Re: [ANNOUNCE] v5.14-rc4-rt4

On Wed, 4 Aug 2021 18:31:19 +0200
Sebastian Andrzej Siewior [off-list ref] wrote:

CPU-local wake-ups just set NEED_RESCHED and wait for preempt_enable()
to do the magic. Just because the code not perform wake_up() now does
not mean it will not do so in the future. Also it is here as an example
which might be copied somewhere else.

Does this mean all local_irq_disable/enable() is audited? What do you do for;

	local_irq_disable();
	[..]
	wakeup_process(x); /* on local CPU */
	[..]
	local_irq_enable();

And if local_irq_disable() is not used anymore, or seldom, what harm
would it be to add a preemption check to that caller? And change
local_irq_enable() that is used internally by other atom functions be
called __local_irq_enable()?

Not to mention that we could just open code that too:

	if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
		local_irq_enable();
		preempt_check_resched();
	}

And make it ugly enough that nobody will want to copy it :-)

-- Steve