From: Steven Rostedt <rostedt@goodmis.org>
To: Vincent Whitchurch <vincent.whitchurch@axis.com>
Cc: John Ogness <john.ogness@linutronix.de>,
"jbaron@akamai.com" <jbaron@akamai.com>,
"mingo@redhat.com" <mingo@redhat.com>, kernel <kernel@axis.com>,
"corbet@lwn.net" <corbet@lwn.net>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Subject: Re: [PATCH] dynamic debug: allow printing to trace event
Date: Thu, 23 Jul 2020 11:26:44 -0400 [thread overview]
Message-ID: <20200723112644.7759f82f@oasis.local.home> (raw)
In-Reply-To: <20200723105735.mqfkfbljjda7qz7n@axis.com>
On Thu, 23 Jul 2020 12:57:35 +0200
Vincent Whitchurch <vincent.whitchurch@axis.com> wrote:
> Would it be acceptable to just use a fixed size for the event? At least
> for my own debugging use cases it's preferable to just have to increase
> the trace buffer size in case it's insufficient, rather than to have to
> restort to one-off debugging code.
There's two other options.
Option 1, is to allocate 256 bytes times 4 (in case of interruption,
where you have a separate buffer for every context - normal, softirq,
irq, nmi), and use it like I do for stack traces in the latest kernel
(see __ftrace_stack_trace() in kernel/trace/trace.c)
Option 2, would be to use trace_array_vprintk(), but you need to create
your own instance to do so to keep from messing with the top level buffer.
-- Steve
next prev parent reply other threads:[~2020-07-23 15:26 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-21 14:11 [PATCH] dynamic debug: allow printing to trace event Vincent Whitchurch
2020-07-21 21:30 ` Steven Rostedt
2020-07-22 11:37 ` Sergey Senozhatsky
2020-07-22 13:52 ` John Ogness
2020-07-22 14:49 ` Vincent Whitchurch
2020-07-22 15:28 ` Steven Rostedt
2020-07-23 10:57 ` Vincent Whitchurch
2020-07-23 15:26 ` Steven Rostedt [this message]
2020-08-14 13:34 ` Vincent Whitchurch
2020-07-22 15:25 ` Steven Rostedt
2020-07-23 14:02 ` John Ogness
2020-07-23 14:20 ` John Ogness
2020-07-23 15:39 ` Steven Rostedt
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