From: Jason Low <jason.low2@hp.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
Mike Galbraith <umgwanakikbuti@gmail.com>,
Thavatchai Makphaibulchoke <tmac@hp.com>,
Steven Rostedt <rostedt@goodmis.org>,
LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>,
linux-rt-users <linux-rt-users@vger.kernel.org>,
jason.low2@hp.com
Subject: Re: [PATCH v2 1/2] rtmutex Real-Time Linux: Fixing kernel BUG at kernel/locking/rtmutex.c:997!
Date: Tue, 07 Apr 2015 12:57:23 -0700 [thread overview]
Message-ID: <1428436643.2556.66.camel@j-VirtualBox> (raw)
In-Reply-To: <alpine.DEB.2.11.1504072102510.3845@nanos>
On Tue, 2015-04-07 at 21:17 +0200, Thomas Gleixner wrote:
> On Tue, 7 Apr 2015, Jason Low wrote:
> > The lock shouldn't be used in get_next_timer_interrupt() either right?
> >
> > unsigned long get_next_timer_interrupt(unsigned long now)
> > {
> > ...
> >
> > #ifdef CONFIG_PREEMPT_RT_FULL
> > /*
> > * On PREEMPT_RT we cannot sleep here. If the trylock does not
> > * succeed then we return the worst-case 'expires in 1 tick'
> > * value. We use the rt functions here directly to avoid a
> > * migrate_disable() call.
> > */
> > if (!spin_do_trylock(&base->lock))
> > return now + 1;
> > #else
>
> And how do you protect the walk of the timer wheel against a
> concurrent insertion/removal?
So I just wanted to mention that the issue also applies to
get_next_timer_interrupt(), in addition to run_local_timers(), but if we
really want to remove the lock there, can we always return "now + 1" for
PREEMPT_RT_FULL?
next prev parent reply other threads:[~2015-04-07 19:57 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-20 1:31 [PATCH 3.14.25-rt22 0/2] rtmutex Real-Time Linux: fix kernel BUG at kernel/locking/rtmutex.c:997! and some optimization Thavatchai Makphaibulchoke
2015-02-20 1:31 ` [PATCH 3.14.25-rt22 1/2] rtmutex Real-Time Linux: Fixing kernel BUG at kernel/locking/rtmutex.c:997! Thavatchai Makphaibulchoke
2015-02-20 4:53 ` Steven Rostedt
2015-02-20 18:54 ` Thavatchai Makphaibulchoke
2015-02-21 1:49 ` Steven Rostedt
2015-02-23 18:37 ` Steven Rostedt
2015-02-24 0:16 ` Thavatchai Makphaibulchoke
2015-02-24 0:57 ` Steven Rostedt
2015-02-26 13:56 ` Sebastian Andrzej Siewior
2015-02-26 14:06 ` Steven Rostedt
2015-03-06 12:19 ` Sebastian Andrzej Siewior
2015-03-09 16:36 ` Steven Rostedt
2015-03-09 16:49 ` Sebastian Andrzej Siewior
2015-02-20 1:31 ` [PATCH 3.14.25-rt22 2/2] kernel/locking/rtmutex.c: some code optimization Thavatchai Makphaibulchoke
2015-04-07 1:26 ` [PATCH v2 0/2] rtmutex Real-Time Linux: fix BUG at kernel/locking/rtmutex.c:997! Thavatchai Makphaibulchoke
2015-04-07 1:26 ` [PATCH v2 1/2] rtmutex Real-Time Linux: Fixing kernel " Thavatchai Makphaibulchoke
2015-04-07 1:59 ` Steven Rostedt
2015-04-07 5:09 ` Mike Galbraith
2015-04-07 10:29 ` Peter Zijlstra
2015-04-07 10:49 ` Mike Galbraith
2015-04-07 10:56 ` Peter Zijlstra
2015-04-07 11:01 ` Mike Galbraith
2015-04-08 0:55 ` Thavatchai Makphaibulchoke
2015-04-08 8:50 ` Thomas Gleixner
2015-04-09 22:56 ` Thavatchai Makphaibulchoke
2015-04-07 11:23 ` Thomas Gleixner
2015-04-07 11:47 ` Mike Galbraith
2015-04-07 12:04 ` Peter Zijlstra
2015-04-07 12:07 ` Peter Zijlstra
2015-04-07 12:41 ` Steven Rostedt
2015-04-07 12:54 ` Peter Zijlstra
2015-04-07 13:58 ` Steven Rostedt
2015-04-07 18:12 ` Jason Low
2015-04-07 19:17 ` Thomas Gleixner
2015-04-07 19:57 ` Jason Low [this message]
2015-04-07 21:38 ` Thomas Gleixner
2015-04-07 1:26 ` [PATCH v2 2/2] kernel/locking/rtmutex.c: some code optimization Thavatchai Makphaibulchoke
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=1428436643.2556.66.camel@j-VirtualBox \
--to=jason.low2@hp.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rt-users@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=tmac@hp.com \
--cc=umgwanakikbuti@gmail.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).