From: Scott Wood <swood@redhat.com>
To: paulmck@linux.ibm.com
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
Juri Lelli <juri.lelli@redhat.com>,
Clark Williams <williams@redhat.com>,
linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RT 1/4] rcu: Acquire RCU lock when disabling BHs
Date: Thu, 20 Jun 2019 16:38:47 -0500 [thread overview]
Message-ID: <8bcc818b1b08850e109d1cde529ab98c4ed788df.camel@redhat.com> (raw)
In-Reply-To: <20190620212035.GY26519@linux.ibm.com>
On Thu, 2019-06-20 at 14:20 -0700, Paul E. McKenney wrote:
> On Thu, Jun 20, 2019 at 04:06:02PM -0500, Scott Wood wrote:
> > On Thu, 2019-06-20 at 13:53 -0700, Paul E. McKenney wrote:
> > > And I have to ask...
> > >
> > > What did you do to test this change to kernel/softirq.c? My past
> > > attempts
> > > to do this sort of thing have always run afoul of open-coded BH
> > > transitions.
> >
> > Mostly rcutorture and loads such as kernel builds, on a debug
> > kernel. By
> > "open-coded BH transition" do you mean directly manipulating the preempt
> > count? That would already be broken on RT.
>
> OK, then maybe you guys have already done the needed cleanup work. Cool!
Do you remember what code was doing such things? Grepping for the obvious
things doesn't turn up anything outside the softirq code, even in the
earlier non-RT kernels I checked.
> But don't the additions of rcu_read_lock() and rcu_read_unlock() want
> to be protected by "!IS_ENABLED(CONFIG_PREEMPT_RT_FULL)" or similar?
This is already a separate PREEMPT_RT_FULL-specific implementation.
-Scott
next prev parent reply other threads:[~2019-06-20 21:38 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-19 1:19 [PATCH RT 0/4] Address rcutorture issues Scott Wood
2019-06-19 1:19 ` [PATCH RT 1/4] rcu: Acquire RCU lock when disabling BHs Scott Wood
2019-06-20 20:53 ` Paul E. McKenney
2019-06-20 21:06 ` Scott Wood
2019-06-20 21:20 ` Paul E. McKenney
2019-06-20 21:38 ` Scott Wood [this message]
2019-06-20 22:16 ` Paul E. McKenney
2019-06-19 1:19 ` [PATCH RT 2/4] sched: migrate_enable: Use sleeping_lock to indicate involuntary sleep Scott Wood
2019-06-19 1:19 ` [RFC PATCH RT 3/4] rcu: unlock special: Treat irq and preempt disabled the same Scott Wood
2019-06-20 21:10 ` Paul E. McKenney
2019-06-20 21:59 ` Scott Wood
2019-06-20 22:25 ` Paul E. McKenney
2019-06-20 23:08 ` Scott Wood
2019-06-22 0:26 ` Paul E. McKenney
2019-06-22 19:13 ` Paul E. McKenney
2019-06-24 17:40 ` Scott Wood
2019-06-19 1:19 ` [RFC PATCH RT 4/4] rcutorture: Avoid problematic critical section nesting Scott Wood
2019-06-20 21:18 ` Paul E. McKenney
2019-06-20 21:43 ` Scott Wood
2019-06-21 16:38 ` Sebastian Andrzej Siewior
2019-06-21 23:59 ` Paul E. McKenney
2019-06-26 15:08 ` Steven Rostedt
2019-06-26 16:49 ` Scott Wood
2019-06-27 18:00 ` Paul E. McKenney
2019-06-27 20:16 ` Scott Wood
2019-06-27 20:50 ` Paul E. McKenney
2019-06-27 22:46 ` Scott Wood
2019-06-28 0:52 ` Paul E. McKenney
2019-06-28 19:37 ` Scott Wood
2019-06-28 20:24 ` Paul E. McKenney
2019-06-20 19:12 ` [PATCH RT 0/4] Address rcutorture issues Paul E. McKenney
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