On Thu Nov 10, 2022 at 10:43 AM AEST, Jordan Niethe wrote:

On Thu, 2022-07-28 at 16:31 +1000, Nicholas Piggin wrote:
[resend as utf-8, not utf-7]

quoted

Use the spin_begin/spin_cpu_relax/spin_end APIs in qspinlock, which helps
to prevent threads issuing a lot of expensive priority nops which may not
have much effect due to immediately executing low then medium priority.

Just a general comment regarding the spin_{begin,end} API, more complicated
than something like

	spin_begin()
	for(;;)
		spin_cpu_relax()
	spin_end()

it becomes difficult to keep track of. Unfortunately, I don't have any good
suggestions how to improve it. Hopefully with P10s wait instruction we can
maybe try and move away from this.

It might be useful to comment the functions pre and post conditions regarding
expectations about spin_begin() and spin_end().

Yep, added some small comments.

Thanks,
Nick