From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andrew Morton <akpm@linux-foundation.org>,
Tzvetomir Stoyanov <tz.stoyanov@gmail.com>,
Vincent Donnefort <vdonnefort@google.com>,
Kent Overstreet <kent.overstreet@gmail.com>
Subject: Re: [PATCH v5 03/15] ring-buffer: Add interface for configuring trace sub buffer size
Date: Thu, 21 Dec 2023 09:10:13 +0900 [thread overview]
Message-ID: <20231221091013.9af9f0a5ff926069babe4989@kernel.org> (raw)
In-Reply-To: <20231220094030.5d13438b@gandalf.local.home>
On Wed, 20 Dec 2023 09:40:30 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:
> On Wed, 20 Dec 2023 23:26:19 +0900
> Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:
>
> > On Tue, 19 Dec 2023 13:54:17 -0500
> > Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > > +/**
> > > + * ring_buffer_subbuf_order_set - set the size of ring buffer sub page.
> > > + * @buffer: The ring_buffer to set the new page size.
> > > + * @order: Order of the system pages in one sub buffer page
> > > + *
> > > + * By default, one ring buffer pages equals to one system page. This API can be
> > > + * used to set new size of the ring buffer page. The size must be order of
> > > + * system page size, that's why the input parameter @order is the order of
> > > + * system pages that are allocated for one ring buffer page:
> > > + * 0 - 1 system page
> > > + * 1 - 2 system pages
> > > + * 3 - 4 system pages
> > > + * ...
> >
> > Don't we have the max order of the pages?
>
> Actually there is. I think it's 7?
>
> Honestly, anything over 5 is probably too much. But hey.
Ah, I see. It is checked in subbuf_order_write() method (and it is embedded
directly). I think that 7 should be replaced with a macro, something like
RB_SUBBUF_ORDER_MAX and check it in this exposed function instead of write
method.
Thank you,
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
next prev parent reply other threads:[~2023-12-21 0:10 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-19 18:54 [PATCH v5 00/15] ring-buffer/tracing: Allow ring buffer to have bigger sub buffers Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 01/15] ring-buffer: Refactor ring buffer implementation Steven Rostedt
2023-12-20 9:48 ` Masami Hiramatsu
2023-12-20 12:53 ` Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 02/15] ring-buffer: Page size per ring buffer Steven Rostedt
2023-12-20 8:48 ` David Laight
2023-12-20 13:01 ` Steven Rostedt
2023-12-21 9:17 ` David Laight
2023-12-21 14:19 ` Steven Rostedt
2023-12-21 14:51 ` David Laight
2023-12-21 14:57 ` Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 03/15] ring-buffer: Add interface for configuring trace sub buffer size Steven Rostedt
2023-12-20 14:26 ` Masami Hiramatsu
2023-12-20 14:40 ` Steven Rostedt
2023-12-21 0:10 ` Masami Hiramatsu [this message]
2023-12-19 18:54 ` [PATCH v5 04/15] ring-buffer: Set new size of the ring buffer sub page Steven Rostedt
2023-12-20 16:34 ` Masami Hiramatsu
2023-12-20 16:56 ` Steven Rostedt
2023-12-21 0:11 ` Masami Hiramatsu
2023-12-19 18:54 ` [PATCH v5 05/15] ring-buffer: Read and write to ring buffers with custom sub buffer size Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 06/15] ring-buffer: Clear pages on error in ring_buffer_subbuf_order_set() failure Steven Rostedt
2023-12-20 16:23 ` Masami Hiramatsu
2023-12-20 16:30 ` Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 07/15] ring-buffer: Do no swap cpu buffers if order is different Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 08/15] ring-buffer: Make sure the spare sub buffer used for reads has same size Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 09/15] tracing: Update snapshot order along with main buffer order Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 10/15] tracing: Stop the tracing while changing the ring buffer subbuf size Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 11/15] ring-buffer: Keep the same size when updating the order Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 12/15] ring-buffer: Just update the subbuffers when changing their allocation order Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 13/15] ring-buffer: Add documentation on the buffer_subbuf_order file Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 14/15] ringbuffer/selftest: Add basic selftest to test changing subbuf order Steven Rostedt
2023-12-21 0:23 ` Masami Hiramatsu
2023-12-19 18:54 ` [PATCH v5 15/15] tracing: Update subbuffer with kilobytes not page order Steven Rostedt
2023-12-21 0:26 ` Masami Hiramatsu
2023-12-21 1:57 ` Steven Rostedt
2023-12-19 22:38 ` [PATCH v5 16/15] ring-buffer: Use subbuf_order for buffer page masking Steven Rostedt
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