From: Steven Rostedt <rostedt@goodmis.org>
To: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Linux trace kernel <linux-trace-kernel@vger.kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Dan Carpenter <dan.carpenter@linaro.org>,
outreachy@lists.linux.dev, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] tracing: Update snapshot buffer on resize if it is allocated
Date: Mon, 11 Dec 2023 12:51:52 -0500 [thread overview]
Message-ID: <20231211125152.045f8b8a@gandalf.local.home> (raw)
In-Reply-To: <20231211213134.bd21cf745b8c5a0892891946@kernel.org>
On Mon, 11 Dec 2023 21:31:34 +0900
Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:
> On Sun, 10 Dec 2023 22:54:47 -0500
> Steven Rostedt <rostedt@goodmis.org> wrote:
>
> > From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
> >
> > The snapshot buffer is to mimic the main buffer so that when a snapshot is
> > needed, the snapshot and main buffer are swapped. When the snapshot buffer
> > is allocated, it is set to the minimal size that the ring buffer may be at
> > and still functional. When it is allocated it becomes the same size as the
> > main ring buffer, and when the main ring buffer changes in size, it should
> > do.
>
> nit: There seems two "when the snapshot buffer is allocated" case, maybe latter
> "it" means main buffer?
I changed the paragraph to be:
The snapshot buffer is to mimic the main buffer so that when a snapshot is
needed, the snapshot and main buffer are swapped. When the snapshot buffer
is allocated, it is set to the minimal size that the ring buffer may be at
and still functional. When it is allocated it becomes the same size as the
main ring buffer, and when the main ring buffer changes in size, the
snapshot should also change in size if it is allocated.
>
> >
> > Currently, the resize only updates the snapshot buffer if it's used by the
> > current tracer (ie. the preemptirqsoff tracer). But it needs to be updated
> > anytime it is allocated.
> >
> > When changing the size of the main buffer, instead of looking to see if
> > the current tracer is utilizing the snapshot buffer, just check if it is
> > allocated to know if it should be updated or not.
> >
> > Also fix typo in comment just above the code change.
> >
>
> Looks good to me.
>
> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Thanks!
>
> BTW, the historical naming leads this kind of issues.
> Maybe we'd better to rename 'max_buffer' to 'snapshot_buffer'?
Agreed. But that's a cleanup for another day. Hmm, maybe that too should be
marked as "KTODO"?
https://lore.kernel.org/all/369bc919-1a1d-4f37-9cc9-742a86a41282@kadam.mountain/
There's a lot of things that we have been discussing on these ring-buffer
patches that could be KTODO items.
-- Steve
next parent reply other threads:[~2023-12-11 17:51 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20231210225447.48476a6a@rorschach.local.home>
[not found] ` <20231211213134.bd21cf745b8c5a0892891946@kernel.org>
2023-12-11 17:51 ` Steven Rostedt [this message]
2023-12-11 23:14 ` [PATCH] tracing: Update snapshot buffer on resize if it is allocated Masami Hiramatsu
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=20231211125152.045f8b8a@gandalf.local.home \
--to=rostedt@goodmis.org \
--cc=dan.carpenter@linaro.org \
--cc=kernel-janitors@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-trace-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=mathieu.desnoyers@efficios.com \
--cc=mhiramat@kernel.org \
--cc=outreachy@lists.linux.dev \
/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 read-only IMAP folder(s) and NNTP newsgroup(s).