Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.33 as permitted sender) client-ip=23.128.96.33;
Date:   Fri, 13 Oct 2023 20:23:28 +0800
From:   Ming Lei <ming.lei@redhat.com>
To:     Frederic Weisbecker <frederic@kernel.org>
Cc:     Tejun Heo <tj@kernel.org>, 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: <ZSk2wNH4KIR4rR+N@fedora>
References: <20231010142216.1114752-1-ming.lei@redhat.com>
 <ZSWb2DNV9cIPYv5H@slm.duckdns.org>
 <ZSkpUFlw8FINofLG@lothringen>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <ZSkpUFlw8FINofLG@lothringen>
Precedence: bulk

On Fri, Oct 13, 2023 at 01:26:08PM +0200, Frederic Weisbecker wrote:
> 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?

Yeah, I think this parameter isn't necessary, will remove it in V2.


Thanks,
Ming