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Date:   Fri, 13 Oct 2023 13:26:08 +0200
From:   Frederic Weisbecker <frederic@kernel.org>
To:     Tejun Heo <tj@kernel.org>
Cc:     Ming Lei <ming.lei@redhat.com>, Jens Axboe <axboe@kernel.dk>,
        linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        Juri Lelli <juri.lelli@redhat.com>,
        Andrew Theurer <atheurer@redhat.com>,
        Joe Mario <jmario@redhat.com>, Sebastian Jug <sejug@redhat.com>
Subject: Re: [PATCH] blk-mq: add module parameter to not run block kworker on
 isolated CPUs
Message-ID: <ZSkpUFlw8FINofLG@lothringen>
References: <20231010142216.1114752-1-ming.lei@redhat.com>
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On Tue, Oct 10, 2023 at 08:45:44AM -1000, Tejun Heo wrote:
> > +static bool respect_cpu_isolation;
> > +module_param(respect_cpu_isolation, bool, 0444);
> > +MODULE_PARM_DESC(respect_cpu_isolation,
> > +		"Don't schedule blk-mq worker on isolated CPUs passed in "
> > +		"isolcpus= or nohz_full=. User need to guarantee to not run "
> > +		"block IO on isolated CPUs (default: false)");
> 
> Any chance we can centralize these? It's no fun to try to hunt down module
> params to opt in different subsystems and the housekeeping interface does
> have some provisions for selecting different parts. I'd much prefer to see
> these settings to be collected into a central place.

Do we need this parameter in the first place? Shouldn't we avoid scheduling
blk-mq worker on isolated CPUs in any case?

Thanks.

> 
> Thanks.
> 
> -- 
> tejun