Add NVGPU_IOCTL_CHANNEL_PREEMPT_NEXT ioctl to check host and FECS status
and preempt pending load of context not belonging to the calling channel on
GR engine during context switch. This should be called after a submit with
NVGPU_SUBMIT_GPFIFO_FLAGS_RESCHEDULE_RUNLIST to decrease worst case submit
to start latency for high interleave channel.
There is less than 0.002% chance that the ioctl blocks up to couple
miliseconds due to race condition of FECS status changing while being read.
Also fix bug with host reschedule for multiple runlists which needs to write
both runlist registers.
Bug 1987640
Bug 1924808
Change-Id: I0b7e2f91bd18b0b20928e5a3311b9426b1bf1848
Signed-off-by: David Li <davli@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1549598
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
c6cd82008f