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: [RFC PATCH RT 3/4] rcu: unlock special: Treat irq and preempt disabled the same
Date: Thu, 20 Jun 2019 16:59:30 -0500 [thread overview]
Message-ID: <cf42d8516ac99f69913b1f7a7e8abe578ad27e7f.camel@redhat.com> (raw)
In-Reply-To: <20190620211005.GW26519@linux.ibm.com>
On Thu, 2019-06-20 at 14:10 -0700, Paul E. McKenney wrote:
> On Tue, Jun 18, 2019 at 08:19:07PM -0500, Scott Wood wrote:
> > [Note: Just before posting this I noticed that the invoke_rcu_core stuff
> > is part of the latest RCU pull request, and it has a patch that
> > addresses this in a more complicated way that appears to deal with the
> > bare irq-disabled sequence as well.
>
> Far easier to deal with it than to debug the lack of it. ;-)
>
> > Assuming we need/want to support such sequences, is the
> > invoke_rcu_core() call actually going to result in scheduling any
> > sooner? resched_curr() just does the same setting of need_resched
> > when it's the same cpu.
> > ]
>
> Yes, invoke_rcu_core() can in some cases invoke the scheduler sooner.
> Setting the CPU-local bits might not have effect until the next interrupt.
Maybe I'm missing something, but I don't see how (in the non-use_softirq
case). It just calls wake_up_process(), which in resched_curr() will set
need_resched but not do an IPI-to-self.
-Scott
next prev parent reply other threads:[~2019-06-20 21:59 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
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 [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=cf42d8516ac99f69913b1f7a7e8abe578ad27e7f.camel@redhat.com \
--to=swood@redhat.com \
--cc=bigeasy@linutronix.de \
--cc=juri.lelli@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rt-users@vger.kernel.org \
--cc=paulmck@linux.ibm.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=williams@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).