Re: [PATCH RT v2 0/3] riscv: add PREEMPT_RT support

Sebastian Andrzej Siewior
2023-10-31T16:44:24Z

On 2023-10-31 23:49:29 [+0800], Jisheng Zhang wrote:
> Yes there's no third patch. I didn't use the correct number in patch0's
> subject.

So it looks fine. The warning was CPU-hotplug related
https://lore.kernel.org/all/0abd0acf-70a1-d546-a517-19efe60042d1@microchip.com/

and it looks to be gone as of commit
5944ce092b97c ("arch_topology: Build cacheinfo from primary CPU")

so that good. Any double checking is welcome of course ;)
JUMP_LABELs don't use stop_cpu. Check.
The timer is PERCPU. Check.
Can't find perf events. But the commit for threaded interrupts claims to
have them per-CPU.
Has HAVE_POSIX_CPU_TIMERS_TASK_WORK with generic kvm. Check.

die() and die_lock. It looks like die_lock is acquired when the system
is done and requires medical assistance. This would qualify it for a
raw_spinlock_t. Also, should any of the bad things happen in a section
with disabled preemption or interrupts then a spinlock_t can not be
acquired. Unless die() is always invoked in a preemptible context…

The other things are covered by the generic code. I think I didn't miss
anything…
I going to have new release by the end of the week at the latest with
this bits. Please look after the die_lock.

Sebastian