From: Steven Rostedt <rostedt@goodmis.org>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>,
linux-trace-devel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 02/13] user_events: Add minimal support for trace_event into ftrace
Date: Fri, 10 Dec 2021 12:43:05 -0500 [thread overview]
Message-ID: <20211210124305.24acd61f@gandalf.local.home> (raw)
In-Reply-To: <20211210194358.e590d49a1620df7345f9f679@kernel.org>
On Fri, 10 Dec 2021 19:43:58 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:
> > +/* Limit how long of an event name plus args within the subsystem. */
> > +#define MAX_EVENT_DESC 512
> > +#define EVENT_NAME(user_event) ((user_event)->tracepoint.name)
> > +#define MAX_FIELD_ARRAY_SIZE (2 * PAGE_SIZE)
>
> I don't recommend to record the event which size is more than a page size...
> Maybe 256 entries?
> It is also better to limit the total size of the event and the number
> of fields (arguments).
>
> Steve, can we write such a big event data on the trace buffer?
In the future yes!
https://lore.kernel.org/all/20211125175253.186422-1-tz.stoyanov@gmail.com/
But it will still require some configuration changes from user space. But
that said, if the user wants to add a larger size, then they can do so (in
the future).
-- Steve
next prev parent reply other threads:[~2021-12-10 17:43 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-09 22:31 [PATCH v7 00/13] user_events: Enable user processes to create and write to trace events Beau Belgrave
2021-12-09 22:31 ` [PATCH v7 01/13] user_events: Add UABI header for user access to user_events Beau Belgrave
2021-12-10 13:30 ` Masami Hiramatsu
2021-12-10 17:29 ` Beau Belgrave
2021-12-09 22:31 ` [PATCH v7 02/13] user_events: Add minimal support for trace_event into ftrace Beau Belgrave
2021-12-10 10:43 ` Masami Hiramatsu
2021-12-10 17:43 ` Steven Rostedt [this message]
2021-12-13 0:09 ` Masami Hiramatsu
2021-12-13 16:48 ` Steven Rostedt
2021-12-10 18:03 ` Beau Belgrave
2021-12-13 4:24 ` Masami Hiramatsu
2021-12-13 17:58 ` Beau Belgrave
2021-12-09 22:32 ` [PATCH v7 03/13] user_events: Add print_fmt generation support for basic types Beau Belgrave
2021-12-10 2:50 ` Masami Hiramatsu
2021-12-09 22:32 ` [PATCH v7 04/13] user_events: Handle matching arguments from dyn_events Beau Belgrave
2021-12-09 22:32 ` [PATCH v7 05/13] user_events: Add basic perf and eBPF support Beau Belgrave
2021-12-09 22:32 ` [PATCH v7 06/13] user_events: Add self-test for ftrace integration Beau Belgrave
2021-12-09 22:32 ` [PATCH v7 07/13] user_events: Add self-test for dynamic_events integration Beau Belgrave
2021-12-09 22:32 ` [PATCH v7 08/13] user_events: Add self-test for perf_event integration Beau Belgrave
2021-12-09 22:32 ` [PATCH v7 09/13] user_events: Optimize writing events by only copying data once Beau Belgrave
2021-12-10 14:51 ` Masami Hiramatsu
2021-12-10 18:36 ` Beau Belgrave
2021-12-09 22:32 ` [PATCH v7 10/13] user_events: Add documentation file Beau Belgrave
2021-12-09 22:32 ` [PATCH v7 11/13] user_events: Add sample code for typical usage Beau Belgrave
2021-12-09 22:32 ` [PATCH v7 12/13] user_events: Validate user payloads for size and null termination Beau Belgrave
2021-12-10 14:46 ` Masami Hiramatsu
2021-12-09 22:32 ` [PATCH v7 13/13] user_events: Use __get_rel_str for relative string fields Beau Belgrave
2021-12-10 1:23 ` Masami Hiramatsu
2021-12-10 18:45 ` Beau Belgrave
2021-12-12 15:12 ` Masami Hiramatsu
2021-12-13 18:47 ` Beau Belgrave
2021-12-14 6:30 ` Masami Hiramatsu
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