linux-kernel - Re: [dm-devel] [PATCH 0/3] dm-verity: optionally use tasklets in dm-verity

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Message-ID: <cabd732a-9942-3ece-8141-c0bc6378faca@acm.org>
Date:   Fri, 22 Jul 2022 11:12:38 -0700
From:   Bart Van Assche <bvanassche@....org>
To:     Christoph Hellwig <hch@...radead.org>,
        Nathan Huckleberry <nhuck@...gle.com>
Cc:     Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Mike Snitzer <snitzer@...nel.org>,
        linux-kernel@...r.kernel.org, Eric Biggers <ebiggers@...nel.org>,
        dm-devel@...hat.com, Sami Tolvanen <samitolvanen@...gle.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Alasdair Kergon <agk@...hat.com>
Subject: Re: [dm-devel] [PATCH 0/3] dm-verity: optionally use tasklets in
 dm-verity

On 7/22/22 09:41, Christoph Hellwig wrote:
> We've been tying to kill off task lets for about 15 years.  I don't
> think adding new users will make you a whole lot of friends..

+1 for not using tasklets. At least in Android the real-time thread 
scheduling latency is important. Tasklets are not visible to the 
scheduler and hence cause latency spikes for real-time threads. These 
latency spikes can be observed by users, e.g. if the real-time thread is 
involved in audio playback.

Bart.