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Subject: Re: [ANNOUNCE] v5.14-rc4-rt4
To:     Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc:     Steven Rostedt <rostedt@goodmis.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Daniel Wagner <wagi@monom.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-rt-users@vger.kernel.org
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From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <71d37a7d-af53-945e-0c49-3cb902487df4@kernel.dk>
Date:   Wed, 4 Aug 2021 10:57:11 -0600
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On 8/4/21 10:47 AM, Sebastian Andrzej Siewior wrote:
> On 2021-08-04 10:22:59 [-0600], Jens Axboe wrote:
>>
>> In that regard, I do still consider those patches out-of-tree, which
>> they are. And while I'm more sympathetic to them compared to other
>> out-of-tree code as there's a long term plan to get it all in, it's
>> still out-of-tree. Best solution here is probably to just carry that
>> particular change in the RT patchset for now.
> 
> So today in the morning I learned that there is a memory allocation in
> an IRQ-off section and now, a patch later, it is almost gone. So that
> makes me actually happy :)

1 out of 2 is better than 0 ;-)

> The spin_lock_irq() vs local_irq_disable() + spin_lock() is documented
> in Documentation/locking/locktypes.rst.
> That said I have no problem by carrying that patch in the RT-patchset
> and revisit it later.

Right, I suspect that was added as a pre RT patch dump at some point.
It's a newer thing. Is it actually possible to set PREEMPT_RT in the
mainline kernel? Looks like it depends on ARCH_SUPPORTS_RT and nobody
sets that.

So I agree that just carrying your solution in the RT patchset is fine
for now, we can revisit later.

-- 
Jens Axboe