Messages in this thread | ![/](/images/icornerl.gif) | | Date | Thu, 21 Dec 2023 09:10:13 +0900 | From | Masami Hiramatsu (Google) <> | Subject | Re: [PATCH v5 03/15] ring-buffer: Add interface for configuring trace sub buffer size |
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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>
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