Is it possible to "wake up" linux kernel process from user space without system call?

I'm trying to modify a kernel module that manages a special hardware. The user space process, performs 2 ioctl() system calls per milliseconds to talk with the module. This doesn't meet my real.time requirements because the 2 syscalls sometimes take to long to execute and go out my time slot. I know that with mmap I could share a memory area, and this is great, but how can I synchronize the data ex开发者_Python百科change with the module without ioctl() ?