From: "Paul E. McKenney" <paulmck@kernel.org>
To: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Peter Zijlstra <peterz@infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux Next Mailing List <linux-next@vger.kernel.org>
Subject: Re: linux-next: manual merge of the rcu tree with the tip tree
Date: Wed, 13 Oct 2021 09:31:54 -0700 [thread overview]
Message-ID: <20211013163154.GT880162@paulmck-ThinkPad-P17-Gen-1> (raw)
In-Reply-To: <20211012154828.312f870f@canb.auug.org.au>
On Tue, Oct 12, 2021 at 03:48:28PM +1100, Stephen Rothwell wrote:
> Hi all,
>
> Today's linux-next merge of the rcu tree got a conflict in:
>
> kernel/rcu/tasks.h
>
> between commit:
>
> 9b3c4ab3045e ("sched,rcu: Rework try_invoke_on_locked_down_task()")
>
> from the tip tree and commit:
>
> 18f08e758f34 ("rcu-tasks: Add trc_inspect_reader() checks for exiting critical section")
>
> from the rcu tree.
>
> I fixed it up (I hope - see below) and can carry the fix as
> necessary. This is now fixed as far as linux-next is concerned, but any
> non trivial conflicts should be mentioned to your upstream maintainer
> when your tree is submitted for merging. You may also want to consider
> cooperating with the maintainer of the conflicting tree to minimise any
> particularly complex conflicts.
Thank you for catching this! I have it down for my upcoming pull
request.
Thanx, Paul
> --
> Cheers,
> Stephen Rothwell
>
> diff --cc kernel/rcu/tasks.h
> index 171bc848e8e3,e4a32db9f712..000000000000
> --- a/kernel/rcu/tasks.h
> +++ b/kernel/rcu/tasks.h
> @@@ -928,10 -919,10 +919,10 @@@ reset_ipi
> }
>
> /* Callback function for scheduler to check locked-down task. */
> -static bool trc_inspect_reader(struct task_struct *t, void *arg)
> +static int trc_inspect_reader(struct task_struct *t, void *arg)
> {
> int cpu = task_cpu(t);
> - bool in_qs = false;
> + int nesting;
> bool ofl = cpu_is_offline(cpu);
>
> if (task_curr(t)) {
> @@@ -951,18 -942,18 +942,18 @@@
> n_heavy_reader_updates++;
> if (ofl)
> n_heavy_reader_ofl_updates++;
> - in_qs = true;
> + nesting = 0;
> } else {
> // The task is not running, so C-language access is safe.
> - in_qs = likely(!t->trc_reader_nesting);
> + nesting = t->trc_reader_nesting;
> }
>
> - // Mark as checked so that the grace-period kthread will
> - // remove it from the holdout list.
> - t->trc_reader_checked = true;
> -
> - if (in_qs)
> - return 0; // Already in quiescent state, done!!!
> + // If not exiting a read-side critical section, mark as checked
> + // so that the grace-period kthread will remove it from the
> + // holdout list.
> + t->trc_reader_checked = nesting >= 0;
> + if (nesting <= 0)
> - return !nesting; // If in QS, done, otherwise try again later.
> ++ return (!nesting) ? 0 : -EINVAL; // If in QS, done, otherwise try again later.
>
> // The task is in a read-side critical section, so set up its
> // state so that it will awaken the grace-period kthread upon exit
next prev parent reply other threads:[~2021-10-13 16:32 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-12 4:48 linux-next: manual merge of the rcu tree with the tip tree Stephen Rothwell
2021-10-13 16:31 ` Paul E. McKenney [this message]
-- strict thread matches above, loose matches on Subject: below --
2024-02-27 1:55 Stephen Rothwell
2022-04-06 2:45 Stephen Rothwell
2022-04-06 16:28 ` Paul E. McKenney
2022-02-21 18:17 broonie
2021-08-17 7:09 Stephen Rothwell
2021-06-23 5:33 Stephen Rothwell
2021-06-22 4:51 Stephen Rothwell
2021-06-22 4:47 Stephen Rothwell
2021-06-22 5:04 ` Stephen Rothwell
2021-06-22 17:10 ` Paul E. McKenney
2020-10-09 4:59 Stephen Rothwell
2020-07-29 6:23 Stephen Rothwell
2020-06-26 3:14 Stephen Rothwell
2020-06-25 2:44 Stephen Rothwell
2020-06-25 3:44 ` Paul E. McKenney
2020-06-24 3:04 Stephen Rothwell
2020-06-24 4:06 ` Paul E. McKenney
2020-05-29 6:22 Stephen Rothwell
2020-05-29 6:41 ` Stephen Rothwell
2020-05-29 14:15 ` Paul E. McKenney
2020-05-29 23:38 ` Stephen Rothwell
2020-03-25 3:08 Stephen Rothwell
2020-03-25 3:18 ` Paul E. McKenney
2020-03-25 21:31 ` Paul E. McKenney
2019-12-19 0:50 Stephen Rothwell
2019-12-19 1:27 ` Paul E. McKenney
2019-12-19 1:31 ` Paul E. McKenney
2019-12-19 8:41 ` Peter Zijlstra
2019-12-19 13:38 ` Paul E. McKenney
2019-12-16 23:37 Stephen Rothwell
2018-06-22 2:27 Stephen Rothwell
2018-06-26 19:33 ` Paul E. McKenney
2017-11-10 2:14 Stephen Rothwell
2017-08-22 4:13 Stephen Rothwell
2017-07-31 3:50 Stephen Rothwell
2017-07-31 16:13 ` Paul E. McKenney
2017-08-01 0:04 ` Mathieu Desnoyers
2017-08-01 4:03 ` Paul E. McKenney
2017-08-01 4:25 ` Mathieu Desnoyers
2017-08-01 16:31 ` Paul E. McKenney
2017-08-01 13:43 ` Andy Lutomirski
2017-08-01 13:58 ` Peter Zijlstra
2017-08-01 14:15 ` Peter Zijlstra
2017-08-01 14:17 ` Andy Lutomirski
2017-08-01 14:02 ` Mathieu Desnoyers
2017-08-01 14:15 ` Andy Lutomirski
2017-08-01 15:40 ` Mathieu Desnoyers
2017-08-01 21:36 ` Paul E. McKenney
2016-07-18 5:26 Stephen Rothwell
2016-07-19 3:00 ` Paul E. McKenney
2016-06-09 5:14 Stephen Rothwell
2016-06-09 15:59 ` Paul E. McKenney
2016-03-04 4:13 Stephen Rothwell
2016-03-04 15:04 ` Paul E. McKenney
2015-07-16 2:57 Stephen Rothwell
2015-05-07 3:56 Stephen Rothwell
2014-02-24 4:18 Stephen Rothwell
2014-02-24 4:42 ` Paul E. McKenney
2012-09-05 3:59 Stephen Rothwell
2012-09-05 16:39 ` Paul E. McKenney
2012-09-05 17:11 ` Peter Zijlstra
2012-08-23 3:01 Stephen Rothwell
2012-08-23 3:22 ` Paul E. McKenney
2012-08-22 4:27 Stephen Rothwell
2012-08-22 5:05 ` Paul E. McKenney
2012-08-22 4:27 Stephen Rothwell
2012-08-22 5:03 ` Paul E. McKenney
2011-06-20 4:47 Stephen Rothwell
2011-06-20 15:17 ` Paul E. McKenney
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