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Message-ID: <af031e33-74db-40ba-abdd-ef1bf32e4caf@redhat.com>
Date: Wed, 5 Jun 2024 16:07:37 +0200
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Subject: Re: [PATCH v5 1/2] sched/rt: Clean up usage of rt_task()
To: Qais Yousef <qyousef@layalina.io>,
 Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>, Peter Zijlstra <peterz@infradead.org>,
 Juri Lelli <juri.lelli@redhat.com>, Steven Rostedt <rostedt@goodmis.org>,
 Vincent Guittot <vincent.guittot@linaro.org>,
 Thomas Gleixner <tglx@linutronix.de>,
 Alexander Viro <viro@zeniv.linux.org.uk>,
 Christian Brauner <brauner@kernel.org>,
 Andrew Morton <akpm@linux-foundation.org>, Jens Axboe <axboe@kernel.dk>,
 Metin Kaya <metin.kaya@arm.com>, linux-kernel@vger.kernel.org,
 linux-fsdevel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
 linux-mm@kvack.org, Phil Auld <pauld@redhat.com>
References: <20240604144228.1356121-1-qyousef@layalina.io>
 <20240604144228.1356121-2-qyousef@layalina.io>
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 <20240605093246.4h0kCR67@linutronix.de>
 <20240605132454.cjo4sjtybaeyeuze@airbuntu>
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From: Daniel Bristot de Oliveira <bristot@redhat.com>
In-Reply-To: <20240605132454.cjo4sjtybaeyeuze@airbuntu>
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On 6/5/24 15:24, Qais Yousef wrote:
>>> But rt is a shortened version of realtime, and so it is making *it less*
>>> clear that we also have DL here.
>> Can SCHED_DL be considered a real-time scheduling class as in opposite
>> to SCHED_BATCH for instance? Due to its requirements it fits for a real
>> time scheduling class, right?
>> And RT (as in real time) already includes SCHED_RR and SCHED_FIFO.
> Yeah I think the usage of realtime to cover both makes sense. I followed your
> precedence with task_is_realtime().
> 
> Anyway. If people really find this confusing, what would make sense is to split
> them and ask users to call rt_task() and dl_task() explicitly without this
> wrapper. I personally like it better with the wrapper. But happy to follow the
> crowd.

For me, doing dl_ things it is better to keep them separate, so I can
easily search for dl_ specific checks.

rt_or_dl_task(p);

would also make it clear that we have both.

-- Daniel