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Sender: Tejun Heo <htejun@gmail.com>
Date:   Wed, 18 Jan 2023 08:25:57 -1000
From:   Tejun Heo <tj@kernel.org>
To:     Sandeep Dhavale <dhavale@google.com>
Cc:     Nathan Huckleberry <nhuck@google.com>,
        Daeho Jeong <daehojeong@google.com>,
        Eric Biggers <ebiggers@kernel.org>,
        Sami Tolvanen <samitolvanen@google.com>,
        Lai Jiangshan <jiangshanlai@gmail.com>,
        Jonathan Corbet <corbet@lwn.net>, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] workqueue: Add WQ_SCHED_FIFO
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On Wed, Jan 18, 2023 at 10:22:32AM -0800, Sandeep Dhavale wrote:
> If with the kernel config option, every WQ_HIGHPRI is elevated to
> sched_fifo_low, wouldn't that be kind of defeating the purpose? Having
> another class for even more urgent work is better in my opinion.

I mean, everybody thinks their work items are the most important. Even with
explicit FIFO, you're still gonna have similar problems as people crowd that
flag. If this is a concern, please benchmark with realistic scenarios and
consider other options (e.g. maybe that problematic workqueue doesn't need
to be HIGHPRI or should be split somehow). Right now, I don't think there
are enough justifications for adding another level.

Thanks.

-- 
tejun