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Date:   Wed, 29 Jun 2022 10:04:02 -0700
From:   "Paul E. McKenney" <paulmck@kernel.org>
To:     "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc:     Christoph Hellwig <hch@lst.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Arve =?iso-8859-1?B?SGr4bm5lduVn?= <arve@android.com>,
        Todd Kjos <tkjos@android.com>,
        Martijn Coenen <maco@android.com>,
        Joel Fernandes <joel@joelfernandes.org>,
        Christian Brauner <brauner@kernel.org>,
        Hridya Valsaraju <hridya@google.com>,
        Suren Baghdasaryan <surenb@google.com>,
        Theodore Ts'o <tytso@mit.edu>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        "Alex Xu (Hello71)" <alex_y_xu@yahoo.ca>,
        Paolo Abeni <pabeni@redhat.com>, Rob Herring <robh@kernel.org>,
        Frederic Weisbecker <frederic@kernel.org>,
        Neeraj Upadhyay <quic_neeraju@quicinc.com>,
        Josh Triplett <josh@joshtriplett.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Lai Jiangshan <jiangshanlai@gmail.com>,
        Shuah Khan <shuah@kernel.org>, linux-kernel@vger.kernel.org,
        wireguard@lists.zx2c4.com, netdev@vger.kernel.org,
        rcu@vger.kernel.org, linux-kselftest@vger.kernel.org,
        sultan@kerneltoast.com
Subject: Re: [PATCH] remove CONFIG_ANDROID
Message-ID: <20220629170402.GJ1790663@paulmck-ThinkPad-P17-Gen-1>
Reply-To: paulmck@kernel.org
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On Wed, Jun 29, 2022 at 06:45:48PM +0200, Jason A. Donenfeld wrote:
> On Wed, Jun 29, 2022 at 06:37:01PM +0200, Christoph Hellwig wrote:
> > be a policy set somewhere either in the kernel or fed into the kernel
> > by userspace.  Then we can key it off that, and I suspect it is
> > probably going to be a runtime variable and not a config option.
> 
> Right, this would be a good way of addressing it.
> 
> Maybe some Android people on the list have a good idea off hand of what
> Android uses at runtime to control this, and how it'd be accessible in
> the kernel?

In case it helps, in the case of CONFIG_RCU_EXP_CPU_STALL_TIMEOUT,
the Android guys can use things like defconfig at kernel-build time or
the rcu_exp_cpu_stall_timeout kernel-boot/sysfs parameter at boot time
or runtime.

							Thanx, Paul