Are mutexes in RTL-RTX volatile ?

Hello,

I am using mutexes in my project in order to protect resources shared among tasks.

The shared resources are volatile (of course), but I cannot declare the mutex volatile (if I did so, the compiler would complain).

Now, my question is: are the mutexes declared by the KEIL RTX already volatile themselves ?
I mean, if I turned the maximum optimization on, could the behaviour of the mutex change as a consequence ?

Thanks.

Regards,
Sebastiano