From: Peter Zijlstra <peterz@infradead.org>
To: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@kernel.org>,
Arnaldo Carvalho de Melo <acme@infradead.org>,
lkml <linux-kernel@vger.kernel.org>,
Stephane Eranian <eranian@google.com>,
Namhyung Kim <namhyung.kim@lge.com>, Jiri Olsa <jolsa@redhat.com>,
paulmck <paulmck@us.ibm.com>
Subject: Re: BUG: using smp_processor_id() in preemptible [00000000] code: asm/8267
Date: Wed, 27 Mar 2013 15:17:32 +0100 [thread overview]
Message-ID: <1364393852.5053.74.camel@laptop> (raw)
In-Reply-To: <20130327131532.GL30540@8bytes.org>
On Wed, 2013-03-27 at 14:15 +0100, Joerg Roedel wrote:
> What makes me wonder here is that the code is preemptible in an
> rcu_read_locked section. As far as I know preemption needs to be
> disabled while holding the rcu_read_lock().
Nah, a long long time ago some -rt people complained to paulmck that
keeping preemption disabled over all this RCU stuff was killing
latencies. Paul liked the challenge and came up with some mind twisting
stuff to make it work.
If you're into that kind of pain, look at CONFIG_*_PREEMPT_RCU :-)
But yeah, you need to have that stuff enabled before you can hit this
particular snag.
next prev parent reply other threads:[~2013-03-27 14:17 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-24 11:55 BUG: using smp_processor_id() in preemptible [00000000] code: asm/8267 Borislav Petkov
2013-03-24 15:59 ` Borislav Petkov
2013-03-26 18:34 ` Borislav Petkov
2013-03-27 6:02 ` Namhyung Kim
2013-03-27 9:49 ` Borislav Petkov
2013-03-27 10:42 ` Jiri Olsa
2013-03-27 14:09 ` Peter Zijlstra
2013-03-27 16:31 ` Borislav Petkov
2013-04-30 15:27 ` [RFCv2] " Jiri Olsa
2013-03-27 13:15 ` Joerg Roedel
2013-03-27 14:17 ` Peter Zijlstra [this message]
2013-03-27 14:37 ` Paul E. McKenney
2013-03-27 16:34 ` Joerg Roedel
2013-03-27 16:38 ` Borislav Petkov
2013-03-27 18:04 ` Paul E. McKenney
2013-03-27 19:07 ` Borislav Petkov
2013-03-27 19:20 ` Borislav Petkov
2013-03-27 19:22 ` Paul E. McKenney
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