From: Lai Jiangshan <laijs@cn.fujitsu.com>
To: rostedt@goodmis.org
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
Frederic Weisbecker <fweisbec@gmail.com>,
Theodore Tso <tedtso@gmail.com>
Subject: Re: [PATCH] tracing: reduce latency and remove percpu trace_seq
Date: Fri, 04 Jun 2010 10:23:57 +0800 [thread overview]
Message-ID: <4C0863BD.6000307@cn.fujitsu.com> (raw)
In-Reply-To: <1275572170.15884.30.camel@gandalf.stny.rr.com>
Steven Rostedt wrote:
>
> The "print" in the trace_seq_printf() is the TP_printk() field of the
> TRACE_EVENT. I believe that there were some events (ext4?) that did
> things that required preemption disabled.
>
It seems that ext4 has no such events.
I find jbd2_dev_to_name() in the TP_printk() field of ext4's tracepoints.
And it seems that jbd2_dev_to_name() requires preemption enabled and sleepable.
Maybe there were some events did things that required preemption disabled.
But No document ensure TP_printk() preemption disabled, such events should
be fixed, I think.
next prev parent reply other threads:[~2010-06-04 2:24 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-03 10:26 [PATCH] tracing: reduce latency and remove percpu trace_seq Lai Jiangshan
2010-06-03 13:36 ` Steven Rostedt
2010-06-04 2:23 ` Lai Jiangshan [this message]
2010-06-04 3:03 ` Steven Rostedt
2010-06-07 7:50 ` Lai Jiangshan
2010-07-21 2:03 ` Steven Rostedt
2010-07-23 12:10 ` [tip:perf/core] tracing: Reduce " tip-bot for Lai Jiangshan
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