From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Scott Wood <swood@redhat.com>
Cc: linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org,
"Paul E . McKenney" <paulmck@linux.ibm.com>,
Joel Fernandes <joel@joelfernandes.org>,
Thomas Gleixner <tglx@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Clark Williams <williams@redhat.com>
Subject: Re: [PATCH RT v3 1/5] rcu: Acquire RCU lock when disabling BHs
Date: Tue, 17 Sep 2019 09:44:57 +0200 [thread overview]
Message-ID: <20190917074456.yj7t3wdwuhn3zcng@linutronix.de> (raw)
In-Reply-To: <20190911165729.11178-2-swood@redhat.com>
On 2019-09-11 17:57:25 [+0100], Scott Wood wrote:
> index 388ace315f32..9ce7c5006a5e 100644
> --- a/include/linux/rcupdate.h
> +++ b/include/linux/rcupdate.h
> @@ -600,6 +600,36 @@ static inline void rcu_read_unlock(void)
> rcu_lock_release(&rcu_lock_map); /* Keep acq info for rls diags. */
> }
>
> +#ifdef CONFIG_PREEMPT_RT_FULL
> +/*
> + * On RT, local_bh_disable() calls rcu_read_lock() -- no need to
> + * track it twice.
> + */
> +static inline void rcu_bh_lock_acquire(void)
> +{
> +}
> +
> +static inline void rcu_bh_lock_release(void)
> +{
> +}
> +#else
> +static inline void rcu_bh_lock_acquire(void)
> +{
> + __acquire(RCU_BH);
> + rcu_lock_acquire(&rcu_bh_lock_map);
> + RCU_LOCKDEP_WARN(!rcu_is_watching(),
> + "rcu_read_lock_bh() used illegally while idle");
> +}
> +
> +static inline void rcu_bh_lock_release(void)
> +{
> + RCU_LOCKDEP_WARN(!rcu_is_watching(),
> + "rcu_read_unlock_bh() used illegally while idle");
> + rcu_lock_release(&rcu_bh_lock_map);
> + __release(RCU_BH);
> +}
> +#endif
> +
> /**
> * rcu_read_lock_bh() - mark the beginning of an RCU-bh critical section
> *
> @@ -615,10 +645,7 @@ static inline void rcu_read_unlock(void)
> static inline void rcu_read_lock_bh(void)
> {
> local_bh_disable();
> - __acquire(RCU_BH);
> - rcu_lock_acquire(&rcu_bh_lock_map);
> - RCU_LOCKDEP_WARN(!rcu_is_watching(),
> - "rcu_read_lock_bh() used illegally while idle");
> + rcu_bh_lock_acquire();
> }
>
> /*
I asked previously why do you need to change rcu_read_lock_bh() and you
replied that you don't remember:
https://lore.kernel.org/linux-rt-users/b948ec6cccda31925ed8dc123bd0f55423fff3d4.camel@redhat.com/
Did this change?
Sebastian
next prev parent reply other threads:[~2019-09-17 7:45 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-11 16:57 [PATCH RT v3 0/5] RCU fixes Scott Wood
2019-09-11 16:57 ` [PATCH RT v3 1/5] rcu: Acquire RCU lock when disabling BHs Scott Wood
2019-09-12 22:09 ` Joel Fernandes
2019-09-17 7:44 ` Sebastian Andrzej Siewior [this message]
2019-09-17 14:06 ` Scott Wood
2019-09-17 14:42 ` Sebastian Andrzej Siewior
2019-09-17 16:12 ` Scott Wood
2019-09-23 16:41 ` Sebastian Andrzej Siewior
2019-09-11 16:57 ` [PATCH RT v3 2/5] sched: Rename sleeping_lock to rt_invol_sleep Scott Wood
2019-09-17 7:52 ` Sebastian Andrzej Siewior
2019-09-11 16:57 ` [PATCH RT v3 3/5] sched: migrate_dis/enable: Use rt_invol_sleep Scott Wood
2019-09-17 7:59 ` Sebastian Andrzej Siewior
2019-09-17 14:06 ` Scott Wood
2019-09-23 16:59 ` Scott Wood
2019-09-23 17:52 ` Sebastian Andrzej Siewior
2019-09-24 11:21 ` Sebastian Andrzej Siewior
2019-09-24 13:53 ` Scott Wood
2019-09-24 15:25 ` Sebastian Andrzej Siewior
2019-09-24 15:47 ` Scott Wood
2019-09-24 16:05 ` Sebastian Andrzej Siewior
2019-09-24 16:35 ` Scott Wood
2019-10-04 16:45 ` Sebastian Andrzej Siewior
2019-09-11 16:57 ` [PATCH RT v3 4/5] rcu: Disable use_softirq on PREEMPT_RT Scott Wood
2019-09-12 21:38 ` Joel Fernandes
2019-09-12 22:19 ` Joel Fernandes
2019-09-17 9:31 ` Sebastian Andrzej Siewior
2019-09-17 14:08 ` Scott Wood
2019-09-11 16:57 ` [PATCH RT v3 5/5] rcutorture: Avoid problematic critical section nesting on RT Scott Wood
2019-09-12 22:17 ` Joel Fernandes
2019-09-16 16:55 ` Scott Wood
2019-09-17 10:07 ` Sebastian Andrzej Siewior
2019-09-17 14:36 ` Scott Wood
2019-09-17 14:50 ` Sebastian Andrzej Siewior
2019-09-17 16:32 ` Scott Wood
2019-09-23 16:25 ` Sebastian Andrzej Siewior
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