock)
complete
check & set owner --> owner = work1
(spin_unlock)
wait ok
(spin_lock)
check & check owner --> free by work 1
(spin_unlock)
free completion
Use case 2: (timeout case; free completion object by work 2)
work 1 work 2
wait
wait timeout
(spin_lock)
check & set owner --> owner = work 2
(spin_unlock)
(spin_lock)
completion
check & set owner --> free by work 2
(spin_unlock)
free completion
I will apply this by v5.
Ping-Ke
