In linux threaded interrupts run with a Realtime priority
of 50. This bumps up the priority of bottom-half handlers
over regular kernel/User threads even during process
context.
In the current implementation scheduler thread still
runs in normal kernel thread priority. In order to
allow a seamless scheduling experience, the worker
thread is now created with a Realtime priority of 1.
This allows for the Worker thread to work at a priority
lower than interrupt handlers but higher than the regular
kernel threads.
Linux kernel allows setting priority with the help of
sched_set_fifo() API. Only two modes are supported
i.e. sched_set_fifo() and sched_set_fifo_low().
For more reference, refer to this article
https://lwn.net/Articles/818388/.
Added an implementation of nvgpu_thread_create_priority()
for linux thread using the above two APIs.
Jira NVGPU-860
Signed-off-by: Debarshi Dutta <ddutta@nvidia.com>
Change-Id: I0a5a611bf0e0a5b9bb51354c6ff0a99e42e76e2f
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2751736
Reviewed-by: Prateek Sethi <prsethi@nvidia.com>
Reviewed-by: Vijayakumar Subbu <vsubbu@nvidia.com>
GVS: Gerrit_Virtual_Submit <buildbot_gerritrpt@nvidia.com>
The pmu init thread typically returns immediately
without calling nvgpu_thread_should_stop().
pmu_pg_kill_task() checks if the thread is running, and
if it is, calls nvgpu_thread_stop().
However, there's a race condition where the init thread could
have exited between the time that kill_task() checked the
running flag and the time we actually stop the thread, leading
to a kernel crash.
Fix this by making the running flag in the nvgpu_thread struct
atomic. Both the thread proxy function and the thread_stop()
function will set the flag to false.
In the case of nvgpu_thread_proxy(), if the flag is already false,
then nvgpu_thread_stop() has already reset it, at which point we
just wait for nvgpu_thread_should_stop() to return true.
In the case of nvgpu_thread_stop(), if the flag is already false,
then the thread proxy function has already exited, and there is
nothing more to do.
Bug 2591298
Change-Id: I9ba6b63c30a5c3e1df11e790094836b44373122b
Signed-off-by: Peter Daifuku <pdaifuku@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/2230358
GVS: Gerrit_Virtual_Submit
Reviewed-by: Thomas Fleury <tfleury@nvidia.com>
Reviewed-by: Alex Waterman <alexw@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
