From: Tejun Heo <tj@kernel.org>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Boqun Feng <boqun.feng@gmail.com>,
Stephen Rothwell <sfr@canb.auug.org.au>,
linux-next@vger.kernel.org, linux-kernel@vger.kernel.org,
Christoph Lameter <cl@linux-foundation.org>
Subject: Re: linux-next: build failure after merge of the rcu tree
Date: Fri, 8 Jan 2016 10:57:27 -0500 [thread overview]
Message-ID: <20160108155727.GP1898@mtj.duckdns.org> (raw)
In-Reply-To: <20160108155341.GC3818@linux.vnet.ibm.com>
On Fri, Jan 08, 2016 at 07:53:41AM -0800, Paul E. McKenney wrote:
> commit 61822ff81839ee3c5b6094ce348944d972b87892
> Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Date: Fri Jan 8 07:43:50 2016 -0800
>
> rcu: Document unique-name limitation for DEFINE_STATIC_SRCU()
>
> SRCU uses per-CPU variables, and DEFINE_STATIC_SRCU() uses a static
> per-CPU variable. However, per-CPU variables have significant
> restrictions, for example, names of per-CPU variables must be globally
> unique, even if declared static. These restrictions carry over to
> DEFINE_STATIC_SRCU(), and this commit therefore documents these
> restrictions.
>
> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> Reported-by: kbuild test robot <fengguang.wu@intel.com>
> Suggested-by: Boqun Feng <boqun.feng@gmail.com>
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
>
> diff --git a/include/linux/srcu.h b/include/linux/srcu.h
> index f5f80c5643ac..dc8eb63c6568 100644
> --- a/include/linux/srcu.h
> +++ b/include/linux/srcu.h
> @@ -99,8 +99,23 @@ void process_srcu(struct work_struct *work);
> }
>
> /*
> - * define and init a srcu struct at build time.
> - * dont't call init_srcu_struct() nor cleanup_srcu_struct() on it.
> + * Define and initialize a srcu struct at build time.
> + * Do -not- call init_srcu_struct() nor cleanup_srcu_struct() on it.
> + *
> + * Note that although DEFINE_STATIC_SRCU() hides the name from other
> + * files, the per-CPU variable rules nevertheless require that the
> + * chosen name be globally unique. These rules also prohibit use of
> + * DEFINE_STATIC_SRCU() within a function. If these rules are too
> + * restrictive, declare the srcu_struct manually. For example, in
> + * each file:
> + *
> + * static struct srcu_struct my_srcu;
> + *
> + * Then, before the first use of each my_srcu, manually initialize it:
> + *
> + * init_srcu_struct(&my_srcu);
> + *
> + * See include/linux/percpu-defs.h for the rules on per-CPU variables.
FWIW,
Reviewed-by: Tejun Heo <tj@kernel.org>
Thanks Stephen for posting the rules around static percpu definitions.
I wonder whether there is a better way to tell people what's going on.
Thanks.
--
tejun
next prev parent reply other threads:[~2016-01-08 15:57 UTC|newest]
Thread overview: 152+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-07 8:57 linux-next: build failure after merge of the rcu tree Stephen Rothwell
2016-01-07 18:02 ` Paul E. McKenney
2016-01-07 20:19 ` Stephen Rothwell
2016-01-07 20:52 ` Paul E. McKenney
2016-01-08 1:37 ` Boqun Feng
2016-01-08 3:41 ` Paul E. McKenney
2016-01-08 4:08 ` Stephen Rothwell
2016-01-08 4:48 ` Paul E. McKenney
2016-01-08 4:54 ` Boqun Feng
2016-01-08 15:53 ` Paul E. McKenney
2016-01-08 15:57 ` Tejun Heo [this message]
2016-01-08 16:18 ` Paul E. McKenney
2016-01-08 15:58 ` Boqun Feng
2016-01-08 4:10 ` Stephen Rothwell
-- strict thread matches above, loose matches on Subject: below --
2024-01-24 4:17 Stephen Rothwell
2024-01-24 9:49 ` Jiri Wiesner
2024-01-24 12:12 ` Paul E. McKenney
2024-01-24 13:31 ` Jiri Wiesner
2024-01-24 14:20 ` Paul E. McKenney
2023-07-27 4:19 Stephen Rothwell
2023-07-27 14:08 ` Paul E. McKenney
2023-05-19 0:59 Stephen Rothwell
2023-05-19 2:12 ` Paul E. McKenney
2023-05-22 1:45 ` Stephen Rothwell
2023-05-22 14:57 ` Paul E. McKenney
2023-03-14 1:29 Stephen Rothwell
2023-03-14 4:43 ` Paul E. McKenney
2022-10-17 23:26 Stephen Rothwell
2022-10-18 10:43 ` Frederic Weisbecker
2022-10-18 14:57 ` Paul E. McKenney
2022-04-19 2:36 Stephen Rothwell
2022-04-19 3:31 ` Paul E. McKenney
2021-05-03 0:11 Stephen Rothwell
2021-05-03 16:25 ` Paul E. McKenney
2021-04-22 4:10 Stephen Rothwell
2021-04-22 16:36 ` Paul E. McKenney
2021-03-17 5:36 Stephen Rothwell
2021-03-17 14:23 ` Paul E. McKenney
2021-01-04 0:37 Stephen Rothwell
2021-01-04 12:56 ` Frederic Weisbecker
2020-12-04 8:25 Stephen Rothwell
2020-12-04 19:20 ` Paul E. McKenney
2020-12-06 21:39 ` Stephen Rothwell
2020-12-07 4:48 ` Paul E. McKenney
2020-12-07 8:59 ` Stephen Rothwell
2020-09-17 5:19 Stephen Rothwell
2020-09-17 22:01 ` Paul E. McKenney
2020-09-18 0:00 ` Stephen Rothwell
2020-09-08 5:38 Stephen Rothwell
2020-09-08 13:54 ` Paul E. McKenney
2020-08-18 1:43 Stephen Rothwell
2020-08-18 14:08 ` Paul E. McKenney
2020-06-25 2:57 Stephen Rothwell
2020-06-25 3:45 ` Paul E. McKenney
2020-05-28 9:05 Stephen Rothwell
2020-05-28 16:33 ` Paul E. McKenney
2020-05-28 21:03 ` Paul E. McKenney
2020-04-05 1:49 Stephen Rothwell
2020-04-05 3:10 ` Paul E. McKenney
2020-01-17 3:07 Stephen Rothwell
2019-12-12 2:45 Stephen Rothwell
2019-12-12 4:07 ` Paul E. McKenney
2019-12-12 4:26 ` Stephen Rothwell
2019-12-12 4:41 ` Paul E. McKenney
2020-01-17 3:09 ` Stephen Rothwell
2019-08-13 7:57 Stephen Rothwell
2019-08-13 15:31 ` Paul E. McKenney
2019-08-12 6:12 Stephen Rothwell
2019-08-12 16:19 ` Paul E. McKenney
2019-08-13 5:25 ` Stephen Rothwell
2019-08-13 14:38 ` Paul E. McKenney
2017-09-04 4:50 Stephen Rothwell
2017-09-04 16:39 ` Paul E. McKenney
2017-08-28 4:25 Stephen Rothwell
2017-08-28 17:50 ` Paul E. McKenney
2017-08-11 4:43 Stephen Rothwell
2017-08-11 4:54 ` Paul E. McKenney
2017-08-11 9:14 ` Peter Zijlstra
2017-08-11 14:39 ` Paul E. McKenney
2017-08-11 14:45 ` Peter Zijlstra
2017-08-11 14:41 ` Peter Zijlstra
2017-08-11 20:12 ` Paul E. McKenney
2017-05-29 6:02 Stephen Rothwell
2017-05-29 21:15 ` Paul E. McKenney
2017-05-30 1:40 ` Stephen Rothwell
2017-05-30 1:54 ` Joe Perches
2017-05-30 2:14 ` Paul E. McKenney
2017-05-30 2:20 ` Joe Perches
2017-05-30 3:13 ` Stephen Rothwell
2017-05-30 4:10 ` Michael Ellerman
2017-06-02 17:51 ` Paul E. McKenney
2017-04-20 5:36 Stephen Rothwell
2017-04-20 14:23 ` Paul E. McKenney
2017-04-19 3:50 Stephen Rothwell
2017-04-19 4:06 ` Paul E. McKenney
2017-04-19 5:45 ` Stephen Rothwell
2017-03-08 1:16 Stephen Rothwell
2017-03-08 10:13 ` Daniel Vetter
2017-03-08 17:40 ` Paul E. McKenney
2017-01-19 3:34 Stephen Rothwell
2017-01-19 21:54 ` Paul McKenney
2017-02-13 2:21 ` Stephen Rothwell
2017-02-13 4:37 ` Paul E. McKenney
2017-02-13 6:43 ` Stephen Rothwell
2017-03-08 1:16 ` Stephen Rothwell
2017-03-08 1:37 ` Paul E. McKenney
2017-03-08 18:05 ` Paul E. McKenney
2016-05-02 4:37 Stephen Rothwell
2016-05-02 11:06 ` Paul E. McKenney
2016-02-01 2:55 Stephen Rothwell
2016-02-01 9:53 ` Paul E. McKenney
2015-09-01 3:50 Stephen Rothwell
2015-09-01 7:49 ` Paul E. McKenney
2015-09-02 3:58 ` Stephen Rothwell
2015-09-02 5:26 ` Paul E. McKenney
2015-09-02 6:40 ` Davidlohr Bueso
2015-09-02 7:14 ` Paul E. McKenney
2015-09-02 7:29 ` Ingo Molnar
2015-09-02 8:34 ` Paul E. McKenney
2015-07-16 3:14 Stephen Rothwell
2015-07-16 3:51 ` Paul E. McKenney
2015-07-16 5:50 ` Stephen Rothwell
2015-07-17 11:40 ` Ingo Molnar
2015-07-17 17:35 ` Paul E. McKenney
2015-07-17 18:53 ` Paul E. McKenney
2015-07-17 19:51 ` Ingo Molnar
2015-07-17 21:33 ` Paul E. McKenney
2015-07-18 2:40 ` Ingo Molnar
2015-04-13 10:39 Stephen Rothwell
2015-04-13 11:06 ` Borislav Petkov
2015-04-13 11:34 ` Ingo Molnar
2015-04-13 12:40 ` Paul E. McKenney
2015-02-27 2:18 Stephen Rothwell
2015-02-27 5:59 ` Paul E. McKenney
2014-12-26 7:51 Stephen Rothwell
2014-12-26 16:54 ` Paul E. McKenney
2014-12-27 16:24 ` Pranith Kumar
2014-12-27 17:20 ` Pranith Kumar
2014-12-31 1:45 ` Paul E. McKenney
2014-12-12 6:12 Stephen Rothwell
2014-12-12 17:23 ` Paul E. McKenney
2014-12-10 8:09 Stephen Rothwell
2014-12-10 15:03 ` Pranith Kumar
2014-12-10 15:18 ` Paul E. McKenney
2014-12-09 11:42 Stephen Rothwell
2014-12-09 14:07 ` Paul E. McKenney
2012-04-16 4:11 Stephen Rothwell
2012-04-16 17:02 ` Paul E. McKenney
2010-09-17 2:42 Stephen Rothwell
2010-09-17 4:39 ` David Miller
2010-09-17 5:34 ` Eric Dumazet
2010-09-17 23:17 ` Paul E. McKenney
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